Delingha is located in the northeast margin of Qaidam Basin.Bayin River alluvial proluvial fan is the main aquifer of Delingha,in which groundwater generally flows from north to south.The hydrochemistry results showed...Delingha is located in the northeast margin of Qaidam Basin.Bayin River alluvial proluvial fan is the main aquifer of Delingha,in which groundwater generally flows from north to south.The hydrochemistry results showed that two different hydrochemical evolution paths formed along southeast and southwest directions,respectively.Cl-Na type groundwater was formed in front of Gahai Lake,and SO_(4)·HCO_(3)-Na·Ca type groundwater was formed in front of Keluke Lake.The results of deuterium(D)and 18O revealed that the groundwater mainly originated from the continuous accumulation of precipitation during geological history under cold and humid climate conditions.In addition,results of^(14)C indicated that the groundwater age was more than 1140 years,implying relatively poor renewal capability of regional groundwater.Moreover,our numerical modeling results showed that the regional groundwater level will continue to rise under the warm and humid climate conditions.展开更多
Sympathetic cooling is a method used to lower the kinetic energy of ions with complicated energy-level structures,via Coulomb interactions with laser-cooled ions in an ion trap.The ion to be sympathetically cooled is ...Sympathetic cooling is a method used to lower the kinetic energy of ions with complicated energy-level structures,via Coulomb interactions with laser-cooled ions in an ion trap.The ion to be sympathetically cooled is sometimes prepared outside of the trap,and it is critical to introduce this ion into the trap by temporarily lowering the potential of one endcap without allowing the coolant ion to escape.We study the time required for a laser-cooled ion to escape from a linear Paul trap when the voltage of one endcap is lowered.The escape time is on the order of a few microseconds,and varies significantly when the low-level voltage changes.A re-cooling time of a maximum of 13 s was measured,which can be reduced to approximately one hundred of milliseconds by decreasing the duration of the low-level voltage.The measurement of these critical values lays the foundation for the smooth injection and cooling of the ion to be sympathetically cooled.展开更多
Ion deceleration has played a critical role in ion-related research when the ions are produced in the form of a high-energy beam.We present a deceleration method combining electrostatic lens and ion trap technique,whi...Ion deceleration has played a critical role in ion-related research when the ions are produced in the form of a high-energy beam.We present a deceleration method combining electrostatic lens and ion trap technique,which can effectively decelerate ions to energy below the trapping potential of a typical ion trap.The experiments were performed on metastable 1s2s3S1Li+ions,and demonstrated that the kinetic energy could easily be reduced from^450 e V to a few e V,with the latter being confirmed using the Doppler-shifted fluorescence spectra.展开更多
Time dilation constitutes a crucial aspect of Lorentz invariance within special relativity and undergoes constant scrutiny through numerous Ives-Stilwell-type experiments employing the Doppler effect.In our study,we e...Time dilation constitutes a crucial aspect of Lorentz invariance within special relativity and undergoes constant scrutiny through numerous Ives-Stilwell-type experiments employing the Doppler effect.In our study,we employed optical Ramsey spectroscopy on a Li^(+)ion beam to enhance the precision of measuring the intrinsic transition frequency 23S1-23P2 to the level of four parts in 1010 with speed of 0.00035c.Our findings reconciled an existing 2 MHz disparity between collinear and perpendicular laser spectroscopy.Furthermore,in conjunction with previous studies on Li^(+)ion beams traveling at speeds of 0.064c and 0.338c[Nat.Phys.3,861(2007);Phys.Rev.Lett.113,120405(2014)],we updated the Robertson-Mansouri-Sexl parameterαto be(-10.0±9.9)×10^(-8)and(-2.9±2.0)×10^(-8),respectively.展开更多
基金This work was supported by the National Natural Science Foundation of China(41672243)the China Geological Survey Program(DD20160291,DD20189270).
文摘Delingha is located in the northeast margin of Qaidam Basin.Bayin River alluvial proluvial fan is the main aquifer of Delingha,in which groundwater generally flows from north to south.The hydrochemistry results showed that two different hydrochemical evolution paths formed along southeast and southwest directions,respectively.Cl-Na type groundwater was formed in front of Gahai Lake,and SO_(4)·HCO_(3)-Na·Ca type groundwater was formed in front of Keluke Lake.The results of deuterium(D)and 18O revealed that the groundwater mainly originated from the continuous accumulation of precipitation during geological history under cold and humid climate conditions.In addition,results of^(14)C indicated that the groundwater age was more than 1140 years,implying relatively poor renewal capability of regional groundwater.Moreover,our numerical modeling results showed that the regional groundwater level will continue to rise under the warm and humid climate conditions.
基金Supported by the National Natural Science Foundation of China(Grant Nos.11934014,11622434 and 11804373)the Scientific Instrument Developing Project of the Chinese Academy of Sciences(Grant No.YZ201552)+2 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant Nos.XDB21030100 and XDB21030300)CAS Youth Innovation Promotion Association(Grant Nos.Y201963 and 2018364)the Hubei Province Science Fund for Distinguished Young Scholars(Grant No.2017CFA040)。
文摘Sympathetic cooling is a method used to lower the kinetic energy of ions with complicated energy-level structures,via Coulomb interactions with laser-cooled ions in an ion trap.The ion to be sympathetically cooled is sometimes prepared outside of the trap,and it is critical to introduce this ion into the trap by temporarily lowering the potential of one endcap without allowing the coolant ion to escape.We study the time required for a laser-cooled ion to escape from a linear Paul trap when the voltage of one endcap is lowered.The escape time is on the order of a few microseconds,and varies significantly when the low-level voltage changes.A re-cooling time of a maximum of 13 s was measured,which can be reduced to approximately one hundred of milliseconds by decreasing the duration of the low-level voltage.The measurement of these critical values lays the foundation for the smooth injection and cooling of the ion to be sympathetically cooled.
基金Supported by the Scientific Instrument Developing Project of the National Natural Science Foundation of China(Grant Nos.11934014,11622434,and 11804373)the Scientific Instrument Developing Project of the Chinese Academy of Sciences(Grant No.YZ201552)+2 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant Nos.XDB21010400 and XDB21030300)CAS Youth Innovation Promotion Association(Grant Nos.Y201963 and 2018364)the Hubei Province Science Fund for Distinguished Young Scholars(Grant No.2017CFA040)。
文摘Ion deceleration has played a critical role in ion-related research when the ions are produced in the form of a high-energy beam.We present a deceleration method combining electrostatic lens and ion trap technique,which can effectively decelerate ions to energy below the trapping potential of a typical ion trap.The experiments were performed on metastable 1s2s3S1Li+ions,and demonstrated that the kinetic energy could easily be reduced from^450 e V to a few e V,with the latter being confirmed using the Doppler-shifted fluorescence spectra.
基金National Natural Science Foundation of China(92265206,12121004,12393823,11934014,12247150,12175076)CAS Project for Young Scientists in Basic Research(YSBR055,YSBR085)+1 种基金Natural Science Foundation of Hubei Province(2022CFA013)CAS Youth Innovation Promotion Association(Y2022099).
文摘Time dilation constitutes a crucial aspect of Lorentz invariance within special relativity and undergoes constant scrutiny through numerous Ives-Stilwell-type experiments employing the Doppler effect.In our study,we employed optical Ramsey spectroscopy on a Li^(+)ion beam to enhance the precision of measuring the intrinsic transition frequency 23S1-23P2 to the level of four parts in 1010 with speed of 0.00035c.Our findings reconciled an existing 2 MHz disparity between collinear and perpendicular laser spectroscopy.Furthermore,in conjunction with previous studies on Li^(+)ion beams traveling at speeds of 0.064c and 0.338c[Nat.Phys.3,861(2007);Phys.Rev.Lett.113,120405(2014)],we updated the Robertson-Mansouri-Sexl parameterαto be(-10.0±9.9)×10^(-8)and(-2.9±2.0)×10^(-8),respectively.
