• Title/Summary/Keyword: merit order effect

Search Result 47, Processing Time 0.031 seconds

Bandwidth Enhancement of Underwater Acoustic Transducer Using a Bandpass Matching Network (대역통과 정합회로를 이용한 수중음향변환기의 대역폭 확장)

  • Lee, Dae-Jae
    • Korean Journal of Fisheries and Aquatic Sciences
    • /
    • v.52 no.6
    • /
    • pp.702-708
    • /
    • 2019
  • The range resolution of echo sounders can be improved by enhancing the transducer bandwidth. We designed a bandpass matching network for expanding the bandwidth of a transducer by scaling in both impedance and frequency after transforming a lowpass network into a bandpass configuration for a third-order Bessel filter. We measured the effect of the Bessel matching network for a 50 kHz sandwich type transducer on the transmitting voltage response (TVR), receiving sensitivity (SRT) and figure of merit (FOM), using a chirp echo sounder system. Both the simulation and experimental results indicated that the transducer with a bandpass matching network was capable of producing a symmetrical acoustic output over a wider bandwidth (8.25 kHz) than was the transducer without a matching network (3.75 kHz). By implementing the Bessel matching network, we achieved a 120% bandwidth enhancement.

Focusing Servo System in Pickup Actuator with friction (마찰이 존재하는 픽업 구동기의 포커싱 서보 시스템)

  • 이정현;한창수;원종화;윤형덕;김수현;곽윤근
    • Proceedings of the Korean Society of Precision Engineering Conference
    • /
    • 1996.11a
    • /
    • pp.346-350
    • /
    • 1996
  • In optical disk drives, one of commonly used pickup actuator is a Sliding and rotary type of pickup actuator which is cheaper than other pickup actuators and has simple assembly. However, it reported that non-linearity due to friction between a shaft and a sleeve had to be considerably analyzed in design and servo system in employing this type of pickup actuator. In this paper, this friction is modeled as a Coulomb's friction and the effect of friction is examined in the simulation. A digital servo system is applied to pickup actuator with friction in order to have good focusing servo. To enhance focusing servo performance using digital servo merit, frist PD-controller is applied to have fast response performance, second lead-lag compensator is applied to have stable focusing performance.

  • PDF

Permeability of CoZrNb film with thickness (CoZrNb막의 두께에 따른 투자율의 변화)

  • Hoe, J.;Kim, Y.H.;Shin, K.H.;Sa-Gong, G.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 2001.07a
    • /
    • pp.443-446
    • /
    • 2001
  • MI(Magneto-Impedance) sensor which is made by thin films has significantly high detecting sensitivity in weak magnetic field. It also has a merit to be able to build in low power system. Its structure is simple, which makes it easier to prepare a miniature. In this study, its magnetic permeability and anisotropy field(H$\sub$k/) as a function of a thickness of sputtered amorphous CoZrNb thin film with high saturation magnetostriction and excellent soft magnetic property are investigated. In order to make a uniaxial anisotropy, thin film was subjected to post annealing with a static magnetic field with 1KOe intensity at 250, 300, and 320$^{\circ}C$ for 2 hour. Anisotropy field(H$\sub$k/)of thin film is measured by using MH loop tracer. Its magnetic permeability of thin film is measured over the frequency range from 1 MHz to 750MHz. It has shown that the magnetic permeability of amorphous CoZrNb thin film is decreased due to the skin effect with increasing a thickness of CoZrNb thin film, and hence its driving frequency is lowered.

  • PDF

Impedance of CoZrNb Film as a Function of Frequency (CoZrNb막의 주파수에 따른 임피던스의 변화)

  • Hur, J.;Kim, Y.H.;Shin, K.H.;Park, K.I.;SaGong, G.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 2002.07b
    • /
    • pp.778-781
    • /
    • 2002
  • MI(Magneto-Impedance) sensor which is made by thin films has significantly high detecting sensitivity in weak magnetic field. It also has a merit to be able to build in the low power system. Its structure is simple, which makes it easier to prepare a miniature. In this study, its magnetic permeability and anisotropy field$(H_k)$ as a function of a thickness of sputtered amorphous CoZrNb films with zero-magnetostriction and excellent soft magnetic property are investigated. In order to make a uniaxial anisotropy, film was subjected to the post annealing in a static magnetic field with 1KOe intensity at 250, 300, and $320^{\circ}C}$ respectively for 2 hours. Anisotropy field$(H_k)$ of film is measured by using a MH loop tracer. Its magnetic permeability of a film is measured over the frequency range from 1 MHz to 750MHz. It has shown that the magnetic permeability of amorphous CoZrNb film is decreased due to the skin effect with increasing a thickness of the CoZrNb film, and hence its driving frequency is lowered. And, it was examined on the permeability and impedance to fabricate the MI sensor which acts at a low frequency by thickening a CoZrNb film relatively.

  • PDF

Optimal Seam-line Determination for the Image Mosaicking Using the Adaptive Cost Transform (적응 정합 값 변환을 이용한 영상 모자이크 과정에서의 최적 Seam-Line 결정)

  • CHON Jaechoon;KIM Hyongsuk
    • The Transactions of the Korean Institute of Electrical Engineers D
    • /
    • v.54 no.3
    • /
    • pp.148-155
    • /
    • 2005
  • A seam-line determination algorithm is proposed to determine image border-line in mosaicing using the transformation of gray value differences and dynamic programming. Since visually good border-line is the one along which pixel differences are as small as possible, it can be determined in association with an optimal path finding algorithm. A well-known effective optimal path finding algorithm is the Dynamic Programming (DP). Direct application of the dynamic programming to the seam-line determination causes the distance effect, in which seam-line is affected by its length as well as the gray value difference. In this paper, an adaptive cost transform algorithm with which the distance effect is suppressed is proposed in order to utilize the dynamic programming on the transformed pixel difference space. Also, a figure of merit which is the summation of fixed number of the biggest pixel difference on the seam-line (SFBPD) is suggested as an evaluation measure of seamlines. The performance of the proposed algorithm has been tested in both quantitively and visually on various kinds of images.

Effect of a Cu Buffer Layer on the Structural, Optical, and Electrical Properties of IGZO/Cu bi-layered Films

  • Moon, Hyun-Joo;Gong, Tae-Kyung;Kim, Daeil;Choi, Dong-Hyuk;Son, Dong-Il
    • Transactions on Electrical and Electronic Materials
    • /
    • v.17 no.1
    • /
    • pp.18-20
    • /
    • 2016
  • Transparent and conducting IGZO thin films were deposited by RF magnetron sputtering on thin Cu coated glass substrates to investigate the effect of a Cu buffer layer on the structural, optical, and electrical film properties. Although X-ray diffraction (XRD) analysis revealed that both the IGZO single layer and IGZO/Cu bi-layered films were in the amorphous phase, the IGZO/Cu films showed a lower resistivity of 5.7×10−4 Ωcm due to the increased mobility and high carrier concentration. The decreased optical transmittance of the IGZO/Cu films was also attributed to a one order of magnitude higher carrier concentration than the IGZO films. From the observed results, the thin Cu layer is postulated to be an effective buffer film that can enhance the opto-electrical performance of the IGZO films in transparent thin film transistors.

THE STUDY ON TISSUE CULTURED WILD MOUNTAIN GINSENG(Panax Ginseng C.A. Meyer) ADVENTITIOUS ROOTS EXTRACT AS A COSMETIC INGREDIENT

  • Jung, Eun-Joo;Park, Jong-Wan;Kim, Joong-Hoi;Paek, Kee-Yoeup
    • Proceedings of the SCSK Conference
    • /
    • 2003.09a
    • /
    • pp.611-616
    • /
    • 2003
  • Korean ginseng(Panax Ginseng C.A. Meyer) known as a oriental miracle drug is an important medicinal plant. Ginseng has been used for geriatric, tonic, stomachic, and aphrodisiac treatments for thousands years. Also, it is an antibiotic and has therapeutic properties against stress and cancer. Ginseng is widely distributed all over the world. Among them, Korean mountain ginseng has the most valuable effect on pharmaceuticals. The roots of mountain ginseng contained several kinds of ginsenosides that have many active functions for the human body. However, the study of mountain ginseng has a limit because the mountain ginseng is very expensive and rare. So, we artificially cultured mountain ginseng adventitious roots using the bioreactor culture system. We induced callus from original mountain ginseng, directly dug up in mountain and aged about one hundred ten years. Separated adventitious roots were precultured in 500ml conical flasks and then, transferred in 20L bioreactors. The adventitious roots of mountain ginseng were harvested after culturing for 40days, dried and then, extracted with several solvents. In this study, we investigated the whitening effect, anti-wrinkle effect and the safety of tissue cultured adventitious roots extract of mountain ginseng in order to identify the merit as a cosmetic ingredient. Particularly, extract of mountain ginseng adventitious roots showed whitening and anti-wrinkle effects. The inhibitory effect of this extract on the melanogenesis was examined using B-16 melanoma cell. When B-16 melanoma cells were cultured with adventitious root extract, there was a dramatically decrease in melanin contents of 8-16 melanoma cell. And we identified this extract inhibited Dopa auto-oxidation significantly. Also, when transformed mouse fibroblast L929 cells were treated with this extract, there was a significant increase in collagen synthesis. The results show significant inhibited melanization and wrinkle without inhibiting cell viability.

  • PDF

A Study of Consumption Practices and Needs for Cosmeceuticals of Female University Students (여대생의 기능성화장품 구매 및 사용실태와 요구도)

  • Yun, Ji-Joo;Kweon, Soo-Ae
    • Korean Journal of Human Ecology
    • /
    • v.13 no.2
    • /
    • pp.271-282
    • /
    • 2004
  • The purposes of this study were to research the behavior of consumption and needs about the female university students to provide useful information which would help finding the marketing source of cosmeceuticals. The sample was consisted of 464 female university students who had experiences of using the cosmeceuticals. Data were analyzed by factor analysis, frequency, x2-test, t-test, ANOVA(LSD) using SPSSWIN. The results were as follows: When the female university students purchased the cosmeceuticals, they considered the effectiveness and the price, so were satisfied with good effect and low price. The most important marketing methods in cosmeceuticals for female university students were through the internet and mail order shopping. Whereas, demerit factors of internet shopping were founded to be the complexity of exchange or refund and the little chance of free samples for trial. The good marketing strategies might be sending trial samples, future payment system after trial period, and/or supporting the event held in the university. Besides, it might be a consideration to have an event for the improvement by public trial. Anti-aging cosmeceutical was the most preferred item for female students, sun protection and whitening cosmetics next in order. Therefore, a target customer for cosmeceuticals might be lowered in age. The purchasing cost system and therapeutic effect of cosmeceuticals had to be developed for 20's. It was necessary to be safe and effective. The factors affecting the level of satisfaction for cosmeceuticals could be categorized into 4; market environment, simplicity of purchase, product merit and additional service. The needs for cosmeceuticals showed significant differences according to grade and kinds of product.

  • PDF

Linearity-Distortion Analysis of GME-TRC MOSFET for High Performance and Wireless Applications

  • Malik, Priyanka;Gupta, R.S.;Chaujar, Rishu;Gupta, Mridula
    • JSTS:Journal of Semiconductor Technology and Science
    • /
    • v.11 no.3
    • /
    • pp.169-181
    • /
    • 2011
  • In this present paper, a comprehensive drain current model incorporating the effects of channel length modulation has been presented for multi-layered gate material engineered trapezoidal recessed channel (MLGME-TRC) MOSFET and the expression for linearity performance metrics, i.e. higher order transconductance coefficients: $g_{m1}$, $g_{m2}$, $g_{m3}$, and figure-of-merit (FOM) metrics; $V_{IP2}$, $V_{IP3}$, IIP3 and 1-dB compression point, has been obtained. It is shown that, the incorporation of multi-layered architecture on gate material engineered trapezoidal recessed channel (GME-TRC) MOSFET leads to improved linearity performance in comparison to its conventional counterparts trapezoidal recessed channel (TRC) and rectangular recessed channel (RRC) MOSFETs, proving its efficiency for low-noise applications and future ULSI production. The impact of various structural parameters such as variation of work function, substrate doping and source/drain junction depth ($X_j$) or negative junction depth (NJD) have been examined for GME-TRC MOSFET and compared its effectiveness with MLGME-TRC MOSFET. The results obtained from proposed model are verified with simulated and experimental results. A good agreement between the results is obtained, thus validating the model.

Dielectric and Piezoelectric Properties of Low Temperature Sintering (Na,K,Li)(Nb,Sb,Ta)O3 Ceramics Doped with SnO2 (SnO2가 첨가된 저온소결 (Na,K,Li)(Nb,Sb,Ta)O3계 세라믹스의 유전 및 압전 특성)

  • Lee, Gwang-Min;Yoo, Ju-Hyun;Lee, Ji-Young
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.28 no.11
    • /
    • pp.690-693
    • /
    • 2015
  • In this paper, in order to develop excellent Pb-free composition ceramics for ultrasonic sensor. The $SnO_2$-doped ($Na_{0.525}K_{0.443}Li_{0.037})(Nb_{0.883}Sb_{0.08}Ta_{0.037})O_3$)(abbreviated as NKL-NST) ceramics have been synthesized using the ordinary solid state reaction method. The effect of $SnO_2$-doping on their dielectric and piezoelectric properties was investigated. The ceramics doped with 0 wt% $SnO_2$ have the optimum values of piezoelectric constant($d_{33}$), piezoelectric figure of merit($d_{33}.g_{33}$), planar piezoelectric coupling coefficient($k_p$) and density : $d_{33}=195[pC/N]$, $d_{33}.g_{33}=5.62pm^2/N.kp=0.40$, $density=4.436[g/cm^3]$. suitable for duplex ultrasonic sensor application.