TRIUMF ARIEL 电子直线加速器设计

 TRIUMF 的三期升级工程(ARIEL) 计划建造一个 50 MeV 平均流强为10 mA的电子直线加速器作为注入器,通过光裂反应生成放射性核素。电子直线加速器包括两个主要部分：注入器和后加速器,注入器完成电子能量从100 keV到10 MeV的转换,随后的后加速器将电子能量从10 MeV加速到50 MeV。电子源拟采用重复频率为650 MHz的热电子枪提供初始能量为100 keV,束长为 171 ps的电子束。束流动力学模拟了几种不同的设计方案以获得最优化的设计,模拟显示通过对腔体以及聚焦元件的仔细设计以及电子枪出射电子的参数选择, 电子束能量在达到50 MeV时束长可以被聚焦到 11.75 ps (对应于1.3 GHz 频率下5.5°) ,并且可以使电子束在超导低温柜中的尺寸保持在1.26 cm以下。     

“五面三方教学法”在园林规划设计课程中的应用

园林规划设计是高等院校园林专业的专业骨干课之一,园林专业的性质和园林职业对专业技术人员的要求决定了必须改变现有的单一教学模式。该文探索性的提出了＂五面三方教学法＂在园林规划设计课程中的应用情况。     

Physics design for the C-ADS main linac based on two different injector design schemes

The China ADS (C-ADS) project proposes to build a 1000 MW Accelerator Driven sub-critical System around 2032. The accelerator will work in CW mode with 10 mA in beam current and 1.5 GeV in final beam energy. The linac is composed of two major sections: the injector section and the main linac section. There are two different schemes for the injector section. The Injector-Ⅰ scheme is based on a 325 MHz RFQ and superconducting spoke cavities of the same RF frequency and the Injector-Ⅱ scheme is based on a 162.5 MHz RFQ and superconducting HWR cavities of the same frequency. The main linac design will be different for different injector choices. The two different designs for the main linac have been studied according to the beam characteristics from the different injector schemes.     

PVP辅助低氟溶液法制备YBa_2Cu_3O_(7-x)厚膜研究(英文)

传统的化学溶液法制备微米级YBa2Cu3O7-x(YBCO)涂层导体过程中,需要反复多次镀膜和热分解过程才能使膜厚达到1μm以上。本研究以独特的先进低氟溶液为YBCO前驱溶液,通过添加聚吡咯烷酮(PVP)作为增稠剂,提高了YBCO胶体的粘度,并提高了最终YBCO薄膜的厚度及致密性。单次镀膜获得的YBCO薄膜厚度达到了600nm。77K,0T条件下,临界电流密度Jc达到1MA/cm2以上。这种高分子改性的低氟YBCO前驱溶液沉积技术有望在未来涂层导体开发中发挥作用.     

Power coupler kick of the TRIUMF ICM capture cavities

The TRIUMF Injector CryoModule (ICM) adapted two superconducting single cavities as the capture section for the low injecting energy of 100 keV electrons. Coupler kick induced beam deflection and projected emittance growth are one of the prime concerns of the beam stability, especially at low energies. In low energy applications, the electron velocity changes rapidly inside the cavity, which makes the numerical analysis much more complicated. The commonly used theoretical formulas of the direct integral or the Panofsky-Wenzel theorem is not suitable for the kick calculation of β<1 electrons. Despite that, the above mentioned kick calculation method doesn't consider injecting electron energy, the beam offset due to the coupler kick may not be negligible because of the low injection energy even if the kick is optimized. Thus the beam dynamics code TRACK is used here for the simulation of the power coupler kick perturbation. The coupler kick can be compensated for by a judicious choice of the coupler position in successive cavities from upstream to downstream. The simulation shows that because of the adiabatic damping by the following superconducting 9-cell cavity, even for the worst orbit distortion case after two capture cavities, the kick is still acceptable at the exit of the ICM after reaching 10 MeV. This paper presents the analysis of the transverse kick and the projected emittance growth induced by the coupler for β<1 electrons. The simulated results of the TRIUMF ICM capture cavities are described and presented.     

考虑三级货损成本的冷链物流配送中心选址优化

为解决冷链物流配送中心的选址优化问题,依据易腐品完好率线性递减理论,提出了易腐品完好率与运输距离之间的分段递减函数关系,通过分析从供应点到配送中心运输过程,配送中心内部操作过程和从配送中心到需求点配送过程中所产生的三级货损实际情况,探究了本级货损对下级货损的叠加影响,以货物完好量作为客户的最终需求,构建了考虑三级货损成本的冷链物流配送中心选址优化模型,算例验证了所建模型的适用性和可行性.     

Physics design for the C-ADS main linac based on two dif f erent injector design schemes

The China ADS（C-ADS） project proposes to build a 1000 MW Accelerator Driven sub-critical System around 2032. The accelerator will work in CW mode with 10 mA in beam current and 1.5 GeV in final beam energy. The linac is composed of two major sections： the injector section and the main linac section. There are two diferent schemes for the injector section. The Injector-scheme is based on a 325 MHz RFQ and superconducting spoke cavities of the same RF frequency and the Injector-scheme is based on a 162.5 MHz RFQ and superconducting HWR cavities of the same frequency. The main linac design will be diferent for diferent injector choices. The two diferent designs for the main linac have been studied according to the beam characteristics from the diferent injector schemes.     

中国加速器驱动系统的中能传输线-2设计

中能传输线-2（MEBT2）在中国加速器驱动次临界系统（CADS）1.5 GeV加速器的前端具有非常重要的作用。介绍了MEBT2设计思路和束流动力学分析。MEBT2的设计和模拟均使用多粒子跟踪程序TraceWin完成。给出了可以完成束流传输和匹配的消色散MEBT2设计方案。模拟结果显示:在经过此方案所设计的MEBT2后,束流横向和纵向的发射度分别有5%和13%的增长,在此系统可接受的发射度增长范围内。     

传承民族民间音乐应从基础音乐教育做起

民族民间音乐对我国音乐的发展具有十分重要的作用。我国的民族民间音乐博大精深，尤为需要保护和推广，传承民族民间音乐应从基础音乐教育做起，可形式多样，可从学唱民歌做起。     

托运人联盟下的订单组合及车货调配问题研究

中小型企业的快速发展使得如何有效利用其物流资源、降低其物流成本成为一个亟需解决的问题。本文基于运输联盟的角度,建立了以最小化总成本为优化目标,综合考虑各运输需求时间窗、运输量等因素的车货调度模型。而后,提出了3种时间窗处理策略,设计了粒子群算法对上述模型进行求解,并通过算例对模型和算法的有效性进行了分析。算例结果表明,该模型一方面能够显著降低物流总成本,另一方面可有效节约使用车辆数。因此,本文研究对降低社会物流成本、整合社会物流资源具有一定的理论意义。