HL-2A装置ECRH回旋管磁场分布测量

HL-2A装置的电子回旋系统使用了俄罗斯进口的新型回旋管，在俄罗斯专家的协助下，去年将其安装完毕，并且投入了实验运行，取得了丰富的实验数据和良好的实验参数。     

具有变系数的二阶中立型差分方程的有界振动

研究一类具有连续变量的二阶中立型时滞差分方程，给出了该类方程一切有界解振动的几个充分条件.     

美托洛尔的合成工艺研究

本文以价廉易得的对羟基苯乙酸甲酯为原料,通过酚羟基苄基保护、酯键还原、甲基化、脱苄基得到关键中间体对甲氧基乙基苯酚5,再与环氧氯丙烷发生烷基化反应,最后与异丙胺反应开环得到美托洛尔。对于合成路线中的关键步骤进行了工艺优化,分步平均收率高达89.3%,6步反应总收率也高达48%。中间体及目标化合物均通过~1HNMR和~(13)CNMR确证了结构。该方法具有原料易得、合成步骤短、收率高以及易于工业化制备等优点。     

国际课程IB与我国高中化学教材的比较——以原子结构和氧化还原为例

以认知心理学的观点,对IB与人民教育出版社出版的高中化学教材原子结构概念图和氧化还原本质相关内容进行比较,研究发现：IB教材知识层次性更强,更有利于学生的长时记忆;更注重对知识的多角度阐释和精细加工;运用整体分解对知识精加工。对我国高中化学教材编写的启示是：丰富知识层次和概念关系,便于学生自主构建知识网络,促进学生良好认知结构的形成和发展;对知识进行多角度阐释和精细加工,加深学生对知识的深入理解;运用多种策略促进学生程序性知识的习得。     

超高效液相色谱-质谱法快速分析番茄及其制品中矮壮素和缩节胺残留量

采用超高效液相色谱-串联质谱(UPLC/MS-MS)研究了番茄及其制品中矮壮素和缩节胺残留量的测定方法。样品用水提取,无需经过任何净化过程;在粒径为1.7μm的超高压亲水作用色谱柱上以V(乙腈)∶V(含0.1%甲酸的10 mmol/L乙酸铵溶液)=6∶4为流动相,等度洗脱分离;电喷雾正离子检测(ESI ),多反应监测模式(MRM)对定性和定量离子进行MS测定。结果表明:矮壮素和缩节胺的添加水平在5、10和20μg/kg时,回收率范围分别为78.5%~90.1%和80.0%~104.0%;相对标准偏差在9.5%~11.3%和10.5%~13.2%之间;方法检出限均为0.8μg/kg。本方法仅需约2 m in的检测时间,且灵敏、准确,完全满足番茄及其制品中矮壮素和缩节胺残留量的快速、高灵敏度的分析要求。     

Locating the QCD critical end point through peaked baryon number susceptibilities along the freeze-out line

We investigate the baryon number susceptibilities up to fourth order along different freeze-out lines in a holographic QCD model with a critical end point(CEP), and we propose that the peaked baryon number susceptibilities along the freeze-out line can be used as a clean signature to locate the CEP in the QCD phase diagram.On the temperature and baryon chemical potential plane, the cumulant ratio of the baryon number susceptibilities(up to fourth order) forms a ridge along the phase boundary, and develops a sword-shaped "mountain" standing upright around the CEP in a narrow and oblate region. The measurement of baryon number susceptibilities from heavy-ion collision experiments is along the freeze-out line. If the freeze-out line crosses the foot of the CEP mountain, then one can observe the peaked baryon number susceptibilities along the freeze-out line, and the kurtosis of the baryon number distributions has the highest magnitude. The data from the first phase of the beam energy scan program at the Relativistic Heavy Ion Collider indicates that there should be a peak of the kurtosis of the baryon number distribution at a collision energy of around 5 Ge V, which suggests that the freeze-out line crosses the foot of the CEP mountain and the summit of the CEP should be located nearby, around a collision energy of 3–7 GeV.     

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68GHz ECRH系统由6套0.5MW/1s(1.5s)子系统构成,140GHz ECRH系统由2套1MW/3s子系统构成。每套子系统由独立的传输线与天线相连,再通过天线注入等离子体。68GHz ECRH子系统为非真空传输线,以内径为80mm的过模波纹圆波导为主要传输部件,包括隔直器、弹性波导、换向波导和一个槽纹深度为l/2的极化器;140GHz ECRH子系统为真空传输线,以内径为63.5mm的过模波纹圆波导为主要传输部件,包括隔直器、弹性波导、换向波导、转换开关、抽气波导和槽纹深度分别为l/4与l/8的极化器。经过不断地完善,68GHz ECRH系统传输线已成功运用于ECRH运行中,整条传输线的输送效率可以达到90%左右。对于140GHz ECRH系统,已完成了传输部件的整体设计,目前正在进行相关部件加工测试。     

Scalar mesons and glueballs in Dp-Dq hard-wall models

We investigate the light scalar mesons and glueballs in the Dp-Dq hard-wall models, including D3-Dq, D4-Dq, and D6-Dq systems. It is found that only in the D4-D6 and D4-Ds hard-wall models are the predicted masses of the clq scalar meson fo scalar glueball consistent with their experimental or lattice results. This indicates that D4-D6 and D4-Ds hard-wall models are the favorite candidates of the realistic holographic QCD model.     

Scalar mesons and glueballs in D_p-D_q hard-wall models

We investigate the light scalar mesons and glueballs in the Dp-Dq hard-wall models, including D3-Dq, D4-Dq, and D6-Dq systems. It is found that only in the D4-D6 and D4-D8 hard-wall models are the predicted masses of the qˉq scalar meson f0 scalar glueball consistent with their experimental or lattice results. This indicates that D4-D6 and D4-D8 hard-wall models are the favorite candidates of the realistic holographic QCD model.     

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HL-2A装置3MW ECRH系统采用双高压电源形式的电子回旋管,阴极高压电源为回旋管提供加速束电流,阳极高压电源对通过转换区后的束电流施加减速作用,利于回旋管收集极吸收。根据回旋管运行特点和各回旋管不同的工作特性,合理优化回旋管阴极、阳极高压电源工作电压和其他参数。通过远程监控系统,使同时工作的回旋管处于较好的工作状态,充分提高 HL-2A 装置 ECRH 系统多管运行的微波输出功率。实验中,6支回旋管同时运行时,微波最高输出功率2.5MW,达到设计额定值83%,使HL-2A装置中等离子体得到了有效的加热。