• Title/Summary/Keyword: Back electrode

Search Result 182, Processing Time 0.026 seconds

Potentiometric Back Titration of Isoniazid in Pharmaceutical Dosage Forms Using Copper Based Mercury Film Electrode (구리수은막 전극에을 사용한 이소니아자이드의 전위차 역적정)

  • Gajendiran, M.;Nazer, M.M. Abdul Kamal
    • Journal of the Korean Chemical Society
    • /
    • v.55 no.4
    • /
    • pp.620-625
    • /
    • 2011
  • A simple, rapid potentiometric back titration of Isoniazid (INH) in the presence of Rifampicin (RIF) in tablets and syrups is described. The method is based on the oxidation of INH by a known excess of copper (II) ion and the back titration of unreacted copper (II) ion potentiometrically with ascorbic acid using a lab-made Copper Based Mercury Film Electrode (CBMFE). The titration conditions have been optimized for the determination of 1.0-10.0 mg of INH in pure and dosage forms. The precision and accuracy of the method have been assessed by the application of lack-of-fit test and other statistical methods. Interference was not caused by RIF and other excipients present in dosage forms. Application of the method for INH assay in tablets and syrups was validated by comparison of the results of proposed method with that of the British Pharmacopoeia (BP) method using F- and t- statistical tests of significance.

A Study on the Back Bead control by Using Short Circuit Frequency in GMA Welding of Sheet Metal (박판 GMA 용접에서 단락 주파수를 이용한 이면비드의 제어에 관한 연구)

  • 안재현;김재웅
    • Journal of Welding and Joining
    • /
    • v.13 no.4
    • /
    • pp.75-84
    • /
    • 1995
  • In GMA welding of sheet metal, the short circuit metal transfer mdoe is preferred because of its low heat input and capability of bridging the root gap. The molten electrode is transferred to the workpiece during repectitive short circuit in the model. The waveform of welding current or voltage and the frequency of short circuiting are affected by a number of factors including: magnitude of welding current and voltage, root gap, electrode extension, power supply characteristics, and so on. In this study experimental models were proposed, which are able to determine the relationship between the root gap and short circuit frequency and the relationship between the root gap and appropriate welding speed that produces the good quality of back bead without burn through. Using the experimental models, the root gap can be obtained from measuring the short circuit frequency, and then the appropriate weldig speed to the root gap can be determined. Thus a back bead control system was constructed by controlling the welding speed for maintaining the quality of back bead. The developed system has shown the successful capability of back bead control.

  • PDF

Application of Buffer Layers for Back Contact in CdTe Thin Film Solar Cells

  • Chun, Seungju;Kim, Soo Min;Lee, Seunghun;Yang, Gwangseok;Kim, Jihyun;Kim, Donghwan
    • Proceedings of the Korean Vacuum Society Conference
    • /
    • 2014.02a
    • /
    • pp.318.2-318.2
    • /
    • 2014
  • The high contact resistance is still one of the major issues to be resolved in CdS/CdTe thin film solar cells. CdTe/Metal Schottky contact induced a high contact resistance in CdS/CdTe solar cells. It has been reported that the work function of CdTe thin film is more than 5.7 eV. There has not been a suitable back contact metal, because CdTe thin film has a high work function. In a few decades, some buffer layer was reported to improve a back contact problem. Buffer layers which are Te, $Sb_2Te_3$, $Cu_2Te$, ZnTe:Cu and so on was inserted between CdTe and metal electrode. A formed buffer layers made a tunnel junction. Hole carriers which was excited in CdTe film by light absorption was transported from CdTe to back metal electrode. In this report, we reported the variation of solar cell performance with different buffer layer at the back contact of CdTe thin film solar cell.

  • PDF

Improvement of The Saturation Voltage Characteristics of BJT Using Folded Back Electrode (Folded Back Electrode를 이용한 BJT의 포화전압특성 개선)

  • 김현식;손원소;최시영
    • Journal of the Institute of Electronics Engineers of Korea SD
    • /
    • v.41 no.5
    • /
    • pp.15-21
    • /
    • 2004
  • In this paper a new structure of BJT is proposed to improve the saturation voltage characteristics so that it can be used to the low power switching devices. In the case of the conventional finger transistor(FT), the saturation voltage is so high that it dose not satisfy the requirements for the low power device. So the other multi base island transistor(MBIT) is suggested and its saturation voltage is so low in the region of low current that it satisfy the requirement for the low power switching devices, but in region of the high current the saturation voltage tends to increase so that it does not satisfy the requirements for the low power switching devices. So in this paper a new structure of folded back electrode transistor(FBET) is proposed and the characteristics is investigated. When the new structure is applied the emitter area is increased by 35 % so the saturation voltage is reduced by 30 % at the low current region and the contact area is increased by 92 % so the saturation voltage is reduced by totally f % at the high current region with the reduction of 30 % by the increase of the emitter area and the reduction of 7 % by the increase of the emitter contact area.

Morphology and Electro-Optical Property of Mo Back Electrode for CuInGaSe2 Solar Cells (CuInGaSe2 태양전지용 Mo 후면 전극의 조직 및 전기광학적 특성)

  • Chae, Su-Byung;Kim, Myung-Han
    • Korean Journal of Materials Research
    • /
    • v.20 no.8
    • /
    • pp.412-417
    • /
    • 2010
  • Mo thin films were used for the back electrode because of the low resistivity in the Mo/$CuInGaSe_2$ contact in chalcopyrite solar cells. $1\;{\mu}m$ thick Mo thin films were deposited on soda lime glass by varying the Ar pressure with the dc-magnetron sputtering process. The effects of the Ar pressure on the morphology of the Mo back electrode were studied and the relationships between the morphology and electro-optical properties, namely, the resistivity as well as the reflectance of the Mo thin films, were investigated. The resitivity increased from $24\;{\mu}{\Omega}{\cdot}cm$ to $11833\;{\mu}{\Omega}{\cdot}cm$; this was caused by the increased surface defect and low crystallinity as the Ar pressure increased from $3{\times}10^{-3}$ to $3{\times}10^{-2}\;Torr$. The surface morphologies of the Mo thin films changed from somewhat coarse fibrous structures to irregular and fine celled structures with increased surface cracks along the cell boundaries, as the Ar pressure increased from $3{\times}10^{-3}$ to $3{\times}10^{-2}\;Torr$. The changes of reflectances in the visible light range with Ar pressures were mainly attributed to the surface morphological changes of the Mo thin films. The reflectance in the visible light range showed the highest value of 45% at $3{\times}10^{-3}\;Torr$ and decreased to 18.5% at $3{\times}10^{-2}\;Torr$.

The Change of Electrical Characteristics in the EST with Trench Electrodes (트랜치 전극을 가진 Emitter Switched Thyristor의 전기적 특성 변화)

  • Kim, Dae-Won;Kim, Dae-Jong;Sung, Man-Young;Kang, Ey-Goo;Lee, Dong-Hee
    • 한국컴퓨터산업교육학회:학술대회논문집
    • /
    • 2003.11a
    • /
    • pp.71-74
    • /
    • 2003
  • A vertical trench electrode type EST has been proposed in this paper. The proposed device considerably improve the snap-back effect which leads to a lot of problem of device applications. In this paper, the vertical dual gate Emitter Switched Thyristor(EST) with trench electrode has been proposed for improving snap-back effect. It is observed that the forward blocking voltage of the proposed device is 800V. The conventional EST of the same size were no more than 633V. Because the proposed device was constructed of trench-type electrode, the electric field moved toward trench-oxide layer, and the punch through breakdown of the proposed EST is occurred at latest.

  • PDF

Morphology and Electrical Properties of Back Electrode for Solar Cell Depending on the Mo : Na/Mo Bilayer Thickness (Mo : Na/Mo 이중층 구조 두께에 따른 태양전지 후면전극의 조직 및 전기적 특성)

  • Shin, Younhak;Kim, Myunghan
    • Korean Journal of Materials Research
    • /
    • v.23 no.9
    • /
    • pp.495-500
    • /
    • 2013
  • Mo-based thin films are frequently used as back electrode materials because of their low resistivity and high crystallinity in CIGS chalcopyrite solar cells. Mo:Na/Mo bilayer thin films with $1{\mu}m$ thickness were deposited on soda lime glass by varying the thickness of each layer using dc-magnetron sputtering. The effects of the Mo:Na layer on morphology and electrical property in terms of resistivity were systematically investigated. The resistivity increased from $159{\mu}{\Omega}cm$ to $944{\mu}{\Omega}cm$; this seemed to be caused by increased surface defects and low crystallinity as the thickness of Mo:Na layer increased from 100 nm to 500 nm. The surface morphologies of the Mo thin films changed from a somewhat coarse fibrous structures to irregular and fine celled structures with increased surface cracks along the cell boundaries as the thickness of Mo:Na layer increased. Na contents varied drastically from 0.03 % to 0.52 % according to the variation of Mo:Na layer thickness. The change in Na content may be ascribed to changes in surface morphology and crystallinity of the thin films.

Characteristics of Mono Crystalline Silicon Solar Cell for Rear Electrode with Aluminum and Aluminum-Boron (Aluminum 및 Aluminum-Boron후면 전극에 따른 단결정 실리콘 태양전지 특성)

  • Hong, Ji-Hwa;Baek, Tae-Hyeon;Kim, Jin-Kuk;Choi, Sung-Jin;Kim, Nam-Soo;Kang, Gi-Hwan;Yu, Gwon-Jong;Song, Hee-Eun
    • 한국태양에너지학회:학술대회논문집
    • /
    • 2011.11a
    • /
    • pp.34-39
    • /
    • 2011
  • Screen printing method is a common way to fabricate the crystalline silicon solar cell with low-cost and high-efficiency. The screen printing metallization use silver paste and aluminum paste for front and rear contact, respectively. Especially the rear contact between aluminum and silicon is important to form the back surface filed (Al-BSF) after firing process. BSF plays an important role to reduces the surface recombination due to $p^+$ doping of back surface. However, Al electrode on back surface leads to bow occurring by differences in coefficient of thermal expansion of the aluminum and silicon. In this paper, we studied the properties of mono crystalline silicon solar cell for rear electrode with aluminum and aluminum-boron in order to characterize bow and BSF of each paste. The 156*156 $m^2$ p-type silicon wafers with $200{\mu}m$ thickness and 0.5-3 ${\Omega}\;cm$ resistivity were used after texturing, diffusion, and antireflection coating. The characteristics of solar cells was obtained by measuring vernier callipers, scanning electron microscope and light current-voltage. Solar cells with aluminum paste on the back surface were achieved with $V_{OC}$ = 0.618V, JSC = 35.49$mA/cm^2$, FF(Fill factor) = 78%, Efficiency = 17.13%.

  • PDF

Electrical and Optical Characteristics of Flat Fluorescent Lamp for LCD Back-lighting (LCD 후면 광원용 FEL의 전기적 및 광학적 특성)

  • 김명녕;권순석
    • Journal of the Korea Institute of Information and Communication Engineering
    • /
    • v.7 no.4
    • /
    • pp.725-729
    • /
    • 2003
  • In this paper, a mercury-free flat discharge lamp with opposite electrode structure, a couple of phosphor layer and discharge vessel has been studied for LCD back-lighting. When the drive voltage conditions were set properly, a uniform discharge generates over entires emitting surface. The firing voltage was increased with increasing the discharge gas pressure. It was considered that this tendency was resulted from the decrease of mean free paths due to the increase of discharge gas pressure. The maximum luminance of 2700[cd/m2] was obtained in the green emitting FFL.

Analysis of a Hot Rolling Roller and Spring-back of Electrode Materials for Secondary Batteries (이차전지 전극제조용 열간압연롤러와 전극재료의 열 변형 및 스프링백 해석)

  • Kim, Kyung-Sik;Kim, Cheol
    • Proceedings of the KSME Conference
    • /
    • 2008.11a
    • /
    • pp.538-543
    • /
    • 2008
  • A roller with a shaft and hot oil paths for pressing electrodes of polymer batteries were modeled and analyzed by FEM. There are many hot oil tubes in the roller and shaft, through which $72^{\circ}C$ hot oil flows for heating the surface of a roller and shaft. Thermal deformations and temperatures distributions of the roller and shaft were calculated and a convection boundary condition on surfaces was used. The influence of existence of a groove in the shaft on the flatness of a roller surface caused by thermal deformation was investigated. In addition, the amount of spring-back of electrodes under vacuum pressure and heating was calculated after the hot rolling process. It was shown from this study that the groove in one shaft had a favorable effect on the surface flatness.

  • PDF