螺线管磁场缺陷对电子束横向温度的影响

分析了直螺线管磁场缺陷的来源,考虑了电子束的空间电荷作用,采用数值方法模拟计算了磁场缺陷对电子束横向温度的影响 ,获得了电子冷却装置中直螺线管磁场的均匀性要求.结果表明,当相对磁场缺陷小于1× 1 0-3时 ,影响可以被忽略.In order to obtain the tolerance requirement for the magnetic field homogeneity of the solenoids in electron cooling device, the source of the magnetic imperfection and its influence on the transverse temperature of electron beam were investigated by means of numerical simulation, and taking the space charge effect of electron beam into account. The calculated result shows that the influence of the imperfection of magnetic field will be negligible when the relative magnetic field...     

SFC的新的轴向注入束流线

为了满足HIRFL-CSR对注入器SFC的束流强度和品种的越来越高的要求, 兰州重离子加速器国家实验室在研制超导ECR离子源的同时, 设计了一个新的SFC的轴向注入束流线. 这个系统可以分别使用现有的常规ECR离子源和新建造的超导ECR离子源, 期望把从C到U的各种离子的能量和束流强度提高到一个新的水平. 这个系统由二极磁铁, 四极透镜, GLASSER透镜, 螺线管, 螺旋形静电偏转器和两台丝网型线性聚束器组成. 在总结现有系统运行经验的基础上,无论在横向还是纵向, 其性能结构都做了必要的改进. 文章给出了新系统的设计思想, 系统的布局结构和束流光学计算结果, 并对进一步提高聚束效率和聚束器的改进设计作了简要的描述. 目前, 系统正在安装中.     

A Fractal Model for the Effective Thermal Conductivity of Granular Flow with Non—uniform Particles

The equipartition of energy applied in binary mixture of granular flow is extended to granular flow with non-uniform particles.Based on the fractal characteristic of granular flow with non-uniform particles as well as energy equipartition,a fractal velocity distribution function and a fractal model of effective thermal conductivity are derived.Thermal conduction resulted from motions of particles in the granular flow,as well as the effect of fractal dimension on effective thermal conductivity,is discussed.     

High-capacity porous carbons prepared by KOH activation of activated carbon for supercapacitors

High-performance supercapacitor electrode materials are prepared from the commercially available activated carbon （AC） through a facile and low-cost chemical activation method. The obtained results show that AC activated by KOH with an alkali/carbon ratio of 6/1 （ACK6） possesses a specific surface area of 3405 m^2/g, a large pore volume of 2.01 cm^3/g, and exhibits the highest initial specific capacitance of 335 F/g at the current density of 0.5 A/g in 6 mol/L KOH, and 85% coloumbic efficiency for 5000 cycles at 20 mV/s.     

简易模板法制备有序介孔碳

通过一种简易的模板法制备了有序介孔碳,即硅/P123三嵌段共聚物复合物经硫酸处理后,再加入蔗糖碳源经碳化和除硅处理合成出有序介孔碳。该方法与传统硬模板相比,其合成工序简单,成本更低;与其他简化合成方法相比,避免了由碳源不足而造成的介孔碳有序性低的缺点。通过小角XRD、N2吸脱附和HRTEM对样品及其中间过程进行了表征。结果表明,自晶化过程后,样品在合成的各个时期均保持着有序的介孔结构,当蔗糖添加量为1.5g时合成出的介孔碳材料有序性最高,比表面积和孔容也最高,分别为1261m2·g-1,1.03cm3·g-1。     

RF knock-out extraction in HITFiL

A compact facility for cancer therapy has been designed and is presently under construction. A slow beam extraction system using the RF-Knock Out method and 3rd-order resonance is adopted in the synchrotron of this facility. Eight sextupoles are used, four of them are for correcting the chromaticity and the rest for driving the 3rd-order resonance. In order to save the aperture of vacuum chamber, a 3-magnet bump is adopted during the extraction process. The extraction phase space map and the last 3 turns' particle trajectory before extraction are given. The matching betatron functions with HEBT (high energy beam transport) are also presented.     

新型阴极材料Ba0.5Sr0.5CO0.8Fe0.2O3-σ制备与性能研究

0引言中温固体氧化物燃料电池(Interm ediate Tem-perature Solid Oxide FuelCell,ITSOFC)是目前SOFC的主要发展方向[1～3]。温度的降低可以减少成本,增加材料的选择和电池的使用寿命等一系列问题,但同时温度的降低对电池的阴极材料的性能提出了更高的要求,如在400~700℃下对氧     

Design of slow extraction system for therapy synchrotron

Based on the optimized design of the lattice for therapy synchrotron and considering the requirement of radiation therapy, the third order resonant extraction is adopted. Using the momentum-amplitude selection method, the extraction system is designed and optimized. An extraction efficiency of more than 97% and a momentum spread less than 0.11% are obtained.     

再结晶和外力场下第二相析出的相场法模拟

在讨论相场法模拟基本方程的基础上,提出了晶界范围宽度的新概念,解释了相场模拟模型中有序化参数梯度范围的物理意义,论证了晶界范围不是晶界原子错排的宽度,而是界面能和界面元素偏析存在范围的观点.建立了一个模拟合金再结晶的相场模型,提出了一系列法则来获得模型中各参数的物理真实值,以AZ31镁合金为例,实现了再结晶过程晶粒长大的真实时间和空间的模拟,通过与试验数据的对比证明了模型的有效性.此外,还列举了相场法模拟Ti-25Al-10Nb合金中O相在外力场作用下析出过程的一系列有趣的新结果,讨论了外力场对第二相析出的重要影响和机理以及模拟结果对合金开发潜在的重要指导意义. 关键词： 相场法 再结晶 析出 外力场