• Design & Manufacturing
• /
• 제14권1호
• /
• pp.56-62
• /
• 2020

An electron beam was used to mainly utilize for polishing, finishing, welding, a lithography process, etc. Due to the high technical level of difficulty of high-power density electron beam, it is difficult to secure related technologies. In this study, research was carried out to improve the machinability by developing the vaporized amplification sheets to realize the electron beam drilling technology. Their vaporized amplification sheets were analyzed by using the measurement of chemical and composition, which is such as TGA, SEM. We analyzed micro-hole processing using a microscope. Also, the thermal characteristics of vaporized amplification sheets are highly significant for applying to high-power density electron beam technique. So, we finished the vaporized amplification sheets according to the process conditions and analyzed it according to the machining conditions of the electron beam. It was confirmed that the effect on the experimental results differs depending on the influence of the metal powder contained in the developed material.

• 한국표면공학회:학술대회논문집
• /
• 한국표면공학회 2001년도 추계학술발표회 초록집
• /
• pp.35-35
• /
• 2001

agnesium Oxide (MgO) with a NaCI structure is well known to exhibit high secondary electron emission, excellent high temperature chemical stability, high thermal conductance and electrical insulating properties. For these reason MgO films have been widely used for a buffer layer of high $T_c$ superconducting and a protective layer for AC-plasma display panels to improve discharge characteristics and panel lifetime. Up to now MgO films have been synthesized by lE-beam evaporation, Molecular Beam Epitaxy (MBE) and Metalorganic Chemical Vapor Deposition (MOCVD), however there have been some limitations such as low film density and micro-cracks in films. Therefore magnetron sputtering process were emerged as predominant method to synthesis high density MgO films. In previous works, we designed and manufactured unbalanced magnetron source with high power density for the deposition of high quality MgO films. The magnetron discharges were sustained at the pressure of O.lmtorr with power density of $110W/\textrm{cm}^2$ and the maximum deposition rate was measured at $2.8\mu\textrm{m}/min$ for Cu films. In this study, the syntheses of MgO films were carried out by unbalanced magnetron sputtering with various $O_2$ partial pressure and specially target power densities, duty cycles and frequency using pulsed DC power supply. And also we investigated the plasma states with various $O_2$ partial pressure and pulsed DC conditions by Optical Emission Spectroscopy (OES). In order to confirm the relationships between plasma states and film properties such as microstructure and secondary electron emission coefficient were analyzed by X-Ray Diffraction(XRD), Transmission Electron Microscopy(TEM) and ${\gamma}-Focused$ Ion Beam (${\gamma}-FIB$).

• 한국레이저가공학회지
• /
• 제1권1호
• /
• pp.11-17
• /
• 1998

The electron beam welding system has the advantages of the high power density, narrow welding section, and small thermal distortion of a workpiece. Recently, the electron beam welding system is widely used to the airplane engineering, nuclear power plant, and automobile industry. In the present paper, the structural analyses on the vacuum chamber of the electron beam welding system are performed by the F.E.M. analysis. The stiffening characteristics on the geometric shape, stiffener height and stiffener span are investigated. The deflection of the stiffened vacuum chamber under pressure is minimized by longitudinal and transverse stiffeners which are continuous in both direction.

• 한국정보통신학회논문지
• /
• 제12권6호
• /
• pp.1051-1055
• /
• 2008

ZnS는 전기적 에너지를 받으면 전자와 정공이 무수히 발생하며 이들이 평형상태로 갈 때 보다 높은 준위로 여기되면 빛이 생성될 수 있다. 박막 ELD는 탁월한 시각효과, 고체상태 및 제조의 용이성 등의 장점을 갖고 있으나 발광세기의 향상, 소모전력의 감소, 구동전압의 저하 등 해결되어야 할 문제점이 많이 남아있다. 이러한 문제점을 해결하기 위하여 보다 우수한 박막EL의 전계발광(EL)표시장치를 설계 제작하였다. 우수한 재료선택을 위하여 일본의 High purity사의 제품을 선택하였고, 이 제품이 Electron Beam으로 증착 시에 우수한 특성을 나타냈고, 휘도도 상용화된 800fL에 80% 수준으로 제작과정을 개선하여 더욱 우수한 결과를 얻을 수 있고 본 연구는 Yellow의 경우 650fL의 휘도를 얻었고, Green의 경우 350fL의 휘도를 얻었다. Electron Beam 제작용으로 자체 제작된 기판 홀더로 막을 제작한 결과 두께 균일도는 6% 내외 의 결과로 상당히 우수한 특성을 나타내었다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2000년도 하계학술대회 논문집 C
• /
• pp.2092-2094
• /
• 2000

As a next generation lithography (NGL) technology for VLSI semiconductor fabrication, electron beam, ion beam, X-ray and extreme ultraviolet(EUV) are considered as possible candidates. Among these methods, EUV lithography(EUVL) is thought to be the most probable because it is easily realized by improving current optical lithography technology. In order to set EUV radiation which can be applied to EUVL, it is essential to generate very high density and high temperature plasma stably. The method using a pulse power laser and a high voltage pulse discharge is commonly used to accomplish such a high density and high temperature plasma. In this paper we review the recent trends of the EUV generation technique by high density and high temperature plasma.

• 한국기계가공학회지
• /
• 제21권7호
• /
• pp.10-20
• /
• 2022

Recently, metal additive manufacturing (AM) is being investigated as a new manufacturing technology. In metal AM, powder bed fusion (PBF) is a promising technology that can be used to manufacture small and complex metallic components by selectively fusing each powder layer using an energy source such as laser or an electron beam. PBF includes selective laser melting (SLM) and electron beam melting (EBM). SLM uses high power-density laser to melt and fuse metal powders. EBM is similar to SLM but melts metals using an electron beam. When these processes are applied, the mechanical properties and microstructures change due to the many parameters involved. Therefore, this study is conducted to investigate the effects of the parameters on the mechanical properties and microstructures such that the processes can be performed more economically and efficiently.

• Progress in Superconductivity
• /
• 제6권1호
• /
• pp.13-18
• /
• 2004

High-.ate in-situ$ YBa_2$Cu$Cu_3$$O_{7-x}$ (YBCO) film growth was demonstrated by means of the electron beam co-evaporation. Even though our oxygen pressure is low, ∼$5 ${\times}$10^{-5}$ Torr, we can synthesize as-grown superconducting YBCO films at a deposition rate of around 10 nm/s. Relatively high temperatures of around 90$0^{\circ}C$ was necessary in this process so far, and it suggests that this temperature at a given oxygen activity allows a Ba-Cu-O liquid formation along with an YBCO epitaxy. Local critical current density shows a clear correlation with local resistivity. Homogeneous transport properties with a large critical current density ($4 ∼ 5 MA/\textrm{cm}^2$ at 77K, 0T) are observed in top faulted region while it is found that the bottom part carries little supercurrent with a large local resistivity. Therefore, it is possible that thickness dependence of critical current density is closely related with a topological variation of good superconducting paths and/or grains in the film bodies. The information derived from it may be useful in the characterization and optimization of superconducting films for electrical power and other applications.

• 한국의학물리학회지:의학물리
• /
• 제32권4호
• /
• pp.165-171
• /
• 2021

Purpose: This study aimed to evaluate the effect of collimator width on effective atomic number (EAN), relative electron density (RED), and stopping power ratio (SPR) measured by dual-layer dual-energy computed tomography (DL-DECT). Methods: CIRS electron density calibration phantoms with two different arrangements of material plugs were scanned by DL-DECT with two different collimator widths. The first phantom included two dense bone plugs, while the second excluded dense bone plugs. The collimator widths selected were 64 mm×0.625 mm for wider collimators and 16 mm×0.625 mm for narrow collimators. The scanning parameters were 120 kVp, 0.33 second gantry rotation, 3 mm slice thickness, B reconstruction filter, and spectral level 4. An image analysis portal system provided by a computed tomography (CT) manufacturer was used to derive the EAN and RED of the phantoms from the combination of low energy and high energy CT images. The EAN and RED were compared between the images scanned using the two different collimation widths. Results: The CT images with the wider collimation width generated more severe artifacts, particularly with high-density material (i.e., dense bone). RED and EAN for tissues (excluding lung and bones) with the wider collimation width showed significant relative differences compared to the theoretical value (4.5% for RED and 20.6% for EAN), while those with the narrow collimation width were closer to the theoretical value of each material (2.2% for EAN and 2.3% for RED). Scanning with narrow collimation width increased the accuracy of SPR estimation even with high-density bone plugs in the phantom. Conclusions: The effect of CT collimation width on EAN, RED, and SPR measured by DL-DECT was evaluated. In order to improve the accuracy of the measured EAN, RED, and SPR by DL-DECT, CT scanning should be performed using narrow collimation widths.

• 한국조명전기설비학회:학술대회논문집
• /
• 한국조명전기설비학회 2006년도 춘계학술대회 논문집
• /
• pp.268-271
• /
• 2006

We have studied the backward wave oscillator, a power-pulsed generator oscillator at 20 GHz has higher frequency then current one. An absolute instability linear analysis was used for the purpose of designing the slow wave structure. A large diameter of the slow wave structure was adopted to prevent the breakdown brought about by the increase of power density.

• 한국진공학회지
• /
• 제5권1호
• /
• pp.48-53
• /
• 1996

We present a microscopic description for generation of 1/f noise in interfaces between cobalt thin film and silicon substrate. Along with surface resistance measurements and transmission electron diffraction observations. 1/f noise power spectral density has been measured for the interfacial structures at the liquid nitrogen temperature . The cobalt films have been deposited by the electron-beam evaporation technique onto p-type (100) silicon in the high vacuum condition. The measured noise power spectral density shows highest magnitude near the structural transition and metallization transition region. The noise magnitude rapidly decreased after the cobalt silicide nucleation. The noise parameter is concluded to be originated form the structural fluctuations.