主要介绍了抚仙湖1 m新真空太阳望远镜(the 1-meter New Vacuum Solar Telescope,NVST)6 m水平式近红外光谱仪的安装过程和实测结果。主要讨论内容是光路设计特点、光学系统的装调以及利用该光谱仪对活动区NOAA 11662黑子进行的初步近...主要介绍了抚仙湖1 m新真空太阳望远镜(the 1-meter New Vacuum Solar Telescope,NVST)6 m水平式近红外光谱仪的安装过程和实测结果。主要讨论内容是光路设计特点、光学系统的装调以及利用该光谱仪对活动区NOAA 11662黑子进行的初步近红外光谱实测(波长1.56μm附近)。成功观测到由黑子强磁场造成的Fe I 1.56μm谱线裂变现象,并初步估算了磁场强度。该光谱的成功装调和使用,充分实现了对9 m光谱仪光学系统的整体检测,为9 m光谱仪的安装调试提供了宝贵的经验和参考。展开更多
研究了1 m新真空太阳望远镜(New Vacuum Solar Telescope,NVST)终端仪器消旋平台上平台的载荷形变情况。利用检测激光光斑在CCD探测器上的位移探测微小的形变。实验时,激光光源固定在稳定区域指向被测区域CCD探测器。通过质心算法计算CC...研究了1 m新真空太阳望远镜(New Vacuum Solar Telescope,NVST)终端仪器消旋平台上平台的载荷形变情况。利用检测激光光斑在CCD探测器上的位移探测微小的形变。实验时,激光光源固定在稳定区域指向被测区域CCD探测器。通过质心算法计算CCD探测器靶面光斑质心数据,质心的变化量反映测量被测区域的形变量,仅研究重力方向的形变。通过多组实验及ANSYS仿真发现:上平台的3个悬臂边缘位置在旋转至80°~200°区域出现的正、反转重力方向形变的明显不一致问题很大程度由驱动平面和轴承定位平面不一致及正、反转滚轮组不严格指向转台中心两个因素共同作用引起;3个悬臂中,一个悬臂在多个转动区域形变明显且对载荷敏感,一个悬臂部分区域对载荷敏感,均主要由于其与转台中心连接刚度较差引起。展开更多
The present study deals with a spatially homogeneous and anisotropic Bianehi-I cosmological models representing massive strings with magnetic field and decaying vacuum energy density A. The energy-momentum tensor, as ...The present study deals with a spatially homogeneous and anisotropic Bianehi-I cosmological models representing massive strings with magnetic field and decaying vacuum energy density A. The energy-momentum tensor, as formulated by Letelier （1983）, has been used to construct massive string cosmological models for which we assume the expansion scalar in the models is proportional to one of the components of shear tensor. The Einstein＇s field equations have been solved by applying a variation law for generalized Hubble＇s parameter in Bianchi-I space-time. The variation law for Hubble＇s parameter generates two types of solutions for the average scale factor, one is of power-law type and other is of the exponential form. Using these two forms, Einstein＇s field equations are solved separately that correspond to expanding singular and non-singular models of the universe respectively. We have made a comparative study of accelerating and decelerating models in the presence of string scenario. The study reveals that massive strings dominate in the decelerating universe whereas strings dominate in the accelerating universe. The strings eventually disappear from the universe for sufficiently large times, which is in agreement with current astronomical observations. The cosmological constant A is found to be a positive decreasing function of time which is corroborated by results from recent supernovae Ia observations. The physical and geometric properties of the models have been also discussed in detail.展开更多
文摘主要介绍了抚仙湖1 m新真空太阳望远镜(the 1-meter New Vacuum Solar Telescope,NVST)6 m水平式近红外光谱仪的安装过程和实测结果。主要讨论内容是光路设计特点、光学系统的装调以及利用该光谱仪对活动区NOAA 11662黑子进行的初步近红外光谱实测(波长1.56μm附近)。成功观测到由黑子强磁场造成的Fe I 1.56μm谱线裂变现象,并初步估算了磁场强度。该光谱的成功装调和使用,充分实现了对9 m光谱仪光学系统的整体检测,为9 m光谱仪的安装调试提供了宝贵的经验和参考。
文摘研究了1 m新真空太阳望远镜(New Vacuum Solar Telescope,NVST)终端仪器消旋平台上平台的载荷形变情况。利用检测激光光斑在CCD探测器上的位移探测微小的形变。实验时,激光光源固定在稳定区域指向被测区域CCD探测器。通过质心算法计算CCD探测器靶面光斑质心数据,质心的变化量反映测量被测区域的形变量,仅研究重力方向的形变。通过多组实验及ANSYS仿真发现:上平台的3个悬臂边缘位置在旋转至80°~200°区域出现的正、反转重力方向形变的明显不一致问题很大程度由驱动平面和轴承定位平面不一致及正、反转滚轮组不严格指向转台中心两个因素共同作用引起;3个悬臂中,一个悬臂在多个转动区域形变明显且对载荷敏感,一个悬臂部分区域对载荷敏感,均主要由于其与转台中心连接刚度较差引起。
基金Supported in part by the Council of Science and Technology,Uttar Pradesh,India
文摘The present study deals with a spatially homogeneous and anisotropic Bianehi-I cosmological models representing massive strings with magnetic field and decaying vacuum energy density A. The energy-momentum tensor, as formulated by Letelier （1983）, has been used to construct massive string cosmological models for which we assume the expansion scalar in the models is proportional to one of the components of shear tensor. The Einstein＇s field equations have been solved by applying a variation law for generalized Hubble＇s parameter in Bianchi-I space-time. The variation law for Hubble＇s parameter generates two types of solutions for the average scale factor, one is of power-law type and other is of the exponential form. Using these two forms, Einstein＇s field equations are solved separately that correspond to expanding singular and non-singular models of the universe respectively. We have made a comparative study of accelerating and decelerating models in the presence of string scenario. The study reveals that massive strings dominate in the decelerating universe whereas strings dominate in the accelerating universe. The strings eventually disappear from the universe for sufficiently large times, which is in agreement with current astronomical observations. The cosmological constant A is found to be a positive decreasing function of time which is corroborated by results from recent supernovae Ia observations. The physical and geometric properties of the models have been also discussed in detail.
