• Title/Summary/Keyword: halide

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Thiadiazolopyrimidines as Acid Corrosion Inhibitors for Mild Steel

  • Chitra, S.;Parameswari, K.;Vidhya, M.;Kalishwari, M.;Selvaraj, A.
    • Corrosion Science and Technology
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    • v.10 no.1
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    • pp.13-23
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    • 2011
  • The inhibitive action of thiadiazolopyrimidines on mild steel in 1 M $H_{2}SO_{4}$ has been studied using weight loss, gasometric studies and electrochemical polarization and AC impedance measurements. The effect of temperature on the corrosion behaviour of mild steel in 1 M $H_{2}SO_{4}$ with optimum concentration of inhibitors was studied in the temperature ranging from 313-333K The adsorption of the inhibitor on the surface of mild steel was found to be exothermic, spontaneous and followed the mechanism of physisorption. The adsorption of these compounds on mild steel surface was found to obey Langmuir adsorption isotherm. The protective film formed on the surface of mild steel by the adsorption of inhibitor in 1 M $H_{2}SO_{4}$ solution was confirmed by optical microscopic technique. Synergistic effect of halide ions on mild steel in 1 M $H_{2}SO_{4}$ was studied by weight loss technique.

The Electronic Ballast Design of Acoustic Resonance Free and Transient Over Current Limit for High Power MHL (음향 공명 제거 및 과도 상태 전류를 제한시킨 고출력 메탈 헬라이드 램프용 전자식 안정기 설계)

  • Kim, Ki-Nam;Park, Jong-Yun;Choi, Young-Min
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.5
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    • pp.904-911
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    • 2010
  • This paper presents the design of acoustic resonance free and over current limit during transient state consideration electronic ballast for 1.5kW Metal-Halide Lamp(MHL) that employs frequency modulation (FM) technique. The proposed ballast consists of a Full-Bridge(FB) rectifier, a passive power factor correction (PFC) circuit, a full-bridge inverter, an ignitor using LC resonance and a control circuit for frequency modulation. The frequency modulation technique is the most effective solution to eliminate acoustic resonance among other technique. It spreads power spectrum of lamp to reduce the supplied power spectrum under the energy level of eigen-value frequency. Moreover, the proposed ballast is simple and cost effective above conventional ballast. A new PFC circuit is proposed which combines with LCD type and PCSR filter. A new PFC circuit has higher PF and lower THD than conventional LCD type and secure high reliability. Finally, to protected switching components in transient state, the surge current into ballast is limited by increase the switching frequency. Performance of the proposed ballast was validated through computer simulation using Pspice, experimentation and by applying it to an electronic ballast for a prototype 1.5kW MHL.

Quinine Assay with Home-Built UV-LED Fluorometer: Quantitative Analysis, Photo-Bleaching, Fluorescence Quenching, and Urine Analysis

  • Cheon, Tae-Min;Cheong, Byeong-Seo;Cho, Han-Gook;Kim, Jin-Hee;Kim, Kyoug-Soo
    • Journal of the Korean Chemical Society
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    • v.56 no.5
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    • pp.577-582
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    • 2012
  • Quinine quantitative analysis, photo-bleaching, fluorescence quenching, and urine analysis have been performed by means of a UV-LED fluorometer, which can be easily built and used in a high-school laboratory. The quinine detection range is estimated to be 0.05-80 ppm, enough for many classroom luminescence experiments. The quinine content in commercial tonic water is determined from the calibration curve, and UV photo-bleaching of this anti-malarial drug is demonstrated with clear wavelength dependence. Halide quenching of quinine fluorescence is also observed and the increase in quenching efficiency in the order of $Cl^-$, $Br^-$, and $I^-$ is evident. Urine analyses for the student volunteers have been carried out and the results clearly reveal excretion of the ingested quinine. The student participants are exuberant throughout the course of this study and sense the practices resourceful.

The Magnetic Properties of Amorphous Molding Cores using for Ballast (안정기용 비정질 함침코어의 자기적 특성)

  • Kim, B.G.;Jeong, S.J.;Kim, K.U.;Song, J.S.;Song, Y.S.;Kim, B.G.
    • Proceedings of the KIEE Conference
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    • 1996.07c
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    • pp.1666-1669
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    • 1996
  • To produce low loss amorphous molding cores which are used as choke cores in high efficiency electronic ballast for Metal Halide Lamp, the magnetic properties of amorphous molding cores were investigated with the various fabrication methods. The results are as follows : (1) The total weight of molding core gradually increased as molding time increases. (2) The magnetic properties($B_{10}$, $B_r$, $B_t/B_s$, $H_c$, $W_c$) of molding core drastically deteriorated. This is presumably due to the compressive stress imposed on amorphous core occurred during epoxy curing treatment. (3) Two step annealing process(curing+field annealing) was more or less effective to recover the damaged properties.

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Evaluation of Mechanical Property Variation of Epoxy Based Compliant Polymer Concretes Exposed to UV Light (에폭시 기반 연성 폴리머 콘크리트의 자외선 노출에 의한 기계적 물성평가)

  • Roh, In-Taek;Jung, Kyung-Chae;Chang, Seung-Hwan
    • Composites Research
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    • v.27 no.6
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    • pp.236-241
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    • 2014
  • This paper aims to evaluate material property variation of polymer concretes under ultra-violet exposure condition. The components and mixing ratio of the polymer composite specimens were determined by the previous research results. The equivalent UV exposure time was calculated with the consideration of the power of metal halide lamp and maximum 3 years were selected for the experiments. From the tests, it was found that the generated heat during UV exposure affected much the material properties of polymer concrete by means of post cure. As a result, the compressive strength increased and ductility factor decreased.

Design on illumination of structures for lighthouse in Korea

  • Han, Ju-Seop;Yu, Yong-Su;Kim, Jong-Uk
    • Journal of Advanced Marine Engineering and Technology
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    • v.38 no.10
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    • pp.1327-1332
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    • 2014
  • This paper presents information about the examples of the design on Illumination of Structures(LED Light Pipe for lighthouse) in Korea. We have applied illumination by flood-lighting or facade-lighting in place of the 57 lighthouses (offshore structures) and 4 beacons. The ways of illumination of structures are using direct illumination with LED, halogen lamps and metal halide lamps, and indirect illumination with LED non-neon lamps. The illumination of structures helps a observer to identify the Aids to Navigation and w aterway. The fabricated LED Light Pipe is a transparent acrylic round bar and easy to install. The Light Pipe is arranged in two rows of L ED (78ea). It can be connected in series. It has 4 colours(Red, Green, Yellow, White). We analyzed and the horizontal divergence angle of the LED light pipe is defined as the range with 50% of maximum luminous intensity. Also, we evaluated the conspicuity on the origin al lantern and LED Light pipe for lighthouse. The field experiment was conducted in 'Yeosuguhang lighthouse' in Yeosu-city (Korea). F rom the experimental results, it was confirmed that the fabricated LED Light Pipe is clearly distinguished.

Highly Efficient Flexible Perovskite Solar Cells by Low-temperature ALD Method

  • Kim, Byeong Jo;Kwon, Seung Lee;Jung, Hyun Suk
    • Proceedings of the Korean Vacuum Society Conference
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    • 2014.02a
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    • pp.469.2-469.2
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    • 2014
  • All-solid-state solar cell based on Chloride doped organometallic halide perovskite, (CH3NH3)PbIxCl3-x, has achieved a highly power conversion efficiency (PCE) to over 15% [1] and further improvements are expected up to 20% [2]. In this way, solar cells using novel light absorbing perovskite material are actively being studied as a next generation solar cells. However, making solution-process require high temperature up to $500^{\circ}C$ to form compact hole blocking layer and sinter the mesoporous oxide scaffold layer. Because of this high temperature process, fabrication of flexible solar cells on plastic substrate is still troubleshooting. In this study, we fabricated highly efficient flexible perovskite solar cells with PCE in excess of 11%. Atomic layer deposition (ALD) is used to deposit dense $TiO_2$ as hole blocking layer on ITO/PEN substrate. The all fabrication process is done at low temperature below $150^{\circ}C$. This work shows that one of the important blueprint for commercial use of perovskite solar cells.

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A Study on the Holographic Optical Element for Multiple Image Processing (다중 영상처리용 홀로그래피 광학소자에 관한 연구)

  • Kim, Nam
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.17 no.12
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    • pp.1353-1361
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    • 1992
  • Holographic optical element(HOE) is fabricated with the properties of lightweight, thin thickness and interconnectivity for free space. Particularly, HOE for optical interconnection and multiple image processing should have a high efficiency and equal spot intensity, Nonlinear equations for 2-dimensional binary phase grating(BPG) structure is solved by computer simulation based on modified Newton method. Computer-generated pattern drawn by plotter is scaled down and translated into the microfilm. After contact printing between the microfilm and silver halide hologram film, phase diffraction grating produces the $5{\times}5$ multiple spots. Experimental results are shown that bleached phase grating has a high efficiency and equal focused beams except central zero order.

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A Study on the Luminous Environments of Architectural Building for Improvement of Night-Scape in Coastal Resort - Focused on the Gyengpo Park - (해안 휴양지의 야간경관 개선을 위한 건축물의 조명환경 연구 - 경포도립공원을 중심으로 -)

  • Cho, Won-Seok;Kim, Heung-Gee
    • Journal of the Korean Institute of Rural Architecture
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    • v.10 no.3
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    • pp.27-34
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    • 2008
  • Recently, the outdoor lighting of architectural Facade has increased for the improvement of night-scape in urban and coastal resort. The purpose of this research is to analyze lighting characteristics; Luminance, Illuminance, Color Temperature, Chromaticity in Gyengpo Park of Eastern famous coastal resort. The result of this paper is as follows: 1) The Luminance ratio was measured that compare to the 1:10 criterion(IESNA) was in excess to the most building except "K". Because of these condition, Luminance environments was injurious to visual health the overuse of the outdoor lighting or glare to the eyes. 2) The level of vertical Illuminance value was insufficient 33.3% among the cases of survey with 4Lux standard of CIE. 3) The kinds of outdoor lighting of BLDG were increased lighting emitting diode(LED), metal halide(MH) instead of reduction trend of neon, fluorescent light, halogen. As the crisis of Energy resources we will be investigate adapt method of outdoor lighting, which design is based on economical efficiency by the use of optimum lighting.

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Effect of High Injection Pressure and Ambient Pressure on the DME Spray Characteristics Injected Through a Common-rail Diesel Injector (커먼레일 디젤 인젝터에서 연료 분사 및 분위기 압력이 DME 분무 특성에 미치는 영향)

  • Kim, Hyung-Jun;Park, Su-Han;Lee, Chang-Sik
    • Journal of ILASS-Korea
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    • v.14 no.2
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    • pp.71-76
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    • 2009
  • The aim of this investigation is to study the effect of the high injection pressure on the dimethyl ether (DME) spray characteristics injected through a common-rail diesel injector under various ambient pressures. In order to investigate the effect of the injection pressure and ambient condition, the common-rail injection system with two high pressure pumps and high pressure chamber pressurized up to 40 bar were used, respectively. Spray images of DME fuel obtained from a visualization system composed of high speed camera and two metal halide lamps as the light source. From the obtained images, the spray behaviors such as a spray development process, spray tip penetration, spray width, and spray cone angle were measured for analyzing the DME spray characteristics under various experimental conditions. It was found that the spray development slowed as the ambient pressure increased and spray tip penetration at injection pressure of 90 MPa is longer than that at 50 MPa. In addition, the spray width at the end stage of injection decreased under the atmospheric conditions due to the evaporation property of DME fuel, and DME spray shows narrow spray cone angle according to the injection pressure increased.

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