Structural modification in swift heavy ion irradiated muscovite mica

Two-layer monoclinic(2 M) muscovite mica sheets with a thickness of 12 μm are irradiated with Sn ions at room temperature with electronic energy loss( dE/dx)_e of 14.7 keV/nm. The ion fluence is varied between 1×10~(11) and1×10~(13) ions/cm~2. Structural transition in irradiated mica is investigated by x-ray diffraction(XRD). The main diffraction peaks shift to the high angles, and the inter-planar distance decreases due to swift heavy ion(SHI) irradiation. Dehydration takes place in mica during SHI irradiation and mica with one-layer monoclinic(1 M) structure is thought to be generated in 2 M mica after SHI irradiation. In addition, micro stress and damage cross section in irradiated mica are analyzed according to XRD data. High resolution transmission electron microscopy(HRTEM) is used on the irradiated mica to obtain the detailed information about the latent tracks and structural modifications directly. The latent track in mica presents an amorphous zone surrounded by strain contrast shell, which is associated with the residual stress in irradiated mica.     

Modulation depth of series SQUIDs modified by Josephson junction area

The superconducting quantum interference device(SQUID) amplifier is widely used in the field of weak signal detection for its low input impedance, low noise, and low power consumption. In this paper, the SQUIDs with identical junctions and the series SQUIDs with different junctions were successfully fabricated. The Nb/Al-AlO_x/Nb trilayer and input Nb coils were prepared by asputtering equipment. The SQUID devices were prepared by a sputtering and the lift-off method.Investigations by AFM, OM and SEM revealed the morphology and roughness of the Nb films and Nb/Al-AlO_x/Nb trilayer.In addition, the current–voltage characteristics of the SQUID devices with identical junction and different junction areas were measured at 2.5 K in the He~3 refrigerator. The results show that the SQUID modulation depth is obviously affected by the junction area. The modulation depth obviously increases with the increase of the junction area in a certain range. It is found that the series SQUID with identical junction area has a transimpedance gain of 58 ? approximately.     

Tunable Nd,La:SrF_2 laser and passively Q-switched operation based on gold nanobipyramids saturable absorber

A novel Nd, La:SrF_2 disordered crystal is prepared, and its continuous-wave wavelength tuning operation is performed for the first time. Employing a surface plasmon resonance(SPR) based gold nanobipyramids(G-NBPs) saturable absorber,we obtain a compact diode-pumped passively Q-switched Nd, La:SrF_2 laser. The stable Q-switched pulse operates with the shortest pulse duration of 1.15 μs and the maximum repetition rate of 41 k Hz. The corresponding single pulse energy is 2.24 μJ. The results indicate that G-NBPs could be a promising saturable absorber applied to the diode-pumped solid state lasers(DPSSLs).     

Dynamical effects of switching a super-critical well potential on pair creation from a vacuum

The dynamical effects on electron-positron pair creation from a vacuum caused by the switching processes of a supercritical well potential are investigated in detail. The results show that only when the switching on and switching off time both increase will the final pair yield converge to the integer of embedded bound states nearly exponentially. But a single adiabatic switching on or switching off cannot lead to an integer pair yield. If the potential is turned on abruptly, associated with the discrete and embedded bound states, there is multi-frequency oscillation around the pair number's saturation. The slowly switching on can suppress the amplitude of this oscillation and reduce the final pair yield. The switching off can also reduce the final pair number in the same order of magnitude. The evolution of a single-pair number shows a robust long range correlation between particle and antiparticle. For an adiabatic switching case, the single-pair dominates the early pair creation, their upper limit value is equal to the integer, and these single-pairs will totally disentangle during the switching off.     

MXene Ti_3C_2T_x saturable absorber for pulsed laser at 1.3 μm

The excellent optical properties of MXene provide new opportunities for short-pulse lasers. A diode-pumped passively Q-switched laser at 1.3 μm wavelength with MXene Ti_3C_2T_x as saturable absorber was achieved for the first time. The stable passively Q-switched laser has 454 ns pulse width and 162 kHz repetition rate at 4.5 W incident pumped power. The experimental results show that the MXene Ti_3C_2T_x saturable absorber can be used as an optical modulator to generate short pulse lasers in a solid-state laser field.     

基于联萘酚的水溶性手性大环荧光传感器的合成与晶体结构

以R-联萘酚、氯氰胺、间苯二胺、1,2二苯基乙二胺、乙二胺为原料合成了3个水溶性手性大环荧光传感器;利用核磁共振(1 H NMR和13 C NMR)、质谱、红外光谱验证了合成产物的结构,利用元素分析仪测定了其组成,并利用X射线衍射分析确定了单晶R-3的晶体结构.结果表明,R-3属于单斜晶系,P2(1)/n空间群,晶胞参数为:a=1.128 6nm,b=1.566 1nm,c=2.293 9nm,β=90°,Z=4,Dc=1.328g.cm-3,F(000)=1 684.     

电感耦合等离子体发射光谱法测定钇铝石榴石中掺杂Yb(Ⅲ)离子

采用碳酸钠-硼砂(质量比1：1)做熔剂分解钇铝石榴石,并确定了熔剂的最优化条件．以电感耦合等离子体光谱法对样品中掺杂Yb(Ⅲ)离子作了定量检测考察了样品和熔剂中单个基体和混合基体对分析结果的影响．发现单个基体Y对Yb的测定有增强效应．基体A1对Yb的测定有一定的抑制作用;基体对Yb测定的干扰可通过基体匹配进行消除元素的俭出限为2μg／L,标准加入回收率为88％～100％实际样品7次检测的RSD为2．1％。本方法可以较好地满足实际样品分析的需要。     

毛细管电泳-电感耦合等离子质谱联用的接口设计

描述了毛细管电泳电感耦合等离子体质谱(CE-ICP-MS)联用技术的单T型接口,自行设计了双T型接口,并对两接口的分析性能作了比较。解决了接口中的常见问题,使用节流阀减小自吸作用并降低了CE分离物的稀释倍数,排气阀使提升量保持稳定。经考察得知,采用自吸作用提升液流流量稳定,其重现性RSD小于5％;双T型接口较单T型接口对CE分离更有利。采用双T型接口联用时,CE分离La、Ce、Nd混合离子迁移时间RSD小于2％,MS信号RSD小于15％,且不同浓度样品经CE分离后其MS信号基本呈线性关系。     

1-烷基-3-甲基咪唑溴化盐离子液体的晶体结构及性能

以不同链长溴代烷烃和N-甲基咪唑反应得到1-烷基-3-甲基咪唑溴化盐,用元素分析和核磁共振对化合物进行了表征.室温下用溶剂蒸发法得到了单晶,并用X射线单晶衍射法测定了晶体结构,该晶体属于三斜晶系,空间群为P-1.化合物采用双分子层结构,水分子参与结构的形成,整个化合物由交叉的线性烷基链、咪唑头基、溴离子和水分子组成,溴离子和水分子之间较强的氢键作用在(010)方向上形成了一个无限的O-H···Br氢键链.用偏光显微镜、差示扫描量热(DSC)技术研究了其液晶行为,证明其一水合物为近晶相热致液晶.液晶区域的温度范围较宽说明水分子起到稳定作用.     

基于光的波粒二象性猜想的数学建模与仿真

光具有波粒二象性,诸多学者都对此提出了不同猜想,用以合理解释光的直线传播、衍射和干涉等问题.对三种基于光的波粒二象性的猜想进行了数学建模与仿真验证.以Matlab为工具对光的衍射等现象的进行了数学仿真,并与《光学原理》中的相关结果作了对比,最终验证了猜想的正确性.