• Title/Summary/Keyword: Interference temperature

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A Study on Ozone Passive Sampler (II) -Interference and Field Application (오존간이 측정기에 대한 연구(II)-간섭현상 및 현장 적용성)

  • Jeong, Sang-Jin;Yang, Hee-Jun
    • Journal of Korean Society for Atmospheric Environment
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    • v.22 no.6
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    • pp.904-911
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    • 2006
  • Passive sampler is simple and inexpensive measuring equipment for air pollution. In this study we developed colorimetric ozone passive sampler which was coated a colorimetric reagent to a filter substrate. Interference of criteria all pollutant ($SO_2,\;NO_2,\;CO$) on ozone passive sampler was investigated through experimental chamber. Field measurement of developed ozone passive samper was compared automatic sampler result in Suwon area. The results shows interference of $SO_2$ gas is larger than other gases. Developed passive sampler can be roughly applicable to wind speed range from 0.8 to 3.3 m/s, temperature range from 3.9 to $27.5^{\circ}C$ and relative humidity range from 48 to 84%.

Subcarrier-Pairing Scheme for OFDMA based Multi-Hop Cognitive Radio Systems (OFDMA 기반 다중 홉 무선 인지 시스템을 위한 부반송파 페어링 방법)

  • Kim, Jae-Hyun;Shin, Jung-Chae;Cho, Ho-Shin;Jang, Youn-Seon
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.36 no.6A
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    • pp.601-608
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    • 2011
  • In OFDMA(Orthogonal Frequency Division Multiple Access) based multi-hop networks, the subcarrier-pairing scheme using the SNR(Signal-to-Noise Ratio) has been proposed as the best solution. But, this scheme is not optimal in cognitive radio system, because of the power control due to the interference to the primary user. In this paper, we propose two subcarrier-pairing schemes for OFDMA based 2-hop cognitive radio systems. One is the IT(Interference channel gain) scheme considering only the interference channel gain, and the other is the CI(Channel SNR over interference channel gain) scheme considering the ratio of channel SNR to interference channel gain. The results show that the CI scheme has the best performance in which throughput is improved more than 10% in comparison with other schemes.

Generalized Sidelobe Canceler for TPMS Interference Cancellation (TPMS 간섭제거를 위한 Generalized Sidelobe Canceler)

  • Park, Cheol;Hwang, Suk-Seung
    • Journal of the Korean Institute of Intelligent Systems
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    • v.22 no.5
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    • pp.663-668
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    • 2012
  • A TPMS(Tire Pressure Monitoring System) is a wireless communication system designed to monitor the pressure and temperature of pneumatic tires of a vehicle. In order to provide the aid in protecting a driver, this system reports tire pressure information to the driver of the vehicle. Since the wireless communication technique should be employed to transmit the TPMS data from each tire to signal processing unit in the vehicle, it suffers from interference signals from external electrical or electronics equipments. In this paper, we propose the TPMS interference cancellation technique based on GSC(Generalized Sidelobe Canceler), which does not have only the excellent performance like MVDR(Minimum-Variance-Distortionless-Response) but also has the low computational complexity comparing with MVDR. The performance of interference suppression is conformed by computer simulation examples.

Electrical Properties and Electromagnetic Shielding Effectiveness of Milled Carbon Fiber/Nylon Composites (분쇄형 탄소 섬유/나일론 복합재료의 전기적 성질과 전자파 차폐 효율)

  • 김창제;최형도;서광석;윤호규
    • Polymer(Korea)
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    • v.27 no.3
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    • pp.201-209
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    • 2003
  • DC and AC electrical conductivity and electromagnetic interference shielding effectiveness of milled carbon fiber/nylon composites were investigated with the kind of nylon matrix. Percolation transition at which the conductivity is sharply increased was observed at about 7 vol% of milled carbon fiber. Nylon 46 as a matrix was more effective to obtain high electrical conductivity than nylon 6, and the difference in conductivity was occurred by the treatment of coupling agent. Frequency dependence of AC conductivity could be explained by relaxation phenomenon at just below percolation and resonance phenomenon at 40 vol% of carbon fiber, respectively. Negative temperature coefficient phenomenon was found in all composites. Electromagnetic interference shielding effectiveness was increased with the concentration of carbon fiber. At a high conductivity region the return loss was more dominant to the total shielding effectiveness than the absorption loss.

Analytical Prediction of Heating Temperature to Manufacture Rotor with Shrink Fit for Ultra High Speed Motor According to Change Dimension of Rotor (초고속기용 열박음 로터 제작을 위한 로터의 치수에 따른 가열온도의 해석적 예측)

  • Hong, Do-Kwan;Woo, Byung-Chul;Jeong, Yeon-Ho;Koo, Dae-Hyun;Ahn, Chan-Woo
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.33 no.9
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    • pp.963-968
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    • 2009
  • This paper deals with shrink fit analysis of rotor by 2D cross-section, 2D axis-symmetry, and 3D FEM model. And this paper presents 2nd order approximation function of thermal expansion displacement by design variables (shape dimension, heating temperature, sleeve length, interference etc.), table of orthogonal array and RSM(response surface methodology). The possibility of the rotor with shrink fit is evaluated by thermal expansion displacement. If thermal expansion displacement is larger than interference, shrink fit enable to make the rotor. 2D axis-symmetry model and 3D model are more reasonable than 2D cross-section model, because stress and strain is different along length of shaft.

Reliability Estimation of Door Hinge for Rome Appliances (가전제품용 경첩의 신뢰성 추정)

  • Kim Jin Woo;Shin Jae Chul;Kim Myung Soo;Moon Ji Seob
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.29 no.5 s.236
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    • pp.689-697
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    • 2005
  • This paper presents the reliability estimation of door hinge for home appliances, which consists of bushing and shaft. The predominant failure mechanism of bushing made of polyoxymethylene(POM) is brittle fracture due to decrease of strength caused by voids existing, and that of shaft made of acrylonitrile-butadiene-styrene(ABS) is creep due to plastic deformation caused by excessive temperature and lowering of glass transition temperature by absorbed moisture. Since the brittle fracture of bushing is overstress failure mechanism, the load-strength interference model is used to estimate the failure rate of it along with failure analysis. By the way, the creep of shaft is wearout failure mechanism, and an accelerated life test is then planned and implemented to estimate its lifetime. Through the technical review about failure mechanism, temperature and humidity are selected as accelerating variables. Assuming Weibull lifetime distribution and Eyring model, the life-stress relationship and acceleration factor, $B_{10}$ life and its lower bound with $90\%$ confidence at worst case use condition are estimated by analyzing the accelerated life test data.

Reliability Estimation of Door Hinge for Home Appliances (가전제품용 경첩의 신뢰성 추정)

  • 문지섭;김진우;이재국;이희진;신재철;김명수
    • Proceedings of the Korean Reliability Society Conference
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    • 2004.07a
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    • pp.303-311
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    • 2004
  • This paper presents the reliability estimation of door hinge for home appliances, which consists of bushing and shaft. The predominant failure mechanism of bushing made of polyoxymethylene(POM) is brittle fracture due to decrease of strength caused by voids existing, and that of shaft made of acrylonitrile-butadiene-styrene(ABS) is creep due to plastic deformation caused by excessive temperature and lowering of glass transition temperature by absorbed moisture. Since the brittle fracture of bushing is overstress failure mechanism, the load-strength interference model is used to estimate the failure rate of it along with failure analysis. By the way, the creep of shaft is wearout failure mechanism, and an accelerated life test is then planned and implemented to estimate its lifetime. Through the technical review about failure mechanism, temperature and humidity are selected as accelerating variables. Assuming Weibull lifetime distribution and Eyring model, the life-stress relationship and acceleration factor, B$_{10}$ life and its lower bound with 90% confidence at worst case use condition are estimated by analyzing the accelerated life test data.a.

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Detection of White Light Interference Peak Position utilizing Analog Signal Processing (아날로그 신호처리를 이용한 백색광 간섭 피크의 검출)

  • Yeh, Yun-Hae;Lee, Jong-Kwon
    • Korean Journal of Optics and Photonics
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    • v.16 no.4
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    • pp.319-325
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    • 2005
  • A signal processing method for white light interferometry (WLI), which performs a series of analog signal processing steps to locate the central interference fringe position at high speed: is developed and applied to a WLI temperature sensor system. We found that the new method has random walk of $0.019^{\circ}C/\sqrt{Hz}$ with good linearity. However, the temperature change in the path-matching interferometer results in drift of the measured sensor output. The temperature dependence of drift in the WLI temperature sensor system, was calculated to be $1.42{\mu}m/^{\circ}C$. It is also found that the relationship between the peak spacing in the interferogram and the spacing measured by the method can be nonlinear when the fringe spacing is comparable to the coherence length of the source.

Real-time 14N NQR-based sodium nitrite analysis in a noisy field

  • Mohammad Saleh Sharifi;Ho Seung Song;Hossein Afarideh;Mitra Ghergherehchi;Mehdi Simiari
    • Nuclear Engineering and Technology
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    • v.55 no.12
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    • pp.4570-4575
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    • 2023
  • Noise and Radio-frequency interference or RFI causes a significant restriction on the Free induction Decay or FID signal detection of the Nuclear Quadrupole Resonance procedure. Therefore, using this method in non-isolated environments such as industry and ports requires extraordinary measures. For this purpose, noise reduction algorithms and increasing signal-to-noise-and-interference ratio or SNIR have been used. In this research, sodium nitrite has been used as a sample and algorithms have been tested in a non-isolated environment. The resonant frequencies for the 150 g of test sample were measured at 303 K at about 1 MHz and 3.4 MHz. The main novelty in this study was, (1) using two types of antennas in the receiver to improve adaptive noise and interference cancellation, (2) using a separate helical antenna in the transmitter to eliminate the duplexer, (3) estimating the noise before sending the pulse to calculate the weighting factors and reduce the noise by adaptive noise cancellation, (3) reject the interference by blanking algorithm, (4) pulse integration in the frequency domain to increase the SNR, and (5) increasing the detection speed by new pulse integration technique. By interference rejection and noise cancellation, the SNIR is improved to 9.24 dB at 1 MHz and to 7.28 dB at 3.4 MHz, and by pulse integration 44.8 dB FID signal amplification is achieved, and the FID signals are detected at 1.057 MHz and 3.402 MHz at room temperature.

A Study on the Contact Force and Temperature Distribution of Lip Seals (립실의 접촉력 및 온도분포 해석에 관한 연구)

  • 김청균;전인기;김종억
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.18 no.6
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    • pp.1559-1566
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    • 1994
  • Using the finite element method, the contact force, contact band width and temperature distribution of lip seals analyzed for the interference including some nonlinearities such as material nonlinearity, geometrical nonlinearity and nonlinear contact boundary condition. The calculated results showed that the contact stress concentrated on the contact zone between the garter spring and the rubber toward the flex side, the contact edge of lip seals. The high contact forces due to the increased interference separate the sealing gap between the lip edge and the rotating shaft. This may lead to leak the sealed oil.