Simultaneous Magneto-Optical Trapping of Fermionic ^40K and Bosonic ^87Rb Atoms

We report on simultaneous magneto-optical trapping of fermionic ^40K and bosonic 87Rb atoms. This trap is the first step towards quantum degenerate fermi gas ^40K. Laser lights for the two-species magneto-optical trap （MOT） are generated from diode lasers and tapered amplifier. The enriched ^40K dispenser is utilized in the experimental setup. We obtain up to 10^7 -10^8 ^40K and 10^8 -10^9 ^87Rb atoms respectively in the steady-state single-species MOT.     

Spectroscopy Investigation on Conformational Transition of Tea Glycoconjugate from Green Tea

The conformational transition of a new glycoconjugate, tea glycoconjugate (TGC), was investigated by spectroscopy techniques including circular dichroism (CD) and ultraviolet (UV) spectroscopy. The solution behaviors of TGC in the mediums of different temperature, pH value, and ions were compared. Results showed that the native conformation of TGC was partially ordered. The CD value and UV absorbance of TGC altered with the change of pH value, temperature, the addition of ions, and also accompanied order-disorder transition. Especially the conditions with temperature higher than the glass transition temperature (Tg=62℃), higher pH value or lower pH value will have the most impact on the conformation of TGC, which will destroy the hydrogen bonds between the TGC molecules. The results indicated that the outside factors play important roles on the stability of the conformation of TGC.     

铷原子热蒸气中强非线性效应产生激光模式图样的实验研究

研究了具有高斯横向分布的连续激光束单次通过铷原子蒸气后,在近共振附近铷原子蒸气中,由强的非线性克尔效应导致激光分裂成细丝的现象,并且这些细丝的衍射图样在远场通过相干叠加,可以形成具有规则结构的斑图模式.实验上研究了输入光功率,铷泡温度和抽运激光频率相对于⁸⁵Rb原子D₂线的不同失谐位置等因素对斑图模式的影响.由于铷原子的超精细能级结构,在铷原子蒸气中同时存在与三阶非线性效应相关的四波混频现象,通过扫描探测光的频率同时观察到具有斯托克斯和反斯托克斯光子的拉曼增益现象. 关键词： 铷原子蒸气 克尔效应 自聚焦 斑图     

不同缓冲层对ZnO薄膜的性能影响

用射频反应磁控溅射法在玻璃基底上分别以SnO2、SiO2和Al2O3为缓冲层制备ZnO薄膜.利用X射线衍射仪(XRD)、扫描电镜(SEM)、紫外-可见分光光度计和荧光分光光度计对薄膜的结构和光学性能进行了表征.XRD和SEM的分析结果表明,在SiO2和Al2O3缓冲层上生长的ZnO薄膜具有较好的c轴择优取向,薄膜表面光滑平整,薄膜的结晶质量得到改善;透射光谱表明所有样品在可见光范围内的平均透过率超过70;;通过对薄膜光致发光谱的分析,认为422 nm左右的紫峰来自于电子从晶粒边界的界面缺陷能级到价带的辐射跃迁;PL谱中蓝光和绿光的发光机制与薄膜中的本征缺陷有关.     

基于有限射影平面上(ω,r,d)-CFF(N,T)系统的构作

在有限射影平面上利用有限射影平面的性质构作了(ω,r,d)-CFF(N,T)系统,并利用有限射影平面的性质计算了它的参数.最后利用一个有限点集构作了一个(ω,r,d)-DS(N,T)系统并计算了它的参数.     

且思且行 教学相长

正江苏省海安县明道小学已有240多年办学历史。明道数学教学传承百年,去年耄耋之年的老校友寻根校园时,都情不自禁地诉说着"明道数学的诱人芬芳""对明道数学的魂牵梦绕"。数学育人已成为明道小学的学科特色和教学传统。从2012年秋季起,海安县明道小学被列入江苏省第一批珠心算实验学校,这无疑给明道小学的数学育     

Evaporative cooling rubidium atoms with microwave radiation

<正>We report the experimental achievement of ~(87)Rb Bose-Einstein condensation in a magnetic trap with microwave and radio frequency(RF) induced evaporation.Evaporative cooling is realized by using 6.8 GHz microwave radiation driving the ~(87)Rb atoms to transit from the ground-state hyperfine state |F=2,m_F= 2〉to |F=l,m_F=1〉.Compared with RF-induced evaporation,~(87)Rb atoms are hardly to achieve pure condensate by microwave evaporation cooling due to the effect of atoms in the |F=1,m_F=1〉state being pumped back into the trapping |F=2,m_F=1〉state.     

Quantum Degenerate Fermi--Bose Mixtures of 40K and 87Rb Atoms in a Quadrupole-Ioffe Configuration Trap

We report on the attainment of quantum degeneracy of 40^K by means of efficient thermal collisions with the evaporatively cooled 87^Rb atoms. In a quadrupole-Ioffe configuration trap, potassium atoms axe cooled to 0.5 times the Fermi temperature. We obtain up to 7.59 × 10^5 degenerate fermions 40^K.     

“破五减”教学设计及思考——让学生经历珠算方法的探索过程

正【课前思考】"满五加和破五减"是珠心算"10以内加减法"中的重点和难点。由于这一难点的突破与否,将直接影响后一阶段的教学,因此它被形象地称为"过5关"。最初,我试图在一节课教学中完成"-1、-2、-3、-4"所有破五减的类型,然后一起发现、总结得出破五减的口诀"减5加凑"。如果仅仅是训练技能式的教学,一节课40分钟是可以做到的。但由于一年级学生好动、注意力持续集中的时间比较短的特点,因此,我想要让学生获得对数学理解的同时,在思维能力、情感态度与价值观等多方面也能得到进步和发展。基于这样的思考,我进行了如下教学设计。     

40K-87Rb原子冷却的半导体激光系统

对40K-87Rb原子冷却的半导体激光系统提出了一种实验方案,并进行了初步实验.采用三台外腔光栅反馈半导体激光器(ECDL)、四台注入锁定从激光器和一台半导体激光放大器组成激光系统.三台ECDL通过声光调制器产生四束光,分别作为40K和87Rb原子的冷却光和再抽运光,四束不同频率成分的激光分别注入锁定四台从激光器,然后Rb冷却光、K冷却光和K再抽运光再同时注入半导体激光放大器进行放大.该装置可同时产生冷却40K和87Rb原子的冷却光和再抽运光,结构紧凑、工作稳定.