一种氧化海藻酸钠基温敏凝胶的制备与性能

合成出一种具有温敏特性的多官能团的大分子聚(N-异丙基丙烯酰胺-丙烯酸甲酯-丙烯酰肼)(PNMH),用它交联氧化的海藻酸钠(OSA),得到可生物降解的温敏凝胶PNMH-OSA.分别以凝胶的透光率随温度变化和凝胶在磷酸盐缓冲液(PBS)中的溶胀比随时间变化来考察凝胶的温敏性能和降解性能,并采用傅立叶变换红外光谱(FTIR)和激光共焦拉曼光谱(LCRS)对样品进行了表征.结果表明,PNMH-OSA凝胶是通过PNMH上的—NHNH2和OSA上的—CHO反应生成C N键而形成的化学交联凝胶;随着凝胶中PNMH量的增加,PNMH-OSA凝胶的温敏性增强,降解时间延长;温敏组分的含量对PNMH-OSA凝胶的溶胀和降解性能与温度的关系影响显著.     

氢的制备、储存、安全检测与生物燃料电池研究

目前，化石能源日益枯竭和二氧化碳排放导致的温室效应引起了世界各国的高度关注。约五分之一的二氧化碳是由使用化石燃料的交通工具所导致的。氢能是人类至今为止已知的、最为理想的清洁能源，使用零排放的氢燃料电池驱动交通工具是减少二氧化碳排放的有效手段之一。世界各国把氢能作为战略能源进行研究，我国既是能源短缺国，又是能源消耗最大的国家之一。《国家中长期科学和技术发展规划纲要》明确指出，能源是未来15年我国科技发展的重要领域，清洁能源低成本规模化开发利用则是重点领域和优先主题。 本文将将简要介绍课题组在铝基材料制氢技术、多孔金属有机框架化合物（MOFs）材料储氢技术、基于石英微天平的氢气安全检测技术和生物燃料电池的有关研究工作。     

H2D+与固体的相互作用及H2D+的结构测量

报道了分子离子H₂D⁺与超薄固体膜相互作用的实验研究.阐述了H₂D⁺对天体物理等领域的重要性,简述了近几年针对H₂D⁺的研究,分析了在实验室条件下H₂D⁺的形成机理,给出了其与固体膜相互作用产生库仑爆炸的能谱.进行了辅助实验,使D₂⁺与相同固体膜发生作用,并利用这个结果和其他分析与处理方法,将H₂D⁺的D⁺能谱中D₂⁺计数部分做了去除.实验再次证实了分子离子与固体相互作用时尾流效应的存在,采用三体尾流效应对比的方法最终确定了H₂D⁺结构形状和键长.对H₂D⁺库仑爆炸后的较重离子尾流谱形状的反常现象做了讨论和分析.     

Comments on Three-point explicit compact difference scheme with arbitrary order of accuracy and its application in CFD

The explicit compact difference scheme,proposed in Three-point explicit compact difference scheme with arbitrary order of accuracy and its application in CFD by Lin et al.,published in Applied Mathematics and Mechanics (English Edition),2007,28(7),943-953,has the same performance as the conventional finite difference schemes.It is just another expression of the conventional finite difference schemes. The proposed expression does not have the advantages of a compact difference scheme. Nonetheless,we can more easily obtain and implement compared with the conventional expression in which the coefficients can only be obtained by solving equations,especially for higher accurate schemes.     

重离子治癌装置4 MeV/u IH型漂移管直线注入器的动力学设计

基于KONUS束流动力学理论,完成了一台工作频率为162.5 MHz、占空比为1%的交叉指型漂移管直线注入器（IH-DTL）的动力学设计。该IH-DTL内置两套三组合四极透镜,共有41个加速单元,可为同步加速器提供流强400 eμA、能量4 MeV/u的C4+束流。在动力学设计过程中着重对每个加速间隙的同步能量偏差、注入相位和间隙电压等参数进行优化,使得该IH-DTL的横向归一化RMS接收度达到0.24 πmm·mrad,且横纵向归一化发射度增长小于10%,有利于提高同步环的注入效率。然后根据动力学设计的结构参数进行IH-DTL的高频仿真计算,将得到的三维电磁场分布导入PIC粒子跟踪程序中进行束流动力学模拟。动力学模拟结果显示,束流在IH-DTL出口的横向自然发射度小于13 πmm·mrad,达到了同步环的注入要求,而且在7%的垂直二极场分量下,束流中心的横向偏移在±0.5 mm以内,整体的束流传输效率高于99%。An interdigital H-mode drift tube linac (IH-DTL) with KONUS beam dynamic has been designed, which operation frequency was chosen 162.5 MHz. This IH-DTL consists of 41 accelerating cells and two quadrupole magnets triplets, can provide the C4+ with the current of 400 eμA and energy of 4 MeV/u for the synchrotron. In the beam dynamic design, the synchronous particle energy, inject RF phase and the acceleration voltage of each gap are optimized carefully to make the transverse normalized RMS acceptance of the IH-DTL to be 0.24 πmm·mrad and the beam emittance growth small than 10%. Then the RF structure was designed and the 3D electromagnetic field was imported into the PIC particle tracking code for the beam dynamic simulation. The transverse beam emittance at the exit of the IH-DTL is small than 13πmm·mrad which meets the injection requirement of the synchrotron. What is more, under the 7% vertical dipole fields component, the offset between the beam center and the drift tube's axis is ±0.5 mm at most. The transmission efficiency of the IH-DTL is higher than 99% for the whole beam in the acceptance.     

Investigations of the dielectronic recombination of phosphorus-like tin at CSRm

The electron–ion recombination for phosphorus-like~(112) Sn~(35+)has been measured at the main cooler storage ring of the Heavy Ion Research Facility in Lanzhou, China, employing an electron–ion merged-beams technique. The absolute total recombination rate coefficients for electron–ion collision energies from 0 e V–14 e V are presented. Theoretical calculations of recombination rate coefficients were performed using the Flexible Atomic Code to compare with the experimental results. The contributions of dielectronic recombination and trielectronic recombination on the experimental rate coefficients have been identified with the help of the theoretical calculation. The present results show that the trielectronic recombination has a substantial contribution to the measured electron–ion recombination spectrum of~(112)Sn~(35+). Although a reasonable agreement is found between the experimental and theoretical results the precise calculation of the electron–ion recombination rate coefficients for M-shell ions is still challengeable for the current theory.     

多目标粒子群优化算法在交变相位聚焦直线加速器模拟中的应用

现代智能优化算法粒子群算法\,(Particle Swarm Optimization)\,在加速器设计优化上的应用逐渐增多。交变相位聚焦直线加速器\,(Alternative Phase Focused Drift Tube Linac)\,具有节省空间和造价的优点。将交变相位聚焦直线加速器的初步设计方案作为种子,植入粒子群算法中;以加速器的传输效率和束流能量作为目标,得到该方案的Pareto最优解集;在粒子进化过程中,以前沿解集作为粒子的运动方向,以前沿解集的束流径迹作为粒子的参数来源。最终得到了满足能量增益的高传输效率、大接受度的优化方案。The Particle Swarm Optimization(PSO), one of the modern intelligent optimization algorithms,is increasingly employed in the design and optimization of accelerators. Alternative Phase Focused Drift Tube Linac(APF DTL) has an advantage in cost-effecient fabrication and reduced construction space. The preliminary design of APF DTL is involved in the optimization as the anchor; by taking the acceleration efficiency and the beam energy as two fitness functions, the Pareto optimal set is obtained; the evolutionary direction is determined by the Pareto optimal set and the particles’ parameters in the optimization are derived from the simulations of the randomly selected Pareto optimal solutions. A final optimized design with extracted energy of 5.35 MeV/uand acceleration efficiency greater than 83% is acquired.     

实验环Betatron振荡随机冷却的模拟

随机冷却是一种基于带宽反馈系统对束流振荡进行衰减的冷却方法,更适合冷却较大发射度和动量分散的次级粒子束,与电子冷却互补,可以得到更高品质的束流。兰州重离子研究装置(HIRFL) 目前处于冷却存储环的实验环随机冷却系统的设计和建造阶段。通过对横向Betatron 振荡的模拟,得到了提高系统带宽、增加探测器(Pick-up) 和冲击器(Kicker) 的个数、降低系统噪声温度等对缩短冷却时间和减小冷却平衡值的重要作用。同时,分析了较大的动量分散或较大的放大器增益对Betatron 振荡冷却过程产生的加热现象。Stochastic cooling, based on a feedback system, aims at damping the oscillation of particles. Stochastic cooling is more suitable to cool secondary beam with larger size and momentum spread, and it is therefore can be complemented with electron cooling, in order to obtain beam of higher quality. Stochastic cooling system is being designed and constructed on the experimental Cooling Storage Ring of HIRFL. By simulation of Betatron stochastic cooling, it is obtained that the importance for shortening the cooling time and reducing cooling equilibrium by improving bandwidth, increasing the numbers of pickup and kicker, and decreasing the system noises. Meanwhile, the heating during the cooling process caused by larger momentum spread or larger gain of amplifier is analyzed.     

IH型漂移管直线加速器的束流动力学研究（英文）

为了提高兰州重离子加速器冷却储存环（HIRFL-CSR）的运行效率、改善加速器输出束流品质,并实现几个加速装置分时供束,提高整个重离子加速装置的利用率,特为（HIRFL-CSR）增建一台新的注入器--CSRLINAC。在108.48 MHz的RFQ之后的CSR-LINAC主加速段,主要由一台108.48 MHz和两台216.96 MHz的IH型漂移管直线加速器组成,用于加速荷质比为1/8.5~1/3之间的重离子,其最大的束流流强为3 mA,并将粒子从0.3 MeV/u加速到3.71 MeV/u。运用KONUS动力学原理,在满足设计指标的情况下,首先利用TraceWin程序进行中能束线MEBT设计,后针对高频腔体设计和束流匹配的基本参数的系列讨论,特别是对CSR-LINAC的中能束流匹配线、参数选择和IH型KONUS结构的漂移管直线加速器进行设计模拟优化。最终得出,在保证腔体设计指标和95.3%的传输效率的情况下,该紧凑型直线加速结构经过三个腔体的加速后,束流的纵向归一化均方根发射度增长仅有25%;同时发现,当流强达到3 mA时,存在空间电荷效应,导致其纵向相宽增长约25%,最大横向包络也存在16.5%的涨落。In order to improve the operation efficiency of the Cooling Storage Ring of Heavy Ion Research Facility in Lanzhou (HIRFL-CSR), a heavy ion linac (linear accelerator) was proposed and designed as a new injector for HIRFL-CSR. Following the 108.48 MHz Radio-Frequency Quadrupole (RFQ), three tanks in total with Interdigital H-mode drift tube linac (IH-DTL) structure are installed to boost the beam energy from 0.3 to 3.71 MeV/u, and the beam current of ions with charge-to-mass ratio from 1/8.5 to 1/3 can reach to 3 mA. The first tank operatesat the same frequency as the RFQ, and the rest two operate at 216.96 MHz. The “Combined Zero-Degree Synchronous Particle Structure” (KONUS) beam dynamics was used in the beam dynamics design. The overview of the physics design on the main accelerating components, including RF design and beam dynamics design are introduced in this paper. The optimized structure design, fabrication status and simulation results are presented in this contribution. It shows that under the condition of assurance of 95.3% transmission efficiency, the normalized rms emittance is about 25%. When the beam current is up to 3 mA, owing to the space charge effect, the increase of longitudinal phase spread and transverse envelope are about 25% and 16.3%, respectively.     

氚增殖剂球床内氦气流动特性的数值模拟

通过计算流体力学(CFD)数值模拟方法,对氚增殖剂球床内部的氦气流动特性进行了初步研究。分析了球床流通长度和流通截面对提氚气体压降的影响,获得了不同入口流速下规则堆积球床和随机堆积球床的压降和阻力系数。