• Title, Summary, Keyword: Ultra-structure

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Development of an Engineering Model of Hydrogen-Fueled Ultra-micro Combustor for UMGT

  • Shimotori, Shoko;Yuasa, Saburo;Sakurai, Takashi
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • pp.828-836
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    • 2008
  • To develop an engineering-model of hydrogen-fueled ultra-micro combustor for Ultra Micro Gas Turbine(UMGT), we reviewed and summarized the problems in downsizing combustors, and determined a suitable burning method. The key issue to actualize practical ultra-micro combustors is reducing heat loss from the combustor to compressor and turbine. The reduction of heat loss was discussed from 3 different viewpoints; heat-insulation material, high-space-heating-rate combustion, and combustor-insolated gas turbine structure. Use of heat-insulation material induced the heat loss reduction to the surroundings. The heat loss ratio decreased substantially in reverse proportion to space heating rate, leading the idea that it could be reduced by burning at a high space heating rate. By settling the combustor insolated from the compressor and turbine, the heat transfer from the combustor to the compressor and turbine becomes smaller. For a selection of the suitable burning method, comparison between 2 burning methods, flat-flame and swirling-flamer types, was conducted. Synthetically the flat-flame burning method was confirmed to be more suitable for ultra-micro combustors than latter one. Base on them, an engineering-model of hydrogen-fueled flat-flame ultra-micro combustor was developed. To obtain high overall heat-insulation, heat-resistant and strength, the engineering-model combustor had triple layer structure with an advanced ceramic, a heat insulation material and a stainless steel. To simplify heat transfer issue in the combustor, it was isolated from the other components. Furthermore it was designed by considering structure, size, material, velocity, pressure loss and prevention of flashback.

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Design and Structure Improvement of Ultra Low Volume Sprinkler (초미립자 살포기의 설계 및 구조개선)

  • Lee, Jong-Sun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.11 no.1
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    • pp.43-48
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    • 2010
  • In this paper, structural analysis was conducted by designing a ultra low volume sprinkler applied to spray liquid and applying a ANSYS commercial code for three dimensional finite element method to the ultra low volume sprinkler. Based on this numerical structural analysis, stress, strain and total deformation were obtained and the structure improvement of the ultra low volume sprinkler was made along with improved productivity and shorten design period.

Design Guideline for Press Tool Structure of Ultra-high Strength Steel Part with Shape Optimization Technique (형상최적화 기법을 이용한 초고강도강판 성형용 프레스 금형의 구조설계 가이드라인)

  • Kang, K.H.;Kwak, J.H.;Bae, S.B.;Kim, S.H.
    • Transactions of Materials Processing
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    • v.26 no.6
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    • pp.372-377
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    • 2017
  • In this paper, an effective design procedure was proposed to design the rib of die structure for auto-body member with ultra-high strength steel (UHSS) having ultimate tensile strength (UTS) of 1.5 GPa. From analysis results of the die structure, structural safety of the die was evaluated with information such as displacement and von-Mises stress. It was concluded that the casting part could be designed in order to reduce tool deformation. A design guideline of the die structure was proposed, especially for the rib structure in the casting part with an optimization scheme and local reinforcement concept. Simulation result following the design guideline fully explained that stability of the tool structure could be obtained simultaneously with weight minimization.

Radix-2 Based Structure for Ultra-long FFT (Ultra-long FFT를 위한 Radix-2 기반 구조)

  • Kang, Hyeong-Ju
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.17 no.9
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    • pp.2121-2126
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    • 2013
  • This paper compares radix-2 based structures for 32768-point FFT. Radix-$2^k$ structures have been widely used because the butterfly is simple and the number of multipliers can be reduced in those structures. This paper applied various radix-$2^k$ structures to 32768-point FFT that is representing ultra-long FFT. The ultra-long FFT has been studied much recently. This paper shows that the radix-$2^4$ structure is the most adequate because it shows the smallest complexity in the synthesis and the best SQNR performance. should be placed here.

A New Way to Manufacture Ultra Light Metal Structures (초경량 금속구조재의 제작을 위한 새로운 방안)

  • Kang, Ki-Ju;Jeon, Gye-Po;Nah, Seong-Jun;Ju, Bo-Seong;Hong, Nam-Ho
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.28 no.3
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    • pp.296-303
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    • 2004
  • Recently, the ultra light metal structure with periodic and three dimensional truss elements takes attention because of its multi-functionality and substantial heat resistance. However, the complicated fabrication process leading to high cost has been a major obstacle to wide applications. In this paper, a new idea to construct an ultra light structure with periodic, three dimensional truss using metal wires is presented. To prove the practical validity, a Kagome-like structure was fabricated from stamped wires and punched face sheets. It was assembled by soldering. Through three-point bending and compression tests, the strength was evaluated and compared with the theory.

Design of a Low Distortion Head-Mounted Display with Freeform Reflective Mirror Based on Two Ellipsoids Structure

  • Wang, Junhua;Liang, Yuechao;Xu, Min
    • Journal of the Optical Society of Korea
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    • v.20 no.2
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    • pp.234-238
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    • 2016
  • A new method to design a low distortion, even relative illumination, optical see-through head-mounted display (HMD) with a freeform reflective mirror (FFRM) based on the two similar ellipsoids structure is proposed. The HMD we have realized has a simple structure which consists of two similar ellipsoid surfaces, an FFRM, a 7-piece co-axis relay lens, and an OLED. This structure can be applied to offset distortion, reach even relative illumination, and correct the off-axis aberrations. The HMD we finally have realized has a near 3% low distortion, a higher than 80% relative illumination, and a 40°×30° field of view (FOV).

A Study on the Electrical Characteristics of Ultra Thin Gate Oxide

  • Eom, Gum-Yong
    • Transactions on Electrical and Electronic Materials
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    • v.5 no.5
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    • pp.169-172
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    • 2004
  • Deep sub-micron device required to get the superior ultra thin gate oxide characteristics. In this research, I will recommend a novel shallow trench isolation structure(STI) for thin gate oxide and a $N_2$O gate oxide 30 $\AA$ by NO ambient process. The local oxidation of silicon(LOCOS) isolation has been replaced by the shallow trench isolation which has less encroachment into the active device area. Also for $N_2$O gate oxide 30 $\AA$, ultra thin gate oxide 30 $\AA$ was formed by using the $N_2$O gate oxide formation method on STI structure and LOCOS structure. For the metal electrode and junction, TiSi$_2$ process was performed by RTP annealing at 850 $^{\circ}C$ for 29 sec. In the viewpoints of the physical characteristics of MOS capacitor, STI structure was confirmed by SEM. STI structure was expected to minimize the oxide loss at the channel edge. Also, STI structure is considered to decrease the threshold voltage, result in a lower Ti/TiN resistance( Ω /cont.) and higher capacitance-gate voltage(C- V) that made the STI structure more effective. In terms of the TDDB(sec) characteristics, the STI structure showed the stable value of 25 % ~ 90 % more than 55 sec. In brief, analysis of the ultra thin gate oxide 30 $\AA$ proved that STI isolation structure and salicidation process presented in this study. I could achieve improved electrical characteristics and reliability for deep submicron devices with 30 $\AA$ $N_2$O gate oxide.

An Experimental Study For Basic Property of Ultra High Strength Concrete using Belite Cement (저열 포틀랜드 시멘트를 사용한 초고강도 콘크리트의 특성에 관한 연구)

  • Min, Hong-Jun;Kim, Ji-Man;Gong, Min-Hoi;Yang, Dong-Il;Lee, Han-Souk;Jung, Sang-Jin
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.457-460
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    • 2006
  • Recently ultra high strength concrete is actively being developed and studied, and this trend is explained with the following effects. Technological effects expected from the application of ultra high strength concrete include the reduction of section, the decrease of structure mass and the improvement of workability. Belite cement has properities like low heat of hydration, excellent long term strength, and durablity without admixture. so, Belite cement is suitable for mass structure which is needed high strenghth, high fluidity and heat property. The objective of this study is to examine the suitability of mixture ratio through experiment of basic physical properties and provide materials for the field application of ultra high strength concrete.

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Ultra-shallow Junction with Elevated SiCe Source/ Drain fabricated by Laser Induced Atomic Layer Doping (레이저 유도 원자층 도핑(Ll-ALD)법으로 성장시킨 SiGe 소스/드레인 얕은 접합 형성)

  • 장원수;정은식;배지철;이용재
    • Proceedings of the IEEK Conference
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    • pp.29-32
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    • 2002
  • This paper describes a novel structure of NMOSFET with elevated SiGe source/drain region and ultra-shallow source/drain extension(SDE)region. A new ultra-shallow junction formation technology. Which is based on damage-free process for rcplacing of low energy ion implantation, is realized using ultra-high vacuum chemical vapor deposition(UHVCVD) and excimer laser annealing(ELA).

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Ultra accelerated molecular dynamics study on electronic structure and luminous efficacy of PDP protecting layer

  • Takaba, Hiromitsu;Serizawa, Kazumi;Suzuki, Ai;Tsuboi, Hideyuki;Hatakeyama, Nozomu;Endou, Akira;Kubo, Momoji;Kajiyama, Hiroshi;Miyamoto, Akira
    • 한국정보디스플레이학회:학술대회논문집
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    • pp.169-172
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    • 2009
  • We developed ultra-accelerated quantum chemical molecular dynamics and characterization simulators for study and design of plasma display panel (PDP) related materials. By use of these simulators, realistic structure of PDP materials is drawn on the computer. Furthermore, based on the structures, various properties such as secondary electron emission coefficient are successfully evaluated. In this report, we will discuss the theoretical secondary electron emission coefficient for several protecting layer materials and the effect of surface structure on the properties based on the result of atomistic simulations.

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