用长气体靶研究22Na+α共振散射

在日本东京大学CRIB 次级束装置上,用长气体靶开展了22Na+ α共振散射的厚靶实验研究。针对长气体靶实验中的两体运动学重构问题,提出了一套包括构建空间复杂几何关系、计算能量损失以及反应运动学的逐事件分析方法;对22Na+α共振散射的实验数据进行了重构分析,得到了E_c.m. = 4.2 ~ 5.4 MeV 区间22Na( α,α ) 的激发函数,从实验的激发函数中观测到了复合核26Al 5 个较为明显的共振峰。鉴于26Al 共振态的衰变模式比较复杂,本工作发现的26Al新共振态的能级性质有待进一步的理论分析。The 22Na+α resonant scattering is studied via a conventional thick target inverse kinematic method with an extended gas target. A data analysis method is proposed for the two-body reaction kinematic reconstruction, in which the spatial geometry, the reaction kinematics and the energy losses are considered. The experimental data of 22Na+ αresonant scattering have been thus reconstructed, and the excitation function is obtained in the energy interval of Ec.m. =4.2~5.4 MeV. Five resonant states in 26Al are observed in the experimental excitation function. Since several decay modes coexist for the observed 26Al resonant states, multi-channel theoretical analysis is thus needed to reveal their structure and decay features.     

超级电容的发展与应用

介绍了超级电容器的基本原理和分类;列举了超级电容器的一些基本参数(寿命、电压、充放电等)和优点(功率密度高、充电速度快、寿命长等);给出了超级电容器的发展和应用。     

超高效液相色谱-串联质谱法同时测定牛肉中18种食源性兴奋剂类药物残留

建立了超高效液相色谱-串联质谱（UHPLC-MS/MS）检测牛肉中18种食源性兴奋剂类药物残留的方法。牛肉组织经酸化乙腈提取,Captiva小柱脱脂净化后,用无水硫酸镁干燥,上清液氮吹浓缩,残渣用甲醇-水（7：3,v/v）溶解。采用Agilent Zorbax Phenyl-Hexyl色谱柱分离,以5 mmol/L醋酸铵水溶液（含0.01%（v/v）醋酸）和甲醇-乙腈（7：3,v/v）作为流动相进行梯度洗脱,在电喷雾正负离子切换模式下以多反应监测（MRM）方式检测,用基质匹配标准曲线外标法定量。结果表明,18种食源性兴奋剂类药物在0.10~50 μg/L范围内线性关系良好,相关系数（R²）≥ 0.9950;在0.4、1.0和2.0 μg/kg添加水平下的回收率为57.3%~117.5%,相对标准偏差为3.1~15.6%（n=5）;方法的检出限和定量限分别为0.0006~0.0900 μg/kg和0.0020~0.3000 μg/kg。该法可以实现对牛肉样本中18种兴奋剂类药物残留的定性定量分析,具有简单、快速、准确性高的特点。     

Simulating resonance-mediated two-photon absorption enhancement in rare-earth ions by a rectangle phase modulation

Improving the up-conversion luminescence efficiency of rare-earth ions via the multi-photon absorption process is crucial in several related application areas. In this work, we theoretically propose a feasible scheme to enhance the resonance-mediated two-photon absorption in Er~(3+) ions by shaping the femtosecond laser field with a rectangle phase modulation. Our theoretical results show that the resonance-mediated two-photon absorption can be decomposed into the on-resonant and near-resonant parts, and the on-resonant part mainly comes from the contribution of laser central frequency components, while the near-resonant part mainly results from the excitation of low and high laser frequency components.So, the rectangle phase modulation can induce a constructive interference between the two parts by properly designing the modulation depth and width, and finally realizes the resonance-mediated two-photon absorption enhancement. Moreover, our results also show that the enhancement efficiency of resonance-mediated two-photon absorption depends on the laser pulse width(or laser spectral bandwidth), final state transition frequency, and intermediate and final state absorption bandwidths. The enhancement efficiency modulation can be attributed to the relative weight manipulation of on-resonant and near-resonant two-photon absorption in the whole excitation process. This study presents a clear physical insight for the quantum control of resonance-mediated two-photon absorption in the rare-earth ions, and there will be an important significance for improving the up-conversion luminescence efficiency of rare-earthions.     

锰掺杂的钙钛矿型钛铌酸盐基复合阴极高温电解水蒸气

通过在氧化还原稳定的钙钛矿材料钛铌酸盐的B位晶格中掺杂具有氧化还原活性的锰元素提高固体氧化物电解池复合电极电催化性能．研究发现,锰元素成功取代钛铌酸盐B位的Ti／Nb．掺杂后的样品的离子电导率在800℃下的氧化气氛和还原气氛下的离子电导率分别提高了约1和0．5个数量级．基于掺杂后的钛铌酸盐基复合阴极,氧离子传导型固体氧化物电解池电解水蒸汽的电流效率在有和无还原气体保护下分别提高了25％和30％．     

β-环糊精衍生物毛细管气相色谱固定相的研究

将全甲基-β-环糊精、全戊基-β-环糊精及二者的混合液分别静态涂渍在氯化钠粗糙化的弹性石英毛细管内壁.为提高固定相的色谱性能,将环糊精衍生物与OV-1701按1∶4的质量比相混合,制备手性柱.对毛细管的特性、固定相的极性进行了测试,并对手性化合物(±)茚满醇、DL-丙氨酸、DL-缬氨酸、(±)乙酸二氢香芹酮等难分离物质对进行了拆分.结果表明,三种手性固定相均属于中等极性,具有较好的分离性能和成膜能力.分离效果表明,混合固定相对手性化合物及难分离物质对的分离存在协同效应.     

HL-2A tokamak disruption forecasting based on an artificial neural network

Artificial neural networks are trained to forecast the plasma disruption in HL-2A tokamak. Optimized network architecture is obtained. Saliency analysis is made to assess the relative importance of different diagnostic signals as network input. The trained networks can successfully detect the disruptive pulses of HL-2A tokamak. The results obtained show the possibility of developing a neural network predictor that intervenes well in advance for avoiding plasma disruption or mitigating its effects.     

以“安培环路定理”为例谈大学物理“SEFDS”教学模式

“SEFDS”教学模式是聚焦“新工科”人才培养需求，以学生为中心，注重学生知识的参与度、知识体系的生成过程与产出，注重对学生的自学能力、创新能力、应用能力的培养与锻炼。文章以“安培环路定理”为例，探讨该教学模式在教学实践中的应用.