Kuo,Yeh-Tzu founded Taiwan’s Sung Shan Tsu Huei Temple in 1970.She organized more than 200 worshipers as a group named“Taiwan Tsu Huei Temple Queen Mother of the West Delegation to China to Worship at the Ancestral ...Kuo,Yeh-Tzu founded Taiwan’s Sung Shan Tsu Huei Temple in 1970.She organized more than 200 worshipers as a group named“Taiwan Tsu Huei Temple Queen Mother of the West Delegation to China to Worship at the Ancestral Temples”in 1990.At that time,the temple building of the Queen Mother Palace in Huishan of Gansu Province was in disrepair,and Temple Master Kuo,Yeh-Tzu made a vow to rebuild it.Rebuilding the ancestral temple began in 1992 and was completed in 1994.It was the first case of a Taiwan temple financing the rebuilding of a far-away Queen Mother Palace with its own donations.In addition,Sung Shan Tsu Huei Temple celebrated its 45th anniversary and hosted Yiwei Yuanheng Lizhen Daluo Tiandi Qingjiao(Momentous and Fortuitous Heaven and Earth Prayer Ceremony)in 2015.This is the most important and the grandest blessing ceremony of Taoism,a rare event for Taoism locally and abroad during this century.Those sacred rituals were replete with unprecedented grand wishes to propagate the belief in Queen Mother of the West.Stopping at nothing,Queen Mother’s love never ceases.展开更多
Energy used for industrial production, buildings and transport will be accumulated in Atmosphere and Earth land. Global use of energy is known and documented for a long period of time and proportion of fossil and rene...Energy used for industrial production, buildings and transport will be accumulated in Atmosphere and Earth land. Global use of energy is known and documented for a long period of time and proportion of fossil and renewable energy is also known. Calculated accumulated energy in Earth land from 1971 to 2018 corresponds to 40% of IPCC Global Energy Inventory and calculated Atmosphere temperature increase from 1971 to 2018 corresponds to 100% of actual measurements.展开更多
Global climate change has caused general and serious damage to cultural heritage sites,and earthen settlements and buildings are particularly vulnerable to water-afected disasters.Thus,this paper uses Liang Village in...Global climate change has caused general and serious damage to cultural heritage sites,and earthen settlements and buildings are particularly vulnerable to water-afected disasters.Thus,this paper uses Liang Village in Pingyao County,China,as a case study,linking the human–land study in the Liang Village Sino-French workshop of 2009/2010 to a disaster assessment completed after the devastating rainstorm in October 2021.We found that the village’s rain disaster resulted from the vulnerability of earthen material to rainstorms and from the earthen settlement’s evolution from a culture emphasising the coexistence of‘water and earth’to a technic fostering the disintegration of‘water and earth’.The latter is the main cause of the village’s decrease in its capacity for disaster prevention and damage reduction.Therefore,in the context of global climate change,we fnd that the reestablishment of the harmonious relationship of water and earth is critical to both rural heritage conservation and village sustainable development.In addition to repairing their relation from the technical perspective of‘planning and design’by planners and architects,it is more crucial for local people to understand and enhance their contemporary appreciation for the traditional‘coexistence of water and earth’concept.展开更多
In the last several years since 2004 an important new finding has been unveiled by combined efforts due to Japanese (Satoru Tanaka), French (Renaud Deguen, Y Albousierre and Marc Monnereau), American and Chinese g...In the last several years since 2004 an important new finding has been unveiled by combined efforts due to Japanese (Satoru Tanaka), French (Renaud Deguen, Y Albousierre and Marc Monnereau), American and Chinese geophysicists (Xiaodong Song and Vernon F Cormier) who employed from unambi- guous detailed seismological evidence and explained by clear theoretical and sound laboratory arguments drawn from fluid dynamics that there exists a strong East-West hemi-spherical asymmetry on the inner- outer core boundary,展开更多
Let your gaze rest upon the poster for Earth Day on April 22. A small polar bear clings tightly to the stem of an aero-vane. Staring at the vanishing floating ice on the wild sea, his eyes are full of panic and fear.
THIS photograph was published in the book, A Century of Historical Chinese Photographs, with only a one-line caption: "A private school for Christian girls opened by the foreign Mission of the Virgin Mary in Shan...THIS photograph was published in the book, A Century of Historical Chinese Photographs, with only a one-line caption: "A private school for Christian girls opened by the foreign Mission of the Virgin Mary in Shanghai." Determining which country’s church, which year it opened, and what kind of a private girls’ school it was would be nearly impossible. But this should not stop展开更多
Propagation properties of coherent and partially coherent beams in atmospheric turbulence are investigated respectively by using numerical simulation It is found that a partially coherent beam has a spreading larger t...Propagation properties of coherent and partially coherent beams in atmospheric turbulence are investigated respectively by using numerical simulation It is found that a partially coherent beam has a spreading larger than a coherent beam. However, from the point view of relative beam spreading and intensity scintillation, a partially coherent beam is less affected than the corresponding coherent beam, which may be the most important virtue of partially coherent beams that could be utilized to improve the performance of laser engineering. The beam wandering is almost independent of the degree of the source coherence. More aperture averaging occurs when beam becomes more coherent.展开更多
A mobile molecular Doppler wind lidar (DWL) based on double-edge technique is presented for wind measurement at altitudes from 10 km to 40 km. A triple Fabry-Perot etalon is employed as a frequency discriminator to ...A mobile molecular Doppler wind lidar (DWL) based on double-edge technique is presented for wind measurement at altitudes from 10 km to 40 km. A triple Fabry-Perot etalon is employed as a frequency discriminator to determine the Doppler shift proportional to the wind velocity. The lidar operates at 355 nm with a 45-cm aperture telescope and a matching azimuth-over-elevation scanner that can provide full hemispherical pointing. In order to guarantee the wind accuracy, different forms of calibration function of detectors in different count rates response range would be especially valuable. The accuracy of wind velocity iteration is improved greatly because of application of the calibration function of linearity at the ultra low light intensity especially at altitudes from 10 km to 40 km. The calibration functions of nonlinearity make the transmission of edge channel 1 and edge channel 2 increase 38.9% and 27.7% at about 1 M count rates, respectively. The dynamic range of wind field measurement may also be extended because of consideration of the response function of detectors in their all possible operating range.展开更多
Hourly outgoing longwave radiation (OLR) from the geostationary satellite Communication Oceanography Meteorological Satellite (COMS) has been retrieved since June 2010.The COMS OLR retrieval algorithms are based o...Hourly outgoing longwave radiation (OLR) from the geostationary satellite Communication Oceanography Meteorological Satellite (COMS) has been retrieved since June 2010.The COMS OLR retrieval algorithms are based on regression analyses of radiative transfer simulations for spectral functions of COMS infrared channels.This study documents the accuracies of OLRs for future climate applications by making an intercomparison of four OLRs from one single-channel algorithm (OLR12.0 using the 12.0 μm channel) and three multiple-channel algorithms (OLR10.8+12.0 using the 10.8 and 12.0 pm channels; OLR6.7+10.8 using the 6.7 and 10.8 μm channels; and OLRAll using the 6.7,10.8,and 12.0 μm channels).The COMS OLRs from these algorithms were validated with direct measurements of OLR from a broadband radiometer of the Clouds and Earth's Radiant Energy System (CERES) over the full COMS field of view [roughly (50°S-50°N,70°-170°E)] during April 2011.Validation results show that the root-mean-square errors of COMS OLRs are 5-7 W m-2,which indicates good agreement with CERES OLR over the vast domain.OLR6.7+10.8 and OLRAll have much smaller errors (~ 6 W m-2) than OLR12.0 and OLR10.8+12.0 (~ 8 W m-2).Moreover,the small errors of OLR6.7+10.8 and OLRAll are systematic and can be readily reduced through additional mean bias correction and/or radiance calibration.These results indicate a noteworthy role of the 6.7 μm water vapor absorption channel in improving the accuracy of the OLRs.The dependence of the accuracy of COMS OLRs on various surface,atmospheric,and observational conditions is also discussed.展开更多
The tearing mode instability plays a key role in the triggering process of reconnection. The triggering collisionless tearing mode instability has been theoretically and numerically analyzed by many researchers. Howev...The tearing mode instability plays a key role in the triggering process of reconnection. The triggering collisionless tearing mode instability has been theoretically and numerically analyzed by many researchers. However, due to the difficulty in obtaining the observational wave number, it is still unknown whether the tearing mode instability can be excited in an actual plasma sheet prior to reconnection onset. Using the data from four Cluster satellites prior to a magnetospheric reconnection event on 13 September 2002, we utilized the wave telescope technique to obtain the wave number which corresponds to the peak of power spectral density. The wavelength is about 18RE and is consistent with previous theoretic and numerical results. After substituting the wave vector and other necessary parameters of the observed current sheet into the triggering condition of tearing mode instability, we find that the near-Earth current sheet prior to reconnection is unstable to tearing mode.展开更多
Characteristics of ULF waves associated with the solar wind deceleration in the Earth's foreshock on 6-7 April 2003 is studied using the wave telescope technique. In the satellite frame, the ULF waves are the left-ha...Characteristics of ULF waves associated with the solar wind deceleration in the Earth's foreshock on 6-7 April 2003 is studied using the wave telescope technique. In the satellite frame, the ULF waves are the left-handed polarized and quasi anti-parallel propagating mode, with a power peak at about 18.63mHz. The wave vector in the GSE coordinates is estimated to be k = (-4.29, 2.28, 1.21)×10^-4 km^-1, In the solar wind frame, the frequency of waves becomes - 9.39 mHz after the Doppler shift correction. The propagation direction of the waves is thus reversed and correspondingly the polarization of the waves becomes right-handed. The above-mentioned characteristics of the ULF waves in the solar wind frame indicate that the ULF waves associated with the solar wind deceleration are the Alfven-whistler waves, which have been frequently reported in both the observations and computer simulations.展开更多
Specific activity of primordial radionuclides and associated radiation hazards due to 40K, 226Ra, and 232Th have been measured in backed red brick samples, collected from five highly populated areas of the North West ...Specific activity of primordial radionuclides and associated radiation hazards due to 40K, 226Ra, and 232Th have been measured in backed red brick samples, collected from five highly populated areas of the North West Frontier Province of Pakistan. For the detection, analysis and data acquisition, a high purity germanium detector was used. Associated external doses were calculated using a Monte Carlo neutron photon transport code. A theoretical model to determine the gamma dose rate at 1 m height from the floor, made of bricks, was employed for the calculation of mass attenuation coefficient and self-absorption in the floor for the gamma energies of these radionuclides and their progeny. Monte Carlo simulation shows that in this study the floor, having more than an effective thickness of 15 cm, contributes very little to the external gamma dose rate. The values of the external dose rate and annual effective dose are found to be much lower than the world average as well as from other countries of the world.展开更多
Three-dimensional mode coupling around a conical seamount in an ocean waveguide is studied. It is shown that strong mode coupling occurs at the edge of a conical seamount for the incident normal modes with significant...Three-dimensional mode coupling around a conical seamount in an ocean waveguide is studied. It is shown that strong mode coupling occurs at the edge of a conical seamount for the incident normal modes with significant amplitudes below the top of the seamount. Therefore, mode coupling is critical for the investigation of the acoustic field around a seamount. In addition, we suggest the use of random discretization for representing smoothly varying bathymetry. For the use of uniform discretization, when the horizontal step size is greater than half of the wavelength, artificial diffraction lobes appear due to coherent backscatter. However, by using the random discretization scheme instead, such artificial diffraction lobes are diffused, resulting in a faster convergence rate.展开更多
The analysis of naturally occurring radionuclides (226Ra, 232 Th and 40 K) and an anthropogenic radionuclide 13r Cs is carried out in some soil samples collected from Kohistan district of N.W.F.P. (Pakistan), usin...The analysis of naturally occurring radionuclides (226Ra, 232 Th and 40 K) and an anthropogenic radionuclide 13r Cs is carried out in some soil samples collected from Kohistan district of N.W.F.P. (Pakistan), using gamma-ray spectrometry. The gamma spectrometry is operated using a high purity Germanium (HPGe) detector coupled with a computer based high resolution multi channel analyzer. The specific activity in soil ranges from 24.72 to 78.48Bq.kg-1 for 22TRa, 21.73 to 75.28Bq.kg- 1 for 232Th, 7.06 to 14.9Bq.kg 1 for 1arcs and 298.46 to 570.77Bq.kg-1 for 40K with the mean values of 42.11, 43.27, 9.5 and 418.27Bq.kg-1, respectively. The radium equivalent activity in all the soil samples is lower than the safe limit set in the OECD report (370 Bq.kg-1). Man-made radionuclide 13r Cs is also present in detectable amount in all sell samples. Presence of 13r Us indicates that the samples in this renlote area also recelvo some fallout from nuclear accident in Chernobyl power plant in 1986. The internal and external hazard indices have the mean values of 0.48 and 0.37 respectively. Absorbed dose rates and effective dose equivalents are also determined for the samples. The concentration of radionuclides found in the soil samples during the present study is nominal and does not pose any potential health hazard to the general public.展开更多
Effects of atmospheric turbulence tilt, defocus, astigmatism and coma aberrations on the orbital angular momentum measurement probability of photons propagating in weak turbulent regime are modeled with Rytov approxim...Effects of atmospheric turbulence tilt, defocus, astigmatism and coma aberrations on the orbital angular momentum measurement probability of photons propagating in weak turbulent regime are modeled with Rytov approximation. By considering the resulting wave as a superposition of angular momentum eigenstates, the or- bital angular momentum measurement probabilities of the transmitted digit are presented. Our results show that the effect of turbulent tilt aberration on the orbital angular momentum measurement probabilities of photons is the maximum among these four kinds of aberrations. As the aberration order increases, the effects of turbulence aberrations on the measurement probabilities of orbital angular momentum generally decrease, whereas the effect o[ turbulence defocus can be ignored. For tilt aberration, as the difference between the measured orbital angular momentum and the original orbital angular momentum increases, the orbital angular momentum measurement probability decreases.展开更多
Empirical observations indicate that the interevent time distribution of human actions exhibits heavy-tailed features. The queuing model based on task priorities is to some extent successful in explaining the origin o...Empirical observations indicate that the interevent time distribution of human actions exhibits heavy-tailed features. The queuing model based on task priorities is to some extent successful in explaining the origin of such heavy tails, however, it cannot explain all the temporal statistics of human behavior especially for the daily entertainments. We propose an interest-driven model, which can reproduce the power-law distribution of interevent time. The exponent can be analytically obtained and is in good accordance with the simulations. This model well explains the observed relationship between activities and power-law exponents, as reported recently for web-based behavior and the instant message communications.展开更多
Location of an airborne source is estimated from signals measured by a horizontal line array (HLA), based on the fact that a signal transmitted by an airborne source will reach a underwater hydrophone in different w...Location of an airborne source is estimated from signals measured by a horizontal line array (HLA), based on the fact that a signal transmitted by an airborne source will reach a underwater hydrophone in different ways: via a direct refracted path, via one or more bottom and surface reflections, via the so-called lateral wave. As a result, when an HLA near the airborne source is used for beamforming, several peaks at different bearing angles will appear. By matching the experimental beamforming outputs with the predicted outputs for all source locations, the most likely location is the one which gives minimum difference. An experiment is conducted for airborne source localization in the Yellow Sea in October 2008. An HLA was laid on the sea bottom at the depth of 30m. A high-power loudspeaker was hung on a research ship floating near the HLA and sent out LFM pulses. The estimated location of the loudspeaker is in agreement well with the GPS measurements.展开更多
We propose a new method to reveal a direct transformation from solar energy to solar electricity. Instead of using electricity in the process, we use concentrated solar rays with a crucibleless process to upgrade meta...We propose a new method to reveal a direct transformation from solar energy to solar electricity. Instead of using electricity in the process, we use concentrated solar rays with a crucibleless process to upgrade metallurgical silicon into solar-grade silicon feedstock.展开更多
We propose a new two-type-player prisoner's dilemma game based on the division of work on a square lattice, in which a fraction of the population μ are assigned type A and the rest B. In a one-shot two-player game, ...We propose a new two-type-player prisoner's dilemma game based on the division of work on a square lattice, in which a fraction of the population μ are assigned type A and the rest B. In a one-shot two-player game, we let both of their original payoffs be scaled by a same multiplicative factor α 〉 1, if two neighboring players are of different types; however we leave the payoffs unchanged if they are of the same type. Then we show that combined with the two-type setup, the square lattice can assist to induce different social ranks according to players' abilities to collect payoffs. Simulation results show that the density of cooperation is significantly promoted for a wide range of the temptation to defection parameters and that there are optimal values for both α and μ leading to the maximal cooperation level. We reach these results by analyzing the distribution of the players in the social ranks and we also show some typical snapshots of the system.展开更多
A hybrid high-frequency method is proposed to analyze the bistatic electromagnetic scattering of the ship target on a very large two-dimensional randomly rough sea surface. The scattering of the ship-sea model is eva...A hybrid high-frequency method is proposed to analyze the bistatic electromagnetic scattering of the ship target on a very large two-dimensional randomly rough sea surface. The scattering of the ship-sea model is evaluated with the method of equivalent currents (MEC). The iterative physical optics method (IPO) is utilized to study the electromagnetic coupling effect caused by the hull and rough surface. The shadowing correction based on the Z-Buffer technology is introduced to eliminate the effects of the irrelevant scattering resources. The validity of the hybrid method is confirmed by the SAR simulation results and the scattering property of the ship-sea model is discussed.展开更多
文摘Kuo,Yeh-Tzu founded Taiwan’s Sung Shan Tsu Huei Temple in 1970.She organized more than 200 worshipers as a group named“Taiwan Tsu Huei Temple Queen Mother of the West Delegation to China to Worship at the Ancestral Temples”in 1990.At that time,the temple building of the Queen Mother Palace in Huishan of Gansu Province was in disrepair,and Temple Master Kuo,Yeh-Tzu made a vow to rebuild it.Rebuilding the ancestral temple began in 1992 and was completed in 1994.It was the first case of a Taiwan temple financing the rebuilding of a far-away Queen Mother Palace with its own donations.In addition,Sung Shan Tsu Huei Temple celebrated its 45th anniversary and hosted Yiwei Yuanheng Lizhen Daluo Tiandi Qingjiao(Momentous and Fortuitous Heaven and Earth Prayer Ceremony)in 2015.This is the most important and the grandest blessing ceremony of Taoism,a rare event for Taoism locally and abroad during this century.Those sacred rituals were replete with unprecedented grand wishes to propagate the belief in Queen Mother of the West.Stopping at nothing,Queen Mother’s love never ceases.
文摘Energy used for industrial production, buildings and transport will be accumulated in Atmosphere and Earth land. Global use of energy is known and documented for a long period of time and proportion of fossil and renewable energy is also known. Calculated accumulated energy in Earth land from 1971 to 2018 corresponds to 40% of IPCC Global Energy Inventory and calculated Atmosphere temperature increase from 1971 to 2018 corresponds to 100% of actual measurements.
文摘Global climate change has caused general and serious damage to cultural heritage sites,and earthen settlements and buildings are particularly vulnerable to water-afected disasters.Thus,this paper uses Liang Village in Pingyao County,China,as a case study,linking the human–land study in the Liang Village Sino-French workshop of 2009/2010 to a disaster assessment completed after the devastating rainstorm in October 2021.We found that the village’s rain disaster resulted from the vulnerability of earthen material to rainstorms and from the earthen settlement’s evolution from a culture emphasising the coexistence of‘water and earth’to a technic fostering the disintegration of‘water and earth’.The latter is the main cause of the village’s decrease in its capacity for disaster prevention and damage reduction.Therefore,in the context of global climate change,we fnd that the reestablishment of the harmonious relationship of water and earth is critical to both rural heritage conservation and village sustainable development.In addition to repairing their relation from the technical perspective of‘planning and design’by planners and architects,it is more crucial for local people to understand and enhance their contemporary appreciation for the traditional‘coexistence of water and earth’concept.
基金the Institute of Geodesy and Geophysics, CAS in Wuhanthe National Natural Science Foundation of China
文摘In the last several years since 2004 an important new finding has been unveiled by combined efforts due to Japanese (Satoru Tanaka), French (Renaud Deguen, Y Albousierre and Marc Monnereau), American and Chinese geophysicists (Xiaodong Song and Vernon F Cormier) who employed from unambi- guous detailed seismological evidence and explained by clear theoretical and sound laboratory arguments drawn from fluid dynamics that there exists a strong East-West hemi-spherical asymmetry on the inner- outer core boundary,
文摘Let your gaze rest upon the poster for Earth Day on April 22. A small polar bear clings tightly to the stem of an aero-vane. Staring at the vanishing floating ice on the wild sea, his eyes are full of panic and fear.
文摘THIS photograph was published in the book, A Century of Historical Chinese Photographs, with only a one-line caption: "A private school for Christian girls opened by the foreign Mission of the Virgin Mary in Shanghai." Determining which country’s church, which year it opened, and what kind of a private girls’ school it was would be nearly impossible. But this should not stop
基金Supported by the National Natural Science Foundation of China under Grant No 0704071, and the Fund of Anhui Key Laboratory of Optoelectronic Science and Technology.
文摘Propagation properties of coherent and partially coherent beams in atmospheric turbulence are investigated respectively by using numerical simulation It is found that a partially coherent beam has a spreading larger than a coherent beam. However, from the point view of relative beam spreading and intensity scintillation, a partially coherent beam is less affected than the corresponding coherent beam, which may be the most important virtue of partially coherent beams that could be utilized to improve the performance of laser engineering. The beam wandering is almost independent of the degree of the source coherence. More aperture averaging occurs when beam becomes more coherent.
文摘A mobile molecular Doppler wind lidar (DWL) based on double-edge technique is presented for wind measurement at altitudes from 10 km to 40 km. A triple Fabry-Perot etalon is employed as a frequency discriminator to determine the Doppler shift proportional to the wind velocity. The lidar operates at 355 nm with a 45-cm aperture telescope and a matching azimuth-over-elevation scanner that can provide full hemispherical pointing. In order to guarantee the wind accuracy, different forms of calibration function of detectors in different count rates response range would be especially valuable. The accuracy of wind velocity iteration is improved greatly because of application of the calibration function of linearity at the ultra low light intensity especially at altitudes from 10 km to 40 km. The calibration functions of nonlinearity make the transmission of edge channel 1 and edge channel 2 increase 38.9% and 27.7% at about 1 M count rates, respectively. The dynamic range of wind field measurement may also be extended because of consideration of the response function of detectors in their all possible operating range.
基金supported by the Korea Meteorological Administration Research and Development Program (Grant No. CATER 2012-2040)
文摘Hourly outgoing longwave radiation (OLR) from the geostationary satellite Communication Oceanography Meteorological Satellite (COMS) has been retrieved since June 2010.The COMS OLR retrieval algorithms are based on regression analyses of radiative transfer simulations for spectral functions of COMS infrared channels.This study documents the accuracies of OLRs for future climate applications by making an intercomparison of four OLRs from one single-channel algorithm (OLR12.0 using the 12.0 μm channel) and three multiple-channel algorithms (OLR10.8+12.0 using the 10.8 and 12.0 pm channels; OLR6.7+10.8 using the 6.7 and 10.8 μm channels; and OLRAll using the 6.7,10.8,and 12.0 μm channels).The COMS OLRs from these algorithms were validated with direct measurements of OLR from a broadband radiometer of the Clouds and Earth's Radiant Energy System (CERES) over the full COMS field of view [roughly (50°S-50°N,70°-170°E)] during April 2011.Validation results show that the root-mean-square errors of COMS OLRs are 5-7 W m-2,which indicates good agreement with CERES OLR over the vast domain.OLR6.7+10.8 and OLRAll have much smaller errors (~ 6 W m-2) than OLR12.0 and OLR10.8+12.0 (~ 8 W m-2).Moreover,the small errors of OLR6.7+10.8 and OLRAll are systematic and can be readily reduced through additional mean bias correction and/or radiance calibration.These results indicate a noteworthy role of the 6.7 μm water vapor absorption channel in improving the accuracy of the OLRs.The dependence of the accuracy of COMS OLRs on various surface,atmospheric,and observational conditions is also discussed.
基金Supported the National Natural Science Foundation of China under Grant Nos 40804045 and Innovation Fund of Center for Space Science and Applied Research under Grant No O82112A18S.
文摘The tearing mode instability plays a key role in the triggering process of reconnection. The triggering collisionless tearing mode instability has been theoretically and numerically analyzed by many researchers. However, due to the difficulty in obtaining the observational wave number, it is still unknown whether the tearing mode instability can be excited in an actual plasma sheet prior to reconnection onset. Using the data from four Cluster satellites prior to a magnetospheric reconnection event on 13 September 2002, we utilized the wave telescope technique to obtain the wave number which corresponds to the peak of power spectral density. The wavelength is about 18RE and is consistent with previous theoretic and numerical results. After substituting the wave vector and other necessary parameters of the observed current sheet into the triggering condition of tearing mode instability, we find that the near-Earth current sheet prior to reconnection is unstable to tearing mode.
基金Supported by the National Natural Science Foundation of China under Grant Nos 40931054 and 40523006, the National Basic Research Program of China under Grant No 2006CB806305, the National High-Tech Research and Development Program of China under Grant No 2008AA12A216, and the Specialized Research Fund for State Key Laboratories.
文摘Characteristics of ULF waves associated with the solar wind deceleration in the Earth's foreshock on 6-7 April 2003 is studied using the wave telescope technique. In the satellite frame, the ULF waves are the left-handed polarized and quasi anti-parallel propagating mode, with a power peak at about 18.63mHz. The wave vector in the GSE coordinates is estimated to be k = (-4.29, 2.28, 1.21)×10^-4 km^-1, In the solar wind frame, the frequency of waves becomes - 9.39 mHz after the Doppler shift correction. The propagation direction of the waves is thus reversed and correspondingly the polarization of the waves becomes right-handed. The above-mentioned characteristics of the ULF waves in the solar wind frame indicate that the ULF waves associated with the solar wind deceleration are the Alfven-whistler waves, which have been frequently reported in both the observations and computer simulations.
文摘Specific activity of primordial radionuclides and associated radiation hazards due to 40K, 226Ra, and 232Th have been measured in backed red brick samples, collected from five highly populated areas of the North West Frontier Province of Pakistan. For the detection, analysis and data acquisition, a high purity germanium detector was used. Associated external doses were calculated using a Monte Carlo neutron photon transport code. A theoretical model to determine the gamma dose rate at 1 m height from the floor, made of bricks, was employed for the calculation of mass attenuation coefficient and self-absorption in the floor for the gamma energies of these radionuclides and their progeny. Monte Carlo simulation shows that in this study the floor, having more than an effective thickness of 15 cm, contributes very little to the external gamma dose rate. The values of the external dose rate and annual effective dose are found to be much lower than the world average as well as from other countries of the world.
文摘Three-dimensional mode coupling around a conical seamount in an ocean waveguide is studied. It is shown that strong mode coupling occurs at the edge of a conical seamount for the incident normal modes with significant amplitudes below the top of the seamount. Therefore, mode coupling is critical for the investigation of the acoustic field around a seamount. In addition, we suggest the use of random discretization for representing smoothly varying bathymetry. For the use of uniform discretization, when the horizontal step size is greater than half of the wavelength, artificial diffraction lobes appear due to coherent backscatter. However, by using the random discretization scheme instead, such artificial diffraction lobes are diffused, resulting in a faster convergence rate.
文摘The analysis of naturally occurring radionuclides (226Ra, 232 Th and 40 K) and an anthropogenic radionuclide 13r Cs is carried out in some soil samples collected from Kohistan district of N.W.F.P. (Pakistan), using gamma-ray spectrometry. The gamma spectrometry is operated using a high purity Germanium (HPGe) detector coupled with a computer based high resolution multi channel analyzer. The specific activity in soil ranges from 24.72 to 78.48Bq.kg-1 for 22TRa, 21.73 to 75.28Bq.kg- 1 for 232Th, 7.06 to 14.9Bq.kg 1 for 1arcs and 298.46 to 570.77Bq.kg-1 for 40K with the mean values of 42.11, 43.27, 9.5 and 418.27Bq.kg-1, respectively. The radium equivalent activity in all the soil samples is lower than the safe limit set in the OECD report (370 Bq.kg-1). Man-made radionuclide 13r Cs is also present in detectable amount in all sell samples. Presence of 13r Us indicates that the samples in this renlote area also recelvo some fallout from nuclear accident in Chernobyl power plant in 1986. The internal and external hazard indices have the mean values of 0.48 and 0.37 respectively. Absorbed dose rates and effective dose equivalents are also determined for the samples. The concentration of radionuclides found in the soil samples during the present study is nominal and does not pose any potential health hazard to the general public.
文摘Effects of atmospheric turbulence tilt, defocus, astigmatism and coma aberrations on the orbital angular momentum measurement probability of photons propagating in weak turbulent regime are modeled with Rytov approximation. By considering the resulting wave as a superposition of angular momentum eigenstates, the or- bital angular momentum measurement probabilities of the transmitted digit are presented. Our results show that the effect of turbulent tilt aberration on the orbital angular momentum measurement probabilities of photons is the maximum among these four kinds of aberrations. As the aberration order increases, the effects of turbulence aberrations on the measurement probabilities of orbital angular momentum generally decrease, whereas the effect o[ turbulence defocus can be ignored. For tilt aberration, as the difference between the measured orbital angular momentum and the original orbital angular momentum increases, the orbital angular momentum measurement probability decreases.
基金Supported by the National Natural Science Foundation of China under Grant Nos 70871082, 10975126, 90924011, 70971089, 10635040 and 60973069, the China Postdoctoral Science Foundation under Grant No 20080431273, and the Sino-Swiss Science and Technology Cooperation (SSSTC) Project (EG 20-032009). We acknowledge Xiaopu Han and Wei Hong for their useful discussions.
文摘Empirical observations indicate that the interevent time distribution of human actions exhibits heavy-tailed features. The queuing model based on task priorities is to some extent successful in explaining the origin of such heavy tails, however, it cannot explain all the temporal statistics of human behavior especially for the daily entertainments. We propose an interest-driven model, which can reproduce the power-law distribution of interevent time. The exponent can be analytically obtained and is in good accordance with the simulations. This model well explains the observed relationship between activities and power-law exponents, as reported recently for web-based behavior and the instant message communications.
基金Supported by the National Natural Science Foundation of China under Grant No 10523002.
文摘Location of an airborne source is estimated from signals measured by a horizontal line array (HLA), based on the fact that a signal transmitted by an airborne source will reach a underwater hydrophone in different ways: via a direct refracted path, via one or more bottom and surface reflections, via the so-called lateral wave. As a result, when an HLA near the airborne source is used for beamforming, several peaks at different bearing angles will appear. By matching the experimental beamforming outputs with the predicted outputs for all source locations, the most likely location is the one which gives minimum difference. An experiment is conducted for airborne source localization in the Yellow Sea in October 2008. An HLA was laid on the sea bottom at the depth of 30m. A high-power loudspeaker was hung on a research ship floating near the HLA and sent out LFM pulses. The estimated location of the loudspeaker is in agreement well with the GPS measurements.
文摘We propose a new method to reveal a direct transformation from solar energy to solar electricity. Instead of using electricity in the process, we use concentrated solar rays with a crucibleless process to upgrade metallurgical silicon into solar-grade silicon feedstock.
基金Supported by the National Basic Research Program of China under Grant No 2006CB705500, the National Natural Science Foundation of China under Grant Nos 60744003, 10635040 and 10532060, the Specialized Research Fund for the Doctoral Program of Higher Education of China under Grant No 20060358065, and the National Science Fund for Fostering Talents in Basic Science (J0630319).
文摘We propose a new two-type-player prisoner's dilemma game based on the division of work on a square lattice, in which a fraction of the population μ are assigned type A and the rest B. In a one-shot two-player game, we let both of their original payoffs be scaled by a same multiplicative factor α 〉 1, if two neighboring players are of different types; however we leave the payoffs unchanged if they are of the same type. Then we show that combined with the two-type setup, the square lattice can assist to induce different social ranks according to players' abilities to collect payoffs. Simulation results show that the density of cooperation is significantly promoted for a wide range of the temptation to defection parameters and that there are optimal values for both α and μ leading to the maximal cooperation level. We reach these results by analyzing the distribution of the players in the social ranks and we also show some typical snapshots of the system.
基金Supported by the National Natural Science Foundation of China under Grant No 60871070, the National Pre-research Foundation and the Foundation of National Electromagnetic Scattering Laboratory.
文摘A hybrid high-frequency method is proposed to analyze the bistatic electromagnetic scattering of the ship target on a very large two-dimensional randomly rough sea surface. The scattering of the ship-sea model is evaluated with the method of equivalent currents (MEC). The iterative physical optics method (IPO) is utilized to study the electromagnetic coupling effect caused by the hull and rough surface. The shadowing correction based on the Z-Buffer technology is introduced to eliminate the effects of the irrelevant scattering resources. The validity of the hybrid method is confirmed by the SAR simulation results and the scattering property of the ship-sea model is discussed.