基于mini-bar的光纤耦合实验研究

基于mini-bar的光纤耦合是一种进一步提高二极管激光器光纤耦合系统出光亮度的有效方法。本文对Osram公司的一款连续60 W mini-bar的发光特性进行了实验研究,选用的mini-bar在工作电流60 A时输出功率60 W,电光转换效率最大为60%,中心波长973.7 nm,慢轴发散角为9.3（1/e2）。分析了其慢轴准直的特性,了解慢轴准直透镜的选择原则。器件准直后的慢轴发散角为47.6 mrad。通过对光束参量积的计算了解到mini-bar的光束可以直接耦合进入600 m的光纤,并进行了单片mini-bar的耦合实验,得到准直系统与耦合透镜组的传输效率为83%~85%,光纤的耦合效率为86%~93%,整个系统的光光效率大于72%。     

自适应光学系统变形镜控制电压预测

在校正大气湍流畸变波前相差的自适应光学系统中,利用基于Levenberg-Marquardt学习算法的非线性反向传播神经网络技术（LMBP）对变形镜控制电压进行预测。以对受横向风影响的大气湍流畸变波前斜率数据为研究对象,通过数值仿真方法,研究了基于LMBP算法的自适应光学系统变形镜电压非线性预测控制算法。通过实验发现,预测电压和变形镜实际控制电压拟合效果良好。讨论了回溯帧数对预测效果的影响,并与基于递推最小二乘（RLS）算法的线性预测算法进行比较。对比结果表明,基于LMBP算法的非线性电压预测方法比基于递推最小二乘法的线性电压预测方法能更有效地降低系统由伺服延迟引起的误差。

     

空泡机制产生betatron X射线辐射的数值模拟

针对SILEX钛宝石激光器参数,采用PIC数值模拟程序VORPAL对激光尾波场加速进行了模拟,得到了电子轨迹及能量数据,进而通过理论计算得到了空泡机制下X射线辐射特性。结果表明,空泡机制下高能电子在空泡中做betatron振荡且多数电子被加速到170 MeV左右;加速能量较低的电子（约100 MeV）, 其辐射谱为临界能量约3 keV的类同步辐射谱,发散角约为8 mrad,而能量较高的电子（约170 MeV）对应的光子临界能量约为10 keV。     

Frustrated Lewis Pair Catalysis:It Takes Two to Make a Thing Go Right

Since the introduction of the concept of frustrated Lewis pair by Stephan in 2006,the frustrated Lewis pair (FLP) chemistry has evolved into a rich and fruitful...     

多光束激光干涉光刻图样

利用电磁理论,研究了多光束激光干涉图样的产生原理,结合计算机数值模拟和相关实验结果,分析了干涉图样的影响因素。研究结果表明：多光束激光干涉图样可以看成是多组余弦分布的平行线条纹的叠加;相干光束的偏振方向、入射方向、光束间相差是干涉图样的重要影响因素,改变这些因素,余弦分布的平行线条纹的振幅、置、周期和方向发生变化,图样也随之变化。     

Native agarose gel electrophoresis and electroelution: A fast and cost‐effective method to separate the small and large hepatitis B capsids

Hepatitis B core antigen (HBcAg) expressed in Escherichia coli is able to self‐assemble into large and small capsids comprising 240 (triangulation number T = 4) and 180 (triangulation number T = 3) subunits, respectively. Conventionally, sucrose density gradient ultracentrifugation and SEC have been used to separate these capsids. However, good separation of the large and small particles with these methods is never achieved. In the present study, we employed a simple, fast, and cost‐effective method to separate the T = 3 and T = 4 HBcAg capsids by using native agarose gel electrophoresis followed by an electroelution method (NAGE‐EE). This is a direct, fast, and economic method for isolating the large and small HBcAg particles homogenously based on the hydrodynamic radius of the spherical particles. Dynamic light scattering analysis demonstrated that the T = 3 and T = 4 HBcAg capsids prepared using the NAGE‐EE method are monodisperse with polydispersity values of ～15% and ～13%, respectively. ELISA proved that the antigenicity of the capsids was not affected in the purification process. Overall, NAGE‐EE produced T = 3 and T = 4 capsids with a purity above 90%, and the recovery was 34% and 50%, respectively (total recovery of HBcAg is ～84%), and the operation time is 15 and 4 times lesser than that of the sucrose density gradient ultracentrifugation and SEC, respectively.     

Removal of oxygen from silicon by electron beam melting

Small amounts of multicrystalline silicon were melted in an electron beam furnace in different experimental conditions in order to investigate the oxygen evaporation behavior during the electron beam melting (EBM) process. The oxygen content level before and after EBM was determined by secondary ion mass spectroscopy. The oxygen content was reduced from 6.177 to 1.629 ppmw when silicon was melted completely at 15 kW with removal efficiency up to 73.6 %. After that, it decreased continually to <0.0517 ppmw when the refining time exceeded 600 s with a removal efficiency of more than 99.08 %. During the melting process, the evaporation rate of silicon is 1.10 × 10^?5 kg/s. The loss of silicon could be reduced up to 1.7 % during oxygen removal process to a desirable figure, indicating EBM is an effective method to remove oxygen from silicon and decrease the loss of silicon.     

A bird nest-like manganese dioxide and its application as electrode in supercapacitors

A novel bird nest-like nanostructured MnO2(BNNS-MnO2) was prepared by a facile and cost-effective strategy. Their structures and morphologies were characterized by field emission scanning electron microscopy, transmission electron microscopy and powder X-ray diffraction. Capacitive behaviors were investigated by cyclic voltammetry and galvanostatic charge-discharge. The obtained nano-MnO2 possesses a well designed loose-assembled hierarchical nanoarchitecture with an appropriate crystallinity which gives rise to excellent performances as an electrode material for supercapacitors. A maximum specific capacitance of 917 F/g has been obtained at a current density of 5 mA/cm2 in 6 mol/L KOH aqueous solution, and a specific capacitance of 210 F/g has been maintained for 500 cycles. As the low cost of MnSO4 and KCr2O7 and the low reaction temperature, the present method avoids the requirements for complicated operations, time/energy-consuming and expensive reagents, and perhaps is ready for the industrialization of nano-MnO2 production.     

Resolution enhancement in hydrophobic interaction chromatography via electrostatic interactions

In this work, a new type of hydrophobic stationary phase that provide electrostatic interactions with analytes was developed by bonding β-phenylethylamine as a functional ligand to silica. This stationary phase can separate proteins with similar hydrophobicity that traditional hydrophobic resins cannot. Hen egg white was separated to examine the selectivity. The results show that the introduced electrostatic interactions are an important factor for the resolution enhancement and the new resin could have important applications in separation and purification of biological macromolecules.     

Spatiotemporal dynamics of lump solution to the (1 + 1)-dimensional Benjamin–Ono equation

Nonlinear Dynamics - This paper focuses on the finite-time synchronization problem for a kind of general complex networks with intrinsic time-varying delays and hybrid couplings (i.e., containing...