• Title/Summary/Keyword: charge distribution

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Comparative Studies on Two Fluoro-Substituted 2-Pyrazoline Derivatives with Experimental and Theoretical Methods

  • Guo, Huan-Mei;Wang, Xian;Jian, Fang Fang;Xiao, Hai Lian;Zhao, Pu Su
    • Bulletin of the Korean Chemical Society
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    • v.30 no.5
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    • pp.1061-1066
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    • 2009
  • Two fluoro-substituted 2-pyrazoline derivatives, 1-phenyl-3-(4-methoxyphenyl)-5-(4-fluorophenyl)-2-pyrazoline (1) and 1-phenyl-3-(4-methoxyphenyl)-5-(2-fluoro-phenyl)-2-pyrazoline (2) have been synthesized and characterized by elemental analysis, IR, UV-Vis and fluorescence spectra. The crystal structure of 1 has been determined by X-ray single crystal diffraction. For the two compounds, density functional theory (DFT) calculations of the structures and natural population atomic charge analysis (NPA) have been performed at B3LYP/6-311G** level of theory. By using TD-DFT method, electron spectra of 1 and 2 have been predicted, which are very approximate with the experimental ones. Comparative studies on 1 and 2 indicate that the location change of fluorine atom in 5-position phenyl ring of 2-pyrazoline does not make significant change of geometries and electronic transition bands, but it leads to evident change of atomic charge distributions and peak intensities of UV and fluorescence spectra.

Simulation of Channel Dimension Dependent Conduction and Charge Distribution Characteristics of Silicon Nanowire Transistors using a Quantum Model (양자효과를 고려한 실리콘 나노선 트랜지스터의 채널 크기에 따른 전도 및 전하분포 특성 시뮬레이션)

  • Hwang, Min-Young;Choi, Chang-Yong;Moon, Kyoung-Sook;Koo, Sang-Mo
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.22 no.9
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    • pp.728-731
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    • 2009
  • We report numerical simulations to investigate of the dependendce of the on/off current ratio and channel charge distributions in silicon nanowire (SiNW) field-effect transistors (FETs) on the channel width and thicknesses. In order to investigate the transport behavior in devices with different channel geometries, we have performed detailed two-dimensional simulations of SiNWFETs and control FETs with a fixed channel length L of 10μm, but varying the channel width W from 5 nm to 5μm, and thickness t from 10 nm to 30 nm. We have show that QON/QOFF drastically decreases (from 2.9×104 to 9.8×103) as the channel thickness increases (from 10 nm to 30 nm). As a result of the simulation using a quantum model, even higher charge density in the bottom of SiNW channel was observed then in the bottom of control channel.

The Braking Torque Analysis of Eddy Current Brake with the Use of Coulomb′s law and the Method of Image (쿨롬 법칙과 영상법을 이용한 와전류 브레이크의 제동토크 해석)

  • Lee, Gap-Jin;Park, Gi-Hwan
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.50 no.9
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    • pp.431-437
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    • 2001
  • Since the eddy current problem usually depends on the geometry of the moving conductive sheet and the shape of the pole projection area, there is no general method to find out its analytical solution. The analysis of the eddy current in a rotating disk is performed in the case of time-invariant field to find its analytical solution. As a method to solve the eddy current problem, the concept of the Coulomb charge and image method are proposed with the consideration of the boundary condition. Firstly, the line charge is obtained from the volume charge generated in the rotating disk and Coulomb's law is applied. Secondly, the finite disk radius is considered by introducing an imaginary eddy current to satisfy the boundary condition that the radial component of the eddy current is zero at the edge of the relating disk. Thirdly, the braking torque is calculated by applying Lorentz force law. Finally, the computed braking torque is compared with the measured one As a result, it can be said that the proposed model presents fairly accurate results in a low angular velocity range although a large error is observed as the angular velocity of the disk increases.

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Analysis on particle deposition onto a heated, horizontal free-standing wafer with electrostatic effect (정전효과가 있는 가열 수평웨이퍼로의 입자침착에 관한 해석)

  • Yoo, Kyung-Hoon;Oh, Myung-Do;Myong, Hyon-Kook
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.21 no.10
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    • pp.1284-1293
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    • 1997
  • The electrostatic effect on particle deposition onto a heated, Horizontal free-standing wafer surface was investigated numerically. The deposition mechanisms considered were convection, Brownian and turbulent diffusion, sedimentation, thermophoresis and electrostatic force. The electric charge on particle needed to calculate the electrostatic migration velocity induced by the local electric field was assumed to be the Boltzmann equilibrium charge. The electrostatic forces acted upon the particle included the Coulombic, image, dielectrophoretic and dipole-dipole forces based on the assumption that the particle and wafer surface are conducting. The electric potential distribution needed to calculate the local electric field around the wafer was calculated from the Laplace equation. The averaged and local deposition velocities were obtained for a temperature difference of 0-10 K and an applied voltage of 0-1000 v.The numerical results were then compared with those of the present suggested approximate model and the available experimental data. The comparison showed relatively good agreement between them.

Surface Properties and interfacial Potential Distribution of Surface Treated-Alumina (표면처리한 알루미나의 표면물성과 계면전위분포)

  • 홍영호;함영민
    • Journal of the Korean Ceramic Society
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    • v.33 no.7
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    • pp.823-831
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    • 1996
  • Due to the intrinsic low surface activation of γ-alumina it has been used limitely in practice. Accordingly forward enhancing its utility γ-alumina surface was treated with slfuricf aicd nitric acid and chloric acid respec-tively. Subsequently the effects of surface activity on the surface electrical characteristics were investigated. The γ-alumina was prepared by the precipitation of aluminium nitrate [Al(NO3)3.9H2O] using ammonia water as a precipitator and it was chemically treated with such acids mentioned above. The surface and morphology of the acid-treated γ-alumina were analysed by XRD, BET and the surface activities were measured by the amine titration methods. The interfacial properties of the γ-alumina dispersed in electrolyte solution were esti-mated by the surface charge density measured using potentiometric tiration. Based on the relation between surface charge density and the acid amount the following results were drawn for the surface and interfacial electrical properties ; Acidic properties of surface-treated alumina increase with anion load on alumina surface. P. Z. C decreases with acid amount on alumina surface. The surface charge densities were apart from electrolyte ionic strength. The acidity of γ-alumina is linearly dependent on the P. Z,.C when the γ-alumina was dispersed in aqueous electrolyte solution.

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Decay Process of Charge Distribution in E-Beam Irradiated Polymers (E-빔 조사된 폴리머의 전하 분포의 축퇴 과정)

  • Yun, Ju-Ho;Choi, Yong-Sung;Lee, Kyung-Sup
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2007.11a
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    • pp.329-330
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    • 2007
  • Decay processes of accumulated charge in e-beam irradiated polymers during elevating temperature are observed using pulsed electro-acoustic measurement system. Since the polymeric materials have many superior properties such as light-weight, good mechanical strength, high flexibility and low cost, they are inevitable materials for spacecrafts. In space environment, however, the polymers sometimes have serious damage by irradiation of high energy charged particles. When the polymers of the spacecraft are irradiated by high energy charged particles, some of injected charges accumulate and remain for long time in the bulk of the polymers. Since the bulk charges sometimes cause the degradation or breakdown of the materials, the investigation of the charging and the decay processes in polymeric materials under change of temperature is important to decide an adequate material for the spacecrafts. By measuring the charge behavior in e-beam irradiated polymer, such as polyimide or polystyrene, it is found that the various accumulation and decay patterns are observed in each material. The results seem to be useful and be helpful to progress in the reliability of the polymers for the spacecraft.

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Effects of Polyelectrolytes on the Charge Transfer Complexing between Indole derivatives and Methylviologen: Hydrophobic and Electrostatic Interactions

  • Park, Joon-Woo;Hwang, Book-Kee
    • Bulletin of the Korean Chemical Society
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    • v.6 no.3
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    • pp.145-148
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    • 1985
  • The effect of anionic polyelectrolytes, poly(styrenesulfonate) (PSS) and poly(vinylsulfonate) (PVS), on the charge transfer complexing between indole derivatives and methyl viologen(MV++) cation was investigated. The results were compared with effect of NaCl and an anionic surfactant, sodium dodecylsulfate (SDS). Both PSS and PVS enhanced the complex formation of neutral species (indole and indole acetate at low pH), zwitter ionic tryptophan, and positively charged tryptamine and tryptophan at low pH with MV++. This result was attributed to the contribution of hydrophobic interaction, in addition to electrostatic interaction. The enhancing effect of PSS was much higher than that of PVS reflecting the higher hydrophobicity of PSS. The interaction between indole acetate anion and MV++ was greatly reduced by addition of PVS and PSS. The higher charge density of PVS was appeared as greater reducing effect indicating the importance of electrostatic force in this case. In all cases, the effect of polyelectrolytes showed maxima, and further addition of PVS and PSS decreased the effect. This behavior was explained in terms of distribution of indole derivatives and MV++ in domain of polyanions. The complex formation constants and molar absorptivities of complexes were determined, and the values were compared with those in water and SDS solutions.

Service Distribution Strategy on Business Performance of Padang Restaurants in North Jakarta

  • CHRISTIAN, Michael;HARIS, Kevin;INDRIYARTI, Eko Retno;WIBOWO, Suryo;SUNARNO, Sunarno
    • Journal of Distribution Science
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    • v.19 no.12
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    • pp.57-69
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    • 2021
  • Purpose: This study aims to measure whether the business performance of Padang restaurants in North Jakarta is primarily affected by service distribution strategy and other factors, specifically the local-based organizational culture and entrepreneurial orientation. Research design, data and methodology: This quantitative research has used Structural Model-Partial Least Square (PLS-SEM) with SMART PLS 3.0 as the analytical tool. The study's sample focus is the owner or person in charge of the Padang restaurant business in North Jakarta. Data has been collected using a questionnaire instrument with a Likert scale scale ('1-strongly disagree' to '5-strongly agree'). A total of 86 samples with a random technique were obtained from three areas in North Jakarta: Kelapa Gading, Pademangan, and Penjaringan. Results: Interestingly, this research finds that service distribution strategy does not affect business performance, either directly or indirectly. Business performance in this study is affected by entrepreneurial orientation. In additional results, the local organizational culture significantly affects the entrepreneurial orientation, but does not affect the business performance in terms of management process. Conclusions: This study provides practical implications for restaurant businesses regarding the use of local cultural concepts to consider strategies for survival in today's challenging times while continuing operations during limitations.

Electrostatic Properties of N-Acetyl-Cysteine-Coated Gold Surfaces Interacting with ZrO2 Surfaces

  • Park, Jin-Won
    • Bulletin of the Korean Chemical Society
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    • v.33 no.9
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    • pp.2855-2860
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    • 2012
  • The coating N-acetyl cysteine (NAC) on gold surfaces may be used to design the distribution of either gold particle adsorbed to the ZrO2 surface or vice versa by adjusting the electrostatic interactions. In this study, it was performed to find out electrostatic properties of the NAC-coated-gold surface and the ZrO2 surface. The surface forces between the surfaces were measured as a function of the salt concentration and pH value using the AFM. By applying the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory to the surface forces, the surface potential and charge density of the surfaces were quantitatively acquired for each salt concentration and each pH value. The dependence of the potential and charge density on the concentration was explained with the law of mass action, and the pH dependence was with the ionizable groups on the surface.

An Operation Algorithm for a 2 Shaft Parallel Type Hybrid Electric Vehicle for Optimal Fuel Economy (2축 병렬형 하이브리드 차량의 최저 연비 주행 알고리즘)

  • 최득환;김현수
    • Transactions of the Korean Society of Automotive Engineers
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    • v.9 no.5
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    • pp.122-130
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    • 2001
  • In this paper, an operational algorithm for a 2-shaft parallel hybrid electric vehicle is suggested for the minimization of operation cost. The operation cost is obtained as a summation of the engine fuel cost and the motor electricity cost. The electrical cost function is estimated in case of motoring, and generating when the recuperation is carried out during the braking. In addition, weight function is introduced in order to maintain the battery state of charge. Based on the operation algorithm, the optimal engine operation point that minimizes the operation cost is obtained with respect to the required vehicle power for every state of charge of battery. The optimal operation point provides the optimal power distribution of the engine and the motor for a required vehicle power Simulation was performed and the fuel economy of the hybrid vehicle was compared to that of the conventional vehicle. Simulation results showed that hybrid vehicle's fuel economy can be improved as much as 45∼48% compared to the conventional vehicle's.

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