• Title/Summary/Keyword: diffusion pattern

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Characterization of directional coupling optical switch at High frequency (고주파에서 방향성결합형 광 스위치의 출력 특성변화)

  • 강기성;소대화
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1996.05a
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    • pp.264-268
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    • 1996
  • Directional coupling optical switch which on the LiNbO$_3$ substrate is fabricated by using proton exchange method and self-aligned method. Proton exchange of proton diffusion method was applied to pattern a waveguide on LiNbO$_3$ substrate. The annealing at 400[$^{\circ}C$] was caroled out to control waveguide width and depth. The process of proton exchange was done at 150[$^{\circ}C$] for 120[min], 200[$^{\circ}C$] for 60[min] and annealing process was done at 400[$^{\circ}C$] for 90[min], 400[$^{\circ}C$] for 60[min]. The high speed directional coupling optical switch has very good figures of merits:the measured high frequency power were achieved.

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Disturbance in the Daytime Midlatitude Upper F Region Associated with a Medium Scale Electrodynamic Vortex Motion of Plasma

  • Hegai, Valery V.;Kim, Vitaly P.
    • Journal of Astronomy and Space Sciences
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    • v.33 no.3
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    • pp.207-210
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    • 2016
  • Under the assumption of the presence of a medium-scale E × B drift vortex of plasma in the daytime midlatitude F region, and using a simplified ionospheric model, we demonstrate that the E × B drift produces noticeable perturbations in the horizontal distribution of the plasma density in the upper F region. The pattern of ion density perturbations shows two separate medium scale domains of enhanced and reduced ion density with respect to the background. The E × B drift does not produce multiple small-scale ion density irregularities through plasma mixing because of the suppression effect of the field-aligned ambipolar plasma diffusion.

Antibiotics susceptibility of Proteus mirabilis isolated from domestic animals in Chonbuk province (동물에서 분리한 Proteus mirabilis의 항생제 감수성에 관한 연구)

  • Cho, Jeong-Gon
    • Korean Journal of Veterinary Service
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    • v.26 no.2
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    • pp.95-103
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    • 2003
  • Isolates of 70 Proteus mirabilis were tested against 10 different antibiotics by a disc diffusion method as recommended by National Committee for Clinical Laboratory Standards (NCCLS). The isolates were resistant in order of tetracycline(100.0%), enrofloxacin(95.7%), ampicillin(74.3%), choramphenicol(62.9%), cephalothin(58.6%), streptomycin(50%), kanamycin(47.2%), neomycin(35.8%), gentamicin(15.7%), and amikacin(2.9%). In the antibiotic resistant patterns, 37 kinds of multiple resistance patterns of P mirabilis isolates were detected. The highest resistant pattern was ampicillin-cephalothin-chloramphenicol-enrofloxacin-tetracycline(11.6%).

Circulation Experiment of the Chinhae Bay using a Three-Dimensional Diagnostic Numercal Model (3차원 진단모델을 이용한 진해만의 수치유동실험)

  • 배삼완
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.33 no.4
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    • pp.360-369
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    • 1997
  • We calculated the residual current forced by buoyancy, wind stress, and tidal stress in the Chinhae Bay using a three-dimensional diagnostic model. The calculated current was also compared with the observation. The flow directs outward from the central area of the Bay in the upper layer, and also forms eddy-shape stucture in the upper and middle layers. The flow of bottom layer shows an opposite pattern compared to those of top and middle layers. The maximum speed was 6.05 em/see (September) and 3.49 cm/sec (November) in the upper layer, and 4.39 cm/sec on both month in the middle layer. The Kinetic energy of November (8.39xlO' W) was larger than that of September (1.24xlO 'W), mainly resulting from larger buoyancy effect in September. In spite of the roughness of the grid size(1 km) and wind date, the calculated flow shows eorrelation(r=0.71) with the observation. We expect that the correlation be increased by increased by adopting the fine grid and the variable coefficients of diffusion and viscosity.

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Assessment of clothing ventilation by a trace gas method (Trace gas법에 의한 의복의 환기 양상의 평가)

  • 추미선
    • Journal of the Korean Society of Clothing and Textiles
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    • v.21 no.8
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    • pp.1387-1395
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    • 1997
  • Effects of the ambient air temperature and the opening position on the pattern of the clothing ventilation of a thermal manikin wearing an impermeable blouse were investigated by the trace gas method. Under an isothermal condition, the ventilation was governed by diffusion, and the ventilation rate through the wrist-openings was greatly affected by the distance from the openings. Under non-isothermal conditions, however, the ventilation was accelerated by the convection driven by the temperature gradient between the clothing microclimate and the surrounding air; the greater the temperature gradient, the greater the ventilation. Even though it was certainly affected by the ambient air temperature, the ventilation rate was more significantly influenced by the position of openings. The ventilation patterns at the arm and the body were distinctive.

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The Carrier Diffusion Modeling of CSP-DH Semiconductor Laser Structures (CSP-DH 구조 반도체 레이저의 캐리어 확산 방정식을 위한 모델링)

  • Lee, S.T.;Jeon, H.S.;Lee, C.Y.;Um, K.Y.;Yoon, J.W.;Yoon, S.B.;Oh, H.S.
    • Proceedings of the KIEE Conference
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    • 1988.07a
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    • pp.469-471
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    • 1988
  • The basic modeling is analyzed on the optoelectronic properties of CSP-DH laser structure using self-consistent calculation of optical field and the electron-hole distribution in the active region. Laser properties is modelled include gain profile, threshold, near field and far field pattern. This new characterization is allowed for consideration such as carrier spatial hole burning due to strong optical fields which stimulate recombination.

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From Emerging to Submerging Economies: New Policy Challenges for Research and Innovation

  • Soete, Luc
    • STI Policy Review
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    • v.4 no.1
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    • pp.1-13
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    • 2013
  • The Schumpeterian process of "creative destruction", associated with the emergence and diffusion of new radical, so-called "general purpose" technologies, has throughout history impacted wealth and income, jobs creation, jobs displacement, and the emergence and submergence of new hotspots of innovation. Emerging countries have benefited most from such a renewing of those societies' dynamics, leading them to higher levels of economic development and welfare. Doing so they have shown a remarkable capacity in moving upstream in the value chain, from outsourcing of manufacturing activities to autonomous process technology development, product development, design, and applied research. At the same time however, such Schumpeterian processes have now and then turned into exactly opposite processes of "destructive creation." Such processes seem to have become common among what could be called "submerging" economies: innovation only benefitting a few at the expense of many with as a result an opposite pattern of a long term reduction in overall welfare, productivity, and employment growth.

Identification and Antibiotics Susceptibility of Enterobacteriaceae Isolated from Feces of Wild Mammals in Choniu Zoo (동물원의 야생포유류 분변에서 분리한 장내세균의 동정과 약제감수성)

  • 송회종;윤창용;김성훈;채효석;도흥기;허부흥
    • Journal of Veterinary Clinics
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    • v.14 no.2
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    • pp.263-267
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    • 1997
  • Eighty-seven strains of Enterobacteriaceae isolated from feces of wild mammals in Choniu zoo were tested for their biochemical reaction and susceptibility to 19 antibiotics or chemicals by using disc diffusion test and/or Microscan Walkway 40/96. Out of 87 isolates, Enterobacteriaceae (44), Hafinia alvei (9), Citrobacterfreundi (5) and Proteus vulgaris (5) were frequently detected. The detective frequency of Enterobacteriaceae in animals classified by their eating pattern was higher in carnivorous and omnivorous than in herbivorous animal. In antibiotic susceptibility tests most of isolates were susceptible to cefazolinl ceftazidime, aztreoname, trimethoprin/sulfamethoxazole, gentamicin, ciprofloxacin, cofuroximel ceftriaxone, cefotaxime and eftizoximel and moderately susceptible to cephalotin and ticarcillin but resistant to ticarcillin/K and amikacin.

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A study on the LCD backlight unit using polymer (LCD backlight unit의 고분자 산란형 도광판에 관한 연구)

  • 정일용;박우상
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1999.11a
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    • pp.578-581
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    • 1999
  • Dot pattern print methods composed of a diffusion film and two prism sheets, have been generally used for backlighting systems of LCDs. However, this methods require complex structures and show high power consumption and optical loss. To improve these disadvantages of conventional backlight units, light guides using highly scattering optical transmissions (HSOT) polymer as scatters, have been introduced. In this study we analyzed multiple scattering effect in light guide by means of Monte carlo simulation based on Mie scattering theory and ray tracing method. As a result it was revealed that scattering intensity depends on the size of scatters. On the other hands, it was shown that scattering efficiency depends on the wavelength of fluorescent lamp as well as the size of scatters.

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Controlled Release of Drugs from Reservoir Type Devices Coated with Porous Polyurethane Membranes (다공성 폴리우레탄으로 피막된 Reservoir형 약물 조절 방출 시스템)

  • Kim, Kil-Soo;Lee, Seung-Jin
    • Journal of Pharmaceutical Investigation
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    • v.23 no.4
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    • pp.207-211
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    • 1993
  • Reservoir type devices were designed for long-term implantable drug delivery system. The reservoir type device was prepared with the polymethacrylic acid gel coated with polyurethane membrane. Release controlling agent (RCA) were employed to control drug release from devices via generation of micropores in the membranes. The polyurethane membrane functioned as a rate controlling barrier. The drug release pattern of hydrogel demonstrated zero order kinetics. The release rate of drugs could be regulated by varying hydrophobicity/hydrophilicity and content of the RCA, as well as the thickness of the polyurethane membrane. The release of drugs from this system was governed by pore mechanism via simple diffusion and osmotic pressure.

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