微波消解-氢化物发生原子荧光光谱法同时测定化肥中砷、汞含量

采用微波消解样品前处理手段以及双道原子荧光光度计,建立了微波消解一氢化物发生原子荧光光谱法同时测定化肥中砷、汞含量的方法。通过试验确定了样品前处理方法,对负高压、灯电流,载气、屏蔽气、原子化器高度、酸度等测试条件进行了优化。在优化的工作条件下,砷、汞含量分别在0-50ng／mL和0—1．0ng／mL范围内与荧光强度呈良好的线性关系,线性相关系数分别为0．9996,0．9996,检出限分别为0．085,0．008ng／mL,回收率分别为88．8％～107．4％,90．0％～120％,测定结果的相对标准偏差均小于7％（n=6）。     

Shape-persistent arylenevinylene macrocycles (AVMs) prepared via acyclic diene metathesis macrocyclization (ADMAC)

Shape-persistent arylenevinylene macrocycles (AVMs) were successfully prepared in one step from readily available aromatic diene monomers through olefin metathesis in good yields. (1)H NMR, UV-Vis absorption and fluorescence studies revealed the aggregation behavior of the obtained macrocycles. SEM characterization showed AVM nanofibril formation.     

Supplement on applicability of the Kissinger equation in thermal analysis

The relative errors (e%) in the determination of the activation energy from the slope of the Kissinger straight line ln(β/βT _p²) vs. 1/T _p (β is the heating rate) are in-depth discussion. Our work shows that the relative errors is a function containing the factors of x _p and Δx _p, not only x _p (x _p = E/RT _p, E is the activation energy, T _p is the temperature corresponding to maximum process rate, R is the gas constant). The relative error between E _k and E _p will be smaller with the increase of the value of x and/or with the decrease of the value of Δx. For a set of different heating rates in thermal analysis experiments, the low and close heating rates are proposed from the kinetic theory.     

Synthesis and crystal structure of a novel ternary oxoborate, PbBiBO4

A novel ternary borate oxide, lead bismuth boron tetraoxide, PbBiBO₄, has been prepared by solid-state reaction at temperature below 800 °C. The single-crystal X-ray structural analysis showed that PbBiBO₄ crystallizes in the monoclinic space group P2₁/n with , , , β=91.48(1), Z=4. It represents a new structure type in which distorted BiO₆⁹⁻ octahedra are connected to each other in corner- and edge-sharing manner to form two-dimensional layers that are bridged by B atoms of BO₃ triangles giving rise to a three-dimensional framework, with channels parallel to the [0 1 0] direction accommodating the pyramidally coordinated Pb²⁺ cations.     

多算法融合的眼底图像渗出液分割

利用眼底图像中渗出液的亮度与边缘特征,文中采用一种多算法融合的渗出液自动检测分割方法来解决目前传统算法灵敏度低以及检测中存在视盘和其它微血管瘤等暗病灶的干扰等问题。为了提高分割效率和准确率,文中对原始图像进行顶帽底帽变换来增强图像对比度,采用GA与KSW熵法相结合的双阈值分割法对眼底图像进行渗出液分割。实验在Kaggle数据库上进行测试,结果显示该算法在像素层统计的SE和阳性预测值PPV分别为83.6%和93.2%,在图像层统计的SE、SP与AC分别为95.2%、86.2%和90.8%。在另一个独立的DIARETDB1数据库上进行测试,获得的结果分别为82.4%、93.3%、93.6%、96.2%和89.9%。与其它算法对比,文中方法可以很好地区分开渗出液与暗病灶,且检测时间短,具有准确性和高效性。     

随机保费下扰动风险模型总索赔盈余的大偏差

考虑随机保费下带干扰的风险模型,其中保费额和索赔额各自形成了END的随机变量序列,保费次数是由一个拟更新过程描绘,干扰项是由一个布朗运动过程来刻画.在索赔额分布属于一致变化类的条件下,给出了总索赔盈余过程的精致大偏差.     

宽调谐固体激光器的BF设计

按照掺钛宝石激光器宽调谐的特性，提出了一种关于双折射滤光片的新设计方法，并得出了ＢＦ中光轴倾角的优化公式。据此设计的双折射滤光片已经用于实验，完全符合掺钛宝石激光器的调谐要求。     

纵向泵浦钛宝石激光器中泵浦源模式的影响

从效率和模式两个方面讨论了连续纵向泵浦钛宝石激光器中泵浦光束的横模特性对钛宝石激光器的影响，并与实验结果进行了比较。     

光声检测叠氮化铅分解的化学反应过程

用YAG脉冲激光引发叠氮化铅的分解反应,并且测试分解过程的声效应,实验结果表明叠氮化铅的分解反应由三个阶段完成。     

流动注射分析-酶电极法测定人体血清中总胆固醇的研究

本文报道了用胆固醇氧化酶和胆固醇酯酶制备的酶膜,与氧电极偶合的电极法,结合流动注射分析法,直接测定人体血清总胆固醇,方法准确、快速,线性范围为6.67×10~(-4)mg/ml～1.20×10~(-2)mg/ml,工作曲线的线性相关系数为0.9993,测定的相对标准偏差为1.63%。