Study on application of independent component analysis in the CSNS/RCS

The China Spallation Neutron Source (CSNS) accelerators consist of a low energy H linac and a high energy proton Rapid Cycling Synchrotron (RCS). The proton beam is accumulated in the RCS and accelerated from 80MeV to 1.6GeV with a repetition of 25Hz. Independent component analysis (ICA) is a robust method for processing the collected data (samples) recorded by the turn-by-turn beam position monitor (BPM), which was recently applied to the accelerator. The samples are decomposed to source signals, or the so-called independent components, which correspond to the inherent motion of samples, such as betatron motion and synchrotron motion. A study on the application of the ICA method to CSNS/RCS has been made. It shows that the beta function, phase advance, and dispersion can be well reconstructed by using ICA in CSNS/RCS. The effects of BPM errors on the ICA results are also studied. By comparing the different solving methods in ICA, the so-called SOBI has more advantages for isolating the independent components on the application of ICA to CSNS/RCS. Beam emittance dilution in the process of exciting the turn-by-turn samples is considered,and thus an RF kicker is adopted to avoid such emittance growth.     

L-Shell X-Ray Yields and Production Cross Sections of Zr and Mo Bombarded by Slow Highly Charged Ar16+ Ions

The L-shell x-ray yields of Zr and Mo bombarded by slow Ar16＋ ions are measured. The energy of the Ar^16＋ ions ranges from about 150 keV to 350 keV. The L-shell x-ray production cross sections of Zr and Mo are extracted from these yields data. The explanation of these experimental results is in the framework of the adiabatic direct- ionization and the binding energy modified BEA approximation. We consider, in the slow asymmetric collisions such as Ar and Mo/Zr, the transient united atoms （UA） are formed during the ion-surface interaction and the direct-ionization is the main mechanism for the inner-shell vacancy production. Generally, the theoretical results are in good agreement with the experimental data.     

低电荷态离子原子碰撞过程中的转移电离机理的研究

介绍了使用位置灵敏技术和飞行时间方法研究中低能低电荷态离子-原子碰撞过程中转移电离与单电子俘获过程.对于确定的入射离子电荷态,通过理论分析及与实验数据对比给出了转移电离与单电子俘获截面比R_TS随着入射离子速度V_P的变化规律和转移电离过程中电离的电子主要来自靶原子的最外亚壳层. 关键词： 转移电离 逃离半径 电离半径 俘获半径     

Nonlinearity of InP-Doped Fibers

By combining nano-technology with fiber technology, an optical fiber doped with semiconductor nano-particles as InP is fabricated by using the modified chemical vapor deposition （MCVD） method. Proved by experiment, the fiber has excellent waveguide characteristics, and the concentration of InP is approximately 0.1~o. By using a scanning electron microscope, a stereo-scan photograph of the fiber is obtained, and based on the graph, presentations of the fiber under both magnetic and electronic fields are simulated, the effective core area Aeff≈ 10μm^2 is calculated, and so is the nonlinear index γ = 10.53 W^-1/Km of the fiber. This research leads a new method of high nonlinearity fiber fabrication.     

格子Boltzmann方法对Rayleigh-Benard流的模拟与非线性分析

本文利用格子Boltzmann方法对不同Ra下的Rayleigh-Benard自然对流进行了数值模拟,得到的Nu与前人的结果一致。数值结果表明,Ra=2000时,格子Boltzmann方法得到了三个静态分岔解,其中一个为非稳定解;在Ra=5×10~5时格子Boltzmann方法得到了类似于周期的振荡解。本文采用插值格子Boltzmann方法,在Ra=2000,取不同插值节点进行计算时,得到了一种非稳态解。     

Banach空间L_p（Ω）中非齐次不适定椭圆边值问题的最小范数极值解

该文对Ｂａｎａｃｈ空间犔犘（Ω）中二阶椭圆方程非齐次不适定Ｎｅｕｍａｎｎ问题,引入伪变分解的概念,应用Ｂａｎａｃｈ空间几何及［３］中关于Ｂａｎａｃｈ空间中线性算子的Ｍｏｏｒｅ Ｐｅｎｒｏｓｅ广义逆,证明了上述伪变分解为最小范数极值解,从而为适定的．     

Thin films of magnesium oxide prepared by plasma-enhanced chemical vapour deposition

Thin films of magnesium oxide have been deposited on glass, quartz, stainless steel, and nickel by plasma enhanced chemical vapour deposition using 2,2,6,6-tetramethyl-heptanedionato-3,5-magnesium(II) (Mg(thd)₂) as precursor. The films show (100)-orientation when deposited at temperatures 673 K. The influence of experimental parameters on deposition rate and film properties has been studied.On leave from the Beijing Solar Energy Research Institute, Beijing, China     

三维多枝雪花状银粉的制备及催化性能

室温下,以聚乙烯醇为保护剂,采用抗坏血酸还原硝酸银,于水相中一步合成出三维多枝雪花状银粉。结合X射线粉末衍射(XRD)、扫描电子显微镜(SEM)等结构表征手段,对三维多枝雪花状银粉的微观结构进行详细分析,在此基础上提出其可能的形成机理。此外,三维多枝雪花状银粉在4-硝基苯酚催化加氢反应中还表现出优异的催化活性。     

放射增敏性导弹型卟啉的合成与性质研究

用化学方法成功地将放射增敏剂灭滴灵连接到对癌细胞具有定位作用的原卟啉上，通过红外光谱、紫外可见吸收光谱、质谱、核磁共振谱和元素分析等手段确证了其结构。经动物实验证明，放射增敏效果较好。     

A SPR and AFM study of the effect of surface heterogeneity on adsorption of proteins

The effect of chemical heterogeneity of surfaces on the adsorption of proteins was investigated using model surfaces prepared by self-assembly of omega-functionalized alkanethiols on gold substrates. Surface plasmon resonance was used to monitor the adsorption kinetics of bovine serum albumin (BSA) and the morphology of the adsorbed BSA was imaged with tapping mode atomic force microscopy. The experiments show that the morphology of the adsorbed protein layer was altered significantly only when the surface heterogeneity was distributed in a patchwise manner on a nanometer length scale, which is commensurate with the dimension of the protein. In contrast to linear flexible polymers where the initial adsorption rate remained unchanged upon introduction of the chemical heterogeneity, the initial rate for the globular protein changed from the value observed on homogeneous surfaces and was dependent on the heterogeneous distribution of the chemical sites.