• Title/Summary/Keyword: Cell Buffer

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Characteristics of CdS buffer layer for CIGS thin film solar cells (CIGS 박막 태양전지를 위한 CdS 버퍼층의 특성 연구)

  • Park, Mi-Sun;Sung, Shi-Joon;Hwang, Dae-Kue;Kim, Dae-Hwan;Lee, Dong-Ha;Kang, Jin-Kyu
    • 한국태양에너지학회:학술대회논문집
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    • 2012.03a
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    • pp.394-396
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    • 2012
  • Chemical bath deposition (CBD) process conditions for depositing CdS buffer layers was studied for high efficiencies of CIGS thin film solar cells. Growth rate of CdS thin films has an effect on surface morphology and quality of thin films. By the change of growth rate, CdS buffer layers showed a large difference in surface morphology and this difference was closely related with the photovoltaic properties of CIGS solar cells.

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An Analysis of Cell Loss Process in an ATM Network Under Partial Buffer Sharing Policy (ATM 전송망에서의 PBS를 이용한 셀 우선 순위 제어 방식의 연구)

  • 곽민곤;성수란;김종권
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.19 no.12
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    • pp.2328-2339
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    • 1994
  • The PBS(Partial Buffer Sharing) space priority mechanism is one of priority control methods which may improve the performance of a single server queueing system when mixed traffic with different performance requirements is applied to the system. This paper analyzes the cell loss behavior of PBS assuming loss sensitive traffic and delay sensitive traffic are applied to the system. To derive the successive cell loss probabilities. which are an important performance measure of realtime traffic, we develop a recursive algorithm. Performance results show the successive cell loss probabilities obtained by our method are lager than the probabilities derived from an independent cell loss assumption. These results may indicate the limitation of PBS for realtime traffic and the increase of the admissible load with the criterion of quality of service.

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Fabrication and Characterization of Cu3SbS4 Solar Cell with Cd-free Buffer

  • Han, Gyuho;Lee, Ji Won;Kim, JunHo
    • Journal of the Korean Physical Society
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    • v.73 no.11
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    • pp.1794-1798
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    • 2018
  • We have grown famatinite $Cu_3SbS_4$ films by using sulfurization of Cu/Sb stack film. Sulfurization at $500^{\circ}C$ produced famatinite $Cu_3SbS_4$ phase, while $400^{\circ}C$ and $450^{\circ}C$ sulfurization exhibited unreacted and mixed phases. The fabricated $Cu_3SbS_4$ film showed S-deficiency, and secondary phase of $Cu_{12}Sb_4S_{13}$. The secondary phase was confirmed by X-ray diffraction, Raman spectroscopy, photoluminescence and external quantum efficiency measurements. We have also fabricated solar cell in substrate type structure, ITO/ZnO/(Zn,Sn)O/$Cu_3SbS_4$/Mo/glass, where $Cu_3SbS_4$ was used as a absorber layer and (Zn,Sn)O was employed as a Cd-free buffer. Our best cell showed power conversion efficiency of 0.198%. Characterization results of $Cu_3SbS_4$ absorber indicates deep defect (due to S-deficiency) and low shunt resistance (due to $Cu_{12}Sb_4S_{13}$ phase). Thus in order to improve the cell efficiency, it is required to grow high quality $Cu_3SbS_4$ film with no S-deficiency and no secondary phase.

Studies on the Standardization of pH Measurement System (pH 측정 시스템의 표준화에 관한 연구)

  • Lee, Hwa Shim;Kim, Myung Soo;Kim, Jin Bok;Oh, Sang Hyup
    • Journal of the Korean Chemical Society
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    • v.42 no.4
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    • pp.432-442
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    • 1998
  • Since the definition of pH, $pH=-Ioga_H$ is based on a single ion activity, pH values can not be determined with measurement itself, but require an approximation method. They are derived from EMF measurement of a liquid junction free cell using hydrogen and Ag/AgCl electrodes. Primary standard materials with certified pH values can be obtained with this approximation method. Standard buffer solutions are used to calibrate pH meters. Thus the accuracy of the pH values of standard buffer solutions limits the reliability of measured pH values can be obtained with this approximation method. Standard buffer solution are used to calibrate pH meters. Thus the accuracy of the pH values of standard buffer solutions limits the reliability of measured pH values of sample solutions. To certify the pH values, we have established the system for the primary standard measurement and certified the pH of buffer solutions in the range of 1.6∼12.5 pH unit within uncertainty of ${\pm}0.005$ pH unit.

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A Study on Efficient Scheduling Scheme for QoS in ATM Switch (ATM 스위치에서의 QOS 을 위한 효율적인 스케쥴링 기법에 관한 연구)

  • 이상태;김남희
    • Proceedings of the IEEK Conference
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    • 1998.10a
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    • pp.75-78
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    • 1998
  • In this paper, we propose a new cell discarding and scheduling scheme which reduce cell loss rate by measuring, in real time, the number of discarded cells in the queuing system with a different loss priority for each class of service such that each class of service meets its cell loss rate requirements and reduce average delay rate for the traffic that is sensitive in cell delay in output buffer of the ATM switch. Throughout the computer simulation, the existing scheduling scheme and proposed scheme are compared with respect to cell loss rate and average delay time.

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Cell-interleavd VC merging scheme for multipoint-to-multipoint communication in ATM network (ATM 망에서의 다자간 통신을 위한 cell-interleaved VC merging 기법)

  • 신상헌
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.25 no.9A
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    • pp.1431-1440
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    • 2000
  • In order to support efficiently the multimedia applications, such as virtual classroom, video conferencing and tele-medical, the efficient multipoint-to-multipoint(MP-to-MP) connection management function is essential. Shared tree is reported as the most useful method for this purpose. In this paper we propose a new MP-to-MP connection setup & management scheme, called CIMA(Cell Interleaved Multiplexing on ATM) scheme,which is a VC merging method for MP-to-MP communication using shared tree. In the CIMA scheme,MRM cell delivers the cell merging information to the next node. The receiving node can identfy cells which arrived through a channel using the same VPI/VCI by the merging information in the MRM cell. Therefore the CIMA scheme can solve easily the Cell Interleaving Problem(CIP) that happens in VC merging. We analyzed the overhead of the proposed CIMA by mathematical analysis,and simulated the buffer usage of CIMA with OPNET. As the result of analysis,we found that the CIMA scheme has acceptable merging overhead and doesn't cause the buffer scare problem.

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Cell Buffer Analysis for ATM-to-Frame Relay Interworking (ATM-프레임 릴레이 망 연동장치의 셀 수신 버퍼 용량 분석)

  • Lee, Sung-Chang;Nam, Yoon-Seok;Kim, Jeong-Sik
    • Journal of the Korean Institute of Telematics and Electronics S
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    • v.36S no.10
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    • pp.30-39
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    • 1999
  • In this paper, the size of IWU frame cell buffer is analyzed that receives FR frame cells from other FR networks through ATM backbone network. The frame cell buffer receives multiplexed ATM cells from other IWUs that provide interworking with ATM network for other FR networks A receiving IWU reassembles frames from multiplexed ATM cells by identifying the VPI/VCIs. The reassembled frames are transmitted on FR network links according to their destination. Therefore, IWU needs sufficient amount of buffers for the assembly of the frames and for providing the assembled frames with the queue to wait until the frame is transmitted by FR network link. In this paper, the probability of frame loss at the frame cell buffer is derived in terms of traffic parameters, the number of multiplexed FR connections, the number of FR links and the transmission capacity. By applying the derived results, we analyzed the required buffer size for a given probability of frame loss. Also, it is presented that how the probability and the required size are effected by the number of multiplexed FR connections and FR transmission links.

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Electricity Production from Fe[III]-reducing Bacterium Geobacter sulfurreducens in Microbial Fuel Cell (미생물 연료전지에서 Fe[III] 환원 미생물 Geobacter sulfurreducens를 이용한 전기 생산)

  • Lee, Yu-Jin;Oh, You-Kwan;Kim, Mi-Sun
    • Journal of Hydrogen and New Energy
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    • v.19 no.6
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    • pp.498-504
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    • 2008
  • Metal-reducing bacterium, Geobacter sulfurreducens is available for mediator-less microbial fuel cell (MFC) because it has biological nanowires(pili) which transfer electrons to outside the cell. In this study, in the anode chamber of the MFC system using G. sulfurreducens, the concentrations of NaCl, sodium phosphate and sodium bicarbonate as electrolytes were mainly optimized for the generation of electricity from acetate. 0.4%(w/v) NaClO and 0.5M $H_2SO_4$ could be utilized for the sterilization of acrylic plates and proton exchange membrane (major construction materials of the MFC reactor), respectively. When NaCl concentration in anode phosphate buffer increased from 5 to 50 mM, power density increased from 6 to $20\;mW/m^2$. However, with increasing sodium phosphate buffer concentration from 5 to 50 mM, power density significantly decreased from 18 to $1\;mW/m^2$. Twenty-four mM sodium bicarbonate did not affect electricity generation as well as pH under 50 mM phosphate buffer condition. Optimized anode chamber of MFC using G. sulfurreducens generated relatively high power density ($20\;mW/m^2$) with the maximum coulombic efficiency (41.3%).

A Study to Guarantee Minimum Bandwidth to TCP Traffic over ATM-GFR Service (ATM-GFR 서비스에서 TCP 트래픽의 최소 대역폭 보장에 관한 연구)

  • 박인용
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.27 no.4C
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    • pp.308-315
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    • 2002
  • Guaranteed frame rate (GFR) service has been defied to provide minimum cell rate (MCR) guarantees for virtual connections (VCs) carrying Internet traffic in ATM networks and allow them to fairly share residual bandwidth. The simplest switch implementation mechanism to support the GFR service in ATM networks consists of the frame-based generic cell rate algorithm (F-GCRA) frame classifier and the early packet discard (EPD)-like buffer acceptance algorithm in a single FIFO buffer. This mechanism is simple, but has foiled to guarantee the same bandwidth as an MCR to a VC that has reserved a relatively large MCR. This paper applies the packet spacing scheme to TCP traffic to alleviate its burstness, so as to guarantee a larger MCR to a VC. In addition, the random early detection (RED) scheme is added to the buffer acceptance algorithm in order to improve fairness in use of residual bandwidth. Simulation results show that the applied two schemes improve a quality of service (QoS) in the GFR service for the TCP traffic.

Growth of Pseudomonas aeruginosa in Cosmetics(Emulsion-type) and the Effect of Antiseptics (화장품(에멀젼형)에서 Pseudomonas aeruginosa의 성장과 방부살균제효과)

  • 류미숙;김장규김남기
    • KSBB Journal
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    • v.7 no.2
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    • pp.118-125
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    • 1992
  • Most of cosmetics are emulsion-type products which contain the sources of nutrition, i.e., vegetable oil, mineral oil and carbohyrate etc.. These additives are usually very susceptible to the contamination by microorganisms. The purpose of this study is to obtain the data necessary not only to prevent dermalopathia occurred by microbials but also to maintain the quality. In this experiment we observed the growth of P.aeruginosa in the cosmetics with or without antiseptics so as to prevent contamination. During the contamination period, the phase became unstable and creaming phenomina was happened together with some discoloration and bad smell. The pH of cosmetic was decreased from 7.6 to 6.0 and the concentration was increased from 1.443 to 1.453 in terms of refractive index during 40 days incubation. By adding antiseptics to the cosmetics, the number of P. aeruginosa from the challenge test method were decreased from $10^8$ cell/ml to $5{\times}10^3$ cell/ml. For the antibacterial effect against P. aeruginosa, p-hydroxy benzoic acid propyl ester in phosphoric acid buffer solution showed the best result.

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