A Novel Gravito-Optical Surface Trap for Neutral Atoms

We propose a novel gravito-optical surface trap （COST） for neutral atoms based on one-dimensional intensity gradient cooling. The surface optical trap is composed of a blue-detuned reduced semi-Gaussian laser beam （SGB）, a far-blue-detuned dark hollow beam and the gravity field. The SGB is produced by the diffraction of a collimated Gaussian laser beam passing through the straight edge of a semi-infinite opaque plate and then is reduced by an imaging lens. We calculate the intensity distribution of the reduced SGB, and study the dynamic process of the SGB intensity-gradient induced Sisyphus cooling for ^87Rb atoms by using Monte Carlo simulations. Our study shows that the proposed GOST can be used not only to trap cold atoms loaded from a standard magneto-optical trap, but also to cool the trapped atoms to an equilibrium temperature of 3.47μK from ～120μK, even to realize an all-optical two-dimensional Bose-Einstein condensation by using optlcal-potential evaporative cooling.     

实现冷原子(冷分子)囚禁的可控制光学双阱的产生及其实验研究

简单介绍了实现冷原子或冷分子囚禁的可控制光学双阱的实验方案，报道了二元π相位板的制作方法及其产生可控制光学双阱的实验结果.分析了光学双阱参数(如空间位置、双阱中心间距、相对光强分布等)与π相位板相位偏差的关系.从理论和实验上研究了由于二元π相位板的刻蚀厚度误差引起的光学双阱光强变化及其双阱到单阱的演化规律，得到了实验与理论基本一致的结果. 关键词： 二元相位板 可控制光学双阱 冷原子囚禁 冷分子囚禁     

一种新颖的表面光波导型原子(或分子)分束器

提出了一种采用二元π位相板与柱面透镜组合而构成表面光波导型原子（或分子）分束器及其Mach-Zehnder干涉仪与X-分束器列阵的新方案，介绍了本方案的物理思想与基本原理，导出了光强分布、强度梯度、分束距离和分束路径的宽度与光学系统参数间的解析关系，并分析和讨论了本方案的潜在应用及其可行性. 研究表明，本方案设计新颖、光路简单，便于与其他元件组合构成具有表面微结构的集成原子（或分子）光学元器件及其全光型原子（或分子）芯片. 关键词： 原子（或分子）光波导 原子（或分子）分束器 原子（或分子）芯片 二元π位相板     

Absolute density measurement of nitrogen dioxide with cavity-enhanced laser-induced fluorescence

The absolute number density of nitrogen dioxide(NO_2) seeded in argon is measured with cavity-enhanced laserinduced fluorescence(CELIF) through using a pulsed laser beam for the first time. The cavity ring down(CRD) signal is acquired simultaneously and used for normalizing the LIF signal and determining the relationship between the measured CELIF signal and the NO_2 number density. The minimum detectable NO_2 density down to(3.6±0.1)10~8 cm~(-3) is measured in 60 s of acquisition time by the CELIF method. The minimum absorption coefficient is measured to be(2.0±0.1)10~(-9) cm~(-1), corresponding to a noise equivalent absorption sensitivity of(2.2±0.1)10~(9) cm.~(-1)Hz~(-1/2). The experimental system demonstrated here can be further improved in its sensitivity and used for environmental monitoring of outdoor NO_2 pollution.     

光折变材料Cu∶KNSBN的晶格振动和d－d电子跃迁

比较了铜掺杂钾钠铌酸锶钡（Ｃｕ∶ＫＮＳＢＮ）和钾钠铌酸锶钡（ＫＮＳＢＮ）两样品的晶格振动和ｄ－ｄ电子跃迁谱，对于拉曼（Ｒａｍａｎ）谱，Ａ１（ｚ）对称类的差别较小，Ｅ（ｘｙ）对称类的差别最大；对于红外反射谱，两对称类的均差别较大，认为Ｃｕ２＋部分填充了晶格Ａ位和Ｃ位，可见光范围内，ｄ－ｄ电子跃迁谱表明Ｃｕ２＋在晶体中形成两个深能级２．５０ｅＶ和２．６４ｅＶ。     

非均质砂岩油藏异步周期注水数值模拟理论及应用研究

针对砂岩油藏周期注水特点,综合考虑弹性力、毛管力和重力的影响,建立起非均质砂岩油藏异步周期注水数学模型,并推导出相应的数值解.提出了一种新的流动系数取值方法,能够准确描述停注过程中毛管力作用引起的吸渗现象.在杏树岗油田周期注水试验区进行了实例验证,结果表明:地层压力相对误差为4.0%,产液量相对误差为3.2%,含水率绝对误差为0.9%.应用该方法对杏树岗油田厚油层不同周期注水方案进行了数值模拟计算,决定采取异步周期注水方案,并确定出合理的油层纵向组合方式和水井平面组合方式.平均注水强度为25m3/(d.m)左右,注水和停注半周期都是3个月.现场实施5个月后,区块综合含水率由92.17%下降到91.51%,产油量稳定,预计最终水驱采收率提高1%以上,取得了良好的开发效果.     

反式肉桂酸和反式邻香豆酸的SERS光谱

首次记录了反式肉桂酸和反式邻香豆酸两种具有大π键电子结构的平面型分子在银膜上的SERS谱,讨论了它们在银膜表面上的吸附方式,并对这类分子在SERS现象中的模选择增强机制做了初步探讨。     

高温闪烁晶体GSO:Ce的生长及其光谱性质

本文用中频感应提拉法生长出尺寸为φ30mm×150mm,质量好的GSO:Ce晶体.并对晶体进行XRD测试和差热分析,初步分析引起晶体开裂的原因,最后测试了晶体室温下的吸收和荧光光谱等,GSO:Ce晶体发射峰为433nm,晶体在大于400nm范围其光透过率大于80;.     

Performance Improvement of Bulk Heterojunction Organic Photovoltaic Cellby Addition of a Hole Transport Material

A novel photovoltaic cell with an active layer of poly（phenyleneethynylene） （PPE）/C60/N,N＇-diphenyl-N,N＇-di-（m-tolyl）-p-benzidine （TPD） is designed. In the active layer, PPE is the major component; C60 and TPD are the minor ones. Compared with a control BHJ device based on PPE/C60, the short circuit current density Jsc is increased by 1 order of magnitude, and the whole device performance is increased greatly, however the open circuit voltage Voc is largely decreased. The possible mechanism of the improved performance may be as follows： In the PPE/C60/TPD device, PPE, C60, and TPD serve as the energy harvesting material, the electron transport material, and the hole transport material, respectively. As the TPD and C60 are spatially separated by PPE, the charge recombination is effectively retarded.     

高分子气体分离膜技术研究进展

从纳米材料掺杂改性和新型制备工艺发展两方面,综述了高分子气体分离膜技术的研究进展。总结了不同纳米材料(GO、MOFs和CNTs)与高分子膜界面相容性的主要改善方法;介绍了具有超薄选择层的高分子复合膜制备工艺新进展并对高分子气体分离膜技术的研究重点和发展方向进行了展望。