The generalized Roper-Suffridge extension operator

Let f(z) be a normalized convex (starlike) function on the unit disc D. Let , where z=(z₁,z₂,…,z_n), z₁∈D, , p_i?1, i=2,…,n, are real numbers. In this note, we prove that Φ(f)(z)=(f(z₁),f′(z₁)^1/p₂z₂,…,f′(z₁)^1/p_nz_n) is a normalized convex (starlike) mapping on Ω, where we choose the power function such that (f′(z₁))^1/p_i|_z1=0=1, i=2,…,n. Some other related results are proved.     

拓扑遍历与拓扑双重遍历

令X为紧致度量空间,f:X→X为连续映射,U,V为X的任意非空开集,若{n>0|fn(U)∩V≠ )为正上密度集,则称f拓扑遍历.f拓扑双重遍历意味着f×f拓扑遍历.本文在[2]的基础上进一步讨论拓扑遍历与拓扑双重遍历映射的性质.     

混合单调算子的两点拉伸型不动点定理

本文首次提出了混合单调算子不动点的两点拉伸型条件.同时,利用锥映象的不动点指数理论建立了一类特殊的两点拉伸型混合单调算子的不动点存在性定理,并将所得结论应用于带有超线性项的积分方程与微分方程上,得到了新的结论.因而在本质上推进了混合单调算子不动点问题的研究.     

The tame kernel of imaginary quadratic fields with class number 2 or 3

This paper presents improved bounds for the norms of exceptional finite places of the group , where is an imaginary quadratic field of class number 2 or 3. As an application we show that .

     

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.     

Structured mirror array for two-dimensional collimation of a chromium beam in atom lithography

Direct-write atom lithography,one of the potential nanofabrication techniques,is restricted by some difficulties in producing optical masks for the deposition of complex structures.In order to make further progress,a structured mirror array is developed to transversely collimate the chromium atomic beam in two dimensions.The best collimation is obtained when the laser red detunes by natural line-width of transition 7S3 → 7P40 of the chromium atom.The collimation ratio is 0.45 vertically(in x axis),and it is 0.55 horizontally(in y axis).The theoretical model is also simulated,and success of our structured mirror array is achieved.     

Monitoring of the ducting by a ground-based GPS receiver

In this paper, we describe the estimation of low-altitude refractivity structure from simulation and real ground-based GPS delays. The vertical structure of the refractive environment is modeled using three parameters, i.e., duct height, duct thickness, and duct slope. The refractivity model is implemented with a priori constraints on the duct height, thickness, and strength, which might be derived from soundings or numerical weather-prediction models. A ray propagation model maps the refractivity structure into a replica field. Replica fields are compared with the simulation observed data using a squared-error objective function. A global search for the three environmental parameters is performed using genetic algorithm. The inversion is assessed by comparing the refractivity profiles from the radiosondes to those estimated. This technique could provide near-real-time estimation of ducting effect. The results suggest that ground-based GPS provides significant atmospheric refractivity information, despite certain fundamental limitations of ground-based measurements. Radiosondes typically are launched just a few times daily. Consequently, estimates of temporally and spatially varying refractivity that assimilate GPS delays could substantially improve over-estimates using radiosonde data alone.     

基于X射线的空间语音通信系统

提出了栅控X射线源作为发射器和基于微通道板的X射线单光子探测器作为接收器的X射线通信方案. 搭建了基于X射线的空间语音通信系统, 详细介绍了信号调制发射器、基于微通道板的X射线单光子探测器及信号接收解调器的设计及工作原理. 报道了基于X射线的空间语音通信系统的初步实验结果, 实现了优于20 kbit/s的基于语音信号调制的X射线通信. 实验分析了在不同X射线强度、信号整形时间和阈值设置下通信性能影响, 得出了X射线发射功率限制X射线通信速率的结论, 提出了下一步提高X射线通信性能的改进方案. 关键词： X射线通信 X射线源 探测器     

中国散裂中子源快循环同步加速器中色品校正及六极磁铁非线性效应

中国散裂中子源（CSNS）快循环同步加速器（RCS）把能量为80 MeV的束流储存并加速到1.6 GeV然后引出到靶站。为了减少RCS中的束流损失,有必要对RCS做色品校正,并减小动量偏移对束流光学的影响。尝试了多种色品校正方案并对不同色品校正方案做了比较。用三维跟踪程序SIMPSONS研究了色品校正六极铁与空间电荷效应对束流的影响。色品校正六极铁可以有效减小色品引起的频散,但是由于六极铁为非线性元件,导致不同振幅的粒子间有一定频散。模拟发现同时存在空间电荷效应和色品校正六极铁时,会有少量的束流损失。     

金属薄膜制备及物性测量系列实验

介绍了由模拟真空实验和“金属薄膜的制备”、“金属薄膜厚度的测量”、“金属薄膜电阻率的测量”,以及“金属薄膜生长过程的动态监测”等4个实验组成的金属薄膜制备与物性测量系列实验.这组实验与现代科学技术发展联系紧密,仪器设备可靠,操作简单,适合于普通物理实验阶段的研究性教学.