火焰原子吸收光谱法测定卷烟用纸中Pb和Cu

卷烟滤嘴棒用的纸样品经硝酸、高氯酸湿法消化,在乙炔-空气火焰下,于波长283.3、324.8nm处,用原子吸收光谱法测定铅和铜的百分含量。方法简便、快速,结果准确。     

阴山大戟中一个对映海松烷型二萜2D NMR全归属

从阴山大戟的根部首次分到一个已知的对映-海松烷型二萜,3α, 19-dihydroxyl-ent-pimara-9, 15-diene,通过二维波谱方法（¹H-¹H COSY, HMBC, HMQC, ROESY）确定了其结构,并且首次此化合物的H谱和C谱数据进行了全归属.     

Controllable optical multi-well trap and its optical lattices using compounded cosine patterns

This paper proposes a flexible scheme to form various optical multi-well traps for cold atoms or molecules by using a simple optical system composed of an compounded amplitude cosine-only grating and a single lens illuminated by a plane light wave or a Gaussian beam.Dynamic manipulation and evolution of multi-well trap can be easily implemented by controlling the modulation frequency of the cosine patterns.It also discusses how to expand this multi-well trap to two-dimensional lattices with single-or multi-well trap by using an orthogonally or non-orthogonally modulated grating,as well as using incoherent multi-beam illumination,and these results show that all the symmetric structures of two-dimensional Bravais lattices can be obtained facilely by using proposed scheme.     

Novel electrostatic trap for cold polar molecules

We propose a novel scheme in which cold polar molecules are trapped by an electrostatic field generated by the combination of a pair of parallel transparent electrodes (i.e., two infinite transparent plates) and a ring electrode (i.e., a ring wire). The spatial distributions of the electrostatic fields from the above charged wire and the charged plates and the corresponding Stark potentials for cold CO molecules are calculated; the dependences of the trap centre position on the geometric parameters of the electrode are analysed. We also discuss the loading process of cold molecules from a cold molecular beam into our trap. This study shows that the proposed scheme is not only simple and convenient to trap, manipulate and control cold polar molecules in weak-field-seeking states, but also provides an opportunity to study cold collisions and collective quantum effects in a variety of cold molecular systems, etc.     

Diffracted field distribution from a knife-edge truncated semi-Gaussian beam as an atomic （molecular） mirror

We investigate the diffraction characteristics of an incident Gaussian beam cut by a straight edge bounding a semi-infinite opaque plane using Kirchhoff scalar wave theory in the Fresnel limit, and propose a new and simple mirror scheme to reflect atoms by using the intensity gradient induced by a blue-detuned semi-Gaussian laser beam. The optical potential of the diffracted light of the knife-cut semi-Gaussian beam for $^{85}$Rb atom and its spontaneous emission probability are calculated and compared with the performance of the evanescent-wave mirror. Our study shows that the optical potential of the diffracted light of the semi-Gaussian beam is far higher than that of the evanescent light wave, and the maximum normal velocity of the incident atoms can be far greater than that of the evanescent light wave under the same parameters, so the blue-detuned semi-Gaussian beam, as a novel atomic mirror, can be used to efficiently reflect cold atoms with a normal velocity of greater than 1 m/s. However, the intensity gradient (force) of the diffracted light of the semi-Gaussian-beam is much smaller than that of the evanescent light wave, so its spontaneous emission probability is greater than that from the evanescent-wave when the normal velocity of incident atoms is greater.     

BaF radical: A promising candidate for laser cooling and magneto-optical trapping

Recently, there have been great interest and advancement in the field of laser cooling and magneto-optical trapping of molecules. The rich internal structure of molecules naturally lends themselves to extensive and exciting applications. In this paper, the radical~(138)Ba~(19) F, as a promising candidate for laser cooling and magneto-optical trapping, is discussed in detail.The highly diagonal Franck–Condon factors between the X~2Σ~+_(1/2)and A~2Π_(1/2) states are first confirmed with three different methods. Afterwards, with the effective Hamiltonian approach and irreducible tensor theory, the hyperfine structure of the X~2Σ~+_(1/2)state is calculated accurately. A scheme for laser cooling is given clearly. Besides, the Zeeman effects of the upper(A~2Π_(1/2)) and lower(X~2Σ~+_(1/2)) levels are also studied, and their respective g factors are obtained under a weak magnetic field.Its large g factor of the upper state A~2Π_(1/2) is advantageous for magneto-optical trapping. Finally, by studying Stark effect of Ba F in the X~2Σ~+_(1/2), we investigate the dependence of the internal effective electric field on the applied electric field. It is suggested that such a laser-cooled Ba F is also a promising candidate for precision measurement of electron electric dipole moment.     

江浙沪不同杂草类群性状与入侵性关系的比较

对于江苏、浙江和上海境内现有的647种杂草,统计了包括入侵能力、生活史、果实大小和数量、繁育系统和对水分环境适应方式等32个植物学和生态学性状.以这32个指标为基础,通过聚类分析将647种杂草分成11个类群.再以入侵能力为独立变量,其他31个性状为因子,应用SPSS13.0软件中的GLM和Bivariate分析模块,探讨了647种杂草作为整体和在不同类群中入侵能力与性状之间的关系.结果发现,如果将647种杂草作为一个整体,具有直根或块根、单性花、多年生、中生或阴生和花部两侧对称等性状的植物入侵能力较弱,而种子(或果实)数量多、生活史短、适生于阳生和湿生环境的植物往往具有较强的入侵性.但是,如果统计各类群中杂草入侵性与性状间的关系,发现在某个杂草类群中与入侵性关系密切的性状,在另外的杂草类群中不一定与入侵性有关.因此,不可能用某个统一的指标体系来评估不同生态适应对策的植物的入侵性.提出,要在特定区域开展外来植物入侵性的预测,首先应了解该地区的杂草有哪些生态适应类群,再判断目的植物更接近于何种杂草类群.     

3,4-二氧-羟甲基-乙基噻吩的合成

3,4-二羟基噻吩-2,5-二羧酸甲酯在N,N-二甲基甲酰胺(DMF)/三乙胺的体系中与环氧溴丙烷反应可生成3,4-二氧-羟甲基-乙基噻吩-2,5-二羧酸甲酯,后者在碱性水介质中经水解反应生成3,4-二氧-羟甲基-乙基噻吩-2,5-二羧酸,其在三乙醇胺中经高温脱羧生成3,4-二氧-羟甲基-乙基噻吩,产物是3,4-二氧-羟甲基-乙基噻吩与3,4-二氧-羟丙基噻吩的二元混合物,两者的质量比是6∶1。     

采用Damman光栅实现冷原子或冷分子囚禁的光阱阵列

提出了一种采用Damman光栅和球面透镜组合光学系统产生二维光阱阵列的新方案. 在使用红失谐高斯激光束照射的条件下，推导了计算光阱阵列的周期、光强分布、光强梯度和光阱几何参数的经验公式，讨论了此光阱阵列的特点以及在原子光学和分子光学中的应用. 研究结果表明，这种光阱阵列方案比已有的光阱阵列方案更为简单可行、操作方便，非常适用于冷原子或冷分子的阵列囚禁，以及制备新颖的光学晶格. 关键词： 冷原子或冷分子 光阱阵列 Damman光栅 光偶极势     

高T_c超导体YBa_2Cu_3O_(9-δ)的远红外反射光谱

测量了高T_c超导体YBa_2Cu_3O_(9-δ)(T_c=90K)的远红外反射光谱,温度变化范围为4.2—200K。在30—360cm_(-1)光谱区间内出现了六个结构:S_1,S_2,N_1,N_2,N_3和N_4。S_1和S_2仅在超导态中出现,而其他四个结构在超导态和正常态中都存在。我们将s_1和S_2与超导能隙联系起来,认为N_i(i=(1—4))是材料的横光学声子反射带