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The Application of the Combined Method for Selection of Optimal Excitation Parameters
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作者 Roman Petrichenko Inga Zicmane +1 位作者 Michal Kolcun Matus Novak 《Journal of Energy and Power Engineering》 2014年第4期724-728,共5页
The quality as well as reliability of electrical energy transmitted to consumers is one of the main parameters of successful operation of the power system. The searching of optimal coefficient's combination of PSS (... The quality as well as reliability of electrical energy transmitted to consumers is one of the main parameters of successful operation of the power system. The searching of optimal coefficient's combination of PSS (power system stabilizer) is the main goal of this article. The possibility of application of the new combined approach for the optimal excitation's settings search is presented. MC (Monte Carlo) method, in order to search and select the optimal combination of excitation system, was applied. The proposed method has been researched with a mathematical model of the power system. This model has been built using Matlab/Simulink software. Paper shows advantages and disadvantages of the proposed methods. 展开更多
关键词 Power systems stabilizer excitation parameters Monte Carlo method.
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Calculation of Surface Excitation Parameters by a Monte Carlo Method
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作者 Zhe Zheng Bo Da +1 位作者 Shi-feng Mao Ze-jun Ding 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2017年第1期83-89,I0002,共8页
Electron inelastic mean free path (IMFP) is an important parameter for surface chemical quantification by surface electron spectroscopy techniques. It can be obtained from analysis of elastic peak electron spectrosc... Electron inelastic mean free path (IMFP) is an important parameter for surface chemical quantification by surface electron spectroscopy techniques. It can be obtained from analysis of elastic peak electron spectroscopy (EPES) spectra measured on samples and a Monte Carlo simulation method. To obtain IMFP parameters with high accuracy, the surface excitation effect on the measured EPES spectra has to be quantified as a surface excitation parameter (SEP), which can be calculated via a dielectric response theory. However, such calculated SEP does not include influence of elastic scattering of electrons inside samples during their incidence and emission processes, which should not be neglected simply in determining IMFP by an EPES method. In this work a Monte Carlo simulation method is employed to determine surface excitation parameter by taking account of the elastic scattering effect. The simulated SEPs for different primary energies are found to be in good agreement with the experiments particularly for larger incident or emission angles above 60° where the elastic scattering effect plays a more important role than those in smaller incident or emission angles. Based on these new SEPs, the IMFP measurement by EPES technique can provide more accurate data. 展开更多
关键词 Eelastic peak electron spectroscopy Surface excitation parameter Monte Carlo simulation
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Parameters analysis and application of the differential excitation detection technology
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作者 于霞 张卫民 +2 位作者 陈国龙 邱忠超 曾卫琴 《Journal of Beijing Institute of Technology》 EI CAS 2015年第3期348-354,共7页
A differential excitation probe based on eddy current testing technology was designed. Sheet specimens of Q 235 steel with prefabricated micro-cracks of different widths and of aluminum with prefabricated micro-cracks... A differential excitation probe based on eddy current testing technology was designed. Sheet specimens of Q 235 steel with prefabricated micro-cracks of different widths and of aluminum with prefabricated micro-cracks of different depths were detected through the designed detection system. The characteristics of micro-cracks can be clearly showed after signals processing through the short-time Fourier transform( STFT). By changing the parameter and its value in detecting process,the factors including the excitation frequency and amplitude,the lift-off effect and the scanning direction were discussed,respectively. The results showed that the differential excitation probe was insensitive to dimension and surface state of the tested specimen,while it had a high degree of recognition for micro-crack detection. Therefore,when the differential excitation detection technology was used for inspecting micro-crack of turbine blade in aero-engine,and smoothed pseudo Wigner-Ville distribution was used for signal processing,micro-cracks of 0. 3 mm depth and 0. 1 mm width could be identified. The experimental results might be useful for further research on engineering test of turbine blades of aero-engine. 展开更多
关键词 differential excitation probe eddy current testing micro-crack defect influence parameters analysis
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Operational Modal Analysis of a Ship Model in the Presence of Harmonic Excitation 被引量:1
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作者 Junchen Xu Ming Hong Xiaobing Liu 《Journal of Marine Science and Application》 2013年第1期38-44,共7页
A ship is operated under an extremely complex environment, and waves and winds are assumed to be the stochastic excitations. Moreover, the propeller, host and mechanical equipment can also induce the harmonic response... A ship is operated under an extremely complex environment, and waves and winds are assumed to be the stochastic excitations. Moreover, the propeller, host and mechanical equipment can also induce the harmonic responses. In order to reduce structural vibration, it is important to obtain the modal parameters information of a ship. However, the traditional modal parameter identification methods are not suitable since the excitation information is difficult to obtain. Natural excitation technique-eigensystem realization algorithm (NExT-ERA) is an operational modal identification method which abstracts modal parameters only from the response signals, and it is based on the assumption that the input to the structure is pure white noise. Hence, it is necessary to study the influence of harmonic excitations while applying the NExT-ERA method to a ship structure. The results of this research paper indicate the practical experiences under ambient excitation, ship model experiments were successfully done in the modal parameters identification only when the harmonic frequencies were not too close to the modal frequencies. 展开更多
关键词 natural excitation technique (NExT) eigensystem realization algorithm (ERA) ship structure harmonic excitation signal processing modal parameters identification ship model operational model analysis
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SURFACE EXCITATION PARAMETER IN QUANTITATIVE SURFACE ANALYSIS BY ELECTRON SPECTROSCOPY
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作者 K. Salma 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2005年第3期313-318,共6页
The investigation of influence of surface effects on the energy spectra of elect rons is essential for comprehensive understanding of electron-solid interactions as well as quantitative analysis. The accuracy of the a... The investigation of influence of surface effects on the energy spectra of elect rons is essential for comprehensive understanding of electron-solid interactions as well as quantitative analysis. The accuracy of the analysis depends on the m odels for elastic and inelastic interactions. Electrons impinging on a solid or escaping from it suffer losses in the surface layer. The energy loss spectra the refore have contributions from surface excitations. The role of surface excitati ons is characterized by surface excitation parameter (SEP), which indicates the number of surface plasmons created by an electron crossing the surface. The imag inary part of complex self-energy of an electron is related to the energy loss c ross section. SEP is numerically computed using self-energy formalism and compar ed with the results as described and calculated by different workers. 展开更多
关键词 surface plasmons surface excitations parameter SELF-ENERGY
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Stability and local bifurcation of parameter-excited vibration of pipes conveying pulsating fluid under thermal loading 被引量:3
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作者 Demin ZHAO Jianlin LIU C.Q.WU 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2015年第8期1017-1032,共16页
The parametric excited vibration of a pipe under thermal loading may occur because the fluid is often transported heatedly. The effects of thermal loading on the pipe stability and local bifurcations have rarely been ... The parametric excited vibration of a pipe under thermal loading may occur because the fluid is often transported heatedly. The effects of thermal loading on the pipe stability and local bifurcations have rarely been studied. The stability and the local bifurcations of the lateral parametric resonance of the pipe induced by the pulsating fluid velocity and the thermal loading are studied. A mathematical model for a simply supported pipe is developed according to the Hamilton principle. Two partial differential equations describing the lateral and longitudinal vibration are obtained. The singularity theory is utilized to anMyze the stability and the bifurcation of the system solutions. The transition sets and the bifurcation diagrams are obtained both in the unfolding parameter space and the physical parameter space, which can reveal the relationship between the thermal field parameter and the dynamic behaviors of the pipe. The frequency response and the relationship between the critical thermal rate and the pulsating fluid velocity are obtained. The numerical results demonstrate the accuracy of the single-mode expansion of the solution and the stability and local bifurcation analyses. It also confirms the existence of the chaos. The presented work can provide valuable information for the design of the pipeline and the controllers to prevent the structural instability. 展开更多
关键词 thermal load parameter excited local bifurcation unfolding parameterspace physical parameter space
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Measurement of algae PSII photosynthetic parameters using high-frequency excitation flashes 被引量:2
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作者 石朝毅 张玉钧 +7 位作者 殷高方 赵南京 段静波 余晓娅 肖雪 甘婷婷 方丽 刘文清 《Chinese Optics Letters》 SCIE EI CAS CSCD 2014年第8期1-4,共4页
We establish a system to measure the functional absorption cross section of photosystem lI (PSII) (O-PSII) and maximum quantum yield of photochemistry in PSII (Fv/Fm). The system utilizes a sequence of high-freq... We establish a system to measure the functional absorption cross section of photosystem lI (PSII) (O-PSII) and maximum quantum yield of photochemistry in PSII (Fv/Fm). The system utilizes a sequence of high-frequency excitation flashes at microsecond intervals to induce a microsecond-level fluorescence yield curve. Parameters o-Psii and Fv/Fm are calculated by fitting the curve using nonlinear regression. Experimental results show that the relative standard deviation (RSD) of the system is less than 3%, and the correlation coefficient of Fv/Fm values measured by this system and those measured by pulse amplitude modulation method is 0.950. 展开更多
关键词 PSII Measurement of algae PSII photosynthetic parameters using high-frequency excitation flashes LEDs high
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Characterization and analysis of coded excitation ultrasound parameters for rock properties 被引量:2
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作者 ZHU Wei WU Hezhen 《Chinese Journal of Acoustics》 CSCD 2017年第1期29-42,共14页
Coded excitation technology (CET) can effectively enhance the penetration and resolution of ultrasonic testing. To analyze the influence of rock properties on pulse compression performance (PCP) of coded excitatio... Coded excitation technology (CET) can effectively enhance the penetration and resolution of ultrasonic testing. To analyze the influence of rock properties on pulse compression performance (PCP) of coded excitation signals (CES), a numerical simulation, and an ultrasonic experiment on different rock samples are performed; and the detection ability of several CESs are also investigated and compared. The results of experiments showed that the loss of the signal-to-noise ratio (SNR) of Barker coded signal with tapered linear frequency modulated carrier (BTLFM) is always less than Barker coded signal with sine carrier (BS), while the resolution loss of BTLFM is lower than tapered linear frequency modulated signal (TLFM). In sum, the results not only verifiy the effectiveness of CET, but also provide a basis for the parameter settings of coded signals used in rock ultrasonic testing. 展开更多
关键词 ROCK Characterization and analysis of coded excitation ultrasound parameters for rock properties
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Sub-Harmonic Resonances of Periodic Parameter Excited Oscillators with Discontinuities
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作者 Jifeng Cui 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2015年第4期66-71,共6页
It is difficult to obtain analytic approximations of nonlinear problems such as parameter excited system with strong nonlinearity. An analytic approach based on the homotopy analysis method( HAM) is proposed to study ... It is difficult to obtain analytic approximations of nonlinear problems such as parameter excited system with strong nonlinearity. An analytic approach based on the homotopy analysis method( HAM) is proposed to study the sub-harmonic resonances of highly nonlinear parameter excited oscillating systems with absolute value terms. The non-smoothness of absolute value terms is handled by means of an iteration approach with Fourier expansion. Two typical examples are employed to illustrate the validity and flexibility of this approach. The square residuals of the homotopy-approximations of the two examples decrease to 10-6and 10-5,respectively. Thus,the HAM combining with other methods gives hope to solve complex singular oscillating systems analytically. 展开更多
关键词 periodic parameter excited oscillator sub-harmonic resonance HAM Fourier expansion
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Nonlinear identification of systems with parametric excitation 被引量:2
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作者 YE Min DOU SuGuang +1 位作者 ZHANG Wei ZENG ZhiGang 《Science China(Technological Sciences)》 SCIE EI CAS 2011年第8期2080-2089,共10页
In this paper, the incremental harmonic balance nonlinear identification (IHBNID) is presented for modelling and parametric identification of nonlinear systems. The effects of harmonic balance nonlinear identification... In this paper, the incremental harmonic balance nonlinear identification (IHBNID) is presented for modelling and parametric identification of nonlinear systems. The effects of harmonic balance nonlinear identification (HBNID) and IHBNID are also studied and compared by using numerical simulation. The effectiveness of the IHBNID is verified through the Mathieu-Duffing equation as an example. With the aid of the new method, the derivation procedure of the incremental harmonic balance method is simplified. The system responses can be represented by the Fourier series expansion in complex form. By keeping several lower-order primary harmonic coefficients to be constant, some of the higher-order harmonic coefficients can be self-adaptive in accordance with the residual errors. The results show that the IHBNID is highly efficient for computation, and excels the HBNID in terms of computation accuracy and noise resistance. 展开更多
关键词 nonlinear system identification incremental harmonic balance parameter excitation nonlinear systems
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