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<正>We describe a mobile molecular Doppler wind lidar(DWL) based on double-edge technique for wind measurement of altitudes ranging from 10 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 provides full hemispherical pointing.To guarantee wind accuracy,a single servo loop is used to monitor the outgoing laser frequency to remove inaccuracies due to the frequency drift of the laser or the etalon.The standard deviation of the outgoing laser frequency drift is 6.18 MHz and the corresponding velocity error is 1.11 m/s.The wind profiles measured by the DWL are in good agreement with the results of the wind profile radar(WPR).Evaluation is achieved by comparing at altitudes from 2 to 8 km.The relative error of horizontal wind speed is from 0.8 to 1.8 m/s in the compared ranges.The wind accuracy is less than 6 m/s at 40 km and 3 m/s at 10 km. 相似文献
84.
The interaction between polychromatic fields and atoms is an important subject in quantum optics.Frequency locking for small frequency interval multi-field is usually required in some experiments.In this letter,we experimentally demonstrate a holistic scheme for bichromatic laser frequency stabilization.Compared with traditional saturation absorption methods and complicated frequency shift schemes,offset locking for bichromatic fields is simply achieved using polarization spectroscopy and Doppler effect.Frequency locking with a wide-range asymmetry of the detuning is also shown.Our scheme makes laser spectroscopy experiments with polychromatic fields more convenient. 相似文献
85.
A novel method for velocity measurement is presented. In this scheme, a parallel-linear-polarization dual- frequency laser is incident on the target and senses the target velocity with both the frequencies, which can increase the maximum measurable velocity significantly. The theoretical analysis and verification experiment of the novel method are presented, which show that high-velocity measurement can be achieved with high precision using this method. 相似文献
86.
Lifetimes of high spin states in 129Cs axe measured using the Doppler shift attenuation method. The high spin states of 129 Cs axe populated following the fusion evaporation reaction 124 Sn(UB, 6n)129 Cs at a beam energy of 65 MeV. The reduced transition probabilities B(E2) and the transition quadrupole moments Qt in the negativeand positive-paxity bands are deduced. The experimental results indicate that the Qt values of the negative parity band are smaller than those of the positive parity bands, probably due to different γ-deformation driving effects of different proton orbitals. The Qt values exhibit a considerable increase near the band crossing region in these bands. This behavior demonstrates that nuclear shape changing results from the neutron or proton alignments. The signature splitting of the πh11/2 and πg7/2 bands shows the opposite changing trend after backbending due to the h11~2 neutron and h11/2 proton alignments, respectively. 相似文献
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88.
在太阳系外找到一颗适合人类居住的行星,是天体物理学家长期以来的梦想。适合人类居住,通常要求有液态水,这相应地要求:行星到母恒星的距离在一定的范围之内。按照最近Dumusque等在Nature周刊发表的研究报告,事情或许有了一定的眉目。研究者宣称,发现了一颗类地球太阳系外行星,它围绕半人马座α双星之一(B星)运转,半人马座α双星属于最接近太阳系的恒星,离我们仅4光年远。 相似文献
89.
作为荧光传感材料,荧光聚合物不仅具有传感单元多、荧光亮度高、光稳定性好等特点,而且方便制备荧光传感薄膜,易于实现器件化,在爆炸物荧光检测中得到了广泛的研究与应用。近年来,随着荧光聚合物从传统的线型结构向支化和多孔网络结构的拓展,以及各种功能单元的引入,大量的新型荧光聚合物有效地提升了爆炸物检测的灵敏度、选择性和响应速度等性能。本综述从线型聚合物、支化聚合物、多孔聚合物三类体系出发,总结和评述了用于爆炸物荧光检测的线型共轭与非共轭聚合物、树枝状分子与超支化聚合物、无定形与结晶型多孔聚合物等典型体系的分子结构设计策略、功能特点以及传感性能,并展望了荧光聚合物未来在爆炸物检测应用中所面临的机遇和挑战。 相似文献
90.
医用纱布一般用于包扎伤口,但在物理实验中也有妙用. 1 在多普勒效应演示实验中的应用 按图1所示安装实验装置:在盛有清水的大水槽中,以一端粘有直径约为8mm的石蜡球的细弹簧作为弹簧单振子,使单振子与水面接触. 相似文献