162.5 MHz高功率耦合器测试腔体设计

功率耦合器是粒子加速腔射频功率馈送的关键部件。耦合器在安装至加速腔之前,必须进行常温高功率测试和锻炼,以检验加工工艺和设计指标,提高其射频性能。详细介绍了中国科学院近代物理研究所ADS25 MeV加速器样机162.5 MHz耦合器测试平台的改进设计。针对原有接触式测试锻炼方式的不足,提出非接触式测试锻炼方案。对耦合器测试锻炼过程进行了物理抽象,采用理论模拟的方法分析测试腔体功率传输。基于分析结果设计了低损耗、宽通带、多用途的非接触式耦合器测试腔体。该腔体可实现20 kW测试功率下60 W左右的腔体损耗和15 MHz-3 dB带宽。Fundamental power couplers (FPC) are crucial components for feeding RF power to the accelerating cavities. Before being installed on the accelerating cavity, a coupler must be tested and conditioned at room temperature to check its fabrication quality, to verify its design specifications, and improve its RF performance. This paper thoroughly introduced the design of a test stand for the 162.5 MHz coupler of ADS 25 MeV demo facility at IMP, CAS. In order to overcome the shortcomings of the original contacting test method, a noncontacting test scheme was proposed. A physical model was built for the the coupler test and the test cavity power transmission was analyzed theoretically. Based on the analysis results, a low-loss, wide-passband and multipurpose non-contacting coupler test cavity was designed. With the new test cavity, a power loss of around 60W and a -3 dB bandwidth of 15 MHz at a test power of 20 kW was achieved.     

推广的相互作用玻色子模型中基于对偶代数结构的量子相变研究(英文)

本工作将相互作用玻色子模型推广为包含f-和p-玻色子的情形。利用仿射型代数方法,通过对偶代数结构数值计算了多分量玻色型对力问题。利用对偶关系解析构建了与哈密顿量及其基底相联系的,由幺正的粒子数守恒和非粒子数守恒算符构成的准旋代数。在经该模型对106-116Cd偶偶核素实验能谱拟合的基础上,计算了基态和低激发态中各种玻色子占有率,准γ带中相邻能级摇摆等几个能特征该区域核素形状相变的序参量。从而展示了这些中重质量核从振动到γ-不稳定运动的形状相变行为。An extension of the original interacting boson model to the multi-level case including negative parity f-and p-bosons is made. An affinealgebraic approach is applied to solve the multi-level pairing problem numerically via the dual algebraic structure. The duality relation is explicitly used to construct the number-conserving unitary and number-nonconserving quasi-spin algebra, related with the Hamiltonian and the corresponding bases. After fitting to the experimental level energies of even-even 106-116Cd, several order parameters to signify the shape (phase) transition, such as occupation numbers of the bosons in the ground and a few lowest excited states, the level energy staggering in the (quasi)-γ band, are calculated to demonstrate the shape (phase) transitional behavior of these medium mass transitional nuclei.     

A close look at the competition of isovector and isoscalar pairing in A=18 and 20 even-even N≈Z nuclei

competition of isovector and isoscalar pairing in A=18 and 20 even-even N≈Z nuclei is analyzed in the framework of the mean-field plus the dynamic quadurpole-quadurpole, pairing and particle-hole interactions, whose Hamiltonian is diagonalized in the basis U(24) ?(U(6) ? S U(3) ? S O(3))■(U(4) ? S US(2)■ S UT(2)) in the L = 0 configuration subspace. Besides the pairing interaction, it is observed that the quadurpole-quadurpole and particlehole interactions also play a significant role in determining the relative positions of low-lying excited 0~+ and 1~+ levels and their energy gaps, which can result in the ground state first-order quantum phase transition from J = 0 to J = 1.The strengths of the isovector and isoscalar pairing interactions in these even-even nuclei are estimated with respect to the energy gap and the total contribution to the binding energy. Most importantly, it is shown that although the mechanism of the particle-hole contribution to the binding energy is different, it is indirectly related to the Wigner term in the binding energy.     

U（5）-O（6） Phase Transition in the SD-Pair Shell Model

U（5）-0（6） transitional behaviour in the SD-palr shell model is studied. The results show that the U（5）-O（6） transitional patterns of the interacting boson model can be reproduced in the S D-palr shell model approximately.     

煤粉尘爆炸过程中火焰的传播特性

为了揭示煤粉尘爆炸过程中火焰传播特征,采用2种不同质量分数挥发分的煤粉在半封闭竖直燃烧管中进行实验。分别使用高速摄影装置和红外热成像装置记录火焰传播过程和空间的温度分布情况,并分析2种煤粉尘云的火焰传播速度和温度曲线。结果表明:在同等条件下,火焰在挥发分质量分数高的煤粉尘云中的传播速度和火焰温度要高于其在挥发分质量分数较低的煤粉尘云中的。煤粉尘云的体积质量和点火能量也影响着火焰的传播过程,随着煤粉尘云体积质量的增大,火焰的传播速度和火焰温度整体上呈现先增大后减小的趋势,在传播的后半段火焰速度出现震荡现象;随着点火能量的增大,火焰在煤粉尘云中的传播速度和最高温度也相应升高。通过大量的实验数据计算得到特定条件下火焰传播速度和温度的经验公式。     

中国式分权下地方政府环境规制执行研究——以排污收费为例

在中国式分权的制度背景下,以排污收费为例,对地方政府环境规制执行问题进行研究。通过建立地方政府与企业的动态博弈模型,刻画了环境规制的约束性本质特征。以此为基础,通过对政府规制利益集团理论Peltzman模型进行修正和拓展,构建了地方政府的环境规制执行均衡模型,阐述了环境规制执行均衡的形成机制。基于环境规制执行均衡模型,分析了制度因素、环境规制政策标准、治污成本和污染削减技术对地方政府环境规制执行的影响。研究结果表明,地方政府通过调节环境规制执行强度实现自身效用的最大化,从而达到环境规制执行的均衡状态。中央政府制定的更为严格的环境规制政策标准尽管在理论上能够提高企业的治污投入,但却有可能对地方政府的环境规制执行产生负面影响。降低企业治污成本能够促进地方政府严格执行环境规制,而污染削减技术创新则会在不同条件下对地方政府的环境规制执行产生不同的影响。     

胶束增敏分光光度法测定大豆根茎叶中的镧

首次了二溴基偶氮比例中表面活性剂曲通Ｘ－１００和β环糊精存在下与Ｌａ（Ⅲ）的显色反应。在强酸介质中与Ｌａ（Ⅲ）形成稳定的配合物,最大吸收波长在６３８ｎｍ处,配合物的表观魔鬼洋吸光系数为１．５０×１０＾５Ｌ·ｍｏｌ＾－１·ｃｍ＾－１,比献「１」中的灵敏度高２７％。该法已用于大 奶、茎、叶中镧的测定。     

氧化钪/氧化硅反射薄膜的355 nm激光损伤特性

采用电子束蒸发法制备了Sc2O3单层薄膜和Sc2O3/SiO2多层反射膜.利用原子力显微镜、X射线衍射仪等方法对薄膜的表面和结构进行,研究.采用355 nm激光研究了Sc2O3/SiO2多层薄膜的损伤特性和预处理效应,并对Sc2O3的损伤原因进行了分析.实验发现,Sc2O3具有较宽的带隙,薄膜结构为立方相,影响Sc2O3/SiO2 多层反射膜抗损伤能力的主要因素足材料的纯度.     

高维硬核Fermi-Hubbard模型的严格解

提出了一种导出硬核Fermi-Hubbard模型严格解的简单代数方法. 利用该方法得到了邻近格点跳跃(hopping)硬核Fermi-Hubbard模型在高维情况下的激发能和相应的能量本征波函数, 从而说明该模型在任意维情况下是严格可解的.