弱谐波情况下透射光栅衍射效率标定方法

同步辐射光源中的高次谐波会使透射光栅衍射效率标定精度变差。为了校正光源中的高次谐波对透射光栅衍射效率标定的影响,提出了一种光源存在弱谐波情况下的透射光栅衍射效率标定方法,通过使用谐波X射线的衍射效率修正基波衍射效率标定中谐波的影响,从而得到更为准确的透射光栅衍射效率。使用该标定方法在北京同步辐射光源上开展了透射光栅相对衍射效率标定工作。实验结果表明:在100~800eV存在高次谐波能段,修正后透射光栅一级与零级的相对衍射效率与理论模拟结果吻合较好,修正后光栅二级与一级的相对衍射效率更接近理论模拟结果,但与理论模拟结果仍有较大偏差,该偏差主要来源光栅较弱的二级衍射。     

"Off-On" based fluorescent chemosensor for Cu2+ in aqueous media and living cells

A novel Cu²⁺-specific “off-on” fluorescent chemosensor of naphthalimide modified rhodamine B (naphthalimide modified rhodamine B chemosensor, NRC) was designed and synthesized, based on the equilibrium between the spirolactam (non-fluorescence) and the ring-opened amide (fluorescence). The chemosensor NRC showed high Cu²⁺-selective fluorescence enhancement over commonly coexistent metal ions or anions in neutral aqueous media. The limit of detection (LOD) based on 3 × δ_blank/k was obtained as low as 0.18 μM of Cu²⁺, as well as an excellent linearity of 0.05-4.5 μM (R = 0.999), indicating the chemosensor of high sensitivity and wide quantitation range. And also the coordination mode with 1:1 stoichiometry was proposed between NRC and Cu²⁺. In addition, the effects of pH, co-existing metal ions and anions, and the reversibility were investigated in detail. It was also demonstrated that the NRC could be used as an excellent “off-on” fluorescent chemosensor for the measurement of Cu²⁺ in living cells with satisfying results, which further displayed its valuable applications in biological systems.     

First-principle study on the structural and electronic properties of H2S and SO2 adsorption on Pd-doped MoS2 monolayer

The partial discharge in SF₆-insulated equipment produces characteristic decomposition products: SO₂ and H₂S. The characteristic decomposition products vastly speed up the process of discharge faults. Based on density functional theory (DFT) calculation, single layer Pd-doped MoS₂ (Pd-MoS₂) is adopted as the adsorbent to adsorb SO₂ and H₂S to ensure the operational stability of SF₆-insulated equipment. The adsorption energy, charge transfer and structure parameters of SF₆, H₂S, and SO₂ adsorption on the Pd-MoS₂ monolayer are analysed to find the most stable adsorption structure. The molecular orbital theory, total density of states and partial density of states are studied to analyse the adsorption mechanism. The results show that Pd-MoS₂ adsorbent possesses high catalytic activity and excellent adsorption performance to H₂S and SO₂ by strong chemical adsorption. This study is of great significance to ensure the operational stability of SF6-insulated equipment by removing these characteristic decomposition products.     

Photo-induced effect in the layered perovskite manganite La_(1.2)Sr_(1.8)Mn_(1.8)Co_(0.2)O_7

1IntroductionWiththediscoveryofcolossalmagnetoresistance(CMR)effectinmanganites,hole-dopingperovskitemanganiteswithunusualelectronictransportandmagneticpropertieshaveattractedconsiderableattention.Thesepropertiesresultfromanintrinsicinteractionbetweencharge,spin,orbitalandlatticedegreesoffreedomthatarestronglycoupledtoeachother[1—6].DoubleexchangemodelcombinedwithJohn-Tellereffectwasusedtoexplainthesepropertiespartly[7—9].InordertogetbetterunderstandingofthemechanismofCMReffect,externals…     

基于EPL的openSAFETY平台构架设计

随着现场总线与可编程控制系统的发展,工业领域的自动控制系统对于安全相关设备和安全网络协议的需求正在不断扩大。然而,由于工业以太网的技术飞速进步,传统的安全协议已经不再适用复杂的实时以太网通讯环境。文章研究了开源实时以太网功能安全协议openSAFETY,在实现工业以太网协议Ethernet POWERLINK(EPL)的基础上设计了openSAEFTY的站点的ARM-FPGA通用平台架构,提出了具体的硬件软件解决方案,为进一步研究工业以太网功能安全协议打下基础。     

ON SPURIOUS ASYMPTOTIC NUMERICAL SOLUTIONS OF GAUSS SCHEME

In this paper,we discuss characteristics of Gauss scheme for numerical or- dinary differential equations,which is a one-step high-order accurate difference scheme.We apply such scheme to some equations,and analyze the fixed point and stability accordingly.     

腔靶内超热电子的实验研究

介绍了利用１０道滤波荧光谱仪（简称Ｆ．Ｆ．谱仪）测量新型腔靶中超热电子产生的硬Ｘ光能谱，并结合ＧａＡｓ阵列探测器测量硬Ｘ光角分布，给出了腔外硬Ｘ光总能量，同时用Ｆ．Ｆ．谱仪测量结果与其同方位的ＧａＡｓ探测器测量结果比对，两者在误差范围内是一致的。在Ｆ．Ｆ谱仪和ＧａＡｓ探测器两者数据比较自洽的情况下，并与后向受激拉曼散射光特征量比较，得出了：（１）腔靶内超热电子不是各向同性均匀分布的，大部分超热电子沿着入射激光光轴方向运动；（２）腔内大部分超热电子与冷介质（腔壁）发生库仑作用产生硬Ｘ光。     

1,3-二苯基吡唑的脱氢合成

以取代1,3-二苯基吡唑啉为原料, 采用硅胶负载的高锰酸钾作为脱氢剂, 合成了一系列1,3-二苯基吡唑衍生物. 该方法具有操作简便、条件温和、收率高的优点.     

Magnetic field annealing effects on self-oriented BiFeO3 thin films prepared by chemical solution deposition

Self-oriented BiFeO₃ (BFO) thin films are prepared via chemical solution deposition method with magnetic field in-situ annealing process. The effects of magnetic annealing on the microstructure, magnetic and dielectric properties as well as magnetoelectric coupling effect of the BFO thin films are investigated. With increasing the annealing magnetic field, the crystallization quality, texture, grain boundary connectivity and densification of the films are enhanced, which is attributed to the improvement of connection and diffusion of components. The magnetization of the field-annealing films and dielectric constant as well as remanent polarization increases with increasing the strength of annealing magnetic field. In addition, it is observed that magnetocapacitance value of the magnetic-field-annealing BFO thin film is higher than the non-field-annealing one. Moreover the BFO thin films annealed at 3 kOe magnetic field show the magnetoelectric effect with 4% under 2 kOe at room temperature.     

Crossover of critical behavior in La0.7Ca0.3Mn1−xTixO3

Critical behavior of Ti-doped La_0.7Ca_0.3MnO₃ ceramics are studied using magnetization methods. The results show that the paramagnetic–ferromagnetic transition is first order for the undoped sample, then for low-doping samples the mean-field model is suitable, and finally a 3D Heisenberg model is satisfied for higher doping samples. These findings demonstrate that the critical behavior of the magnetic transition for manganites is sensitive to Mn-site doping.