Versal unfolding of equivariant bifurcation problems in more general case under two equivalent groups

For the unfolding of equivariant bifurcation problems with two types of state variables in the presence of parameter symmetry,the versal unfolding theorem with respect to left-right equivalence is obtained by using the related methods and techniques in the singularity theory of smooth map-germs.The corresponding results in[4,9]can be considered as its special cases.A relationship between the versal unfolding w.r.t.left-right equivalence and the versal deformation w.r.t.contact equivalence is established.     

铒硼硅酸盐稀土玻璃的析晶行为

高含量稀土玻璃在激光防护材料方面具有重要的应用,通过对稀土玻璃析品行为的研究.有助于制备出透明的高稀土含量稀土玻璃.分别制备了透明的铒硼硅酸盐稀土玻璃和富B2O3、富SiO2、富Al2O3的铒硼硅酸盐稀土玻璃,并在1100℃下对各种玻璃样品进行热处理.采用XRD,SEM等分析测试方法对Er2O3-B2O3-SiO2-Al2O3系玻璃的析晶行为进行研究,并探讨了玻璃组成对析晶产物的影响.结果表明,铒硼硅酸盐稀土玻璃的局部结构与ErBO3晶相的结构具有一定的相似性;富B2O3,富SiO2、富Al2O3的铒硼硅酸盐稀土玻璃会发生失透现象.稀土玻璃发生失透是由玻璃析晶引起的,其中铒硼硅酸盐稀土玻璃中最易析出的晶相是ErBO3.     

物理教学中的课堂讨论策略

课堂讨论能够在教学中最大限度地激发学生的智慧，有助于学生更好地掌握所学知识；有利于教师获得教学效果的反馈信息，及时调控教学．物理课堂讨论是教师与学生共同构建的一种教学行为，是彰显学生个性、扩大信息交流和思维容量的有效途径，因而倍受物理教师的青睐但课堂讨论又费时费力和讨论结果多变等，所以授课教师需要注意采用以下策略：     

SECRAL在18GHz频率下产生强流高电荷态离子束的初步结果

A Superconducting ECR ion source with Advanced design in Lanzhou (SECRAL) was successfully built to produce intense beams of highly charged ions for Heavy Ion Research Facility in Lanzhou (HIRFL).The ion source has been optimized to be operated at 28GHz for its maximum performance.The superconducting magnet confinement configuration of the ion source consists of three axial solenoid coils and six sextupole coils with a cold iron structure as field booster and clamping.For 28GHz operation,the magnet assembly can produce peak mirror fields on axis 3.6T at injection,2.2T at extraction and a radial sextupole field of 2.0T at plasma chamber wall.A unique feature of SECRAL is that the three axial solenoid coils are located inside of the sextupole bore in order to reduce the interaction forces between the sextupole coils and the solenoid coils. During the ongoing commissioning phase at 18GHz with a stainless steel chamber,tests with various gases and some metals have been conducted with microwave power less than 3.2kW and it turned out the performance is very promising.Some record ion beam intensities have been produced,for instance,810eμA of O~(7 ),505eμA of Xe~(20 ),306eμA of Xe~(27 ),21eμA of Xe~(34 ),2.4eμA of Xe~(38 ) and so on.To reach better results for highly charged ion beams,further modifications such as an aluminium chamber with better cooling,higher microwave power and a movable extraction system will be done,and also emittance measurements are being prepared.     

新型固液旋流器压降特性实验研究

难分离的微细颗粒可采用小尺寸旋流器进行分离,但必然因为压降不能过高的限制而减低进口流量。为解决这一问题,本研究设计了新型双锥旋流器结构,其中主要的分离发生在小锥段,连接小锥段与圆柱段的大锥段则主要其是时流体平稳过渡、从而降低旋流器的压降,这样就可以提高旋流器操作时的进口流量。本文对这种新型旋流器进行了压降特性的探索性实验研究。实验结果表明:新型旋流器比传统单锥旋流器的进口流量可提高60%～70%;压降随流量呈二次抛物线方式增加;随着溢流口直径的增加而降低。这些规律都类似于传统的固液旋流器。另外,压降随分流比的增加明显上升;当溢流管插入深度增加时,压降首先达到一最大值,而后随着插入深度的增加而降低。     

纤维排列方式对复合材料总体粘弹性常数的影响

对于金属基或高分子聚合物基复合材料，在特定情况下会表现出明显的粘弹性特性。本文采用Riemann—Liouville形式的分数阶导数模型描述基体的粘性特性，通过渐进均匀化方法给出了预测纤维加强复合材料整体本构关系的解析表达式，给出应用于基体具有Makris粘弹性关系的具体形式。最后，考察了圆截面纤维正方形排列和对角排列时的总体粘弹性弹性常数随纤维比的变化曲线。结果表明，这类复合材料仍具有粘弹性特性，其整体粘弹性本构关系的弹性部分综合了纤维弹性和基体弹性的贡献，粘性部分来自基体粘性的贡献，复合材料具有和基体相同的粘性系数和分数阶。为分析微结构特征对整体特性的贡献，须求解两类局部问题。在相同纤维体积比情况下，正方形排列的总体弹性系数大于正方形对角排列，而粘性常数相反。     

SECRAL超导磁体系统的结构分析

An advanced superconducting ECR ion source named SECRAL has been constructed at Institute of Modern Physics of Chinese Academy of Sciences,whose superconducting magnet assembly consists of three axial solenoid coils and six sextupole coils with a cold iron structure as field booster and clamp.In order to investigate the structure of sextupole coils and to increase the structural reliabilities of the magnet system, global and local structural analysis have been performed in various operation scenarios.Winding pack and support structure design of magnet system,mechanical calculation and stress analysis are given in this paper. From the analysis results,it has been found that the magnet system is safe in the referential operation scenarios and the configuration of the magnet complies with design requirements of the SECRAL.     

宣德官窑青花瓷的面扫描分析

用SRXRF对宣德时期官窑青花瓷片上的瓷彩进行面扫描分析,结果表明各元素分析线的峰面积有着不同的分布模式。根据与颜色浓淡、瓷彩上黄斑的耦合关系可以将K,Cr,Mn,Fe,Co,Ni,Cu,Zn,Hg,Rb,Sr,Y和Zr等13个元素分为3组。它可作为各个朝代青花瓷“指纹元素”的选择依据,并提出了研究瓷彩中黄斑的形成机制的新思路。     

管范畴中的模同态与模分解

本讨论管范畴（ｔｕｂｅ）中的模同态。在不可分解模上定义特殊生成元,并运用它研究了管范畴中模同态的一些性质,得到了关于同态ｆ：Ｍｈ,ｌ→Ｌ的导出的模Ｌ的直和分解及其余核的构造。     

推广的与时间无关的噪声算法和相关的分支问题

1.引言 优化问题可以归结为求某个实值函数在某一区域内的最小值。假设f(X)是连续光滑函数,求点X~*∈ΩR~n,使 f(X~*)=minf(X)≡f~* X∈Ω其中ΩR~n是有界区域。传统的确定性算法只能得到局部最优解。S.Kirkpatrik,Gelatt和Vecchi提出的模拟退火算法(SA),通过对确定性算法引入噪声,从理论上解决了这一问题。