This study presents an experiment on diffuse light cooling of atoms in a cylindrical cavity.We focus on the controlling of the shape of the atom cloud by placing the cooling beams in appropriate positions.The Gauss-li...This study presents an experiment on diffuse light cooling of atoms in a cylindrical cavity.We focus on the controlling of the shape of the atom cloud by placing the cooling beams in appropriate positions.The Gauss-like shape of the atomic cloud is demonstrated.The number of cold atoms detected in the cavity is increased,thereby improving the signal-to-noise ratio of the clock signal.展开更多
We present an experiment on the measurement of the spatial distribution of cold atoms in a ceramic cell.The atoms are first cooled by diffusing light produced by multiple scattering of laser light at the inner surface...We present an experiment on the measurement of the spatial distribution of cold atoms in a ceramic cell.The atoms are first cooled by diffusing light produced by multiple scattering of laser light at the inner surface of the cell.An inhomogeneous magnetic field is applied after the atoms are cooled by using a pair of anti-Helmholtz coils,and thus the shift of atomic magnetic sub-levels is position-dependent.We move the anti-Helmholtz coils point by point while keeping the probe laser beam resonant with the cold atoms at zero magnetic field.The number of cold atoms at different positions can be extracted by detecting the absorption to the probe beam.The density of the cold atoms in the cell is measured in two dimensions perpendicular and parallel to the tube connecting to the vacuum system,respectively.The results show that at the center of the cell,fewer atoms exist due to the leakage of diffuse light into the hole connecting to the vacuum pump.The method we developed is used to detect cold atoms in a region where imaging is impossible.展开更多
In the present investigation, the relation of pre-ageing temperature and pre-ageing time to mechanical properties was studied, and a model was established to predict the mechanical properties of AA6005 Al alloy. Compa...In the present investigation, the relation of pre-ageing temperature and pre-ageing time to mechanical properties was studied, and a model was established to predict the mechanical properties of AA6005 Al alloy. Compared with the experimental results, the deviation of the proposed model was limited to 8.1%, which showed reasonable accuracy of forecasting. It was found that the performance of AA6005 alloy was better at higher pre-ageing temperature with shorter pre-ageing time than that at T6 temper. The microstructure of the alloy was observed by transmission electron microscopy, and the results showed that high dislocation density and precipitate density existed at 160 ℃ and 200 ℃ pre-ageing, which were in good agreement with the model.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 11074262 and 11034008the National High-Tech Research and Development Program under Grant No 2012AA120702.
文摘This study presents an experiment on diffuse light cooling of atoms in a cylindrical cavity.We focus on the controlling of the shape of the atom cloud by placing the cooling beams in appropriate positions.The Gauss-like shape of the atomic cloud is demonstrated.The number of cold atoms detected in the cavity is increased,thereby improving the signal-to-noise ratio of the clock signal.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11074262,10874193 and 11034008.
文摘We present an experiment on the measurement of the spatial distribution of cold atoms in a ceramic cell.The atoms are first cooled by diffusing light produced by multiple scattering of laser light at the inner surface of the cell.An inhomogeneous magnetic field is applied after the atoms are cooled by using a pair of anti-Helmholtz coils,and thus the shift of atomic magnetic sub-levels is position-dependent.We move the anti-Helmholtz coils point by point while keeping the probe laser beam resonant with the cold atoms at zero magnetic field.The number of cold atoms at different positions can be extracted by detecting the absorption to the probe beam.The density of the cold atoms in the cell is measured in two dimensions perpendicular and parallel to the tube connecting to the vacuum system,respectively.The results show that at the center of the cell,fewer atoms exist due to the leakage of diffuse light into the hole connecting to the vacuum pump.The method we developed is used to detect cold atoms in a region where imaging is impossible.
基金Projects(51575539, U1837207) supported by the National Natural Science Foundation of ChinaProject(2020RC2002)supported by the Science and Technology Innovation Program of Hunan Province,ChinaProject(2021JJ40774)supported by Natural Science Foundation of Hunan Province,China。
文摘In the present investigation, the relation of pre-ageing temperature and pre-ageing time to mechanical properties was studied, and a model was established to predict the mechanical properties of AA6005 Al alloy. Compared with the experimental results, the deviation of the proposed model was limited to 8.1%, which showed reasonable accuracy of forecasting. It was found that the performance of AA6005 alloy was better at higher pre-ageing temperature with shorter pre-ageing time than that at T6 temper. The microstructure of the alloy was observed by transmission electron microscopy, and the results showed that high dislocation density and precipitate density existed at 160 ℃ and 200 ℃ pre-ageing, which were in good agreement with the model.
