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The application of the self-adaptive tracking method to the sinusoidal phase modulating interferometry
Guotian He,Yuangang Lu,Changrong Liao,Zhi Zeng
Optica Applicata , 2009,
Abstract: In this paper, we analyze theoretically the accuracy of the surface profile measurement in a sinusoidal phase modulating interferometer, derive the relative error formula, and investigate the influence of spectral leakage on the measurement accuracy. The theoretical results show that when the offset of sampling frequency from its theoretical ideal is outside the range of – 0.188% to +0.075%, the spectrum leakage results in an relative error greater than λ/320 nm, and thus the spectral leakage is not negligible. In order to eliminate the influence of the spectral leakage, a self-adaptive tracking method is proposed. The tracking method can adjust automatically the sampling signal frequency in such a way that the sampling signal frequency is an integer multiple of the modulating signal frequency. The simulation and experimental results show that the problem of the spectrum leakage can be solved with the proposed technique, and therefore the measurement accuracy and reliability of the SPM interferometer are enhanced.
Effect of Blade Profile on the Performance of Wells Turbine under Unidirectional Sinusoidal and Real Sea Flow Conditions  [PDF]
A. Thakker,R. Abdulhadi
International Journal of Rotating Machinery , 2007, DOI: 10.1155/2007/51598
Abstract: This paper presents the effect of blade profile and rotor solidity on the performance of Wells turbine operating under unidirectional unsteady flow conditions. In the study, four kinds of blade profile were selected, that is, NACA0020, NACA0015, CA9, and HSIM 15-262123-1576. The experiments have been carried out for two solidities, σ = 0.48 and σ = 0.64, under sinusoidal and irregular unsteady flow conditions based on Irish waves (site2). As a result, it was found that the preferable rotor geometry is the one with blade profile of CA9 with solidity σ = 0.64. In addition, the effect of blade profile and rotor solidity on hysteretic characteristics of the turbine has been clarified experimentally and it was found to be in good agreement qualitatively when compared to numerical results (Setoguchi et al. (2003)).
Non-Sinusoidal PWM Method for Cascaded Multilevel Inverter
Shahrin Md Ayob,Zaenal Salam,Abdul Halim M. Yatim
TELKOMNIKA : Indonesian Journal of Electrical Engineering , 2012, DOI: 10.11591/telkomnika.v10i4.855
Abstract: This paper presents a new switching method for Cascaded Multilevel Inverter (CMI). The new method uses multiple non-sinusoidal signals as the modulating signal. The main advantage of using non-sinusoidal modulating signal is that it provides higher fundamental component but at the cost of having a numbers of low-order harmonics in its unfiltered output voltage; naturally contributed by the non-sinusoidal modulating signal. In this paper, the Trapezoidal waveform is employed as the non-sinusoidal modulating signal for the CMI. Its harmonics profile of different slope angles is analysed. From the analysis, it was found that the trapezoidal with the slope angle of 36o eliminates the third and fifth harmonics yet yields a high fundamental magnitude. To verify, a single-phase CMI prototype is constructed and an ALTERA FPGA is deployed to implement the proposed method’s algorithm. From the results, it was shown that analysis is validated
Interaction of Electromagnetic Wave and Plasma Slab with Partially Linear and Sinusoidal Electron Density Profile
Cigdem Seckin Gürel;Emrah Oncu
PIER Letters , 2009, DOI: 10.2528/PIERL09061707
Abstract: Interaction of an electromagnetic wave and an inhomogenous plasma slab with electron distribution in the form of partially linear and sinusoidal profiles is analysed to determine new reflection, absorbtion and transmission characteristics. Broadband and tunable absorbtion performance of the plasma layer accompanied with narrowband reflection characteristics is presented as the function of electron density profile parameters and external magnetic field excitation. According to the resulting performance characteristics, proposed plasma layer is found to be useful as a new absorbing layer for shielding and stealth applications.
Pattern Projection with a Sinusoidal Phase Grating  [cached]
Elena Stoykova,Jana Harizanova,Ventseslav Sainov
EURASIP Journal on Advances in Signal Processing , 2008, DOI: 10.1155/2009/351626
Abstract: The aim of this work is to study the diffractive properties of a sinusoidal phase grating for incorporation as a pattern projection element in a multisource and multicamera phase-shifting profilometric system. Two challenges should be overcome for successful operation of such a system, which are connected to inherent limitations of the phase-shifting algorithm ¢ € ”requirements for a sinusoidal fringe profile and for equal background and contrast of fringes in the recorded patterns. As a first task, we analyze the frequency content of the projected fringes in the Fresnel diffraction zone for parallel and divergent light illumination at different grating parameters and wavelengths. As a second task, we evaluate the systematical errors due to higher harmonics and multiwavelength illumination. Finally, operation of the four-wavelength profilometric system is simulated, and the error of the profilometric measurement evaluated. The results of test measurements are also presented.
The fluid profile during spin-coating over a small sinusoidal topography
M. A. Hayes,S. B. G. O'Brien
International Journal of Mathematics and Mathematical Sciences , 2004, DOI: 10.1155/s0161171204308136
Abstract: We consider spin-coating over a small sinusoidal topography modelling the physical problem of the coating of a television screen. This involves depositing a phosphor layer on a substrate with a precoating consisting of small parallel striations. Despite the fact that the basic flow is radial, we show that the final liquid coating does not have radial variation; rather, it varies according to the underlying topography. We use a thin film model resulting in an evolution equation for the fluid thickness and sketch several techniques for obtaining approximate solutions in appropriate limiting situations.
A deep investigation into the adipogenesis mechanism: Profile of microRNAs regulating adipogenesis by modulating the canonical Wnt/β-catenin signaling pathway
Limei Qin, Yaosheng Chen, Yuna Niu, Weiquan Chen, Qiwei Wang, Shuqi Xiao, Anning Li, Ying Xie, Jing Li, Xiao Zhao, Zuyong He, Delin Mo
BMC Genomics , 2010, DOI: 10.1186/1471-2164-11-320
Abstract: The high throughput microarray data revealed 18 miRNAs that might promote adipogenesis by repressing WNT signaling: miR-210, miR-148a, miR-194, miR-322 etc. Meanwhile, we also identified 29 miRNAs that might have negative effect on adipogenesis by activating WNT signaling: miR-344, miR-27 and miR-181 etc. The targets of these miRNAs were also analysed by bioinformatics. To validate the predicted targets and the potential functions of these identified miRNAs, the mimics of miR-210 were transfected into 3T3-L1 cells and enlarged cells with distinct lipid droplets were observed; Meanwhile, transfection with the inhibitor of miR-210 could markedly decrease differentiation-specific factors at the transcription level, which suggested the specific role of miR-210 in promoting adipogenesis. Tcf7l2, the predicted target of miR-210, is a transcription factor triggering the downstream responsive genes of WNT signaling, was blocked at transcription level. Furthermore, the activity of luciferase reporter bearing Tcf7l2 mRNA 3' UTR was decreased after co-transfection with miR-210 in HEK-293FT cells. Last but not least, the protein expression level of β-catenin was increased in the lithium (LiCl) treated 3T3-L1 cells after transfection with miR-210. These findings suggested that miR-210 could promote adipogenesis by repressing WNT signaling through targeting Tcf7l2.The results suggest the presence of miRNAs in two cell models, providing insights into WNT pathway-specific miRNAs that can be further characterized for their potential roles in adipogenesis. To our knowledge, present study represents the first attempt to unveil the profile of miRNAs involed in adipogenesis by modulating WNT signaling pathway, which contributed to deeper investigation of the mechanism of adipogenesis.Adipogenesis is the development of fat cells from preadipocytes to mature adipocytes, and has been one of the most intense studied models of cellular differentiation [1], which implicated in insulin resista
Fiber Optic Interferometer for Real-time Wide-range Distance Measurements with ANN
基于人工神经网络的大量程光纤实时距离干涉测量仪

李代林,王向朝,刘英明
光子学报 , 2005,
Abstract: A novel optic fiber interferometer for distance measurements over a wide measurement range using an artificial neural network is designed. The optical phase of the interferometer is simultaneously modulated with a frequency modulated laser diode and optical path-length difference. To enlarge the measurement range and eliminate the influence of the cross-sensitivity, the interferometer readings are used as input data and the actual sensed measuring value as desired output data during the training process of the network model. The principle and signal processing system containing the ANN are described. The experimental results show the use of ANN could widen the measurement range and enhance the measurement accuracy.
New Approaches for Channel Prediction Based on Sinusoidal Modeling  [cached]
Ming Chen,Torbjörn Ekman,Mats Viberg
EURASIP Journal on Advances in Signal Processing , 2007, DOI: 10.1155/2007/49393
Abstract: Long-range channel prediction is considered to be one of the most important enabling technologies to future wireless communication systems. The prediction of Rayleigh fading channels is studied in the frame of sinusoidal modeling in this paper. A stochastic sinusoidal model to represent a Rayleigh fading channel is proposed. Three different predictors based on the statistical sinusoidal model are proposed. These methods outperform the standard linear predictor (LP) in Monte Carlo simulations, but underperform with real measurement data, probably due to nonstationary model parameters. To mitigate these modeling errors, a joint moving average and sinusoidal (JMAS) prediction model and the associated joint least-squares (LS) predictor are proposed. It combines the sinusoidal model with an LP to handle unmodeled dynamics in the signal. The joint LS predictor outperforms all the other sinusoidal LMMSE predictors in suburban environments, but still performs slightly worse than the standard LP in urban environments.
New Approaches for Channel Prediction Based on Sinusoidal Modeling  [cached]
Chen Ming,Ekman Torbj?rn,Viberg Mats
EURASIP Journal on Advances in Signal Processing , 2007,
Abstract: Long-range channel prediction is considered to be one of the most important enabling technologies to future wireless communication systems. The prediction of Rayleigh fading channels is studied in the frame of sinusoidal modeling in this paper. A stochastic sinusoidal model to represent a Rayleigh fading channel is proposed. Three different predictors based on the statistical sinusoidal model are proposed. These methods outperform the standard linear predictor (LP) in Monte Carlo simulations, but underperform with real measurement data, probably due to nonstationary model parameters. To mitigate these modeling errors, a joint moving average and sinusoidal (JMAS) prediction model and the associated joint least-squares (LS) predictor are proposed. It combines the sinusoidal model with an LP to handle unmodeled dynamics in the signal. The joint LS predictor outperforms all the other sinusoidal LMMSE predictors in suburban environments, but still performs slightly worse than the standard LP in urban environments.
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