• Journal of Powder Materials
• /
• v.5 no.3
• /
• pp.192-198
• /
• 1998

Microstructure and mechanical properties were examined on rapidly solidified Al-8wt%Fe alloy. High temperature strength test was also undertaken, and it is shown that the refinement in microstructure resulting from extremely rapid cooling rates gives rise to improved high temperature strength, but the elongation to fracture of this material decreases with increasing temperature, particularly in the temperature range up to 30$0^{\circ}C$. Specimens heat-treated for 100 hrs were analyzed with TEM micrographs to understand the thermal stability of this material.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.28 no.1
• /
• pp.14-20
• /
• 2018

Lead zinc niobate (PZN) added lead zirconate titanate (PZT) thick films with thickness of $5{\sim}10{\mu}m$ were fabricated on silicon and sapphire substrates using aerosol deposition method. The contents of PZN were varied from 0 %, 20 % and 40 %. The initial particles (PZT, 2PZN-8PZT, 4PZN-6PZT) had irregular shape and submicron sizes. The as-deposited film had fairly dense microstructure without any crack, and showed only a perovskite single phase formed with nano-sized grains. The as-deposited films on silicon were annealed at the temperatures of $700^{\circ}C$, and the films deposited on sapphire were annealed at $900^{\circ}C$ in the electrical furnace. The effects of PZN addition on the microstructural evolution were observed using by FE-SEM and HR-TEM.

• Proceedings of the Korea Crystallographic Association Conference
• /
• 2002.11a
• /
• pp.40-41
• /
• 2002

차세대 반도체 및 나노소자 산업에 대한 국제적 기술은 고밀도 직접화의 추세에 따라서 .게이트 산화막의 두께가 급속히 작아지는 추세이다. 지금까지 이산화규소(A1₂O₃)가 게이트 산화막으로 주로 사용되어 왔으나 점차 SiON 혹은 high k 박막으로 바뀌고 있다. 본 연구에서는 차세대 반도체 소자에 사용될 게이트 산화막 물질인 SiON 박막과 Al₂O₃박막에 대한 SE(Spectroscopic Ellipsometry)분석 모델을 확립하였고, SE 측정결과를 TEM, MEIS, XRR의 결과들과 비교하였다. SiON 박막의 굴절률 값은 Si₃N₄와 SiO₂가 물리적으로 혼합되어 있다고 가정하여 Bruggeman effective medium approximation을 사용하여 구하였다. 동일한 시료를 절단하여 TEM, MEIS, 그리고 XRR에 의하여 SiON 박막의 두께를 측정하였으며, 그 결과 SE와 XRR에 의해 얻어진 박막두께가 TEM과 MEIS의 결과 값보다 약 0.5 nm 크게 주어짐을 알 수 있었다(Table 1 참조). 본 연구결과는 비파괴적이며 비접촉식 측정방법인 SE가 2～4nm 두께의 초미세 SiON 박막의 두께와 N 농도의 상대적 값을 빠르고 쉽게 구할 수 있는 유용한 측정방법 임을 보여주었다. 기존의 게이트 산화물인 SiO₂를 대체할 후보 물질들 중의 하나인 A1₂O₃의 유전함수를 구하기 위하여 8 inch, p-type 실리콘 기판 위에 성장된 5 nm, 10 nm, 및 20 nm 두께의 A1₂O₃ 박막의 유전함수와 두께를 측정하였다. 이 시료들에 대한 SE data는 vacuum-UV spectroscopic ellipsometer를 사용하여 세 개의 입사각에서 0.75 eV에서 8.75 eV까지 0.05 eV 간격으로 측정되었다. A1₂O₃ 박막의 유전함수와 두께를 얻기 위하여 공기층/A1₂O₃ 박막/Si 기판으로 구성된 3상계 모델을 사용하였다. Si 기판에 대한 복소 유전함수는 문헌상의 값(1)을 사용하였고, A1₂O₃ 박막의 유전함수는 5개의 미지상수를 갖는 Tauc- Lorentz(TL) 분산함수(2)를 사용하였다. A1₂O₃ 박막의 경우 두께가 증가함에 따라서 굴절률이 커짐을 알 수 있었다.

• Journal of Ocean Engineering and Technology
• /
• v.13 no.2 s.32
• /
• pp.108-115
• /
• 1999

To study measurement of coated steel corrosion in mortar, a transient electro-magnetic(TEM) method was adapted. The sensors were made of enamelled wire with diameter of 0.25mm(transmitter), 0.1mm(receiver) and the secondary electro motive force(EMF) was measured with SIROTEMIII. The sensors configuration was used as in loop configuration. After coated steels were corroded by the salt spray during 3, 7, 15, 25days, they were embedded in mortar which were made from sand : cement : water ratio of 2 : 1 :0.5. To investigate coated steel corrosion in mortar, the sensors were used. ( sensorl - $T_x$ : $4{\Omega}$, $R_x$ : $10{\Omega}$, $3{times}3cm$, sensor2 - $T_x$ : $8{\Omega}$, $R_x$ : $10{\Omega}$, $3{times}3cm$, sensor3 - $T_x$ : $4{\Omega}$, $R_x$ : $10{\Omega}$, $6{times}6cm$, sensor4 - $T_x$ : $8{\Omega}$, $R_x$ : $10{\Omega}$, $6{times}6cm$). The obtained results showed that the secondary EMF was decreased with specimens of 3, 7days corroded coationg steel in mortar and then increased with specccimens of 15, 25days corroded one. And it was confirmed that measurement of coated steel corrosion in mortar by a transient electro-magnetic(TEM) method is possible.

• Korean Journal of Materials Research
• /
• v.32 no.8
• /
• pp.345-353
• /
• 2022

In this study, using deep learning, super-resolution images of transmission electron microscope (TEM) images were generated for nanomaterial analysis. 1169 paired images with 256 × 256 pixels (high resolution: HR) from TEM measurements and 32 × 32 pixels (low resolution: LR) produced using the python module openCV were trained with deep learning models. The TEM images were related to DyVO₄ nanomaterials synthesized by hydrothermal methods. Mean-absolute-error (MAE), peak-signal-to-noise-ratio (PSNR), and structural similarity (SSIM) were used as metrics to evaluate the performance of the models. First, a super-resolution image (SR) was obtained using the traditional interpolation method used in computer vision. In the SR image at low magnification, the shape of the nanomaterial improved. However, the SR images at medium and high magnification failed to show the characteristics of the lattice of the nanomaterials. Second, to obtain a SR image, the deep learning model includes a residual network which reduces the loss of spatial information in the convolutional process of obtaining a feature map. In the process of optimizing the deep learning model, it was confirmed that the performance of the model improved as the number of data increased. In addition, by optimizing the deep learning model using the loss function, including MAE and SSIM at the same time, improved results of the nanomaterial lattice in SR images were achieved at medium and high magnifications. The final proposed deep learning model used four residual blocks to obtain the characteristic map of the low-resolution image, and the super-resolution image was completed using Upsampling2D and the residual block three times.

• Applied Microscopy
• /
• v.8 no.1
• /
• pp.77-79
• /
• 1978

Al-Si junctions were made by vacuum deposition of aluminium on to silicon wafers and examined by TEM. The uneven interfaces of the junctions are formed due to the surface tension of the molten solution resulting in preferential dissolution of silicon in aluminium at some areas. These undesirable uneven interfaces affect the junction shape and so the over-all characteristics of the devices.

• Journal of the Korean Applied Science and Technology
• /
• v.33 no.3
• /
• pp.421-427
• /
• 2016

Nanosized hollow silica was prepared by $St{\ddot{o}}ber$ method in the presence of aluminum isopropoxide. The mixture of polyelectrolytes such as poly(sodium 4-styrene sulfonate)(PSS) and polyacrylic acid(PAA) were used as templates. Tetraethylorthosilicate(TEOS) and aluminum isopropoxide were used as precursors for silica and alumina, respectively. The function of aluminum isopropoxide is to increase the porosity of silica shell. The characterizations of hollow silica were examined by TEM(transmission electron microscopy), TGA(thermogravimetric analysis), BET(Brunauer Emmett Teller), Energy-dispersive X-ray spectroscopy(EDS), and FT-IR spectrum. It was found that the shell thickness of hollow silica was around 8 nm and the core diameter was around 20 nm by TEM.

• Electrical & Electronic Materials
• /
• v.8 no.4
• /
• pp.464-471
• /
• 1995

메그네트론 스퍼터링으로 제작한 고밀도 다층박막($Co_75{{Pt_12}{Cr_13}}$합금) 디스크를 투과전자현미경을 이용해 단면 및 평면의 미세조직의 조사 혹은 미소부위 성분분석을 할 경우, 선행되어야하는 시편준비 경로와 각 단계별 구체적방법 및 그 효과를 연구하였다. Ion밀링시간이 증가함에 따라 시료가 얇게 되는과정에서 스퍼터링된 물질이 관찰될 시편부위의 다른 표면에 증착되므로써 미세조직의 선명도를 해칠 수 있고, 이로인한 해석상의 오류가능성이 시사되었다. 또한, 자기박막 디스크와 같이 다층으로 구성된 단면분석용 시료에서는 서로 맞붙인 실리콘 단결정 접착면을 따라 밀링속도가 선택적으로 커서 우선축이 생김으로써 양질의 시편을 얻기 어려운 문제점이 제기되었다. 이같은 문제를 포함한 전자현미경 시료준비과정에서 생길 수 있는 문제를 해결할 수 있는 실마리와 이를 이용해 수행한 전자현미경 분석결과 및 효과적인 시편준비방법이 본 논문에서 언급되었다.

• Korean Journal Plant Pathology
• /
• v.14 no.6
• /
• pp.714-719
• /
• 1998

Obligate bacterial parasite attacking Heterodera glycines was firstly found from Chungju soybean field in Korea. Diameters of sporangium and central body were 5.6 ${\mu}{\textrm}{m}$ and 1.9 ${\mu}{\textrm}{m}$ under light microscopy (LM), and 3.9 ${\mu}{\textrm}{m}$ and 1.8 ${\mu}{\textrm}{m}$ under transmission electron microscopy (TEM). Endospore showed cup-shaped with smooth-type exosporium without peg-like thickening in polar area under SEM and TEM. Bacteria completed its life cycle in female of soybean cyst nematode after adhering on cuticle of second-stage juvenile. From these results, the Pasteuria found from Chungju was identified with P. nishizawae.

• Applied Chemistry for Engineering
• /
• v.18 no.1
• /
• pp.54-57
• /
• 2007

A cyclotetraphosphazene derivative having eight chains was synthesized from octachlorocyclotetraphosphazene, which was employed along with cholesterol for the preparation of vesicles. The resulting vesicles were characterized by TEM and encapsulation efficiency. The stability of the vesicles was enhanced in the presence of dihexadecylphosphate.