流动速度对核磁共振在线测量的影响及校正

流体流动的核磁共振(NMR)在线测量是一种高效、无损的探测方式,可广泛应用于管道流体输送过程、化学反应动态流程、河流流动等具有时移变化特点的过程在线检测.但是流动状态下样品流速会对NMR测量造成诸如磁化时间不充分、采集信号损失等不容忽视的影响.通过量化分析流动状态对NMR测量的影响因素,提出回波串校正方法,实现流动状态下的NMR流体测量.     

微系统中转矩及电渗流作用下的微粒子电动旋转操控

微粒子的电动旋转操控是表征分散系中微粒子介电特性的有效方法.低雷诺数微系统中,以Maxwell-Wagner极化理论为基础,进行了转矩作用下的微粒子电动旋转机理研究,推导了此机理作用下微粒子电动旋转峰值速度所对应的特征频率,分析了弛豫时间对粒子旋转方向的影响,对转矩作用下的微粒子电动旋转速度进行仿真;以双电层理论为基础,对电渗流导致的微粒子电动旋转机理进行定性分析,提出具有金修饰的粒子表面更适合电渗流作用下的电动旋转研究.分别以羧基修饰的聚苯乙烯微球以及表面被金修饰的聚苯乙烯微球为操控对象,进行电动旋转实 关键词： 微系统 电动旋转 转矩 电渗流     

远紫外像增强器光谱响应特性研究

利用星载光学仪器对极光在远紫外波段进行形态探测是研究沉降粒子能量等空间环境参数的重要手段,而远紫外像增强器是进行空间极光远紫外形态探测仪器中所必不可少的光电成像器件,其性能的优劣将直接影响整个仪器的工作情况,其中光谱响应特性是像增强器的重要的特性之一.采用同步辐射真空紫外波段光作为光源,利用光电倍增管和硅光二极管分别测量同步辐射和像增强器光强,我们对研制的远紫外像增强器在135～250 nm波段范围进行了光谱响应测试,测试结果表明该器件在140～190 nm范围内有较好的响应,响应峰值在160 nm左右,符合远紫外极光成像探测的应用要求.     

Influence of roughness on the detection of mechanical characteristics of low-k film by the surface acoustic waves

The surface acoustic wave （SAW） technique is a precise and nondestructive method to detect the mechanical charac- teristics of the thin low dielectric constant （low-k） film by matching the theoretical dispersion curve with the experimental dispersion curve. In this paper, the influence of sample roughness on the precision of SAW mechanical detection is inves- tigated in detail. Random roughness values at the surface of low-k film and at the interface between this low-k film and the substrate are obtained by the Monte Carlo method. The dispersive characteristic of SAW on the layered structure with rough surface and rough interface is modeled by numerical simulation of finite element method. The Young＇s moduli of the Black DiamondTM samples with different roughness values are determined by SAWs in the experiment. The results show that the influence of sample roughness is very small when the root-mean-square （RMS） of roughness is smaller than 50 nm and correlation length is smaller than 20 μm. This study indicates that the SAW technique is reliable and precise in the nondestructive mechanical detection for low-k films.     

Eu^3 和Tb^3 在LnBaB9O16中的紫外和真空紫外发光性质

研究了Tb^3 和Eu^3 在LnBaB9O16(Ln=La,Gd,Y,Lu)中的紫外和真空紫外光谱性质。X射线粉末衍射数据指标化结果表明,LnBaB9O16(Ln=La,Gd,Y,Lu)系列化合物属于三方晶系.Eu^3 的荧光光谱结果表明,LaBaB9O16和GdBaB9O16中稀土离子占据非中心对称的格位,Eu^3 在其中的特征发射以^5D0→^7F2电偶极跃迁为主;而在YBaB9O16和GdBaB9O16中稀土离子占据中心对铱性的格位,E^3 在其中的特征发射以^5D0→^7F1磁偶极跃迁为主．Tb^3 在LaBaB9O16和GdBaB9O16中的发射为^5D3→^7F0和^5D4→FJ(J=0-6)辐射跃迁,在YBaB9O16和LuBaB9O16中只能观察到^D4→^7FJ(J=3-6)辐射跃迁。与Eu^3 的发光性质相反,Tb^3 占据非中心对称的格位时的发射强度比占据中心对称的格位时要弱得多．Eu^3 和Tb^3 掺杂的样品在真空紫外波段的吸收弱。     

Luminescence Spectra of SrA112O19：Pr^3＋, Mn^2＋ under VUV-UV Excitation

Luminescence spectra of SrAl12O19：Pr^3＋,Mn^2＋ under VUV-UV excitation are investigated. The characteristic emissions between 4f levels and the excitation of 5d for Pr^3＋ are observed. The emission of Mn^3＋ peaks at 517nm and the excitations clue to the ground to multiplets are observed at 276, 360, 386 and 426nm. However, the spectral overlap between the emission of Pr^3＋ and excitation of Mn^2＋ is absent, suggesting that the quantum splitting cannot be achieved via a Pr^3＋ Mn^2＋ ion pair in the host SrAl12O19.     

硬X射线磁圆二色实验方法的建立

在北京同步辐射装置(BSRF)1W1B光束线和XAFS实验站上国内首次建立了硬X射线波段的磁圆二色实验(XMCD)方法. 以单晶金刚石作为相位延迟片, 在透射劳埃(Laue)模式下, 利用衍射双折射效应, 将入射的单色线偏振光转变为相应的左旋和右旋圆偏振光, 测量磁化样品对左旋和右旋圆偏振光吸收的差异, 获得了XMCD信号. 本实验使用透射方法测量了Pt-Fe合金Pt L_2,3边的XMCD, 获得了XMCD信号. XMCD实验方法的建立, 为研究磁性材料尤其是磁性薄膜材料的电子结构和磁结构提供了实验基础.     

Ce3+离子激活的SrB4O7的VUV光谱

Ce³⁺只有一个4f电子,具有最简单的4f¹5d⁰基态结构,其激发光谱直接反映了5d轨道的能量状态。由于同一基质晶格相同格位上不同稀土离子受基质晶体场影响相近,所以根据Ce³⁺离子的光谱可以推测和分析其他稀土离子的5d轨道能量,是研究其他稀土离子f-d跃迁的基础。采用高温固相法合成了Ce³⁺离子激活的SrB₄O₇发光体,测定了样品在130~350nm波长范围的激发光谱和相应的发射光谱。指认了VUV激发光谱上Ce³⁺离子的5个4f¹→4f⁰5d¹跃迁激发带,讨论了SrB₄O₇的基质吸收带和Ce³⁺的5d轨道在SrB₄O₇中的晶体场劈裂、5d轨道能级重心及SrB₄O₇:Ce³⁺的发射光谱和Stokes位移。     

Quantum cutting in Gd2SiO5: Eu3+ by VUV excitation

The emission and excitation spectra of Gd2SiO5: Eu3+ were investigated using the VUVbeam line of the Beijing Synchrotron Radiation Facility (BSRF). The experimental results werediscussed in the frame of visible quantum cutting process involved in Gd3+-Eu3+ system. Upon di-rect excitation into the 6GJ states of Gd3+, two visible photon emissions from Eu3+ were observed.Cursory evaluation proved that Gd2SiO5: Eu3+ is an efficient visible quantum cutter.     

Effect of Ce~(3+) on spectral characteristic of D1/D2/Cytb559 complex from spinach

In our early researches, lanthanum and cerium could enter plant and bind to porphyrin of chlorophyll to form Ln3+-chllorophyll. La and Ce greatly increase photosystem II (PSII) activity and PSII electron transport rate, and the fluorescence emission peaks of PSII are blue-shifted [1—4]. Do REEs coordinate with PSII reaction center complex in vivo? Moreover, do REEs coordinate with D1(30 kD)/D2(32 kD)/Cytb559 (~9 kD) reaction center complex of site of producing pri-mary reaction-p…