• Title/Summary/Keyword: Structure improvement

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White ACPEL Device with ZnS:Cu,Cl, $Tb_3Al_5O_{12}:Ce^{3+}$, and CaS:$Eu^{2+}$ Phosphors Using a Layered Structure

  • Park, Bong-Je;Seo, Hong-Seok;Ahn, Jun-Tae;Oh, Dae-Kon;Chung, Woon-Jin;Han, Ji-Yeon;Jang, Ho-Seong;Jeon, Duk-Young
    • ETRI Journal
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    • v.31 no.6
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    • pp.803-805
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    • 2009
  • Improvement of the color rendering index (CRI) and luminance of a white alternate current powder electroluminescent (ACPEL) device has been attempted using ZnS:Cu,Cl, $Tb_3Al_5O_{12}$:Ce (TAG:Ce), and CaS:Eu phosphors with a layered structure. The device with TAG:Ce and ZnS:Cu,Cl phosphors showed a CRI of 75, with a luminance increase of about 30% depending on the thickness of the TAG:Ce. Further CRI improvement was attempted using CaS:Eu. When they were separately screen-printed, the CRI was increased up to 89 with no decrease in luminance.

A Study of Field Survey on Working Environment for Mercury Treatment Establishments in Korea (전국 수은 취급사업장의 작업환경 실태 조사 연구)

  • 엄성인;백존배;이영섭
    • Journal of the Korean Society of Safety
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    • v.7 no.3
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    • pp.30-34
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    • 1992
  • This study is conducted to evaluate the airborne concentration of mercury, as well as installation and efficiency of local exhaust ventilation system for 57 factories manufactured fluorescence lamps, mercury lamps and thermometers for July and August 1990. Results and conclusion are as fellows : 1) Mercury treatment factories are 32 among 57 ones, which are 18 fluorescence lamp manufacturing ones and 6 mercury lamp ones and 3 thermometer ones and 5 other ones. 2) Mean airborne concentrations of mercury for factories manufactured mercury lamps are 0.01 mg/ ㎥ in injection process and 0.0155mg/㎥ in exhaust process, and mean airborne concentration of mercury for factories manufactured thermometer are 0.023mg/㎥ in injection process and 0.012mg/㎥ in selection process. All of these airborne concentrations of mercury are lower than PEL(Permissible Exposure Limit ), 0.05mg/㎥. 3) Mean airborne concentrations of mercury for factories manufactured fluorescence lamps are 0.094mg/㎥ in injection process and 0.087mg/㎥ in exhaust process, and 0.052mg/㎥ in sealing process and 0.085mg/㎥ in other process, respectively. All of these air borne concentrations of mercury are exceeded to PEL. More than 60% among 32 factories manufactured mercury are exceeded to PEL. 4) Nine factories among 18 factories manufactured fluorestence lamps are equipped with local exhaust ventilation system, and 7 factories among 9 factories are required for the improvement of suction capacity and structure. Five factories among 14 factories manufactured mercury lamps and the other ones are equipped with local exhaust ventilation system, and 2 factories are required for the improvement of suction capacity and structure.

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Structure Analysis and Torque Reduction Design of Industrial Ball Valve (산업용 볼밸브의 구조 해석 및 토크 저감 설계)

  • Ha, Sun-Ho;Kim, Sang-Jin;Song, Jung-Il
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.13 no.6
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    • pp.37-45
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    • 2014
  • Ball valves are used as a key element in the process industries. The industrial development of valves has increased steadily, but continued improvement requires high design reliability and long service life. Currently, the development of high performance valves is not easy because of the lack of relevant technology in Korea. Valves are being imported at a level of up to 58 percent of the domestic market, which represents a value of almost 7 million US dollars. Therefore, in this work, the improvement of the design and performance of industrial valves has been studied in an attempt to achieve valves that will have longer service life and better output during operation. The structural stability was evaluated using the ANSYS FSI (Fluid-Structural Interaction) module. Moreover, to obtain maximum product reliability, torque analysis simulation was performed to compare and experimental results. The simulation results were used to predict the change in torque by changes in shape, thereby reducing the time and cost of manufacturing a number of prototypes for experimental validation.

Color Variation Improvement by Introducing Double Emission Layers in WPLEDs

  • Kwon, Soon-Kab;Lee, Yong-Kyun;Park, Tae-Jin;Jeong, Su-Hyeon;Jeon, Woo-Sik;Kwon, Jang-Hyuk;Jang, Jin
    • Journal of Information Display
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    • v.7 no.3
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    • pp.19-22
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    • 2006
  • White polymeric light-emitting devices (WPLEDs) have been fabricated from polyfluorene-based (PFO) blue and MEH-PPV polymer blending systems. A device structure of ITO / PEDOT:PSS / Blending polymer / Blue polymer / LiF / Al was employed. This structure of double emission layers showed significant improvement of white color shift phenomenon. A current efficiency of 4.67 cd/A (3,900 $cd/m^{2}$, 6.4 V) and a brightness value of 17,600 $cd/m^{2}$ at 9.4 V with (0.34, 0.35) CIE coordinates at 5 V and (0.29, 0.29) at 9 V were achieved achieved.

2D numerical modelling of soil-nailed structures for seismic improvement

  • Panah, Ali Komak;Majidian, Sina
    • Geomechanics and Engineering
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    • v.5 no.1
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    • pp.37-55
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    • 2013
  • An important issue in the design of soil-nailing systems, as long-term retaining walls, is to assess their stability during seismic events. As such, this study is aimed at simulating the dynamic behavior and failure pattern of nailed structures using two series of numerical analyses, namely dynamic time history and pseudo-static. These numerical simulations are performed using the Finite Difference Method (FDM). In order to consider the actual response of a soil-nailed structure, nonlinear soil behaviour, soil-structure interaction effects, bending resistance of structural elements and construction sequences have been considered in the analyses. The obtained results revealed the efficiency of both analysis methods in simulating the seismic failure mechanism. The predicted failure pattern consists of two sliding blocks enclosed by three slip surfaces, whereby the bottom nails act as anchors and the other nails hold a semi-rigid soil mass. Moreover, it was realized that an increase in the length of the lowest nails is the most effective method to improve seismic stability of soil-nailed structures. Therefore, it is recommended to first estimate the nails pattern for static condition with the minimum required static safety factor. Then, the required seismic stability can be obtained through an increase in the length of the lowest nails. Moreover, placement of additional long nails among lowest nails in existing nailed structures can be considered as a simple retrofitting technique in seismic prone areas.

A Study on the DVR System Realization with Watermarking and MPEG-4 for Realtime Processing Speed Improvement (워터마킹과 MPEG4를 적용한 DVR 시스템과 실시간 처리 속도 향상에 관한 연구)

  • Kim, Ja-Hwang;Hur, Chang-Wu;Ryu, Kwang-Ryol
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • v.9 no.2
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    • pp.1107-1111
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    • 2005
  • The DVR system realization with watermarking and MPEG-4 for real time processing speed improvement is presented in this paper. For the real time processing the system is used the DSP processor, Quick DMA for data transmission, watermarking for security and MPEG-4 compression for facility. The algorithms are that the operational structure has the internal memory of processor, and the optimal realization is suitable to form the DSP processor structure r processed for the iterative operations. The experimental result shows the real time processing is improved 12% over for the D1 image in comparison with the other system.

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Thermal Stability Improvement of Ni-silicide Using Ni-Co alloy for Nano-Scale CMOSFET Technology (나노급 CMOSFET을 윈한 Ni-Co 합금을 이용한 Ni-silicide의 열안정성 개선)

  • Park, Kee-Young;Zhang, Ying-Ying;Jung, Soon-Yen;Li, Shi-Guang;Zhun, Zhong;Lee, Ga-Won;Wang, Jin-Suk;Lee, Hi-Deok
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2007.06a
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    • pp.27-28
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    • 2007
  • In this paper, Ni-Co alloy was used for improvement of thermal stability of Ni silicide. The proposed Ni/Ni-Co structure exhibited wide temperature window of rapid thermal process. Sheet resistance as well as cross-sectional profile showed stable characteristics in spite of high temperature annealing up to $700^{\circ}C$ for 30min. Therefore, the proposed Ni/Ni-Co structure is highly promising for highly thermal immune Ni silicide for nano-scale CMOSFET technology.

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A Study on Improvement of Cooling Performance through Vent Structure Optimization of Carbon Ceramic Composite Disc (카본 세라믹 복합재 디스크의 벤트 구조 최적화를 통한 냉각성능 향상에 관한 연구)

  • Shim, J.H.;Shin, U.H.;Lee, J.H.;Jeon, G.B.;Kim, B.C.;Kwack, J.H.;Lim, D.W.;Hyun, E.J.;Jeon, T.H.;Lee, J.M.
    • Journal of Auto-vehicle Safety Association
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    • v.11 no.1
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    • pp.23-29
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    • 2019
  • Recently, use of composite materials has been increasing for body structures and chassis parts in the car industry because of weight reduction effect and excellent mechanical thermal characteristics. However, application of composite materials in brake system is very difficult because it is hard to obtain enough brake performance due to low heat storage capacity of the composite materials. In this paper, we will present new carbon ceramic composite disc with high flow characteristic. To obtain this characteristic, new vent structures were designed by using ARIZ method and substance-field model analysis. The flow effect of these vent structures on the brake performance was verified by pugh matrix and cooling test. The test results show improvement of cooling performance up to $30^{\circ}C$. Finally, These results will improve brake the reliability of the brake performance for the high performance vehicles and electric vehicles.

Material and Structure Optimization of Substrate Support for Improving CVD Equipment Up Time (CVD 장비 Up Time 향상을 위한 기판 지지대의 재질 및 구조 최적화)

  • Woo, Ram;Kim, Won Kyung
    • Korean Journal of Materials Research
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    • v.29 no.11
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    • pp.670-676
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    • 2019
  • We study substrate support structures and materials to improve uptime and shorten preventive maintenance cycles for chemical vapor deposition equipment. In order to improve the rolling of the substrate support, the bushing device adopts a ball transfer method in which a large ball and a small ball are mixed. When the main transfer ball of the bushing part of the substrate support contacts the substrate support, the small ball also rotates simultaneously with the rotation of the main ball, minimizing the resistance that can be generated during the vertical movement of the substrate support. As a result of the improvement, the glass substrate breakage rate is reduced by more than 90 ~ 95 %, and the equipment preventive maintenance and board support replacement cycles are extended four times or more, from once a month to more than four months, and the equipment uptime is at least 15 % improved. This study proposes an optimization method for substrate support structure and material improvement of chemical vapor deposition equipment.

A Review of RRAM-based Synaptic Device to Improve Neuromorphic Systems (뉴로모픽 시스템 향상을 위한 RRAM 기반 시냅스 소자 리뷰)

  • Park, Geon Woo;Kim, Jae Gyu;Choi, Geon Woo
    • Journal of the Semiconductor & Display Technology
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    • v.21 no.3
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    • pp.50-56
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    • 2022
  • In order to process a vast amount of data, there is demand for a new system with higher processing speed and lower energy consumption. To prevent 'memory wall' in von Neumann architecture, RRAM, which is a neuromorphic device, has been researched. In this paper, we summarize the features of RRAM and propose the device structure for characteristic improvement. RRAM operates as a synapse device using a change of resistance. In general, the resistance characteristics of RRAM are nonlinear and random. As synapse device, linearity and uniformity improvement of RRAM is important to improve learning recognition rate because high linearity and uniformity characteristics can achieve high recognition rate. There are many method, such as TEL, barrier layer, NC, high oxidation properties, to improve linearity and uniformity. We proposed a new device structure of TiN/Al doped TaOx/AlOx/Pt that will achieve high recognition rate. Also, with simulation, we prove that the improved properties show a high learning recognition rate.