Transmission power lines are a common source of extremely low frequency(ELF) magnetic fields which are usually analyzed as serial lines in one direction.Overhead vertical-type double-circuit power lines,which are gene...Transmission power lines are a common source of extremely low frequency(ELF) magnetic fields which are usually analyzed as serial lines in one direction.Overhead vertical-type double-circuit power lines,which are generally used in Japan,sometimes carry different current for each circuit and change direction.In this paper,we focused on both the angle of direction change and the current balance in order to clarify the characteristics of distribution of magnetic fields at a height of 1 m.The magnetic field distributions were analyzed considering both the angle of power lines changing direction and the current balance of each circuit.The total magnetic field under overhead vertical-type double-circuit power lines with same current was generally reduced in comparison with that under a single-circuit power line due to phase difference.The total magnetic fields around the turning point where the change of transmission lines direction increased because each circuit came closer in that area.The component of B_z effect on total magnetic field was greatest around the maximum of total magnetic fields nearby the turning point.展开更多
The dynamics of secondary large-scale structures in electron-temperature-gradient （ETG） turbulence is investigated based on gyrofluid simulations in sheared slab geometry. It is found that structural bifurcation to ...The dynamics of secondary large-scale structures in electron-temperature-gradient （ETG） turbulence is investigated based on gyrofluid simulations in sheared slab geometry. It is found that structural bifurcation to zonal flow dominated or streamer-like states depends on the spectral anisotropy of turbulent ETG fluctuation, which is governed by the magnetic shear. The turbulent electron transport is suppressed by enhanced zonal flows. However, it is still low even if the streamer is formed in ETG turbulence with strong shears. It is shown that the low transport may be related to the secondary excitation of poloidal long-wavelength mode due to the beat wave of the most unstable components or a modulation instability. This large-scale structure with a low frequency and a long wavelength may saturate, or at least contribute to the saturation of ETG fluctuations through a poloidal mode coupling. The result suggests a low fluctuation level in ETG turbulence.展开更多
Aim:To elucidate the distribution and regulation of Neuropeptide Y(NPY)gene expression in testes under physiologi- cal and pathophysiological conditions,such as testicular development,fasting and experimental cryptorc...Aim:To elucidate the distribution and regulation of Neuropeptide Y(NPY)gene expression in testes under physiologi- cal and pathophysiological conditions,such as testicular development,fasting and experimental cryptorchidism. Methods:In the first experiment,C57BL/6J male mice at the ages of 3 days as well as 2,3,5 and 8 weeks were used. In the second and third experiments,adult C57BL/6J male mice were subjected to fasting for 48 h and experimental cryptorchidism for 72 h.The NPY transcripts were detected by isotopic in situ hybridization histochemistry.Results: The NPY transcripts were exclusively expressed in the interstitial cells regardless of the age groups and experimental conditions.The NPY mRNA levels were found to increase significantly with age(from the neonatal to prepubertal period [P<0.01] and from the prepubetal to postpubertal period [P<0.01]).Food deprivation for 48 h resulted in a significant increase in the NPY mRNA levels in the arcuate nucleus of the hypothalamus(P<0.01),but not in the testes.Experimental cryptorchidism for 72 h failed to regulate the NPY gene expression in the testes.Conclusion: NPY gene expression is distributed in Leydig cells and increases in line with testicular development.The regulation of testicular NPY is different from that of hypothalamic NPY.(Asian J Androl 2006 Jul;8:443-449)展开更多
He and Ar isotopic compositions of megacrystal minerals from mantle xenoliths were measured by the technique of vacuum crushing extraction. The used samples were clinopyroxene, garnet and ilmenite in Cenozoic alkaline...He and Ar isotopic compositions of megacrystal minerals from mantle xenoliths were measured by the technique of vacuum crushing extraction. The used samples were clinopyroxene, garnet and ilmenite in Cenozoic alkaline basalts, which were from Nushan in Anhui Province and Yingfengling in Guangdong Province, respectively, and represented materials from the upper mantle in the continental margin of SE China. The results show 3He/4He ratios of 7.99 Ra to 8.58 Ra, consistent with the characteristic ratios of the MORB-type mantle. 40Ar/39Ar ratios vary from 313 to 909, suggesting a binary mixing between the MORB-type mantle and air argons. This may reflect the incorporation of the air argon absorbed in oceanic sediments into the mantle beneath the continental margin by subduction of oceanic plate. This study presents the first report that ilmenite megacrysts contain abundant fluid inclusions and noble gases in the mantle xenoliths.展开更多
文摘Transmission power lines are a common source of extremely low frequency(ELF) magnetic fields which are usually analyzed as serial lines in one direction.Overhead vertical-type double-circuit power lines,which are generally used in Japan,sometimes carry different current for each circuit and change direction.In this paper,we focused on both the angle of direction change and the current balance in order to clarify the characteristics of distribution of magnetic fields at a height of 1 m.The magnetic field distributions were analyzed considering both the angle of power lines changing direction and the current balance of each circuit.The total magnetic field under overhead vertical-type double-circuit power lines with same current was generally reduced in comparison with that under a single-circuit power line due to phase difference.The total magnetic fields around the turning point where the change of transmission lines direction increased because each circuit came closer in that area.The component of B_z effect on total magnetic field was greatest around the maximum of total magnetic fields nearby the turning point.
基金supported in part by the National Natural Science Foundation of China(Nos.10135020 and 10575032)
文摘The dynamics of secondary large-scale structures in electron-temperature-gradient （ETG） turbulence is investigated based on gyrofluid simulations in sheared slab geometry. It is found that structural bifurcation to zonal flow dominated or streamer-like states depends on the spectral anisotropy of turbulent ETG fluctuation, which is governed by the magnetic shear. The turbulent electron transport is suppressed by enhanced zonal flows. However, it is still low even if the streamer is formed in ETG turbulence with strong shears. It is shown that the low transport may be related to the secondary excitation of poloidal long-wavelength mode due to the beat wave of the most unstable components or a modulation instability. This large-scale structure with a low frequency and a long wavelength may saturate, or at least contribute to the saturation of ETG fluctuations through a poloidal mode coupling. The result suggests a low fluctuation level in ETG turbulence.
文摘Aim:To elucidate the distribution and regulation of Neuropeptide Y(NPY)gene expression in testes under physiologi- cal and pathophysiological conditions,such as testicular development,fasting and experimental cryptorchidism. Methods:In the first experiment,C57BL/6J male mice at the ages of 3 days as well as 2,3,5 and 8 weeks were used. In the second and third experiments,adult C57BL/6J male mice were subjected to fasting for 48 h and experimental cryptorchidism for 72 h.The NPY transcripts were detected by isotopic in situ hybridization histochemistry.Results: The NPY transcripts were exclusively expressed in the interstitial cells regardless of the age groups and experimental conditions.The NPY mRNA levels were found to increase significantly with age(from the neonatal to prepubertal period [P<0.01] and from the prepubetal to postpubertal period [P<0.01]).Food deprivation for 48 h resulted in a significant increase in the NPY mRNA levels in the arcuate nucleus of the hypothalamus(P<0.01),but not in the testes.Experimental cryptorchidism for 72 h failed to regulate the NPY gene expression in the testes.Conclusion: NPY gene expression is distributed in Leydig cells and increases in line with testicular development.The regulation of testicular NPY is different from that of hypothalamic NPY.(Asian J Androl 2006 Jul;8:443-449)
基金supported by The National Natural Science Foundation of China(Grant Nos.49473175,49972062 and 40110104104).
文摘He and Ar isotopic compositions of megacrystal minerals from mantle xenoliths were measured by the technique of vacuum crushing extraction. The used samples were clinopyroxene, garnet and ilmenite in Cenozoic alkaline basalts, which were from Nushan in Anhui Province and Yingfengling in Guangdong Province, respectively, and represented materials from the upper mantle in the continental margin of SE China. The results show 3He/4He ratios of 7.99 Ra to 8.58 Ra, consistent with the characteristic ratios of the MORB-type mantle. 40Ar/39Ar ratios vary from 313 to 909, suggesting a binary mixing between the MORB-type mantle and air argons. This may reflect the incorporation of the air argon absorbed in oceanic sediments into the mantle beneath the continental margin by subduction of oceanic plate. This study presents the first report that ilmenite megacrysts contain abundant fluid inclusions and noble gases in the mantle xenoliths.
