以云南产卡布里品种鹰嘴豆为原料,采用碱溶酸沉法提取鹰嘴豆蛋白,并分别通过单因素实验和响应面法对蛋白质的提取工艺条件进行优化,然后采用半微量凯氏定氮法测定所提取鹰嘴豆蛋白粉的纯度。结果表明,最佳工艺为液料比12∶1 m L/g,碱溶p...以云南产卡布里品种鹰嘴豆为原料,采用碱溶酸沉法提取鹰嘴豆蛋白,并分别通过单因素实验和响应面法对蛋白质的提取工艺条件进行优化,然后采用半微量凯氏定氮法测定所提取鹰嘴豆蛋白粉的纯度。结果表明,最佳工艺为液料比12∶1 m L/g,碱溶p H10,碱溶时间120 min,在此条件下,脱脂鹰嘴豆蛋白的得率达12.66%±0.14%,与理论值相差2.39%。经过凯氏定氮法测定,用本论文优化方法所提取鹰嘴豆蛋白粉的纯度为77.82%±0.53%,优于已有提取方法,表明利用该论文提出的优化条件可以获得更高纯度的鹰嘴豆蛋白粉。展开更多
We have trapped a cold sample of cesium atoms in a magneto-optical trap.The damped harmonic force of magneto-optical trap was used to capture and trap the cesium atoms directly from a room temperature vapor.About 1.5&...We have trapped a cold sample of cesium atoms in a magneto-optical trap.The damped harmonic force of magneto-optical trap was used to capture and trap the cesium atoms directly from a room temperature vapor.About 1.5×10^(7) cesium atoms with a density of 3×10^(9) atoms/cm^(3) formed a 4mm^(3) cesium atomic cloud with temperature below 500μK.展开更多
A new pumping-probing scheme for the optically pumped cesium beam frequency standard has been experimentally tested in our laboratory.The stability of the optically pumped cesium beam frequency standard was measured b...A new pumping-probing scheme for the optically pumped cesium beam frequency standard has been experimentally tested in our laboratory.The stability of the optically pumped cesium beam frequency standard was measured by comparing its 10 MHz output with an HP5071A commercial cesium atomic clock.The result shows that the frequency stability for the 1 s and 30000s sample times are 1.2×10^(-11) and 3.7×10^(-13),respectively.It was proved that the new pumping scheme works well.展开更多
We have realized a cesium atomic fountain using a novel launching method. We have obtained 108 atoms in the magneto-optical trap experiment and have studied the temperature and launching height with different laser fr...We have realized a cesium atomic fountain using a novel launching method. We have obtained 108 atoms in the magneto-optical trap experiment and have studied the temperature and launching height with different laser frequency detuning to the cesium resonance line. A fountain with a height of 1.8cm and a temperature of 30 ± 10μK was achieved. In comparison with other experiments, we have also discussed the advantages and disadvantages of our method used in the present experiment.展开更多
Analytic expressions have been derived of the alternating current(ac)Zeeman and ac Stark effect in an atomic beam magnetic resonance method using Ramsey separated oscillating fields.An interesting feature which will a...Analytic expressions have been derived of the alternating current(ac)Zeeman and ac Stark effect in an atomic beam magnetic resonance method using Ramsey separated oscillating fields.An interesting feature which will affect the normal Ramsey pattern is that an interference fringe is superimposed on the dispersion lineshapes of the normal ac Zeeman or ac Stark effect.We point out that this new character of ac Zeeman(ac Stark)effect generally exists in all kinds of Ramsey method,for example,in the optical Ramsey atomic interferometer and atomic beam frequency standard.An important implication is that,particularly in an atomic beam frequency standard using Ramsey method,this effect has an influence on the evaluation of the second-order Doppler frequency shift.展开更多
An empirical formula,which demonstrates the interference fringe visibility as a function of the slit separation and the temperature of thermal atoms,is obtained by analysing a recent experiment[Bloch et al.Nature 403(...An empirical formula,which demonstrates the interference fringe visibility as a function of the slit separation and the temperature of thermal atoms,is obtained by analysing a recent experiment[Bloch et al.Nature 403(2000)166]that refers to the spatial correlation function of a trapped Bose gas below the critical temperature.We find that the decay rate of the coherence function for the non-condensed component is of about two orders larger than that of the pure condensed component.The changes of the interference fringe visibility versus the falling time for different temperatures and slit separations are also discussed.展开更多
We propose a scheme for realizing the long-term continuous output of an atom laser.In this scheme the cold atoms in several subsidiary Bose-Einstein condensates(BEC)will be coupled one by one in turn into one main BEC...We propose a scheme for realizing the long-term continuous output of an atom laser.In this scheme the cold atoms in several subsidiary Bose-Einstein condensates(BEC)will be coupled one by one in turn into one main BEC which serves for the continuous output of a coherent atomic beam.We discuss the process of the phase unification of the newly entered BEC atoms with the remaining atoms in the main BEC trap.An ideal dynamical equilibrium can be established when the transition rate of the uncondensed atoms transforming into the condensate and the decay rate of coupling output satisfy some conditions.The coupling method from the subsidiary BEC to the main BEC and the time rates of all different processes are considered.展开更多
A magneto-optical trap (MOT) for cesium atoms that operates without a separate repumping laser is reported. The differences between a normal MOT and this kind of MOT have been experimentally studied. The influences of...A magneto-optical trap (MOT) for cesium atoms that operates without a separate repumping laser is reported. The differences between a normal MOT and this kind of MOT have been experimentally studied. The influences of a repumping laser on cooling and trapping cesium atoms in the MOT have been carefully investigated. The results reveal that it is the critical injection-locked state of the diode laser that makes magneto-optical trapping of cesium atoms possible without a separate repumping laser.展开更多
Based on an improved optical system,which consists of six laser diodes with two injection locking stages and control set-ups of the intensity and frequency of the laser,we have achieved the first optical molasses in C...Based on an improved optical system,which consists of six laser diodes with two injection locking stages and control set-ups of the intensity and frequency of the laser,we have achieved the first optical molasses in China.The time-of-flight(TOF)signal of the cloud of Cs atoms has been obtained,and an analytical-formula for measuring the temperature of the atomic cloud from its TOF signal is given.The lowest temperature of the cloud of Cs atoms is measured to be 10μK.展开更多
Based on the realization of magneto-optical trap for cesium atom in China,great improvement is achieved on its performance.In the new experimental setup,a laser battery in stepwise injection-locking scheme is develope...Based on the realization of magneto-optical trap for cesium atom in China,great improvement is achieved on its performance.In the new experimental setup,a laser battery in stepwise injection-locking scheme is developed as laser source,which has more output power and better beam quality than the previous one.Under the optimum working condition,cesium atoms of more than 10^(9) with the density of 10^(11) atoms/cm^(3) are trapped to form an atomic cloud with the diameter of 3mm.Compared with previous results,both the number of trapped atoms and the density of atomic cloud are increased in two orders of magnitude.展开更多
The intensity dependence of the cesium D_(2)-line saturation absorption spectra in a nearly zero magnetic field was investigated theoretically and experimentally.By using rate equations the D_(2)-line saturation absor...The intensity dependence of the cesium D_(2)-line saturation absorption spectra in a nearly zero magnetic field was investigated theoretically and experimentally.By using rate equations the D_(2)-line saturation absorption spectra were calculated,which agree reasonably well with the experimental results.The variation of the spectra with different cell lengths was also reported and explained with theoretical calculation.展开更多
文摘以云南产卡布里品种鹰嘴豆为原料,采用碱溶酸沉法提取鹰嘴豆蛋白,并分别通过单因素实验和响应面法对蛋白质的提取工艺条件进行优化,然后采用半微量凯氏定氮法测定所提取鹰嘴豆蛋白粉的纯度。结果表明,最佳工艺为液料比12∶1 m L/g,碱溶p H10,碱溶时间120 min,在此条件下,脱脂鹰嘴豆蛋白的得率达12.66%±0.14%,与理论值相差2.39%。经过凯氏定氮法测定,用本论文优化方法所提取鹰嘴豆蛋白粉的纯度为77.82%±0.53%,优于已有提取方法,表明利用该论文提出的优化条件可以获得更高纯度的鹰嘴豆蛋白粉。
基金Supported by the National Natural Science Foundation of China.
文摘We have trapped a cold sample of cesium atoms in a magneto-optical trap.The damped harmonic force of magneto-optical trap was used to capture and trap the cesium atoms directly from a room temperature vapor.About 1.5×10^(7) cesium atoms with a density of 3×10^(9) atoms/cm^(3) formed a 4mm^(3) cesium atomic cloud with temperature below 500μK.
基金Supported by the National Natural Science Foundation of China under Grant No.69678031the Foundation for University Kay Teacher by the Education Ministry of China。
文摘A new pumping-probing scheme for the optically pumped cesium beam frequency standard has been experimentally tested in our laboratory.The stability of the optically pumped cesium beam frequency standard was measured by comparing its 10 MHz output with an HP5071A commercial cesium atomic clock.The result shows that the frequency stability for the 1 s and 30000s sample times are 1.2×10^(-11) and 3.7×10^(-13),respectively.It was proved that the new pumping scheme works well.
基金Supported in part by the National Natural Science Foundation of China under Grant No.10074003,and the Doctoral Programme Foundation of the Institute of Higher Education。
文摘We have realized a cesium atomic fountain using a novel launching method. We have obtained 108 atoms in the magneto-optical trap experiment and have studied the temperature and launching height with different laser frequency detuning to the cesium resonance line. A fountain with a height of 1.8cm and a temperature of 30 ± 10μK was achieved. In comparison with other experiments, we have also discussed the advantages and disadvantages of our method used in the present experiment.
基金Supported by the National Natural Science Foundation of China under Grant No.69678031the Foundation for University Key Teacher by the Education Ministry of China.
文摘Analytic expressions have been derived of the alternating current(ac)Zeeman and ac Stark effect in an atomic beam magnetic resonance method using Ramsey separated oscillating fields.An interesting feature which will affect the normal Ramsey pattern is that an interference fringe is superimposed on the dispersion lineshapes of the normal ac Zeeman or ac Stark effect.We point out that this new character of ac Zeeman(ac Stark)effect generally exists in all kinds of Ramsey method,for example,in the optical Ramsey atomic interferometer and atomic beam frequency standard.An important implication is that,particularly in an atomic beam frequency standard using Ramsey method,this effect has an influence on the evaluation of the second-order Doppler frequency shift.
基金Supported by Important Program for Scientific Research,Education Ministry of China under Grant No.00-09.
文摘An empirical formula,which demonstrates the interference fringe visibility as a function of the slit separation and the temperature of thermal atoms,is obtained by analysing a recent experiment[Bloch et al.Nature 403(2000)166]that refers to the spatial correlation function of a trapped Bose gas below the critical temperature.We find that the decay rate of the coherence function for the non-condensed component is of about two orders larger than that of the pure condensed component.The changes of the interference fringe visibility versus the falling time for different temperatures and slit separations are also discussed.
文摘We propose a scheme for realizing the long-term continuous output of an atom laser.In this scheme the cold atoms in several subsidiary Bose-Einstein condensates(BEC)will be coupled one by one in turn into one main BEC which serves for the continuous output of a coherent atomic beam.We discuss the process of the phase unification of the newly entered BEC atoms with the remaining atoms in the main BEC trap.An ideal dynamical equilibrium can be established when the transition rate of the uncondensed atoms transforming into the condensate and the decay rate of coupling output satisfy some conditions.The coupling method from the subsidiary BEC to the main BEC and the time rates of all different processes are considered.
基金the National Natural Science Foundation of China under Grant No.19704001the Doctoral Program Foundation of the Institute of Higher Education.
文摘A magneto-optical trap (MOT) for cesium atoms that operates without a separate repumping laser is reported. The differences between a normal MOT and this kind of MOT have been experimentally studied. The influences of a repumping laser on cooling and trapping cesium atoms in the MOT have been carefully investigated. The results reveal that it is the critical injection-locked state of the diode laser that makes magneto-optical trapping of cesium atoms possible without a separate repumping laser.
基金Supported by the National Natural Science Foundation of China under Grant No.19392500201。
文摘Based on an improved optical system,which consists of six laser diodes with two injection locking stages and control set-ups of the intensity and frequency of the laser,we have achieved the first optical molasses in China.The time-of-flight(TOF)signal of the cloud of Cs atoms has been obtained,and an analytical-formula for measuring the temperature of the atomic cloud from its TOF signal is given.The lowest temperature of the cloud of Cs atoms is measured to be 10μK.
基金Supported by the National Natural Science Foundation of China under Grant No.19392500201。
文摘Based on the realization of magneto-optical trap for cesium atom in China,great improvement is achieved on its performance.In the new experimental setup,a laser battery in stepwise injection-locking scheme is developed as laser source,which has more output power and better beam quality than the previous one.Under the optimum working condition,cesium atoms of more than 10^(9) with the density of 10^(11) atoms/cm^(3) are trapped to form an atomic cloud with the diameter of 3mm.Compared with previous results,both the number of trapped atoms and the density of atomic cloud are increased in two orders of magnitude.
基金Supported by the National Natural Science Foundation of China,。
文摘The intensity dependence of the cesium D_(2)-line saturation absorption spectra in a nearly zero magnetic field was investigated theoretically and experimentally.By using rate equations the D_(2)-line saturation absorption spectra were calculated,which agree reasonably well with the experimental results.The variation of the spectra with different cell lengths was also reported and explained with theoretical calculation.
