• Title/Summary/Keyword: 공간전류

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Design of Transmission Lines with Arbitrary Reflection Responses Using Synthesis Method for Spatially Adaptive Source Distribution (공간적응형 소스 분포 합성법을 사용한 임의의 반사응답을 갖는 전송선로 설계)

  • Park, Ui-Jun
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.39 no.5
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    • pp.243-250
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    • 2002
  • In the synthesis of the current source distribution function of an array antenna with the arbitrary radiation pattern, the Woodward-Lawson sampling method has been mainly used for the synthesis of an even function lobe pattern. In this paper, the method is extended to the synthesis of the odd function pattern and then the optimum synthesis method for the nonlinear source distribution function is proposed. The proposed method is applied to the design of nonuniform transmission lines with arbitrary reflection responses. The both dispersive impedance profiles of single and coupled nonuniform lines with arbitrary reflection responses are directly synthesized by the sampled values of a reflected spectral pattern which is optimally shaped by a perturbation of its complex null positions, hence removing the conventional step-by-step segmentation process and global optimization routines. The control problem in the case that all of port impedances are identical is also solved. The generality of the proposed method is verified by a filter design with the controlled arbitrary passband

Synthesis, Properties, and X-ray Crystal Structure of Copper(II) Complex with Bis[(2-pyridyl)methyl]-2-(2-pyridyl)ethylamine (Bis[(2-pyridyl)methyl]-2-(2-pyridyl)ethylamine 구리(II) 착물의 합성, 성질 및 X-ray 결정구조)

  • Choi, Ki-Young
    • Journal of the Korean Chemical Society
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    • v.51 no.1
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    • pp.31-35
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    • 2007
  • The tripodal copper(II) complex [Cu(pmea)(H2O)](ClO4)2·H2O (1) (pmea = bis[(2-pyridyl)methyl]-2-(2-pyridyl)ethylamine) has been synthesized and structurally characterized by X-ray diffraction method. It crystallizes in the triclinic system P-1 with a = 9.9362(9), b = 15.7299(17), c = 18.0562(11) A, α = 68.760(8), β = 76.331(6), γ = 77.092(9)°, V = 2526.2(4) A3, Z = 2. Each copper atom reveals a distorted square pyramidal with three nitrogen atoms of the pmea ligand and water molecule occupying the basal plane and one nitrogen atom from the pyridine ring according the axial position. The cyclic voltammogram of 1 undergoes reversible one-electron oxidation to the CuIII and reversible one-electron reduction to the CuI.

Anaysis of Small-sized Power Connectors for Mobile Device Batteries (모바일기기 배터리용 초소형 파워 커넥터 해석)

  • Lee, Keun-Myoung;Oh, Ung;Yoo, Sung-Kyu;Song, Byeong-Suk
    • Journal of IKEEE
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    • v.19 no.1
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    • pp.101-109
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    • 2015
  • As the number of smartphone users grows, number of applications and the expected overall functionality in a smartphone grow simultaneously. With ever-so increasing expectations comes intense competition to squeeze in myriads of functions in a limited space that is only getting 'slimmer' by the year. In order to achieve this, companies often decrease the size of components in smartphones - battery connectors in particular. While they may fit, smaller battery connectors have their disadvantages due to the heat generated by the high current flow in the circuits. In collaborating with Korea's leading battery connector manufacturers, this research presents current issues and design concepts that should be considered when engineers design power connectors based on their electrical and thermal analysis.

Fabrication of a Subminiature 3 Dimensional Antenna for the Mobile Phone Handset (이동 통신 단말기용 초소형 3차원 안테나 제작)

  • Hong, Min-Gi;Son, Tae-Ho
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.19 no.12
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    • pp.1455-1461
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    • 2008
  • We implemented a subminiature internal antenna that is around 1 cc volume for the mobile phone. The fundamental type of studied antenna is IFA(Inverted F Antenna), and this antenna is designed to be improved efficiency and gain due to minimum current cancellation by the avoidance of multiple bending pattern. For the implementation of multiple band, helix is applied to compensate for short antenna length for low frequency band, and a 3 dimensional pattern is used for high frequency band. We made two kinds of 3D structure antenna. One is a 1 cc volume antenna for GSM/DCS band on the bare board set, and the other is a 1.5 cc volume for the GSM/USPCS mobile phone set. Measurements showed good gain performance that average gain of two antenna on each band are $-3.46{\sim}-0.45\;dBi$ and $-4.80{\sim}-3.29\;dBi$ respectively.

Cathodic Protection of Buried Gas Pipelines Using Common Anode Beds (공용양극을 이용한 가스배관의 전기방식)

  • Ha, Y.C.;Kim, D.K.;Bae, J.H.;Ha, T.H.;Lee, H.G.
    • Journal of the Korean Institute of Gas
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    • v.12 no.1
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    • pp.19-24
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    • 2008
  • Due to industrialization and urbanization, underground metallic utilities with different owners have been rapidly increased and cathodic protection (CP) methods, especially impressed current CP systems, have been widely adopted to protect their utilities from corrosion with expanded recognition of this method. The stray current interference problem as well as the difficulty in spatial security for system installation, however, came to a ramification of which each owner couldn't resolve for himself. In this respect, this paper illustrates a field-diagnosed example for mutual interference due to separately operated CP systems and suggests an alternative method to overcome the interference situation by design and field-assessment of a common anode bed cathodic protection system.

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A Study on the Design of Logistics Transportation System using Magnetic Levitation (자기부상 물류이송시스템 설계에 관한 연구)

  • Choi, Dae-Gyu;Cho, Jae-Hoon;Kim, Yong-Tae
    • Journal of the Korean Institute of Intelligent Systems
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    • v.24 no.2
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    • pp.129-135
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    • 2014
  • In the paper, we propose a design method for the logistics transportation system using magnetic levitation that has a good characteristics without mechanical friction, noise and dust. The proposed transportation system consists of a levitation control system and a propulsion control system. Magnetic levitation system is an electromagnetic suspension system in which electromagnet generates magnetic attractive force and the attractive force pulls the rail. We design a PID controller for the current control of electromagnets. We use linear induction motors for propulsion of the proposed logistics transportation system and adapt the space vector PWM method for the propulsion control system. The proposed transportation system using magnetic levitation is verified performances through levitation and propulsion experiments.

Time-resolved Analysis for Electroconvective Instability under Potentiostatic Mode (일정 전위 모드에서의 전기와류 불안정성에 대한 시간-분해 해석)

  • Lee, Hyomin
    • Korean Chemical Engineering Research
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    • v.58 no.2
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    • pp.319-324
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    • 2020
  • Electroconvective instability is a non-linear transport phenomenon which can be found in ion-selective transport system such as electrodialysis, Galvanic cell and electrolytic cell. The instability is triggered by the fluctuation of space charge layer in adjacent of ion-selective surface, leading to increase of mass transport rate. Thus, in the aspect of mass transport, the instability has an important meaning. Although recent experimental techniques have opened up an avenue to direct visualize the instability, fundamental investigations have been conducted in limited area due to several experimental limitations. In this work, the electroconvective instability under potentiostatic mode was solved by numerical method in order to demonstrate correlation between current-time curve and the instability behavior. By rigorous time-resolved analysis, the transition behaviors can be divided into three stages; formation of space charge layer - growth of electroconvective instability - steady state. Furthermore, scaling laws of transition time were numerically obtained according to applied voltage as well.

Three-dimensional Locomotion and Drilling Microrobot Using Electromagnetic Actuation System (전자기 구동 시스템을 이용한 마이크로로봇의 3차원 이동 및 드릴링)

  • Li, Jie;Choi, Hyun-Chul;Cha, Kyoung-Rae;Jeong, Se-Mi;Park, Jong-Oh;Park, Suk-Ho
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.35 no.12
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    • pp.1573-1578
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    • 2011
  • In this study, a novel electromagnetic microrobot system with locomotion and drilling functions in threedimensional space was developed. Because of size limitations, the microrobot does not have actuator, battery, and controller. Therefore, an electromagnetic actuation (EMA) system was used to drive the robot. The proposed EMA system consists of three rectangular Helmholtz coil pairs in x-, y- and z-axes and a Maxwell coil pair in the z-axis. The magnetic field generated in the EMA coil system could be controlled by the input current of the EMA coil. Finally, through various experiments, the locomotion and drilling performances of the proposed EMA microrobot system were verified.

Construction of Low Magnetic Standard System using a Multi-layer Solenoid with Single-current (단전류-다층 솔레노이드 방법을 사용한 저자장 표준시스템 제작)

  • 박포규;김영균
    • Journal of the Korean Magnetics Society
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    • v.11 no.1
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    • pp.38-44
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    • 2001
  • The magnetic field standard below 1 mT with the resolution of 0.26 nT has been established. Earth magnetic field (EMF) is compensated automatically down to 0.1 nT/10 min. by a closed feedback system with Cs optical pumping magnetometer and 3-axis Helmholtz coils in nonmagnetic facilities. A multi-layer precision solenoid with the optimized single-current method generates the uniform magnetic field better than 1.0$\times$10$\^$-7/ within $\pm$ 1 cm region at its center. The coil constant of solenoid determined from Helium optical pumping magnetometer is 1.231 058 9 mT/A, and temperature coefficient is 0.38 nT/$\^{C}$. This standard system is used for calibration of low field magnetometers and testing relates to low field.

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Estimation and Control of Speed of Induction Motor using FNN and ANN (FNN과 ANN을 이용한 유도전동기의 속도 제어 및 추정)

  • Lee Jung-Chul;Park Gi-Tae;Chung Dong-Hwa
    • Journal of the Institute of Electronics Engineers of Korea SC
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    • v.42 no.6
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    • pp.77-82
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    • 2005
  • This paper is proposed fuzzy neural network(FNN) and artificial neural network(ANN) based on the vector controlled induction motor drive system. The hybrid combination of fuzzy control and neural network will produce a powerful representation flexibility and numerical processing capability. Also, this paper is proposed control and estimation of speed of induction motor using fuzzy and neural network. The back propagation neural network technique is used to provide a real time adaptive estimation of the motor speed. The error between the desired state variable and the actual one is back-propagated to adjust the rotor speed, so that the actual state variable will coincide with the desired one. The back propagation mechanism is easy to derive and the estimated speed tracks precisely the actual motor speed. This paper is proposed the experimental results to verify the effectiveness of the new method.