四杆型射频四极场加速器的极间电压调谐及测定北大核心CSCD

为了提高射频四极场加速器(RFQ)的束流传输效率,需要对纵向分布不均匀的极间电压进行补偿,并且准确测量束流实验中极间电压的绝对数值。考虑到极间电压分布不均匀是由于分布电容和端部效应造成的,而采用调谐块可以调节分布电感,通过电磁场数值模拟研究了调谐块对极间电压分布的影响,最终极间电压的平整度被调整到优于95%。在束流实验中,通过测量轫致辐射谱测定了极间电压的数值,通过束流动力学模拟研究了多能峰产生的原因,并最终标定了70kV极间电压对应的输入功率值284kW。     

“妙解”源于“厌繁”

波利亚说：“掌握数学意味着什么？这就是说善于解题,不仅善于解一些标准的题,而且善于解一些要求独立思考,思路合理,见解独到和有发现创造的题．”他认为中学数学教学的首要任务就是“加强解题的训练”,使“解题”成为培养学生的数学才能和学会思考的一种手段和途径．他指出：解题的价值不是答案的本身,而在于弄清“是怎样想到这个解法的”、     

Zero-determinant strategy:An underway revolution in game theory

Repeated games describe situations where players interact with each other in a dynamic pattern and make decisions according to outcomes of previous stage games. Very recently, Press and Dyson have revealed a new class of zero-determinant(ZD) strategies for the repeated games, which can enforce a fixed linear relationship between expected payoffs of two players, indicating that a smart player can control her unwitting co-player’s payoff in a unilateral way [Proc. Acad. Natl. Sci.USA 109, 10409(2012)]. The theory of ZD strategies provides a novel viewpoint to depict interactions among players,and fundamentally changes the research paradigm of game theory. In this brief survey, we first introduce the mathematical framework of ZD strategies, and review the properties and constrains of two specifications of ZD strategies, called pinning strategies and extortion strategies. Then we review some representative research progresses, including robustness analysis,cooperative ZD strategy analysis, and evolutionary stability analysis. Finally, we discuss some significant extensions to ZD strategies, including the multi-player ZD strategies, and ZD strategies under noise. Challenges in related research fields are also listed.     

Characterization of spectral hole depth in Tm^3＋ ：YAG within the cryogenic temperature range

In this paper, spectral hole depth dependence on temperature below 10 K in Tm^3＋ ：YAG crystal is investigated in detail. A novel model is proposed to analyze the temperature dependence on the spectral hole. By using the proposed model, we theoretically deduce the temperature dependence of spectral hole depth. The results are compared with experimental results and they are in good agreement. According to the theoretic results, the optimum temperature in experiment can be found.     

Ge组分分布对基区杂质非均匀分布的SiGe HBT温度特性的影响

众所周知, 双极型晶体管的设计主要是基区的设计. 一般而言, 基区的杂质分布是非均匀的. 本文首先研究了非均匀的杂质高斯分布对器件温度分布、增益和截止频率的温度特性的影响, 发现增益和截止频率具有正温度系数, 体内温度较高. 随后研究了基区Ge组分分布对这些器件参数的影响. 均匀Ge组分分布和梯形Ge组分分布的SiGe 异质结双极型晶体管增益和截止频率具有负温度系数, 具有较好的体内温度分布. 进一步的研究表明, 具有梯形Ge组分分布的SiGe 异质结双极型晶体管, 由于Ge组分缓变引入了少子加速电场, 不但使它的增益和截止频率具有较高的值, 而且保持了较弱的温度敏感性, 在增益、特征频率大小及其温度敏感性、体内温度分布达到了很好的折中.     

FURTHER APPLICATIONS OF POLAR COORDINATES IN Cn

Simplify the proof on the domain of convergence of multiple power series and consider the case where some of z1, · · · , zn are contained only in a finite number of terms of the series. Obtain some results on holomorphic functions in Cn.     

“神光”Ⅱ装置激光烧蚀驱动侧照明R-T不稳定性实验探索

R-T(Rayleigh-Taylor)不稳定性实验研究对于天体物理和ICF都有重要的意义。特别是侧向照明的诊断方案，物理上很直观实验上也相对容易实现因此受到各国的重视。2003年在“神光”Ⅱ开展了一轮打靶实验。     

北京正负电子对撞机(BEPC)上的试验束及其物理工作

本文介绍了北京正负电子对撞机(BEPC)上的试验束的初级束的研制;报道了次级束的产生和次级束中正电荷粒子的鉴别与测量;简单介绍了利用试验束进行的量能器模块的辐照损伤研究.     

DSC分析及原位FT-IR法对聚合物接枝碳纳米管/环氧树脂固化体系的固化反应的研究

合成了一种扩链脲修饰的多壁碳纳米管(MWCNT-PEG-TU),差示扫描量热分析(DSC)结果表明,MWCNT-PEG-TU可明显提高E-51环氧树脂/双氰双胺(DICY)固化体系的固化反应活性。利用原位傅里叶变换红外光谱(in situ FT-IR)法研究了MWCNT-PEG-TU/E-51环氧树脂/DICY固化体系的等温固化动力学,该固化体系在不同温度下的dα/dt与α的关系曲线较好地符合Kamal自催化反应模型。