驻波场中原子的跃迁速率与所受辐射受力的关系

从二能级原子的密度矩阵运动方程出发，研究了原子在驻波场中的受激吸收速率、受激辐射速率和辐射压力的对应关系，提出了在驻波场中原子所受的辐射压力由受激吸收力和受激辐射力构成。此观点可以推广至Ｎ个行波场和原子相互作用的情况。     

城市交通噪声污染评价及预测方法的研究

本文结合我国实际情况,对城市交通噪声的中、长期预测及利用计算机“宏观”评价城市交通噪声的污染状况,提出了评价、预测的方法。建立了一套数学物理模型(包括机动车辆流模型、噪声在建筑群中衰减模型……;),最后研制出整套计算机软件。     

Light-induced evaporative cooling in a magneto-optical trap

This paper presents an experimental demonstration of light-induced evaporative cooling in a magneto-optical trap. An additional laser is used to interact with atoms at the edge of the atomic cloud in the trap. These atoms get an additional force and evaporated away from the trap by both the magnetic field and laser fields. The remaining atoms have lower kinetic energy and thus are cooled. It reports the measurements on the temperature and atomic number after the evaporative cooling with different parameters including the distance between the laser and the centre of the atomic cloud, the detuning, the intensity. The results show that the light-induced evaporative cooling is a way to generate an ultra-cold atom source.     

各向同性光场对原子束的分步减速

通过理论分析计算了积分球中各向同性光场对原子产生的辐射压力,提出了一种新的激光对原子束的减速方案:将原子炉产生的热铷原子束通过五个直径为10 cm的积分球,积分球内部各向同性光场的失谐量从Δ=-70Γ依次减小到Δ=-10Γ,从而可以对原子束进行减速和冷却。通过对减速过程的数值计算结果发现,该方案可以把速度小于331 m/s的原子束减速和冷却到小于1 m/s,接近多普勒极限。     

促生长激素释放素三维定量构效关系及药效团模型

用比较分子场分析方法对促生长激素释放素Ｌ－６９２，４２９的系列物进行了三维定量构效研究，得到具有较强预测能力的模型并确定了母体的活性构象，用距离比较方法将Ｌ－６９２，４２９的活性构象与两个活性多肽进行了迭合，找到了可能的药效团，药效团模型显示Ｌ－６９２，４２９的氨基和四唑是氢键的给体和受体，而Ａ和Ｃ环是主要的疏水核心。     

湖水中的颗粒物对水体生物膜吸附铅、镉的影响

采用逐级过滤的方式对湖水进行过滤,并用含有不同粒径颗粒物的湖水进行生物膜的培养,以研究水中颗粒物对生物膜吸附痕量重金属的影响.研究结果表明,生物膜上铁、锰氧化物含量与水中总铁、总锰含量呈明显的线性关系,锰氧化物的含量受水中颗粒物粒径分布的影响很大.生物膜吸附铅、镉的热力学过程符合Langmuir方程,且膜上铁、锰氧化物吸附铅、镉的能力随着湖水中颗粒物粒径的减小呈增强的趋势.     

Cooling of rubidium atoms in pulsed diffuse laser light

This paper reports an experiment on laser cooling of 87 Rb atoms in pulsed diffuse light,which is the key step towards a compact cold atom clock.It deduces an empirical formula to simulate the pulse cooling process based on the loading of cold atoms in cooling time and the loss in the dead time,which is in agreement with the experimental data.The formula gives a reference to select the parameters for the cold atom clock.     

无线信道统计模型识别

为准确地找到最符合快衰落特性的统计分布模型,论文基于概率论和信息论设计了Kullback-Leibler距离及信息准则表达式,对几种主要的统计分布模型进行了仿真和实验,得到了各统计分布模型的正确识别率,通过统计的方式对比了各种识别模型,发现基于直方图的KL方法识别模型的可靠性比其他方法要高,而韦伯衰落模型更加适合用来对无线信道进行建模。     

A grooved planar ion trap design for scalable quantum information processing

We describe a new electrode design for a grooved surface-electrode ion trap,which is fabricated in printed-circuitboard technology with segmented electrodes.This design allows a laser beam to get through the central groove to avoid optical access blocking and laser scattering from the ion trap surface.The confining potentials are modeled both analytically and numerically.We optimize the radio frequency(rf) electrodes and dc electrodes to achieve the maximum trap depth for a given ion height above the trap electrodes.We also compare our design with the reality ion chip MI I for practical considerations.Comparison results show that our design is superior to MI I.This ion trap design may form the basis for large scale quantum computers or parallel quadrupole mass spectrometers.     

Optimization of temperature characteristics of a transportable ~(87)Rb atomic fountain clock

A high-performance transportable fountain clock is attractive for use in laboratories with high-precision time-frequency measurement requirements. This Letter reports the improvement of the stability of a transportable rubidium-87 fountain clock because of an optimization of temperature characteristics. This clock integrates its physical packaging, optical benches, microwave frequency synthesizers, and electronic controls onto an easily movable wheeled plate. Two optical benches with a high-vibration resistance are realized in this work. No additional adjustment is required after moving them several times. The Allan deviation of the fountain clock frequency was measured by comparing it with that of the hydrogen maser. The fountain clock got a short-term stability of 2.3 × 10~(-13) at 1 s and long-term stability on the order of 10~(-16) at 100,000 s.