• Title/Summary/Keyword: Rejection property

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Multi-Band Rejection Slot-Shaped DGS and Its Equivalent Circuit Model (다중 대역 슬롯형 DGS와 등가 회로 모델)

  • Woo, Duk-Jae
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.21 no.5
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    • pp.537-543
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    • 2010
  • This paper presents a slot-shaped defected ground structure(DGS) which has multi-band rejection property. The proposed structure, in which the spiral slot-shaped defects with different size are aligned in the transverse direction to the guiding direction of the coplanar waveguide(CPW), provides multiple resonance frequencies. Compared with the simulated results, the band rejection characteristic is in good agreement with the measurement. Also, an equivalent circuit model of the proposed structure is presented, where the DGS on the ground plane is modeled as LC-resonators. This resonators are inductively coupled to the signal line through mutual inductance. From the equivalent circuit model, multi-band rejection property was derived.

Rejection Properties of Aromatic Pesticides by a Hollow Fiber NF Membrane (중공사 나노여과막을 이용한 방향족 농약의 배제 특성)

  • Jung, Yong-Jun;Kiso, Yoshiaki;Park, Soon-Gil;Kim, Jong-Yong;Min, Kyung-Sok
    • Journal of Korean Society on Water Environment
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    • v.20 no.3
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    • pp.296-300
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    • 2004
  • The rejection properties of 6 aromatic pesticides were evaluated by a continuous flow system equipped with a hollow fiber NF membrane. Different from the separation experiment of batch cell, the rejection and the removal could be calculated exactly because the concentration of feed, permeate and retentate was separately obtained. The lowest and the highest rejection were found in carbaryl(54.8%) and methoxychlor(99.2%), respectively, and the removals were always shown higher than rejections. This may be caused by some reasons such as the solute adsorption on the membrane, the variation of feed concentration. Although molecular weight, molecular width regarded as solute characteristics and log P(n-octanol/water partition coefficient) as hydrophobicity could be applied to explain the rejection property, these factors should be considered together for better analysis. According to the higher relationship between log B(solute permeability) and molecular weight, it was revealed that the solute separation with this membrane was influenced more by molecular weight.

Rejection property of geosmin and 2-Methylisoborneol (MIB) with high concentration level at multi stage nanofiltration (NF) membrane system (다단 나노여과 공정에서 고농도 geosmin 및 2-Methylisoborneol (MIB)의 제거특성)

  • Yu, Young-Beom;Choi, Yang Hun;Kim, Dong Jin;Kwon, Soon-Buhm;Kim, Chung-Hwan
    • Journal of Korean Society of Water and Wastewater
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    • v.28 no.4
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    • pp.397-409
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    • 2014
  • Algal problem in drinking water treatment is being gradually increased by causing deterioration of water supplies therefore, especially taste and odor compounds such as geosmin and 2-MIB occur mainly aesthetic problem by its unpleasant effects resulting in the subsequent onset of complaints from drinking water consumer. Recently, geosmin and 2-MIB are detected frequently at abnormally high concentration level. However, conventional water treatment without advanced water treatment processes such as adsorption and oxidation process, cannot remove these two compounds efficiently. Moreover, it is known that the advanced treatment processes i.e. adsorption and oxidation have also several limits to the removal of geosmin and 2-MIB. Therefore, the purpose of this study was not only to evaluate full scale nanofiltration membrane system with $300m^3/day$ of permeate capacity and 90% of recovery on the removal of geosmin and 2-MIB in spiked natural raw water sources at high feed concentration with a range of approximately 500 to 2,500 ng/L, but also to observe rejection property of the compounds within multi stage NF membrane system. Rejection rate of geosmin and 2-MIB by NF membrane process was 96% that is 4% of passage regardless of the feed water concentration which indicates NF membrane system with an operational values suggested in this research can be employed in drinking water treatment plant to control geosmin and 2-MIB of high concentration. But, according to results of regression analysis in this study it is recommended that feed water concentration of geosmin and 2-MIB would not exceed 220 and 300 ng/L respectively which is not to be perceived in drinking tap water. Also it suggests that the removal rate might be depended on an operating conditions such as feed water characteristics and membrane flux. When each stage of NF membrane system was evaluated relatively higher removal rate was observed at the conditions that is lower flux, higher DOC and TDS, i.e., $2^{nd}$ stage NF membrane systems, possibly due to an interaction mechanisms between compounds and cake layer on the membrane surfaces.

Analysis of Discrete-Time Disturbance Observer for Second-Order Systems (2차 시스템에 대한 이산시간 외란 관측기의 분석)

  • 양광진;최영진;정완균
    • Journal of Institute of Control, Robotics and Systems
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    • v.9 no.6
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    • pp.425-434
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    • 2003
  • The disturbance observer(DOB) has been widely used in high speed and high precision motion control applications and the characteristics of DOB have been investigated in depth. Though most of DOB's have been implemented as the discrete-time form in digital devices, we are still short of the researches on discrete-time DOB (DDOB) in spite of rich references on continuous-time DOB. In this paper, we discuss about the disturbance rejection property and measurement noise effect of discrete-time DOB. Especially, we will focus on revealing the role of sampling time in designing the discrete-time DOB and show the validity of analysis through simulations and experiments for optical disk drive systems.

Analysis on the properties of an NTSC interference rejection filter in terrestrial DTV receivers (지상파 DTV 수신기에서의 NTSC 간섭 제거 필터에 관한 특성 분석)

  • Kim Hyoung-Nam
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.30 no.1A
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    • pp.84-90
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    • 2005
  • In Korea, transition to digital TV broadcasting started at the metropolitan Seoul area and has expanded to the metropolitan area in 2004. However, until 2010 analog NTSC broadcasting will co-exist with digital TV. In this situation, digital TV may have the same channel as an analog NTSC broadcasting. To remove the effect of the analog NTSC intereference, DTV receivers adopt an NTSC rejection filter. In this paper, analysis on properties of the filter, such as a rejection property and noise performance degradation, is presented.

A Analysis on the Effect of the Controller Design due to Performance Index (평가지표에 따른 제어기 설계 영향 분석)

  • Yoo, Hang-Youal;Lee, Jung-Kuk;Lee, Keum-Won;Lee, Jun-Mo
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 2004.05a
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    • pp.90-94
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    • 2004
  • Among various modern control theories, PID control has been well used for several decades. PID algorithms needs son tuning methods are used for selecting PID parameters. But in some cases various kinds of performance indices are used instead of well-known tuning rules, and so variable type of performance index must be tested so that controllers, output characteristics and disturbance rejection property meets some specifications. In this paper, linear conbinational type of performance using error signal, time, control input and robustness is used to the PID control of air conditioning system. By the 2 DOF PID parmeters minimizing perfromacne index, controllers, output characteristics and robustness properties are analyzed. Simulations are done with MATLAB m file and mdl files.

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D-CRLH Based Band Rejection Filter using a Concavo-Convex Coupled CPW Transmission Line

  • Seo, Soo-Duk;Cho, Hak-Rae;Yang, Doo-Yeong
    • Journal of Electrical Engineering and Technology
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    • v.11 no.2
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    • pp.463-469
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    • 2016
  • In this paper, the use of a dual composite right/left-handed coplanar waveguide (CPW) transmission line is proposed for the design of a band rejection filter. The notch property of the filter is achieved by combining the convex signal line with the shorted concave meander line, and the equivalent circuit model is extracted from the geometry of the unit cell for organizing the band rejection property. Then the equivalent parameters of the unit cell are analyzed to identify those behaviors. And the dispersion characteristics and energy distributions are simulated. In the end, the band rejection filter is manufactured by cascading two proposed unit cells. We show that the measurement result for the resonant frequency demonstrates good agreement with the simulation result and the band rejection filter provides a rejection performance of 17.5 dB at the stopband frequency ranging from 869 MHz to 894 MHz.

Data Transmission lSystem by Pattern Synchronization (패턴동기에 의한 디지탈데이타 통신방식)

  • 안수길
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.9 no.1
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    • pp.25-30
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    • 1972
  • Data Communication by sending pulse train and verifying the lock-in of a phase locked loop in receiving end is studied. The noise rejection property inherent to PLL is analysed. By using about six pulses in a train, data transimission rate of 20k bit/sec. in a telephone cable is achieved, thus permitting high speed data communication and an exellent immunity against noise.

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Rejection Properties of Hydrophilic Solutes and Micro Organic Pollutants with a Hollow Fiber NF Membrane (중공사 나노여과 막분리를 이용한 친수성 용질과 미량 유기 오염물질의 배제 특성)

  • Jung, Yong-Jun;Min, Kyung-Sok
    • Journal of Korean Society on Water Environment
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    • v.21 no.2
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    • pp.205-210
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    • 2005
  • There has been a growing interest in NF membrane for drinking water treatment, because it can remove simultaneously both hardness and hazardous micro pollutants such as pesticides and THM precursors. In this work, a hollow fiber NF membrane known as a composite membrane was employed for the rejection properties of both hydrophilic solutes and micro organic pollutants, where the former was used to evaluate the molecular sieving effect of this membrane and the latter was employed for the investigation of solute-membrane interaction as hydrophobic materials. This membrane effectively rejected the hydrophilic solutes and the permeation of them was mainly controlled by the molecular sieving effects such as molecular weight and molecular width. In the case of all micro organic pollutants, the rejections were varied from 42.2% for Simazine to 91.6% for Malathion, and the parameters related to the steric hindrance could significantly play an important role in the rejection. In the batch type adsorption experiments, all micro organic pollutants were entrapped mildly on the membrane in spite of lower degree compared with that of aromatic compounds, and they were correlated with log K.

Incremental Passivity Based Control for DC-DC Boost Converters under Time-Varying Disturbances via a Generalized Proportional Integral Observer

  • He, Wei;Li, Shihua;Yang, Jun;Wang, Zuo
    • Journal of Power Electronics
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    • v.18 no.1
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    • pp.147-159
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    • 2018
  • In this paper, the voltage tracking control of a conventional DC-DC boost converter affected by unknown, time-varying circuit parameter perturbations is investigated. Based on the fundamental property of incremental passivity, a passivity based control law is designed. Then, to obtain a better disturbance rejection property, two generalized proportional integral (GPI) observers are employed to estimate the time-varying uncertainties in the output voltage and inductor current channels, and the estimated values are applied as feedforward compensation. Moreover, the global trajectory tracking performance of a system with disturbances is ensured under the composite controller. Finally, simulation and experiment studies are provided to demonstrate the feasibility and effectiveness of the proposed method. The results show that the proposed controller delivers a promising disturbance rejection capability as well as a good nominal tracking performance.