We report results of petrologic and mineralogical studies of 25 unequili- brated ordinary chondrites （19 Chinese Antarctic meteorites） using electron microprobe, scanning electron microscopy （SEM） and energy-dispe...We report results of petrologic and mineralogical studies of 25 unequili- brated ordinary chondrites （19 Chinese Antarctic meteorites） using electron microprobe, scanning electron microscopy （SEM） and energy-dispersive X-ray spectrometry （EDS） techniques. With increasing degree of thermal metamorphism, chemical zoning of olivine was erased; plessite was transformed into intergrowths of coarsergrained kamacite and Ni-rich metal; Cr exsolved from ferroan olivine, produced needie-like crystals and coarsened into equant chromite grains; and feldspar crystallized during devitrification of glass and recrystallization of matrix. These features can help to identify different metamorphic grades. Based on the scheme by Sears et al （1982）, we subdivided type 3 Chinese Antarctic ordinary chondrites into petrologic type 3.3 to 4 （3 type 3.3, 3 type 3.4, 1 type 3.5, 2 type 3.6, 2 type 3.7, 5 type 3.8, 3 type 4 ）. This classification scheme is a quite effective way to subdivide Antarctic meteorites. Additionally, we propose to revise the chemical groups of GRV 020032 and GRV 020104 to L and H, respectively.展开更多
With the rapid demand for underwater optical communication(UOC), studies of UOC degradation by oceanic turbulence have attached increasing attention worldwide and become a research hot-spot in recent years. Previous s...With the rapid demand for underwater optical communication(UOC), studies of UOC degradation by oceanic turbulence have attached increasing attention worldwide and become a research hot-spot in recent years. Previous studies used a simplified and inaccurate oceanic turbulence spectrum, in which the eddy diffusivity ratio between temperature and salinity is assumed to be unity and the outer scale of turbulence is assumed to be infinite. However, both assumptions are not true in most of the actual marine environments. In this paper, based on the Rytov theory in weak turbulence, we derive analytical expressions of "the aperture-averaged scintillation index"(SI) for both plane and spherical waves, which can clearly demonstrate how SI is influenced by several key factors in UOC. Then, typical fade statistics of the UOC system in weak turbulence is discussed including the probability of fade, the expected number of fades per time, the mean fade time,signal-to-noise ratio and bit error rate. Our results show that spherical wave is preferable in the UOC system in weak turbulence compared to plane wave, and the aperture-averaged effect has a significant impact on UOC system's performance.Our results can be used to determine those key parameters for designing the UOC system over reasonable ranges.展开更多
研究了不同颜色太阳电池的制备工艺和电学性能。实验表明,随着镀膜压强的增加,减反射层的折射率缓慢增加,当压强超过1800 m Torr时,折射率的增幅变大;随着镀膜时间的增加,太阳电池的开路电压Uoc先增大后减小,当淀积时间为550 s时,Uoc达...研究了不同颜色太阳电池的制备工艺和电学性能。实验表明,随着镀膜压强的增加,减反射层的折射率缓慢增加,当压强超过1800 m Torr时,折射率的增幅变大;随着镀膜时间的增加,太阳电池的开路电压Uoc先增大后减小,当淀积时间为550 s时,Uoc达到最大值;短路电流Isc随淀积时间的变化趋势与Uoc相同,当淀积时间为650 s时,Isc达到最大。因此,对于具有装饰功能的太阳能电池组件采用并联的方式进行设计可达到最佳组件效率。展开更多
基金supported by the National Natural Science Foundation of China(Grant No.40773046 and 10621303)Experimental Standardization and Sharing of the Polar Region Biological and Geological Sample Project(2005DKA21406)the Minor Planet Foundation of China
文摘We report results of petrologic and mineralogical studies of 25 unequili- brated ordinary chondrites （19 Chinese Antarctic meteorites） using electron microprobe, scanning electron microscopy （SEM） and energy-dispersive X-ray spectrometry （EDS） techniques. With increasing degree of thermal metamorphism, chemical zoning of olivine was erased; plessite was transformed into intergrowths of coarsergrained kamacite and Ni-rich metal; Cr exsolved from ferroan olivine, produced needie-like crystals and coarsened into equant chromite grains; and feldspar crystallized during devitrification of glass and recrystallization of matrix. These features can help to identify different metamorphic grades. Based on the scheme by Sears et al （1982）, we subdivided type 3 Chinese Antarctic ordinary chondrites into petrologic type 3.3 to 4 （3 type 3.3, 3 type 3.4, 1 type 3.5, 2 type 3.6, 2 type 3.7, 5 type 3.8, 3 type 4 ）. This classification scheme is a quite effective way to subdivide Antarctic meteorites. Additionally, we propose to revise the chemical groups of GRV 020032 and GRV 020104 to L and H, respectively.
基金supported by the fund from Xi’an Institute of Optics and Precision Mechanics。
文摘With the rapid demand for underwater optical communication(UOC), studies of UOC degradation by oceanic turbulence have attached increasing attention worldwide and become a research hot-spot in recent years. Previous studies used a simplified and inaccurate oceanic turbulence spectrum, in which the eddy diffusivity ratio between temperature and salinity is assumed to be unity and the outer scale of turbulence is assumed to be infinite. However, both assumptions are not true in most of the actual marine environments. In this paper, based on the Rytov theory in weak turbulence, we derive analytical expressions of "the aperture-averaged scintillation index"(SI) for both plane and spherical waves, which can clearly demonstrate how SI is influenced by several key factors in UOC. Then, typical fade statistics of the UOC system in weak turbulence is discussed including the probability of fade, the expected number of fades per time, the mean fade time,signal-to-noise ratio and bit error rate. Our results show that spherical wave is preferable in the UOC system in weak turbulence compared to plane wave, and the aperture-averaged effect has a significant impact on UOC system's performance.Our results can be used to determine those key parameters for designing the UOC system over reasonable ranges.
文摘研究了不同颜色太阳电池的制备工艺和电学性能。实验表明,随着镀膜压强的增加,减反射层的折射率缓慢增加,当压强超过1800 m Torr时,折射率的增幅变大;随着镀膜时间的增加,太阳电池的开路电压Uoc先增大后减小,当淀积时间为550 s时,Uoc达到最大值;短路电流Isc随淀积时间的变化趋势与Uoc相同,当淀积时间为650 s时,Isc达到最大。因此,对于具有装饰功能的太阳能电池组件采用并联的方式进行设计可达到最佳组件效率。
