Appropriate estimates of earthquake response spectrum are essential for design of new structures, or seismic safety evaluation of existing structures. This paper presents an alternative procedure to construct design s...Appropriate estimates of earthquake response spectrum are essential for design of new structures, or seismic safety evaluation of existing structures. This paper presents an alternative procedure to construct design spectrum from a combined normalized response spectrum （NRSc） which is obtained from pseudo-velocity spectrum with the ordinate scaled by different peak ground amplitudes （PGA, PGV, PGD） in different period regions. And a consecutive function./（/） used to normalize the ordinates is defined. Based on a comprehensive study of 220 strong ground motions recorded during recent eleven large worldwide earthquakes, the features of the NRSc are discussed and compared with the traditional normalized acceleration, velocity and displacement response spectra （NRSA, NRSv, NRSD）. And the relationships between ground amplitudes are evaluated by using a weighted mean method instead of the arithmetic mean. Then the NRSc is used to define the design spectrum with given peak ground amplitudes. At last, the smooth spectrum is compared with those derived by the former approaches, and the accuracy of the proposed spectrum is tested through an analysis of the dispersion of ground motion response spectra.展开更多
In order to reduce the disturbance on an authorizing user and lower the competition between cognitive users, assure the normal communication of a cognitive radio system, reliability theory is applied to describe if a ...In order to reduce the disturbance on an authorizing user and lower the competition between cognitive users, assure the normal communication of a cognitive radio system, reliability theory is applied to describe if a channel can be used by a cognitive user or not and the probability that the channel is continually used for a period. Three aspects including space, time domain and frequency domain are united for the research on the distribution of frequency spectrum. The simulation result shows that, in the space domain, time domain, frequency domain algorithm, the transmitted data volume and the total throughput of the system are superior to those in greedy algorithm and time domain—frequency domain algorithm, the novel algorithm is helpful to reduce the disturbance caused by a cognitive user to an authorizing user and lower the competition between cognitive users, this simulation result shows that the proposed algorithm is effective.展开更多
Aiming at the uniform features of acceleration response spectra, two scalar periods-the response spectral predominant period Tp and the smoothed spectral predominant period To are employed to normalize the abscissa of...Aiming at the uniform features of acceleration response spectra, two scalar periods-the response spectral predominant period Tp and the smoothed spectral predominant period To are employed to normalize the abscissa of the normalized response spectra （NRS） of ground motions, respectively. Engineering characteristics of 5% -damped NRS, and the bi-normalized response spectra （BNRS） are investigated accounting for the effects of soil condition and fault distance. Nearly 600 horizontal ground motion components during the Chi-Chi earthquake are included in the analysis. It shows that the NRS strongly depends on soil condition and fault distance. However, soil condition and distance have only a slight influence on two kinds of BNRS. Dispersion analysis indicates that such normalization can reduce scatter in the derivation of response spectral shapes. Finally, a parametric analysis of the scalar periods （Tp, To） is performed and then compared with those of previous studies. These special and particular aspects of earthquake response spectra and scalar periods need to be considered in developing earthquake-resistant design criteria.展开更多
To develop uniform and seismic environment-dependent design spectrum,common acceleration response spectral characteristics need to be identified.In this paper,a bi-normalized response spectrum (BNRS) is proposed,which...To develop uniform and seismic environment-dependent design spectrum,common acceleration response spectral characteristics need to be identified.In this paper,a bi-normalized response spectrum (BNRS) is proposed,which is defined as a spectrum of peak response acceleration normalized with respect to peak acceleration of the excitation plotted vs.the natural period of the system normalized with respect to the spectrum predominant period,Tp.Based on a statistical analysis of records from the 1999 Chi-Chi earthquake,the conventionally normalized response spectrum(NRS) and the BNRS are examined to account for the effects of soil conditions,epicentral distance,hanging wall and damping.It is found that compared to the NRS the BNRS is much less dependent on these factors.Finally,some simple relationships between the BNRS for a specified damping ratio and that for a damping ratio of 5%,and between the spectra predominant period and epicentral distance for different soil types are provided.展开更多
Two kinds of fabricated hollow-core photonic crystal fibres （HC-PCFs） arc studied using finite element method （FEM） because the structures of the fibres are special, Normalized transmission spectra and transverse ...Two kinds of fabricated hollow-core photonic crystal fibres （HC-PCFs） arc studied using finite element method （FEM） because the structures of the fibres are special, Normalized transmission spectra and transverse intensity distribution of the modes are calculated and measured. And the dispersion characteristics of these two kinds of HC- PCFs were analysed from 400 nm to 800 nm. Simulated and measured results show that the special structure could affect the properties of HC-PCFs, By comparing the simulated values with the measured results, it can be clarified that FEM is feasible and accurate for analysing photonic crystal fibres whose structures are irregular and complex.展开更多
Long-period ground motion has become an important consideration because of the increasing number of large and long-period structures.Therefore,a thorough investigation on the formation and characteristics of longperio...Long-period ground motion has become an important consideration because of the increasing number of large and long-period structures.Therefore,a thorough investigation on the formation and characteristics of longperiod ground motion is desirable for engineering applications.In this work,an analytical study is performed to examine the effect of several parameters and the combining mode for equivalent harmonic components on the dynamic response of systems.The results of the work show that the harmonic components in equivalent ground motion are evidently influenced by the intensity rise time,duration,phase and combining mode.Moreover,the long-period ground motions are simplified and simulated by separate harmonic components through proper combination.The findings of the work are believed to be useful in the selection of input ground motion in structural seismic analysis.展开更多
This paper is concerned with the normalized Laplacian spectra of four variants of double join operations based on subdivision graph,Q-graph,R-graph and total graph.The results here generalize some well known results a...This paper is concerned with the normalized Laplacian spectra of four variants of double join operations based on subdivision graph,Q-graph,R-graph and total graph.The results here generalize some well known results about some join operations of graphs.展开更多
For the last several years, the linear array x-ray detector for x-ray imaging with gallium arsenide direct conversion sensitive elements has been developed and tested at the In-stitute for High Energy Physics. The arr...For the last several years, the linear array x-ray detector for x-ray imaging with gallium arsenide direct conversion sensitive elements has been developed and tested at the In-stitute for High Energy Physics. The array consists of 16 sensitive modules. Each module has 128 gallium arsenide (GaAs) sensitive elements with 200 μm pitch. Current article describes two key program procedures of initial dark current compensation of each sensitive element in the linear array, and sensitivity adjustment for alignment of strip pattern in the raw image data. As a part of evaluation process a modular transfer function (MTF) was measured with the slanted sharp-edge object under RQA5 technique as it described in the International Electrotechnical Commission 62220-1 standard (high voltage 70 kVp, additional aluminium filter 21 mm) for images with compensated dark currents and adjusted sensitivity of detector elements. The 10% level of the calculated MTF function has spatial resolution within 2 - 3 pair of lines per mm for both vertical and horizontal orientation.展开更多
This paper studies the asymptotic stability of traveling we solutions of nonlinear systems of integral-differential equations. It has been established that linear stability of traveling waves is equivalent to nonlinea...This paper studies the asymptotic stability of traveling we solutions of nonlinear systems of integral-differential equations. It has been established that linear stability of traveling waves is equivalent to nonlinear stability and some "nice structure" of the spectrum of an associated operator implies the linear stability. By using the method of variation of parameter, the author defines some complex analytic function, called the Evans function. The zeros of the Evans function corresponds to the eigenvalues of the associated linear operator. By calculating the zeros of the Evans function, the asymptotic stability of the travling wave solutions is established.展开更多
基金The Major Research Plan of National Natural Science foundation of China under Grant No.91215301National Natural Science Foundation of China under Grant Nos.51178152,51238012+1 种基金Natural Scientific Research Innovation Foundation in Harbin Institute of Technology under Grant No.HIT.NSRIF.2011115Harbin Institute of Technology Key Innovation Scheme Training Project under Grant No.HIT.KISTP.2014033
文摘Appropriate estimates of earthquake response spectrum are essential for design of new structures, or seismic safety evaluation of existing structures. This paper presents an alternative procedure to construct design spectrum from a combined normalized response spectrum （NRSc） which is obtained from pseudo-velocity spectrum with the ordinate scaled by different peak ground amplitudes （PGA, PGV, PGD） in different period regions. And a consecutive function./（/） used to normalize the ordinates is defined. Based on a comprehensive study of 220 strong ground motions recorded during recent eleven large worldwide earthquakes, the features of the NRSc are discussed and compared with the traditional normalized acceleration, velocity and displacement response spectra （NRSA, NRSv, NRSD）. And the relationships between ground amplitudes are evaluated by using a weighted mean method instead of the arithmetic mean. Then the NRSc is used to define the design spectrum with given peak ground amplitudes. At last, the smooth spectrum is compared with those derived by the former approaches, and the accuracy of the proposed spectrum is tested through an analysis of the dispersion of ground motion response spectra.
基金supported by Natural Science Foundation of Heilongjiang Province of China(No.F2015017)
文摘In order to reduce the disturbance on an authorizing user and lower the competition between cognitive users, assure the normal communication of a cognitive radio system, reliability theory is applied to describe if a channel can be used by a cognitive user or not and the probability that the channel is continually used for a period. Three aspects including space, time domain and frequency domain are united for the research on the distribution of frequency spectrum. The simulation result shows that, in the space domain, time domain, frequency domain algorithm, the transmitted data volume and the total throughput of the system are superior to those in greedy algorithm and time domain—frequency domain algorithm, the novel algorithm is helpful to reduce the disturbance caused by a cognitive user to an authorizing user and lower the competition between cognitive users, this simulation result shows that the proposed algorithm is effective.
基金China Postdoctoral Science Foundation ( No20060400826)
文摘Aiming at the uniform features of acceleration response spectra, two scalar periods-the response spectral predominant period Tp and the smoothed spectral predominant period To are employed to normalize the abscissa of the normalized response spectra （NRS） of ground motions, respectively. Engineering characteristics of 5% -damped NRS, and the bi-normalized response spectra （BNRS） are investigated accounting for the effects of soil condition and fault distance. Nearly 600 horizontal ground motion components during the Chi-Chi earthquake are included in the analysis. It shows that the NRS strongly depends on soil condition and fault distance. However, soil condition and distance have only a slight influence on two kinds of BNRS. Dispersion analysis indicates that such normalization can reduce scatter in the derivation of response spectral shapes. Finally, a parametric analysis of the scalar periods （Tp, To） is performed and then compared with those of previous studies. These special and particular aspects of earthquake response spectra and scalar periods need to be considered in developing earthquake-resistant design criteria.
基金Heilongjiang Natural Science Foundation Under Project No.ZGJ03-03the Research Fund for the Doctoral Program of Higher Education of China Through Project No.20030213042
文摘To develop uniform and seismic environment-dependent design spectrum,common acceleration response spectral characteristics need to be identified.In this paper,a bi-normalized response spectrum (BNRS) is proposed,which is defined as a spectrum of peak response acceleration normalized with respect to peak acceleration of the excitation plotted vs.the natural period of the system normalized with respect to the spectrum predominant period,Tp.Based on a statistical analysis of records from the 1999 Chi-Chi earthquake,the conventionally normalized response spectrum(NRS) and the BNRS are examined to account for the effects of soil conditions,epicentral distance,hanging wall and damping.It is found that compared to the NRS the BNRS is much less dependent on these factors.Finally,some simple relationships between the BNRS for a specified damping ratio and that for a damping ratio of 5%,and between the spectra predominant period and epicentral distance for different soil types are provided.
基金Project supported by the State Key Development Program for Basic Research of China (Grant No 2003CB314905)the National High Technology Development Program of China (Grant No 2003AA311010)
文摘Two kinds of fabricated hollow-core photonic crystal fibres （HC-PCFs） arc studied using finite element method （FEM） because the structures of the fibres are special, Normalized transmission spectra and transverse intensity distribution of the modes are calculated and measured. And the dispersion characteristics of these two kinds of HC- PCFs were analysed from 400 nm to 800 nm. Simulated and measured results show that the special structure could affect the properties of HC-PCFs, By comparing the simulated values with the measured results, it can be clarified that FEM is feasible and accurate for analysing photonic crystal fibres whose structures are irregular and complex.
基金Supported by Major Research Plan of National Natural Science Foundation of China(No.91215301)National Natural Science Foundation of China(No.51238012,No.51178152,No.51008208)the Special Fund for Earthquake Scientific Research in the Public Interest(No.201208013)
文摘Long-period ground motion has become an important consideration because of the increasing number of large and long-period structures.Therefore,a thorough investigation on the formation and characteristics of longperiod ground motion is desirable for engineering applications.In this work,an analytical study is performed to examine the effect of several parameters and the combining mode for equivalent harmonic components on the dynamic response of systems.The results of the work show that the harmonic components in equivalent ground motion are evidently influenced by the intensity rise time,duration,phase and combining mode.Moreover,the long-period ground motions are simplified and simulated by separate harmonic components through proper combination.The findings of the work are believed to be useful in the selection of input ground motion in structural seismic analysis.
基金Supported by the National Natural Science Foundation of China(Grant No.11961040)the Natural Science Foundation of Gansu Province(Grant No.20JR5RA418)。
文摘This paper is concerned with the normalized Laplacian spectra of four variants of double join operations based on subdivision graph,Q-graph,R-graph and total graph.The results here generalize some well known results about some join operations of graphs.
文摘For the last several years, the linear array x-ray detector for x-ray imaging with gallium arsenide direct conversion sensitive elements has been developed and tested at the In-stitute for High Energy Physics. The array consists of 16 sensitive modules. Each module has 128 gallium arsenide (GaAs) sensitive elements with 200 μm pitch. Current article describes two key program procedures of initial dark current compensation of each sensitive element in the linear array, and sensitivity adjustment for alignment of strip pattern in the raw image data. As a part of evaluation process a modular transfer function (MTF) was measured with the slanted sharp-edge object under RQA5 technique as it described in the International Electrotechnical Commission 62220-1 standard (high voltage 70 kVp, additional aluminium filter 21 mm) for images with compensated dark currents and adjusted sensitivity of detector elements. The 10% level of the calculated MTF function has spatial resolution within 2 - 3 pair of lines per mm for both vertical and horizontal orientation.
文摘This paper studies the asymptotic stability of traveling we solutions of nonlinear systems of integral-differential equations. It has been established that linear stability of traveling waves is equivalent to nonlinear stability and some "nice structure" of the spectrum of an associated operator implies the linear stability. By using the method of variation of parameter, the author defines some complex analytic function, called the Evans function. The zeros of the Evans function corresponds to the eigenvalues of the associated linear operator. By calculating the zeros of the Evans function, the asymptotic stability of the travling wave solutions is established.
