Upper Critical Fields and Anisotropy of BaFe1.9Ni0.1As2 Single Crystals

Temperature dependence of the upper critical magnetic field （Hc2） near Tc of 20 K in a BaFe1.9 Ni0.1 As2 single crystal is determined via magneto-resistance measurements, for the out-plane （H ⊥ab） and in-plane （H ｜｜ ab） directions in magnetic fields of up to 8 T. The upper critical fields at zero temperature estimated by the Werthamer-Helfand- Hohenberg （WHH） formula are μ0H^｜｜ c2（0） = 137 T and μ0H⊥c2（0） = 51 T, both exceeding the weak-coupling Pauli paramagnetic limit （μ0Hp = 1.84Tc）. However, the WHH formula could overestimate the μ0H^｜｜12（0） value. The anisotropy of upper critical fields is around 3 in the temperature range close to Tc. The result is very similar to the Co-doped 122 superconductor BaFe2-x Cox As2, indicating that electron-doped 122 superconductors exhibit similar superconducting properties.     

Photodissociation Efficiency Spectroscopy Study of the Rydberg Excited Ion-Pair States of Carbon Dioxide

Photodissociation efficiency spectrum of anionic oxygen atom produced via ion-pair dissociations of carbon dioxide is recorded by means of the synchrotron radiation excitation （XUV photon energy 17.40-20.00eV）. The present spectrum is assigned as the Rydberg-like excited ion-pair states, i.e., Tanaka-Ogawa and Henning series, -↑C^2∑g^＋ （CO2^＋） vibrational ground-state and excitation series. Three Rydberg series, npσu, npπu, and nfu, converging to -↑C^2∑g^＋ （0, 0, 0）, show the higher cross sections.     

Entanglement Dynamics of a Three-Level Atom in Ξ Configuration

Dynamical behaviour of entanglement between the cavity mode and a three-level atom in the configuration is studied by making use of log-negativity. The influence of initial temperature of the thermal field and detuning on the entanglement is investigated. It is found that the maximal values of entanglement decreases with the temperature of the thermal field and can be controlled by the defaming.     

基于最大信噪比测量两相流速度

为了克服噪声对信号的影响,提出一种利用最大信噪比和相关法测量两相流速度的方法.基于最大信噪比的信号分离方法是一种盲源信号分离方法,该算法利用统计独立信号完全分离时信噪比最大作为分离准则,它具有非常低的计算复杂度.这里首先利用盲源信号分离方法分别提取出上游和下游两相流信号,并据此求出两相流信号的相关函数曲线,由此求出信号的渡越时间,最后给出仿真实验的处理结果.实验结果表明该方法能够满足两相流速度的测量要求.     

SiC缓冲层对Si表面生长的ZnO薄膜结构和光电性能的改善

用脉冲激光沉积(PLD)技术制备了ZnO/SiC/Si和 ZnO/Si薄膜并制成了紫外探测器。利用X射线衍射(XRD),光致发光(PL)谱,I-V曲线和光电响应谱对薄膜的结构和光电性能进行了研究。实验结果表明:SiC缓冲层改善了ZnO薄膜的结晶质量和光电性能,其原因可能是SiC作为柔性衬底能够减少ZnO与Si 之间大的晶格失配和热失配导致的界面缺陷和界面态。     

燃煤锅炉粉煤灰中痕量元素赋存形态研究

本文运用改进的Tessier法对某燃煤电厂静电除尘器收集的三个电场的粉煤灰进行分级提取(SEE)实验研究.SEE实验将粉煤灰中的重金属分为五个存在形态进行分级提取:水溶态(pH=7),酸溶态(pH=5),氧化物结合态,难还原态及残渣态.试验结果表明,残渣态在ESP除尘器所收集的飞灰中含量占据绝大部分;在容易迁移的离子可交换态和酸溶态中,所研究的痕量重金属元素均呈现出FA1相似文献   

不同加速层材料对固态阴极射线发光的影响

在固态阴极射线发光中,过热电子碰撞激发有机材料而发光,因此加速层对电子的加速能力是影响器件发光亮度的关键因素之一.分别以SiO2和ZnO作为加速层.制备出两种固态阴极射线发光器件A:ITO/MEH-PPV/SiO2/Al和B:ITO/MEH-PPV/ZnO/Al.通过理论计算比较了电子从电极注入到加速层的隧穿电流密度以及SiO2层与ZnO层的电场强度,计算结果表明:在相同驱动电压下,SiO2作为电子加速层时隧穿电流的密度要大于ZnO层的隧穿电流的密度,并且SiO2层的电场强度比ZnO层的电场强度大.实验结果表明:SiO2作为加速层的器件的发光强度高于以ZnO为电子加速层器件的发光强度.     

白酒单体物质紫外荧光光谱研究

白酒荧光光谱是由各种单体物质的荧光共同叠加而表征出来的。不同品牌的白酒中所含的单体物质种类基本相同,都包括水、酒精以及各种微量成分,然而其荧光光谱却差别很大。白酒中的各种单体物质成分究竟是如何对白酒的荧光光谱产生影响,至今未见相关报道。通过对白酒中的主要单体物质,包扩酒精、水及各种主要的微量成分(共10种)在不同激发波长下产生的荧光光谱进行测定,并将其与已测定的大量白酒三维荧光光谱进行对比发现,可以对白酒的荧光光谱产生影响的单体物质是乙醇和主要微量成分。白酒主要微量成分中醇类、酸类、酯类和醛类物质对其荧光光谱都有着一定的影响,但各自影响的程度及影响的光谱范围又各自有所不同。研究结果对白酒荧光光谱的进一步细化研究有着重要的意义。     

具非线性中立项的二阶时滞微分方程的振动性质

By using the averaging technique, we obtain new oscillation criteria for second order delay differential equation with nonlinear neutral term. These results generalize and improve some known results about neutral delay differential equation of second order.     

Cuccia定理的一个推广

For a finite group G,let S(G)be the set of minimal subgroups of odd order of G which are complemented in G.It is proved that if every minimal subgroup X of odd order of G which does not belong to S(G),C_G(X)is either subnormal or abnormal in G.Then G solvable.