重离子同步加速器SIS中的束团纵向稳定性理论、测量和模拟

本论文中的工作是在德国重离子研究中心（GSI）和中国科学院近代物理研究所的联合培养计划下完成的。论文以GS工的重离子同步加速器SIS为主要研究对象，就其强流运行及为GSI最近批准的新项目而升级的纵向动力学方面进行了研究和探讨。该项工作对于在建的大科学工程兰州重离子储存环HIRFL-CSR有借鉴意义。在GSI的新项目国际重离子、反质子加速器科学研究装置的蓝图中，现有的重离子同步加速器S工S将作为前级提升束流的强度和能量。束团的纵向稳定性是保证可靠的强流运行所必须回答的问题，包括以下内容，在本文中分别进行了探索和解答：纵向的重离子加速器环境阻抗模型；在可能的阻抗条件下束流线性稳定性；在阻尼及不稳定性效应下束流相空间分布的演化行为和结果（发射度增长、粒子丢失等）及其内在机制；对不稳定性和束流相空间稀释效应进行控制的可能性。不同流强下束流纵向相空间测量，这是本论文工作的一个重要基础。自洽的Vlasov束团模型（任意外场加空间电荷效应下的束流匹配）和实际运行中的非理想捕获过程（有限的高频电压上升时间，对应不同的绝热系数），作为任何束团运行和稳定性研究的前提分别在论文中得到了厘清。解析方面的工作包括定态和微扰理论，即将线性Vlasov方程应用于束团，并在适当的近似下得到简洁的解析方程。经过重新推导，得到了修正的Sachrer积分方程，使之在强空间电荷效应下的仍然适用，由此得到了线性稳定图。编写调试成功了PIC（particle-in-cell）算法的模拟程序，和线性理论相互校验，并与己得到的实验结果进行了对比，对实际运行中复杂过程进行了模拟，并研究了不稳定性发展后期非线性阶段。线性理论，模拟和实验结果有很好的一致性。在SIS实验中观察到一种流强相关的束团相干模式演化现象，该现象揭示出束团中朗道阻尼条件，这与束团稳定性密切相关。对空间电荷抑制朗道阻尼效应及发射度增长进行了细致研究。提出用快反馈装置控制相空间稀释的思路。线性理论和模拟的结果都预言，在阻性阻抗和空间电荷阻抗存在下，藕合束不稳定性是515多束团强流运行的潜在威胁。阻性阻抗来自管壁及加速器部件的有效导电性或特殊共振结构，或直接来自频率偏置的高频腔。阻抗补偿或特殊的束团操作可以用来控制桃合束不稳定性。

次级束流线设备FRS和现有RIBLL2的优化

本文工作分为两个部分：第一部分是设计德国重离子研究中心（GSI）的一段新的次级束流线；第二部分计算了在建的R工已LLZ对裂变反应碎片的传输分离，同时为提高分离本领对RIBLLZ进行了优化计算和设计。FRS是德国重离子研究中心（GSI）的次级束流线。其分支FRS-CAVEB的终端是川JAD工N的实验终端，这条线的束流品质不理想（传输率只有0．1％），因此GSI拟将AI'AD州设备（原在CAVEB）移到CAVEC中，形成FRS一CAVEC束流线，又称FRS-R3Bcave。本文对FRS-CoveC进行了束流光学设计和计算，同时模拟了FRS-CAVEC对弹核碎裂反应的传输分离。新束线按计算结果安装了一个二极磁铁和3个四极磁铁，并通过了实验测试，测试结果表明：（1）系统具有良好的消色散特性，即系统在FRS出口和实验终端处达到了消色差。（2）系统的传输率基本符合理论计算值，相对CAVEB分支传输率提高了一个量级以上。当不放任何阻止物质在束流线上时，Ar主束传输率可以达到100％；当放置3mm厚的Sdntillator探测器在S2，S8，CaveC处时，主束传输率基本和理论计算值相近（640k-计算值，610k-实验值）。对比FRS-C八VEB的实验传输率（0．1％），可知通过改进，FRS-C八VEC的传输率将得到极大的改善。RIBLLZ是连接CSR两环之间的次级束流线。现有的RIBLLZ束流线设计的比较紧凑，立体角接收度大，使得所有粒子都可通过系统，可以作为零度质谱仪，尤其是可以将裂变产生的奇异核素注入到实验环进行质量测量。本文模拟了弹核碎片和裂变反应产生的次级束在现有的RIBLLZ上的传输情况。计算表明，现有的RIBLLZ对通过u裂变产生的大量较重奇异核素，具有很高的传输率。另一方面，现有的RIB七LZ在散焦面只有两个四极磁铁，为达到系统的消色差及较大的分辨率会使得Y方向的束流控制困难。基于此，对现有的R咸喝锻蓄尔＼一些改进计算。还理论计算比较了两个系统对裂变反应的传输分离情况。玺认算试知飞（1）优化后的RIBLLZ系统对束流在Y方向的控制将更灵活。（2）对裂变反应产物的传输，除了作为零度质谱仪外还可以作为单一核素的分离器。（3浑税盯确集磁系统的传输率对降能器厚度敏感度降低，对于u裂变反应产生的132sn的传输率，当降能器厚度从19／cmZ变化到39／clnu时，传输率下降20％，而未优化的RIBLLZ系统的传输率将下降90%。

重离子蚀刻径迹中金属纳米线阵列的研制

本论文主要进行了核孔膜的蚀刻和紫外光辐照效应研究，以及在核孔膜模板内进行Cu、CO金属纳米线阵列的制备研究。在UNILAC（GSI，Darmstadt）加速器上真空和室温条件下对30μm厚的聚碳酸酯（PC）薄膜进行快重离子辐照，照射离子为11． 4 MeV／u的Au离子，辐照剂量在lion／cm，-3X109i0ns／cm，之间。重离子辐照导致在PC中产生潜径迹，通过化学蚀刻的方法将潜径迹放大而形成孔道。蚀刻速率与蚀刻温度、蚀刻液浓度、紫外光辐照敏化等参数密切相关。结果表明随着温度的升高蚀刻液浓度的增加、紫外光辐照时间的增长径迹蚀刻速率剧烈增加。此外，通过紫外可见光谱和力学性能测试发现，紫外光辐照会使Pc膜的光学性能和力学性能发生显著的变化。在能量密度为16mw／cm2的紫外光下，当膜两侧分别经过17．5小时的光照以后，392 nm处的吸收峰消失，而且其断裂伸长率大大减小。作为紫外光辐照效应的一个应用，我们利用“紫外光辐照＋液氮冷冻”的方法成功制备出了核孔膜断面的扫描电子显微镜样品，此方法能使样品的断面含有较少的残余应力从而使膜在断裂过程中没有发生明显的变形，使断面很好显现了膜和孔道的原始信息，如孔密度、形状、尺寸等。利用PC核孔膜作为模板用电化学沉积方法制备出了金属纳米线阵列。用磁控溅射的方法在PC膜模板的一面沉积一层Pt金属薄膜在电沉积过程中用作阴极。在自制的电沉积系统中用直流沉积的方法在PC核孔膜模板中成功制备出了Cu和Co金属纳米线，并运用SEM、xRD、VSM等手段对纳米线进行分析。结果表明，制备出的Cu纳米线长度约为30μm，直径从nm到协m量级，具有面心立方（fcc）结构，且纯度很高没有发现杂质。对Co纳米线阵列的xRD结果进行分析可以看出，制备出的c。纳米线阵列具有两种晶体结构：单相hcp结构和hcp、fcc共存结构。从vsM测量结果可以看出，Co纳米线阵列存在磁各向异性，即平行于纳米线轴向和垂直于纳米线轴向的剩余磁化强度和矫顽力存在明显差异，这主要是由于纳米线的形状各向异性和纳米线之间的磁相互作用引起的。

重离子碰撞中多重碎裂及动力学研究

把量子分子动力学模型（QMD）与重构模型耦合，我们称之为改进的QMD（IQMD），研究了重构与非重构情形的差异。用改进了的QMD模型研究了状态方程、动量相关势和介质效应对多重碎裂动力学过程的影响，以及这种影响随入射能量的依赖关系。通过研究能够标识中能重离子碰撞动力学过程的物理量：横动量、碰撞数、核物质密度及热化的时间演化过程，了解中能重离子碰撞系统的碰撞动力学和多重碎裂机制；同时对控制和影响这种碰撞动力学的各种动力学因素：状态议程、动量相关势和介质效应进行了分析和探讨。发现介质效应在较低能区（200MeV和400MeV），由于碰撞截面的减小，导致碰撞数、核物质密度、热化和横动量的减小，因而减弱了碰撞系统的多重碎裂过程，随着入射能量的增加，介质中非弹性碰撞过程增加并逐渐占据重要地位，故与自由核子-核子碰撞比较，尽管碰撞数和核物质密度仍有明显差别，但横动量和热化逐步接近并导致碎裂过程相似。动量相关作用由于增加了排斥作用从而使碰撞数和核物质密度减小，但由于同时增加碰撞核子之间的能量交换和动量转移过程，故增大了横动量和碰撞系统的多重碎裂过程。尽管状态方程对于中能重离子碰撞动力学的作用是明显的，但对多重碎裂过程的作用不明显。最后分析了GSI的实验结果，发现QMD能较好解释GSI实验中产生的轻碎块，但与中等质量碎块的结果差别较大，考虑了动量相关热后结果虽有改善，但仍不足以解释实验结果

岩体力学参数及稳定性能量判据研究

There are two major problems that have been concerned all the times, which are the mechanics characters of joint rock mass and the criterion for stability of engineering rock. Aim at the two problems, several works were conducted as follow: (1) Firstly, the mechanics characters of rock mass was studied by means of the Distinct Element Code. Subsequently, it was studied that the sensibility of joint surface roughness, strength of joint wall, joint stiffness ( i.e. tangential and normal stiffness) on the rock mass strength. (2) Based on the experimental rock mass classification methods of RMR and GSI, the program of “Parameters Calculation of the Rock Mass ” was developed. It has realized the rapid choice of rock mass parameters. (3) The concept of Representive Element Volume was induced based on the study of dimensional effect of rock mass. The Representive Element Volume of the horizontal and vertical pillar (ab. Two Pillars ) in the 2nd zone of Jinchuan mine were gained by the Geology Statistic Method and the Distinct Element Code. And then, the strength and deformatiom parameters of rock mass of the Two Pillars were obtained through numerical experiment. (4) From the confining depressure after thriaxial compression test of rock sample, it was concluded that the failure of rock is caused mainly by the lateral deformation and energy release happened during the confining depressure processure. The criterion of plastic energy catastrophe of rock engineering failure was proposed and validated. Subsquently, the stability of the horizontal pillar and Qianjiangping landslide in Three Gorges was judged by means of above-mentioned method. (5) Based on the fact there is a phenomenon of increasing energy concentration while the rock mass was compressed, rock information entropy (i.e. energy distribution entropy) was proposed. And it was revealed that there was change of energy distribution entropy while the rock mass was compressed to failure.

锦屏电站地下厂房卸荷岩体参数研究

It is a basic work to ascertain the parameters of rock mass for evaluation about stability of the engineering. Anisotropism、inhomogeneity and discontinuity characters of the rock mass arise from the existing of the structural plane. Subjected to water、weathering effect、off-loading, mechanical characters of the rock mass are greatly different from rock itself, Determining mechanical parameters of the rock mass becomes so difficult because of structure effect、dimension effect、rheological character, ‘Can’t give a proper parameter’ becomes one of big problems for theoretic analysis and numerical simulation. With the increment of project scale, appraising the project rock mass and ascertaining the parameters of rock mass becomes more and more important and strict. Consequently, researching the parameters of rock mass has important theoretical significance and actual meaning. The Jin-ping hydroelectric station is the first highest hyperbolic arch dam in the world under construction, the height of the dam is about 305m, it is the biggest hydroelectric station at lower reaches of Yalong river. The length of underground factory building is 204.52m, the total height of it is 68.83m, the maximum of span clearance is 28.90m. Large-scale excavation in the underground factory of Jin-ping hydroelectric station has brought many kinds of destructive phenomenon, such as relaxation、spilling, providing a precious chance for study of unloading parameter about rock mass. As we all know, Southwest is the most important hydroelectric power base in China, the construction of the hydroelectric station mostly concentrate at high mountain and gorge area, basically and importantly, we must be familiar with the physical and mechanical character of the rock mass to guarantee to exploit safely、efficiently、quickly, in other words, we must understand the strength and deformation character of the rock mass. Based on enough fieldwork of geological investigation, we study the parameter of unloading rock mass on condition that we obtain abundant information, which is not only important for the construction of Jin-ping hydroelectric station, but also for the construction of other big hydroelectric station similar with Jin-ping. This paper adopt geological analysis、test data analysis、experience analysis、theory research and Artificial Neural Networks （ANN） brainpower analysis to evaluate the mechanical parameter, the major production is as follows: (1)Through the excavation of upper 5-layer of the underground powerhouse and the statistical classification of the main joints fractures exposed, We believe that there are three sets of joints, the first group is lay fracture, the second group and the fourth group are steep fracture. These provide a strong foundation for the following calculation of and analysis; (2)According to the in-situ measurement about sound wave velocity、displacement and anchor stress, we analyses the effects of rock unloading effect，the results show a obvious time-related character and localization features of rock deformation. We determine the depth of excavation unloading of underground factory wall based on this. Determining the rock mass parameters according to the measurement about sound wave velocity with characters of low- disturbing、dynamic on the spot, the result can really reflect the original state, this chapter approximately the mechanical parameters about rock mass at each unloading area; (3)Based on Hoek-Brown experienced formula with geological strength index GSI and RMR method to evaluate the mechanical parameters of different degree weathering and unloading rock mass about underground factory, Both of evaluation result are more satisfied; (4)From the perspective of far-field stress, based on the stress field distribution ideas of two-crack at any load conditions proposed by Fazil Erdogan (1962)，using the strain energy density factor criterion (S criterion) proposed by Xue changming(1972)，we establish the corresponding relationship between far-field stress and crack tip stress field, derive the integrated intensity criterion formula under the conditions of pure tensile stress among two line coplanar intermittent jointed rock，and establish the corresponding intensity criterion for the exploratory attempt; (5)With artificial neural network, the paper focuses on the mechanical parameters of rock mass that we concerned about and the whole process of prediction of deformation parameters, discusses the prospect of applying in assessment about the parameters of rock mass，and rely on the catalog information of underground powerhouse of Jinping I Hydropower Station, identifying the rock mechanics parameters intellectually，discusses the sample selection, network design, values of basic parameters and error analysis comprehensively. There is a certain significance for us to set up a set of parameters evaluation system，which is in construction of large-scale hydropower among a group of marble mass.