• Title/Summary/Keyword: High vacuum

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Advances in Vacuum Microelectronics toward Vacuum Nanotechnology for FPDs

  • Nakamoto, Masayuki
    • 한국정보디스플레이학회:학술대회논문집
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    • 2002.08a
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    • pp.299-302
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    • 2002
  • Vacuum microelectronics has been expected to provide a number of advanced devices such as flat panel displays, high-frequency devices etc., and rapidly showing tremendous and attractive aspects toward nanotechnology. Nowadays, nanomachining and nanomaterials are coming to new targets in the development for new generation devices. Transfer Mold technique has been developed for the vacuum nanotechnology. Carbon nanotubes (CNTs) are emerging as nanomaterials and expecting the new electron sources for FED. Recent progress of vacuum microelectronics toward vacuum nanotechnology in Japan are described.

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Parametric Study on the Capacity of Vacuum Pump for Tube Structure (튜브열차 구조물의 진공 펌프 용량에 관한 파라메타 연구)

  • Nam, Seong-Won
    • Journal of the Korean Society for Railway
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    • v.13 no.5
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    • pp.516-520
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    • 2010
  • Parametric study has been conducted to calculate the capacity of vacuum pump system that will be used to maintain the pressure of the tube structure under atmosphere level. Recently many railroad researchers pay attention to the tube train system as one of the super high speed transportation system. To achieve the super high speed, the inside of tube system should be maintained at low pressure level. In the low pressure environment, it is well known that air resistance of train is drastically decreased. Vacuum pump system will be used to make low pressure state for tube structure, exhaust the leakage air and supplement additional vacuum pumping. As results of these studies, we get the lump capacity of vacuum pump for various parameters. These results can be applied to analyze the effects of the reduction of air resistance.

Design and Evaluation of a Rotation Table using Air Bearings for Electron Beam Mastering (전자빔 마스터링을 위한 공기베어링 응용 고진공 회전테이블의 설계 및 진공특성 평가)

  • Khim, Gyung-Ho;Song, Chang-Kyu;Park, Chun-Hong
    • Journal of the Korean Society for Precision Engineering
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    • v.25 no.12
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    • pp.132-138
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    • 2008
  • Recently, mastering processes for high density optical disc such as Blu-ray disc rely on electron beams, which are operable in only vacuum. In the mastering process, one of the most important tasks is to design precision stages for providing precise positioning of the works with respect to the source in a high vacuum environment. In this paper, we have developed a precision rotation table usable in the electron beam mastering. The rotation table adopted air bearings for a high positioning repeatability and velocity stability. The air leakage from the air bearings has been minimized by employing the differential exhaust scheme using three steps of air drain. The design parameters such as diameters of exhaust lines, seal lengths, and pumping speeds were decided according to the optimization method using genetic algorithm. The performance on the vacuum level of the rotation table was evaluated experimentally and theoretically. The results indicate that a vacuum level of $10^{-4}$ Pa is achieved with operation of air bearings in a vacuum chamber, which is sufficient for the electron beam mastering.

Fabrication of CIGS/CZTS Thin Films Solar Cells by Non-vacuum Process (비진공 방법에 의한 CIGS/CZTS계 박막 태양전지 제조)

  • Yoo, Dayoung;Lee, Dongyun
    • Korean Journal of Materials Research
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    • v.28 no.12
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    • pp.748-757
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    • 2018
  • Inorganic semiconductor compounds, e.g., CIGS and CZTS, are promising materials for thin film solar cells because of their high light absorption coefficient and stability. Research on thin film solar cells using this compound has made remarkable progress in the last two decades. Vacuum-based processes, e.g., co-evaporation and sputtering, are well established to obtain high-efficiency CIGS and/or CZTS thin film solar cells with over 20 % of power conversion. However, because the vacuum-based processes need high cost equipment, they pose technological barriers to producing low-cost and large area photovoltaic cells. Recently, non-vacuum based processes, for example the solution/nanoparticle precursor process, the electrodeposition method, or the polymer-capped precursors process, have been intensively studied to reduce capital expenditure. Lately, over 17 % of energy conversion efficiency has been reported by solution precursors methods in CIGS solar cells. This article reviews the status of non-vacuum techniques that are used to fabricate CIGS and CZTS thin films solar cells.

Development of Three D.O.F Alignment Stage for Vacuum Environment (진공용 3자유도 얼라인먼트 스테이지 개발)

  • Han, Sang-Jin;Park, Jong-Ho;Park, Hui-Jae
    • Journal of the Korean Society for Precision Engineering
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    • v.18 no.11
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    • pp.138-147
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    • 2001
  • Alignment systems are frequently used under various semiconductor manufacturing environment. Particularly in PDP(Plasma Display Panel) manufacturing process, the alignment system is applied to the combining and sealing processes of the upper and lower glass panels of PDP, where these processes are performed in the vacuum chamber of high vacuum and high temperature. In this paper, the XYΘ-alignment stage is developed to align PDP panels. Because of high vacuum and high temperature environment, the alignment chamber has been designed to isolate the inner part of the alignment chamber from the outer environment of high vacuum and high temperature, in which every part of the alignment stage is inserted. As it is difficult to attach feedback sensors to the alignment stage in the alignment chamber, the alignment stage is implemented with the open loop algorithm, where the parallel link structure has been designed using step-motors and ball-screws for structural simplicity. The kinematic analysis is performed to drive the parallel link structure, based on the experiments of actuation-compensation of the alignment stage. For the error compensation, the hyperpatch model has been used to model the errors. From the experiments, the positional accuracy of the alignment stage can be improved significantly.

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National Vacuum Standards from Low to Ultra-high Vacuum (저진공에서 초고진공까지의 국가 진공표준)

  • Hong S. S.;Lim I. T.;Shin Y. H.;Chung K. H.
    • Journal of the Korean Vacuum Society
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    • v.15 no.1
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    • pp.1-13
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    • 2006
  • Vacuum laboratory in Korea Research Institute of Standards and Science (KRISS) was opened in 1983 for establishing and disseminating vacuum standard in Korea. The major three systems such as the ultrasonic interferometer manometer (UIM), the static expansion system (SES) and the dynamic expansion system (DES) with orifice and porous plug conductance are developed. In this study, the standard systems from low to ultra-high vacuum, uncertainty analysis by ISO regulation, and key and bilateral comparison results will be described.

Effects of Electrode Configurations on the Characteristics of Axial Magnetic Fields in Vacuum Interrupter (전극형상 변화가 진공차단기내 축방향 자기장 특성에 미치는 영향)

  • Hwang, Jung-Hoon;Lee, Jong-Chul;Kim, Youn-Jea
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.32 no.1
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    • pp.7-12
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    • 2008
  • The vacuum interrupter (VI) is used for medium-voltage switching circuits due to its abilities and advantages as a compacted environmental friendly circuit breaker. In general, the application of a sufficiently strong axial magnetic field (AMF) permits the arc to be maintained in a diffused mode to a high-current vacuum arc. A full understanding of the vacuum arc physics is very important since it can aid to improve the performance of vacuum interrupter. In order to closely examine the vacuum arc phenomena, it is necessary to predict the magnetohydrodynamic (MHD) characteristics by the multidisciplinary numerical modeling, which is coupled with the electromagnetic and hydrodynamic fields, simultaneously. In this study, we have investigated the effect of changing geometrical parameters for electromagnetic behaviors of high-current vacuum arcs with two different types of AMP contacts, which are coil-type and cup-type, using a commercial finite element analysis (FEA) package, ANSYS. The present results are compared with those of MAXWELL 3D, a reliable electromagnetic analysis software, for verification.

Optimal Design of High Temperature Vacuum Furnace Using Thermal Analysis Database (전산 열해석 DB를 이용한 초고온 진공로 최적설계)

  • Li Zhen-Zhe;Park Mee-Young;Byun Yung-Hwan;Lee Chang-Jin;Lee Jae-Woo
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.30 no.6 s.249
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    • pp.594-601
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    • 2006
  • Optimization study has been carried out to design an energy efficient, high temperature vacuum furnace which satisfies users' design requirements. First of all, the transient temperature distribution and the uniform temperature zone results have been compared with the steady state results to validate the feasibility of using steady state solution when constructing the thermal analysis DB. In order to check the accuracy, the interpolated results using thermal analysis DB have been compared with the computational and the experimental results. In this study, total heat flux is selected as the objective function, and the geometry parameters of vacuum furnace including the thickness of insulator, the heat zone sizes and the interval between heater and insulator are the design variables. The Uniform temperature zone sizes and the wall temperature are imposed as the design constraints. With negligible computational cost a high temperature vacuum furnace which has $40\sim60%$ reduction in total heat flux is designed using thermal analysis DB.

Stress analysis of the KSTAR vacuum vessel under thermal and electromagnetic loads (KSTAR 진공용기 열 및 전자기력 하중에 의한 응력해석)

  • Cho, S.;Kim, J.B.;Her, N.I.;Im, K.H.;Sa, J.W.;Yu, I.K.;Kim, Y.C.;Do, C.J.;Kwon, M.
    • Proceedings of the KSME Conference
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    • 2001.06d
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    • pp.325-330
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    • 2001
  • One of the principal components of the KSTAR (Korea Superconducting Tokamak Advanced Research) tokamak structure is the vacuum vessel, which acts as the high vacuum boundary for the plasma and also provides the structural support for internal components. Hyundai Heavy Industries Inc. has performed the engineering design of the vacuum vessel. Here the overall configuration of the KSTAR vacuum vessel was briefly described and then the design methodology and the analysis results were presented. The vacuum vessel consists of double walls, several ports, leaf spring style supports. Double walls are separated by reinforcing ribs and filled with baking/shielding water. The overall external dimensions of the main body are 3.39 m high, 1.11 m inner radius, 2.99 m outer radius, and made of SA240-316LN. The vacuum vessel was designed to be capable of achieving the base pressure of $1\times10^{-8}$ Torr, and also to be structurally capable of sustaining the vacuum pressure, the electromagnetic and thermal loads during plasma disruption and bakeout, respectively. The vacuum vessel will be baked out maximum $150^{\circ}C$ by hot pressurized water through the channels formed between double walls and the reinforcing ribs. A 3-D temperature distribution and the resulting thermal loads in the vessel were calculated during bakeout. It was found that the vacuum vessel and its supports were structurally rigid based on the thermal stress analysis. The maximum electromagnetic loads on the vacuum vessel induced by eddy and halo currents resulting from the engineering plasma radial and vertical disruption scenarios have been estimated. The stress analyses have been performed based on these electromagnetic loads and the resulting stresses at he critical locations of the vacuum vessel were within the allowable stresses.

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