• Title/Summary/Keyword: Diffusion Distance

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A Study on the Measurements of Optical Parameters in Photosensitizer by Light Scattering (농도가 진한 매질에서 광증감제에 의한 광학적 파라미터측정에 관한 연구)

  • Kim, Ki-Jun;Lee, Jou-Joub
    • Journal of the Korean Applied Science and Technology
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    • v.28 no.1
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    • pp.102-108
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    • 2011
  • The study of wave propagation and scattering in biological media has become increasingly important in recent years. The propagation of light within tissues is an important problem that confronts the dosimetry of therapeutic laser delivery and the development of diagnostic spectroscopy. In the clinical application of photodynamic therapy(PDT) and in photobiology, the photon deposition within a tissue determines the spatial distribution of photochemical reactions. Scattered light is measured as a function of the distance (r) between the axis of the incident beam and the detection spot. Consequently, knowledge of the photosensitizer(Chlorophyll-a) function that characterizes a phantom is measured. To obtain the results of scattering coefficients(${\mu}s$) of a turbid material from diffusion described by experimental approach. It was measured the energy fluency of photon radiation at the position of penetration depth. From fluorescence experimental method obtained the analytical expression for the scattered light as the values of $(I/I_o)_{wavelength}$ vs the distance between the center of the incident beam and optical fiber in terms of the condition of "in situ spectroscopy(optically thick)" and real time by fluorometric measurements. The result was compromised with transport of intensities though a random distribution of scatters.

A Study on The Photoelectric Characteristics of Dye-sensitized Solar Cell according to Expanding Photo-electrode (염료감응형 태양전지의 광전극 확장에 따른 광전특성 연구)

  • Seo, Hyun-Woong;Kim, Mi-Jeong;Park, Je-Wook;Kim, Ho-Sung;Kim, Hee-Je
    • 한국신재생에너지학회:학술대회논문집
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    • 2007.06a
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    • pp.305-308
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    • 2007
  • The field of dye-sensitized solar cell (DSC) is being researched actively at present. Because DSC has several advantages to pass the limits of Si solar cells such as a low manufacturing expense, a simple manufacturing process and its transparency. A lot of researches are underway about materials and processes in the field of dye-sensitized solar cell but its structure has been fixed up as the sandwich structure that both edges are used as positive and negative terminals. But the structure as of present is a factor of decreasing efficiency because the more electrons are recombined the further distance from terminal, considering about the characteristic of dye-sensitized solar cell that electrons generated inside cell are moved by diffusion. In this study, we made experiment on expanding the terminal to shorten internal moving distance of electron and compared the results according to the variation of active area to find out the effect of this trial. As a result, we achieved about 15.5% improvement of maximum power and 0.5% improvement of efficiency from terminal-expanded dye-sensitized solar cell of $2cm^{2}$ active area and concluded that the increasing rate of efficiency is raised as the active area becomes wider.

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A Study on the Optical Influence by Photosensitizer in Vitro (In Vitro에서 광증감제에 의한 광학적 영향에 관한 연구)

  • Kim, Ki-Jun;Sung, Ki-Chun
    • Journal of the Korean Applied Science and Technology
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    • v.22 no.2
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    • pp.182-190
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    • 2005
  • The propagation of light radiation within tissues is an important problem that confronts the dosimetry of therapeutic laser delivery and the development of diagnostic spectroscopy. In the clinical application of photodynamic therapy(PDT) and in photobiology, the photon deposition within a tissue determines the spatial distribution of photochemical reactions. Scattered light is measured as a function of the distance (r) between the axis of the incident beam and the detection spot. Consequently, knowledge of the photosensitizer(Chlorophyll-a) function that characterizes a phantom is important. To obtain the results of scattering coefficients(${\mu}s$) of a turbid material from diffusion described by experimental approach. It was measured the energy fluency of photon radiation at the position of penetration depth. From fluorescence experimental method obtained the analytical expression for the scattered light as the values of $(I\;/I_o)_{wavelength}$ vs the distance between the center of the incident beam and optical fiber in terms of the condition of "in situ spectroscopy(optically thick)" and real time by fluorometric measurements.

A Dynamic Programming Neural Network to find the Safety Distance of Industrial Field (산업 현장의 안전거리 계측을 위한 동적 계획 신경회로망)

  • Kim, Jong-Man;Kim, Won-Sub;Kim, Yeong-Min;Hwang, Jong-Sun;Park, Hyun-Chul
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.09a
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    • pp.23-27
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    • 2001
  • Making the safety situation from the various work system is very important in the industrial fields. The proposed neural network technique is the real titre computation method based theory of inter-node diffusion for searching the safety distances from the sudden appearance-objests during the work driving. The main steps of the distance computation using the theory of stereo vision like the eyes of man is following steps. One is the processing for finding the corresponding points of stereo images and the other is the interpolation processing of full image data from nonlinear image data of obejects. All of them request much memory space and titre. Therefore the most reliable neural-network algorithm is drived for real time recognition of obejects, which is composed of a dynamic programming algorithm based on sequence matching techniques. And the real time reconstruction of nonlinear image information is processed through several simulations. I-D LIPN hardware has been composed, and the real time reconstruction is verified through the various experiments.

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Computer Simulation of Mo/Si Thin Film Characteristics for EUVL Technology (EUVL 응용을 위한 Mo/Si 박막 특성 전산모사)

  • Lee, Young-Tae;Chung, Yong-Chae
    • Journal of the Korean Ceramic Society
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    • v.39 no.8
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    • pp.807-811
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    • 2002
  • In this work, we investigated the deposition behavior of Mo/Si multilayer thin film structures simulated by a PVD process simulator based on Monte Carlo method to assist the optimized fabrication of the high quality mask in EUVL(Extreme Ultra-Violet Lithography) process. The shape of simulated thin film structures turned out to be largely dependent on the gas pressure(1∼30 mTorr), the target-substrate distance(1∼30 cm) and the diffusion length(1∼10 nm). From the simulation studies, it was predicted that relatively uniform thin film structures can be fabricated by decreasing gas pressure and increasing the target-substrate distance.

THE TRANSFER OF CHLORIDE ION ACROSS ANION EXCHANGE MEMBRANE

  • Yu, Zemu;Wang, Hanming;Wang, Erkang
    • Analytical Science and Technology
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    • v.8 no.4
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    • pp.597-601
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    • 1995
  • The transfer of chloride ion across an anion exchange membrane (AEM) was investigated by cyclic voltammetry (CV) and electrochemical impedance spectra. In CV experiment, when the size of the hole in membrane was much smaller than the distance between membrane holes, the Cl anion transfer showed steady state voltammetric behavior. Each hole in membrane can be regarded as a microelectrode and the membrane was equivalent to a microelectrode array in this condition. When the hole in membrane was large or the distance between membrane holes was small, the CV curve of the Cl anion transfer across membrane showed peak shape, which attributed to linear diffusion. In ac impedance measurement, the impedance spectrum of the membrane system was composed of two semicircles at low de bias, corresponding to the bulk characteristics of the membrane and the kinetic process of ion transfer, respectively. The bulk membrane resistance increases with increasing dc bias and only one semicircle was observed at higher dc bias. The parameters related to kinetic and membrane properties were discussed.

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Study on the Design of a High Condensing LED Searchlight

  • Kim, Tae-Seong;Kim, Jin-Wook;Kim, Sun-Jae;Kil, Gyung-Suk
    • Transactions on Electrical and Electronic Materials
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    • v.16 no.4
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    • pp.201-205
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    • 2015
  • This paper dealt with the condensing technology of an LED light source that uses a parabolic reflector to replace a searchlight equipped with a xenon lamp. A ray-tracing simulation was conducted to analyze the influence of the diameter of the reflector and the size of the light source on light condensing. The combination of a parabolic reflector with a diameter of 620 mm and a focal distance of 220 mm, and a 9 mm multi-chip package (MCP) with a luminous flux of 7,000 lm showed the narrowest beam angle. The luminous intensity at the center was measured at 7.7×106 cd. The distance between the light source and the point where the illuminance was 1 lx was calculated to be 2.8 km. The power consumption of the system was 95 W, which is only 9.5% of that of the 1 kW xenon searchlight, and the beam angle was 1.03°. In a site experiment, it was confirmed that the light ray reflected from the LED searchlight proceeds forward without any diffusion because of the narrow beam angle.

Factors Affecting Efficiency of Electronic Customs and Firm Performance in Vietnam

  • NGUYEN, Hang Thanh;GRANT, David Bruce;BOVIS, Christopher;NGUYEN, Thuy Thi Le;MAC, Yen Thi Hai
    • The Journal of Asian Finance, Economics and Business
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    • v.8 no.2
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    • pp.151-164
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    • 2021
  • The paper identifies the enablers (drivers) and inhibitors (barriers) influencing e-customs implementation in Vietnam (known as a developing country with a lower technological environment) along with determining the impact of e-customs on firm performance. The survey was conducted with the representatives (managers) of firms in five cities and provinces dominating Vietnam's international trade. The data was analyzed using structural equation modeling (SEM). The findings show two significant drivers (enablers) - relative advantages and national culture, while compatibility and ease of use are the barriers. Previous studies showed that cultural dimensions related to 'uncertainty acceptance' and 'individualism' encourage innovation; however, this paper demonstrates that 'uncertainty avoidance' and 'collectivism' promote e-customs deployment in Vietnam. Previously, Vietnamese culture was known for scoring high on cultural dimensions related to 'power distance' and 'short-term orientation'. However, today, as an emerging country, Vietnamese has switched to 'low distance' and 'long-term orientation', especially in terms of e-customs innovation. Additionally, the paper also emphasized that e-customs implementation had a positive influence on firm performance in Vietnam. Based on the results of the paper, policy-makers can devise essential solutions to enhance e-customs implementation as well as managers of firms can set-up strategies to adapt to the modernized environment.

Spectacle and "Keeping Distance from Spectacle" in Fashion (패션에 나타난 '스펙터클' 및 '스펙터클과 거리두기')

  • Park, Ju-Hee
    • Journal of the Korean Society of Costume
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    • v.59 no.5
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    • pp.83-100
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    • 2009
  • In the 'Society of the Spectacle', Guy Debord argued that modern life was dominated by the commodity form and the false desires it engendered. He predicted in 1967 that culture would become the driving force in the development of the economy by the end of the century, He was sure when culture becomes nothing more than a commodity, it must also become the star commodity of the spectacular society. Fashion, the starriest of star commodities with its seductive fantasy approaches to the viewers occluding the commercial reality. From this point, the spectacular property of the modern fashion can be found. This study starts on the notion that the modern fashion is on the center of capitalist consumer culture and is constructed by spectacle. On this premise, the purpose of this study is analysing the attribute of 'spectacle' and 'keeping distance £Tom spectacle' in modern fashion expressed in fashion show, fashion media and fashion store. The fashion houses in the 1990s that recognised the commercial value of shock and spectacle were eager to employ young spectacularly visible named designers. They generated the publicity necessary for sales of perfume, cosmetics, bags and diffusion range of clothes through the visible fashion show and fashion media. In the fashion show and fashion media, fashion goods as the commodity both flaunts and disguises its commercial nature in spectacle. The spectacle on the fashion store is the process turning the commodity into image to arouse viewer's higher interest. In the fashion store, the appearance of the commodity such as space, display, package is considered more importantly than its 'utility value'. Meanwhile, the study also covered the innovative trial to evade the ubiquitous 'spectacle' in fashion area.

Effect of Thermal Diffusion on Autumn Traffic in Street Space (가을철 교통조건에 따른 가로공간 열확산 분포 영향)

  • Yoon, Yong-Han;Kim, Jeong-Ho
    • Journal of Environmental Science International
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    • v.26 no.4
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    • pp.467-481
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    • 2017
  • This study sought to determine the changes in weather conditions in urban streets, along with conditions of traffic and roads in urban areas. The variations in weather conditions depending on traffic differed according to distance. First, the temperature difference measured by traffic results is as follows: T1 point $1.03^{\circ}C$, T2 point $1.04^{\circ}C$, T3 point $0.9^{\circ}C$, T4 point $1.01^{\circ}C$, and T5 point $0.31^{\circ}C$. The average difference between the measured temperatures by the point of measurement was $0.86^{\circ}C$. The changes in wind velocity according to traffic volume results of the measurements is T1 point 1.32 m/s, T2 point 0.80 m/s, T3 point 0.29 m/s, T4 point 0.04 m/s, and T5 point 0.09 m/s. The difference between the average wind speeds was 0.51 m/s and traffic jams caused substantial differences in distance. The relative humidity tended to be inversely proportional to temperature. The measurements results ares T1 point 2.29%, T2 point 2.67%, T3 point 2.47%, T4 point 2.16%, and T5 point 0.91% The difference between the average relative humidity was 7.3%. In case of independent sampling T test according to traffic volume, changes in wind velocity and temperature were directly proportional to the level of statistical significance(p<0.01). On the other hand, relative humidity tended to be inversely proportional; however, there was no statistical significance.