• 제목/요약/키워드: Mixed mode

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Growth and photocurrent study on the splitting of the valence band for $CuInSe_2$ single crystal thin film by hot wall epitaxy (Hot Wall Epitaxy(HWE)범에 의한 $CuInSe_2$ 단결정 박막 성장과 가전자대 갈라짐에 대한 광전류 연구)

  • Hong Myungseak;Hong Kwangjoon
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.14 no.6
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    • pp.244-252
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    • 2004
  • A stoichiometric mixture of evaporating materials for $CuInSe_2$ single crystal thin films was prepared from horizontal electric furnace. To obtain the single crystal thin films, $_CuInSe2$ mixed crystal was deposited on thoroughly etched semi-insulating GaAs(100) substrate by the hot wall epitaxy (HWE) system. The source and substrate temperatures were $620^{\circ}C$ and $410^{\circ}C$, respectively. The crystalline structure of the single crystal thin films was investigated by the photoluminescence and double crystal X-ray diffraction (DCXD). The carrier density and mobility of $CuInSe_2$ single crystal thin films measured with Hall effect by van der Pauw method are $9.62\times10^{16}/\textrm{cm}^3$, 296 $\textrm{cm}^2$/Vㆍs at 293 K, respectively. The temperature dependence of the energy band gap of the $CuInSe_2$ obtained from the absorption spectra was well described by the Varshni's relation, $E_g$(T) = 1.1851 eV -($8.99\times10^{-4} eV/K)T^2$(T + 153 K). The crystal field and the spin-orbit splitting energies for the valence band of the CuInSe$_2$ have been estimated to be 0.0087 eV and 0.2329 eV at 10 K, respectively, by means of the photocurrent spectra and the Hopfield quasicubic model. These results indicate that the splitting of the Δso definitely exists in the $\Gamma$6 states of the valence band of the $CuInSe_2$. The three photocurrent peaks observed at 10 K are ascribed to the $A_1-, B_1$-와 $C_1$-exciton peaks for n = 1.

Performance Evaluation of Workstation System within ATM Integrated Service Switching System using Mean Value Analysis Algorithm (MVA 알고리즘을 이용한 ATM 기반 통합 서비스 교환기 내 워크스테이션의 성능 평가)

  • Jang, Seung-Ju;Kim, Gil-Yong;Lee, Jae-Hum;Park, Ho-Jin
    • Journal of KIISE:Computing Practices and Letters
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    • v.6 no.4
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    • pp.421-429
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    • 2000
  • In present, ATM integrated switching system has been developed to a mixed modules that complexed switching system including maintenance, operation based on B-ISDN/LAN service and plug-in module, , which runs on workstation computer system. Meanwhile, workstation has HMI operation system feature including file system management, time management, graphic processing, TMN agent function. The workstation has communicated with between ATM switching module and clients. This computer system architecture has much burden messages communication among processes or processor. These messages communication consume system resources which are socket, message queue, IO device files, regular files, and so on. Therefore, in this paper we proposed new performance modeling with this system architecture. We will analyze the system bottleneck and improve system performance. In addition, in the future, the system has many additional features should be migrated to workstation system, we need previously to evaluate system bottleneck and redesign it. In performance model, we use queueing network model and the simulation package is used PDQ and C-program.

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Evaluation of Flexural Performance of Eco-Friendly Alkali-Activated Slag Fiber Reinforced Concrete Beams Using Sodium Activator (나트륨계 알칼리 활성화제를 사용한 친환경 알카리활성 슬래그 섬유보강콘크리트 보의 휨성능 평가)

  • Ha, Gee-Joo;Yi, Dong-Ryul;Ha, Jae-Hoon
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.19 no.2
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    • pp.170-178
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    • 2015
  • In this study, it was developed eco-friendly alkali-activated slag fiber reinforced concrete using ground granulated blast furnace slag, alkali activator (water glass, sodium hydroxides), and steel fiber. Eight reinforced concrete beam using alkali-activated slag concrete were constructed and tested under monotonic loading. The major variables were mixture ratio of alkali activator, mixed/without of steel fiber. Experimental programs were carried out to improve and evaluate the flexural performance of such test specimens, such as the load-displacement, the failure mode, the maximum load carrying capacity, and ductility capacity. All the specimens were modeled in scale-down size. The reinforced concrete beams using the eco-friendly alkali-activated slag fiber reinforced concrete was failed by the flexure or flexure-shear in general. In addition, the maximum strength increased with the adding the mol of sodium hydroxide, and the specimen reinforced the steel fiber showed the value of maximum strength which is increased by 15.8% through 25.9%. It is thought that eco-friendly alkali-activated slag fiber reinforced concrete can be used with construction material and product to replace normal concrete. If there is applied to structures such as precast concrete member and production of 2nd concrete product, it could be improved the productivity and reduction of construction duration etc.

Sedimentologic Characteristics of the Erosional Coast in the Tide-dominated Environment (대조차환경 침식연안의 퇴적학적 특성)

  • Kum, Byung-Chul;Oh, Jae-Kyung
    • Journal of the Korean earth science society
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    • v.23 no.7
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    • pp.565-574
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    • 2002
  • Based on previous investigations of aerial photographs and topographical surveys, this study focuses on the sedimentologic features of the Daebudo area including sedimentation processes, sedimentary facies and hydrologic conditions of the erosional coast. A total of 137 surface sediments and one core (by hand auger) sediment were obtained to interpret the depositional environment of the erosional coast in the macro-tidal coast. Surface sediments are distributed from sandy gravel (sG) to silt (Z). Textural parameters are characterized not only by coarse, poorly sorted, positive skewed and multi-modal distribution in the supra-tidal flat, but also finer, relatively well-sorted, symmetric distribution in the intertidal flat. According to the C/M diagram, sediment transport modes of study area are characterized by the mixed mode of suspension and bedload in the upper-, middle-tidal flat and by uniform suspension in the lower-tidal flat due to tidal effect. Vertical sediment distribution of the core, collected near shoreline, shows coarsening-upward, poorly sorted pattern by the input of detritus resulting from coastal erosion. Considering the sedimentological features of the study area, it appears to be composed of a coastal zone changed by not only artificial reclamation, but also by natural processes such as strong wave action due to typhoons and storms during high water level and long/short-term sea level rising. As a result, tide-dominated erosional coasts show that the shore is affected by local, temporal and hydrological conditions near high tide level and that the intertidal flat is represented by a general tide-dominated sedimentary environment.

Progressive Failure Analysis of Adhesive Joints of Filament-Wound Composite Pressure Vessel (필라멘트 와인딩 복합재 압력용기의 접착 체결부에 대한 점진적 파손 해석)

  • Kim, Junhwan;Shin, Kwangbok;Hwang, Taekyung
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.38 no.11
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    • pp.1265-1272
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    • 2014
  • This study performed the progressive failure analysis of adhesive joints of a composite pressure vessel with a separated dome by using a cohesive zone model. In order to determine the input parameters of a cohesive element for numerical analysis, the interlaminar fracture toughness values in modes I and II and in the mixed mode for the adhesive joints of the composite pressure vessel were obtained by a material test. All specimens were manufactured by the filament winding method. A mechanical test was performed on adhesively bonded double-lap joints to determine the shear strength of the adhesive joints and verify the reliability of the cohesive zone model for progressive failure analysis. The test results showed that the shear strength of the adhesive joints was 32MPa; the experiment and analysis results had an error of about 4.4%, indicating their relatively good agreement. The progressive failure analysis of a composite pressure vessel with an adhesively bonded dome performed using the cohesive zone model showed that only 5.8% of the total adhesive length was debonded and this debonded length did not affect the structural integrity of the vessel.

A Simultaneous Improvement in $CO_2$ Flux and $CO_2/N_2$ Separation Factor of Sodium-type FAU Zeolite Membranes through 13X Zeolite Beads Embedding (13X 제올라이트 흡착제 충진에 의한 Na형 Faujasite 제올라이트 분리막의 $CO_2/N_2$ 선택도 및 $CO_2$ 투과도 동시 증가 현상)

  • Cho, Churl-Hee;Yeo, Jeong-Gu;Ahn, Young-Soo;Han, Moon-Hee;Moon, Jong-Ho;Lee, Chang-Ha
    • Membrane Journal
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    • v.17 no.3
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    • pp.269-275
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    • 2007
  • Sodium type faujasite(FAU) zeolite membranes with a thickness of 5${\mu}m$ and a Si/Al molar ratio of 1.5 were prepared by the secondary growth process. The $CO_2/N_2$ separation in the vacuum mode was investigated at $30^{\circ}C$ for an equimolar $CO_2-N_2$ mixed gas before and after embedding 13X zeolite beads in the permeate side. The embedded 13X zeolite beads improved both $CO_2$ permeance and $CO_2/N_2$ separation factor, simultaneously. The phenomenon was explained by an increment in the $CO_2$ desorption rate at the FAU zeolite/$\alpha-Al_2O_3$ phase boundary due to an enhanced $CO_2$ escaping through the pore channels of the $\alpha-Al_2O_3$ support layer. In the present paper, it will be emphasized that a hybridization of a membrane with an adsorbent can provide a key to break through the trade-off between permeance and separation factor, generally shown in a membrane separation.

Storytelling and Digital Discourse in Advertising : focusing on Corporate Ads of Mobile Telecommunication Companies (광고 스토리텔링과 디지털 담론 : 이동통신 3사의 기업PR광고를 중심으로)

  • Chung, Sung Hye
    • The Journal of the Korea Contents Association
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    • v.13 no.12
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    • pp.149-167
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    • 2013
  • This study focuses how storytelling in advertising has introduced and determinated mobile telecommunication technology as a digital technology in the process of its rapid acceptance into our society. The objective of the study is to confirm the role of advertising in introducing technology into a society and the relation between advertising and technology by chasing the digital discourse produced by advertising while digital technology permeates through our society. This study uses content analysis for basic research and discourse analysis for exploring the change of digital discourse in the corporate ads of mobile telecommunication companies since 15 years. As a result, 1) 'digital' and 'analogue' discourses were found to be competing and contesting with each other across the years. Digital discourse mainly connected to a new mode of thinking and lifestyle appeared predominant in the early period, but eventually gave way to its alternative, analogue dialogue. The analogue discourse was brought with such values as humanity, slowness and happiness, which has been by and large undermined by the new, fancy digital technologies and their world, 2) whereas some mixed forms of these two discourses were also found. 3) In the meantime, digital-based mobile communication technologies were identified with people who think outside of box and have an innovative attitude toward their life in the ads. Through this signification process, the ads contribute to permeation of mobile communication technology into our daily life.

A Study on the modification of fantastique mode in You, Sijin's comic strips (유시진 만화의 환상성 변이 연구)

  • Chang, Eun-Young;Kim, Mi-Rim
    • Cartoon and Animation Studies
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    • s.24
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    • pp.25-48
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    • 2011
  • The fantastic has had various semantic layers between 'the Marvelous' and 'the Uncanny', these has been assorted by historical and synchronic aspects. The Marvelous has been harmonious and abundant world of fantasy which includes metaphysical system and all tradition of magical fence. The Uncanny has been a subversive fantasy world which shows absurdity and negative truths of this very world by modern consciousness. In comics, because of the media features, it is more useful the fantastic than the realistic. However, the relationship about comic and fantasy has rarely discussed in detail. So we has wanted to understand the specificities of affiliation with the Marvelous and with the Uncanny. Then it has been necessary to check the works of You, Sijin the comic book writer, for we ought to know how the affiliations with fantasy could influence each works' styles, and themes. You, Sijin started her works with sensibility of uncanny, but she tried to develop the theme "uptight" and devoted to establish "the Secondary World" stably. However, at Shin Meoung Ki(神明記) fantasy world overwhelmed the theme. After that, in The Closer and On, she crashed down the uptight feeing and made new self-consciousness by mixed fantasy style. The Closer and On has been the turning point of writer You, Sijin. Since than her works has showed a propensity for the Uncanny.

Antilisterial Activity of Bacteriocin Produced by Enterococcus faecium MJ5-14 (Enterococcus faecium MJ5-14가 생산한 박테리오신의 항리스테리아 활성)

  • Lim, Sung-Mee;Lee, Jong-Gab;Park, Mi-Yeon;Chang, Dong-Suck
    • Journal of Food Hygiene and Safety
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    • v.19 no.3
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    • pp.151-160
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    • 2004
  • Enterococcus faecium MJ5-14 isolated from Meju produced a bacteriocin, which was antagonistic towards Listeria monocytogenes. Bacteriocin activity reached a maximum (640 BU/mL) after incubation for 12 hr, the early stationary phase, then dropped after the late stationary phase. Bacterocin of E. faecium MJ5-14 was extremely active against a wide range of Listeria species, including L. monocytogenes with sensitives up to about 640 BU/mL. In case of mixed culture with 105 CFU/mL L. monocytogenes and 105 CFU/mL E. faecium MJ5-14, the inhibitory effect against L. monocytogenes at $37^{\circ}C$ was higher than at $25^{\circ}C$. The mode of action was identified as bactericidal, because the addition of 100 BU/mL this bacteriocin to cell suspensions of L. monocytogenes KCTC 3569, led to a marked decrease in the number of viable cells. Further, when held in contact with bacteriocin of E. faecium MJ15-14 for 12 hr, L. monocytogenes KCTC 3569 displayed the disruption of the cells and an important efflux of the intracellular material.

Preparation of PVdF/GO Composite Nanofibrous Flat Membrane and its Permeation Characteristics in Activated Sludge (PVdF/GO 복합 나노섬유 평막의 제조 및 활성슬러지 내 투과특성)

  • Won, In Hye;Jang, Wongi;Chung, Kun Yong;Byun, Hongsik
    • Membrane Journal
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    • v.25 no.1
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    • pp.67-74
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    • 2015
  • In this study the nanofiber was prepared by electrospinning method with polyvinylidene fluoride (PVdF) and a completely dispersed solution of graphene oxide (GO) in the mixed solvent of dimethylformamide (DMF) and acetone. The $0.4{\mu}m$ pore size microfiltration flat membrane was made by increasing layers of the PVdF/GO composite nanofiber. Also, transmembrane pressure (TMP) was measured in order to evaluate fouling of the PVdF/GO composite membrane which was introduced GO reducing biological fouling with the intrinsic antibacterial characteristics. The permeate experiments were carried out simultaneously for the PVdF/GO and commercialized CPVC (chlorinated polyvinyl chloride) flat membranes with $0.01m^2$ effective area in the activated sludge solution of MLSS 4,500 mg/L. TMP of PVdF/GO membrane decreased up to 79% lower than that of CPVC for $10L/m^2{\cdot}h$ permeate flux without air supply. Also, for the case of run/stop operational mode, TMP of PVdF/GO membrane decreased up to 69% lower than that of CPVC for $10L/m^2{\cdot}h$.