镧系一氧化物LnO(Ln=La, Ce, Pr, Nd)的电子亲和能

应用光电子成像技术研究了LaO_{-、CeO-、PrO-和NdO-.从1064 nm的振动分辨的光电子能谱得到LaO、CeO、PrO和NdO的电子亲和能分别为0.99(1)、1.00(1)、1.00(1) 和1.01(1) eV. 密度泛函计算和NBO分析显示镧系原子的4f电子趋于定域在4f轨道上,不受分子电荷状态的影响. 脱附的光电子主要来自镧系金属的6s轨道. 配位场理论的纯离子模型假设仍然是分析镧系一氧化物中性或负离}     

近红外光谱技术在激光热疗监测中的应用研究

针对激光热疗中生物病变组织光学参数随温度变化的特点,将近红外光谱技术应用于激光诱导肿瘤间质热疗疗效监测,在线检测激光作用后生物病变组织的温度与光学参数的变化趋势,以此来对疗效进行评估。基于监测原理分析,设计实验系统,以肝癌小鼠皮下移植瘤为实验对象,研究不同激光功率和作用时间下,生物病变组织约化散射系数和温度的变化,并利用核磁共振成像技术对移植瘤术前、术后的影像进行对比。实验结果表明:病变组织的约化散射系数在激光热疗过程中呈上升趋势,起始阶段上升较快,达到一定数值后趋于稳定,整体变化趋势与温度变化趋势比较吻合,核磁影像对比也证实了治疗效果。因此,通过近红外光谱技术监测激光热疗中病变组织约化散射系数的变化可有助于指导临床激光热疗。     

高效液相色谱-串联质谱法同时测定红小豆中残留的6种咪唑啉酮类除草剂

建立了同时测定红小豆中6种咪唑啉酮类除草剂残留的高效液相色谱-串联质谱分析方法。样品经0.1 mol/L NH4HCO3(pH 5)-甲醇(体积比为70∶30)溶液提取,二氯甲烷液-液萃取和凝胶渗透色谱净化后,采用Inertsil ODS-3色谱柱(2.1 mm×150 mm, 5 μm)分离,以甲醇-0.1%乙酸为流动相梯度洗脱,离子阱质谱在选择离子模式下测定。咪唑啉酮类除草剂在10～200 μg/L(灭草喹在5～100 μg/L)内线性关系良好,相关系数为0.9987～0.9997;方法的检出限为0.2～0.5 μg/kg;在红小豆中3个加标水平的平均加标回收率为81.6%～99.4%,相对标准偏差为3.1%～7.8%。该方法简便、灵敏度高、精密度好,适用于红小豆中多种咪唑啉酮类除草剂残留的测定。     

硅-芳键的断裂反应

利用等摩尔竞争法我们研究了五种芳基三甲基硅烷与氯化氢的非均相断裂反应。用气体色谱法对各竞争反应产物进行定量分析,求出各断裂产物的相对性产率,结果表明其活性顺序是与相应的均相断裂反应相一致的。     

LDA泵浦Nd:YVO4/GaAs饱和吸收调Q激光器

用脉冲激光二极管阵列（LDA）作为泵浦源,微柱透镜阵列和透镜导管作为耦合系统,以As^＋注入GaAs可饱和吸收片作为被动调Q元件,实现了Nd：YVO4激光器每泵浦脉冲单涧Q脉冲输出。获得调Q脉冲宽度为7ns,脉冲峰值功率为3．4kW,激光器调Q效率为26．8％。对泵浦脉冲峰值、脉冲宽度和重复频率对调Q脉冲特性的影响进行了实验研究,并对实验结果进行了讨论。     

Correlation effects on the fine-structure splitting within the 3d~9 ground configuration in highly-charged Co-like ions

A comprehensive theoretical study of correlation effects on the fine-structure splitting within the ground configuration3d~9 of the Co-like Hf~(45+),Ta~(46+),W~(47+),and Au~(52+) ions is performed by employing the multi-configuration Dirac-HartreeFock method in the active space approximation.It shows that the core-valence correlation with the inner-core 2p electron is more significant than with the outer 3p and 3s electrons,and the correlation with the 2s electron is also noticeable.The core-core correlation seems to be small and can be ignored.The calculated ~2D_(3/2,5/2) splitting energies agree with the recent electron-beam ion-trap measurements[Phys.Rev.A 83 032517(2011),Eur.Phys.J.D 66 286(2012)]to within the experimental uncertainties.     

高分子材料专业《计算机在材料研究中的应用》课程教学改革与实践

为了适应行业发展的新趋势,众多高分子材料专业开设了《计算机在材料研究中的应用》这门特色专业课,其对提升学生利用计算机解决高分子材料中实际问题的能力起着重要的支撑作用.本文结合高分子材料的专业特点和多年来的教学改革实践,从课程体系的建设、教学内容的优化、多种教学手段的应用以及教学效果的评价等几个方面介绍了该课程的教学改革...     

基于反对称双正交小波分解系数的模极大值的信号快速重构

因为反对称双正交小波具有近似微分算子性质,该文用它对信号作无下采样(Un-decimated)的小波变换,以此获得信号在各尺度下与信号的边缘点相对应的局部模极大值。在只保留这些局部模极大值(即边缘)点信息的条件下,利用高斯函数直接拟合各级小波系数,然后再作小波逆变换就可恢复原信号。实验表明,与现有的采用二进小波变换的方法比较,该方法更加简便快捷。     

Could two-dimensional perovskites fundamentally solve the instability of perovskite photovoltaics

The high efficiency and low production cost enable the halide perovskite solar cells as a promising technology for the next generation photovoltaics. Nevertheless, the relatively poor stability of the organic-inorganic halide perovskites hinders their commercial applications. In the past few years, two-dimensional (2D) perovskite has emerged as a more stable alternative to the three-dimensional (3D) counterparts and attracted intense research interests. Although many attempts and advances have been made, it is still ambiguous that whether the 2D perovskites could bring closure to the stability issue. To answer this essential question, a systematic study of the nature of 2D halide perovskites is necessary. Here, we focus on the stability investigations of 2D perovskites from different perspectives, especially light, heat, ion migration and strain. Several remaining challenges and opening problems are also discussed. With further material and device engineering, we believe that the 2D perovskites would promote perovskite solar cells to a promising future.