• Title/Summary/Keyword: P-V curve

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Structural Analysis of Ag Agglomeration in Ag-based Ohmic Contact to p-type GaN (고분해능 X선 회절을 이용한 Ag 기반 p형 반사막 오믹 전극 집괴 분석)

  • Son, J.H.;Song, Y.H.;Lee, J.L.
    • Journal of the Korean Vacuum Society
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    • v.20 no.2
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    • pp.127-134
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    • 2011
  • We investigate the crystallographic orientation and strain states of the Ni/Ag ohmic contacts on p-type GaN. The Ag film in the Ni/Ag contact was severely agglomerated during high temperature annealing in air ambient. As a results, after annealing for 24 h, the Ni/Ag contact shows non-linear I-V curve and low light reflectance of ~21% at 460 nm wavelength. High-resolution X-ray diffraction results show that the interplanar spacing of Ag (111) planes is almost same to that of bilk Ag after annealing for 24 hrs, indicating that the in-plane tensile strain in the Ag film was fully relaxed due to the Ag agglomeration.

Overexpression, Purification, and Biochemical Characterization of the Thermostable NAD-dependent Alcohol Dehydrogenase from Bacillus stearothermophilus

  • Shim, Eun-Jung;Jeon, Sang-Hoon;Kong, Kwang-Hoon
    • Journal of Microbiology and Biotechnology
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    • v.13 no.5
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    • pp.738-744
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    • 2003
  • The gene ADH encoding NAD-dependent alcohol dehydrogenase from Bacillus stearothennophilus was cloned and overexpressed as a GST fusion protein at a high level in Escherichia coli. The expressed fusion protein was purified simply by glutathione affinity chromatography. GST fusion protein was then cleaved by thrombin, while soluble enzyme was further purified by glutathione affinity chromatography. The recombinant enzyme had the same elctrophoretic mobility as the native enzyme from Bacillus stearothennophilus. The recombinant enzyme catalyzed the oxidation of a number of alcohols and exhibited high activities towards secondary alcohols. The $K_m\;and\;V_{max}$ values of the recombinant enzyme for ethanol were 5.11 mM and 61.35 U/mg, respectively. Pyridine and imidazole notably inhibited the enzymatic activity. The activity of the recombinant enzyme optimally proceeded at pH 9.0 and $70^{\circ}C$. The midpoint of the temperature-stability curve for the recombinant enzyme was approximately $68^{\circ}C$, and the enzyme was not completely inactivated even at $85^{\circ}C$. The recombinant enzyme showed a high resistance towards denaturing agents (0.05% SDS, 0.1 M urea). Therefore, due to its stability and relatively broad substrate specificity, the recombinant enzyme could be utilized in bio-industrial processes and biosensors.

A Study on Punchthrough and Hot-carrier Effects as LDD Process Parameters (LDD 공정 조건에 따른 편치쓰루 및 핫 캐리어 효과에 관한 연구)

  • An, Tae-Hyun;Kim, Nam-Hoon;Kim, Chang-Il;Seo, Yong-Jin;Chang, Eui-Goo
    • Proceedings of the KIEE Conference
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    • 1998.07d
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    • pp.1367-1369
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    • 1998
  • To achieve the ULSI goals of higher density, greater performance and operation speed have been scaled down. However, the reduction of channel length cause undesirable problems such as drop of punchthrough voltage, hot-carrier degradation and high leakage current, etc.. It is shown that the device characteristics depend on process parameters. In this Paper, we catched hold of trends of hot-carrier effects and punchthrough voltages due to variation of some process parameters such as LDD doses(P), spacer lengths, channel doses($BF_2$) and $V_T$ adjusting channel implantation energies using design trend curve (DTC). As the LDD and channel doses increased, hot-carrier phenomena became more severe, and punchthrough voltage was decreased. It were represented that punchthrough and hot carrier effects were critically depend on LDD and channel doses.

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Sorption Preconcentration and Determination of Nickel in Wastes of Heat Power Industry by Diffuse Reflection Spectroscopy

  • Kalyakina, O.P.;Kononova, O.N.;Kachin, S.V.;Kholmogorov, A.G.
    • Bulletin of the Korean Chemical Society
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    • v.24 no.2
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    • pp.173-177
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    • 2003
  • The present work is focused on the preconcentration of nickel and its determination by means of diffuse reflection spectroscopy. The preconcentration of nickel was carried out by sorption on macroporous aminocarboxylic amphoteric resin ANKB-35. Based on this collector, a method to determine nickel in wastes of heat power industry was worked out using solid-phase spectroscopy. The colored surface compound to be determined was obtained by a preceding nickel sorption on the resin and by subsequent treatment of the concentrate obtained with definite amounts of 1-(2-pyridilazo)-2-naphtol (PAN). The Ni calibration curve is linear in the concentration range of 0.5-20.0 mg/L (sample volume is 200.0 mL) and the detection limit is 0.05 mg/L. The presence of $Cu^{2+},\;Fe^{3+},\;Co^{2+}$ ions as well as macrocomponents of natural water $(Na^+,\;K^+,\;Ca^{2+},\;Mg^{2+})$ do not hinder the solid-phase spectroscopy determination of nickel. The nickel determination by diffuse reflection spectroscopy was carried out in model solutions as well as in solutions obtained after the dissolution of wastes of heat power industry.

A study on the design wax up technique for mandibular molar occlusion surface (하악구치 교합면의 design 조각법에 관한 연구)

  • Moon, Hee-Kyung
    • Journal of Technologic Dentistry
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    • v.24 no.1
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    • pp.107-126
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    • 2002
  • The first function of occlusion is mastication. Therefore the functional restoration of occlusal surface is very important. The restoration of occlusal surface is three method as wax bite technique, F.G.P. technique, cone technique. Many dental technician is using compound method. I am using compound method of wax bite technique and cone technique. I have knew common point on each teeth during I have waxing up wax pattern. So I studied on the design waxup technique for mandible molar occlusion. The results of the study were as follows; 1. The dam wax up method can restore axial contour of teeth very easy and make short working time of wax pattern. 2. The height of dam must be same with cusp of adjacent teeth. 3. Automatically the contour of tooth is appeared if the contour of dam is relationship with cuspid line of adjacent teeth. 4. The height of contour of buccal, lingual surface is formed natural curve to add fluid wax by gravitation. 5. The development groove of mandible first premolar is appeared V form. 6. The development groove of mandible second premolar is appeared Y form. 7, The development groove of mandible first molar is appeared M form. 8. The development groove of mandible second molar is W form. 9. The embrasure is formed to carve around contact point area as round convex. It affects to axial form of tooth. 10. The buccal, lingual groove of molar is formed parallel with direction of teeth arrangement.

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Improving the performance of PV system using the N-IC MPPT methods (N-IC MPPT방법을 이용한 태양광 발전시스템의 성능개선)

  • Seo, Tae-Young;Ko, Jae-Sub;Kang, Sung-Min;Kim, Yu-Tak;Chung, Dong-Hwa
    • Proceedings of the KIEE Conference
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    • 2015.07a
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    • pp.958-959
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    • 2015
  • This paper proposes adaptive incremental conductance(A-IC) algorithm for maximum power point tracking(MPPT) control of photovoltaic. Conventional Perturbation & Observation(PO) and IC MPPT control algorithm generally uses fixed step size. A small fixed step size will cause the tracking speed to decrease and tracking accuracy of the MPP will decrease due to large fixed step size. Therefore, this paper proposes N-IC MPPT algorithm that adjust automatically step size according to operating conditions. To improve tracking speed and accuracy, when operating point is far from maximum power point(MPP), step size uses maximum value and when operating point is near from MPP, step size uses variable step size that adjust according to slope of P-V curve. The validity of MPPT algorithm proposed in this paper prove through compare with conventional IC MPPT algorithm.

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Enhanced Simulated Annealing-based Global MPPT for Different PV Systems in Mismatched Conditions

  • Wang, Feng;Zhu, Tianhua;Zhuo, Fang;Yi, Hao;Fan, Yusen
    • Journal of Power Electronics
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    • v.17 no.5
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    • pp.1327-1337
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    • 2017
  • Photovoltaic (PV) systems are influenced by disproportionate impacts on energy production caused by frequent mismatch cases. The occurrence of multiple maximum power points (MPPs) adds complexity to the tracking process in various PV systems. However, current maximum-power point tracking (MPPT) techniques exhibit limited performance. This paper introduces an enhanced simulated annealing (ESA)-based GMPPT technique against multiple MPP issues in P-V curve with different PV system structures. The proposed technique not only distinguishes global and local MPPs but also performs rapid convergence speed and high tracking accuracy of irradiance changing and restart capability detection. Moreover, the proposed global maximum power tracking algorithm can be applied in the central converter of DMPPT and hybrid PV system to meet various application scenarios. Its effectiveness is verified by simulation and test results.

Studies on Suppositories of $Phenytoin-{\beta}-Cyclodextrin$ Inclusion Complexes (페니토인-${\beta}$-시클로덱스트린 포접 복합체의 좌제에 관한 연구)

  • Cha, Jae-Ho;Han, Kun
    • Journal of Pharmaceutical Investigation
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    • v.18 no.1
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    • pp.15-21
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    • 1988
  • An inclusion complex of phenytoin (PT) with ${\beta}-cyclodextrin\;({\beta}-CyD)$ in molar ratio of 1 : 1 was prepared, and the interaction between host and guest molecules was confirmed by infrared spectrometry, differential scanning calorimetry and X-ray diffractometry. Suppositories were prepared by the fusion method. PT and $PT-{\beta}-CyD$ complex were added to PEG 1540 and Witepsol H-15 under the vigorous stirring at $40^{\circ}C$. Content uniformity was tested for different formulations of the PT suppositories. The release rates were dependent on the K.P. V dissolution apparatus and the dialyzing tubing method. Then, the release rates were increased in the following order: $PT-{\beta}-CyD$ complex in PEG 1540>PT in PEG 1540>$PT-{\beta}-CyD$ complex in Witepsol H-15>PT in Witepsol H-15. The area under the curve and maximum blood concentration after rectal administration were increased in the following order: $PT-{\beta}-CyD$ complex in PEG 1540>PT in PEG 1540>$PT-{\beta}-CyD$ complex in Witepsol H-15>PT in Witepsol-15.

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Characterization of electrophoretically deposited low voltage phosphors mixed with $In_2O_3$ conducting powders for field emission display

  • Seo, D.S.;Song, B.G.;Kim, C.O.;Hong, J.P.;Jin, Y.W.;Cha, S.N.;Lee, N.S.;Jung, J.E.;Kim, J.M.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2000.01a
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    • pp.145-146
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    • 2000
  • Primary emphasis was placed on the electrophoretic deposition of low voltage phosphor to indium-tin oxide-coated glass for the application of field emission display. The phosphor deposited by various parameters, such as deposition time and applied voltages was examined in detail. In addition, a comparison was made by analyzing luminance properties of the phosphor mixed with and without conducting $In_2O_3$ powder of less than 1um size. The measurement was performed as a function of $In_2O_3$ concentration from 3% to 15% by weight. The enhanced impact of indium powder mixing on the phosphor was clearly demonstrated by aging performance curve at 1000V excitation voltages with a current density of $1\;mA/cm^2$

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Synthesis and Characterization of Nickel(II) Tetraaza Macrocyclic Complex with 1,1-Cyclohexanediacetate Ligand

  • Lim, In-Taek;Kim, Chong-Hyeak;Choi, Ki-Young
    • Journal of the Korean Chemical Society
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    • v.62 no.6
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    • pp.427-432
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    • 2018
  • The reaction of [$[Ni(L)]Cl_2{\cdot}2H_2O$ (L = 3,14-dimethyl-2,6,13,17-tetraazatricyclo[$14,4,0^{1.18},0^{7.12}$]docosane) with 1,1-cyclohexanediacetic acid ($H_2cda$) yields mononuclear nickel(II) complex, [$Ni(L)(Hcda^-)_2$] (1). This complex has been characterized by X-ray crystallography, electronic absorption, cyclic voltammetry and thermogravimetric analyzer. The crystal structure of 1 exhibits a distorted octahedral geometry with four nitrogen atoms of the macrocycle and two 1,1-cyclohexanediacetate ligands. It crystallizes in the triclinic system P-1 with a = 11.3918(7), b = 12.6196(8), $c=12.8700(8){\AA}$, $V=1579.9(2){\AA}^3$, Z = 2. Electronic spectrum of 1 also reveals a high-spin octahedral environment. Cyclic voltammetry of 1 undergoes one wave of a one-electron transfer corresponding to $Ni^{II}/Ni^{III}$ process. TGA curve for 1 shows three-step weight loss. The electronic spectra, electrochemical and TGA behavior of the complex are significantly affected by the nature of the axial $Hcda^-$ ligand.