Preparation, structure, and properties of polyurethane foams modified by nanoscale titanium dioxide with three different dimensions

TiO2-based nanosheets (TiNSs), TiO2-based nanotubes (TiNTs) were prepared by hydrothermal processing, and polyurethane foams with TiO2 nanopowders (P25), TiNSs and TiNTs were synthesized by free-rising foaming method. The Fourier-transform infrared (FT-IR) spectra show that the addition of titanium dioxide does not affect the chemical structure of polyurethane foam. However, microscope observations show that PU/TiNSs composite foams have more uniform cells and the average aperture smaller than that of pure poly-urethane foams. According to the results of thermal analysis, the PU/TiNSs composite foams have better thermal stability, the temperature of decompostion occurring with a maximum weight loss rate is about 30 ℃ higher than that of pure PU foams. The decompostion temperatures are 167 ℃ and 148 ℃ for the PU/P25 composite foams and the PU/TiNTs composite foams respectively, which are lower than that of pure PU foams. Moreover, with the addition of the fillers, the sound absorption property also has changed; the addition of TiNSs improved the sound absorbing property efficiently. The better thermal stability and sound absorption of PU/TiNSs composite foams are mainly due to the uniform cells diffuse and smaller aperture.     

火焰原子吸收分光光度法测定尾砂矿中的微量铟

以HCl、HNO3、HF、HClO4溶解样品,釆用火焰原子吸收分光光度法测定尾砂矿中的铟含量,对仪器的工作条件和反应条件进行了选择和优化。该方法线性范围为0～10μg.ml-1,线性方程y=0.001809＋0.01497x,相关系数为0.9994,检出限0.090μg.ml-1,RSD=1.39%,回收率96.0%～106.0%。该方法操作简便,准确度和精密度能够满足分析要求。     

光声光谱技术在白血病诊断中的应用

建立一套用于血液涂片或固体研究的双光束光声光谱测量装置,实验研究正常人、急性淋巴细胞白血病等血样的光声光谱,发现白血病人的全血谱与正常人全血谱有显著的差别.结合临床,分析讨论了白血病人全血谱与病情程度的关系,并利用瑞士兰对全血涂片染色的方法,为白血病进行早期诊断找到了一种简便的手段.     

介质吸收对体积全息图衍射效率的影响

给出了体积全息图的衍射效率与记录介质吸收系数和厚度的关系,指出必须考虑制做全息图时介质吸收的影响,并提出了改善体积全息图性能的方法.     

论火焰原子吸收法测镁时铝干扰的机理

用熔融体性质对杂质蒸发速度的影响解释了火焰原子吸收法栅镁时对铝的干扰以及镧对铝干扰的抑制作用。推论出高沸点氧化物都有抑制铝干扰镁的作用,并得到了实验证实。     

接镉作业人员发镉的石墨炉原子吸收法测定

用石墨炉原子吸收法测定了从事镉化工、镉熔炼作业人员的发镉，证实其污染严重，含量达９．３～２５．２μｇ／ｇ，为正常人的１００～４００倍。样品用ＨＮＯ３和ＨＣｌＯ４消解；加１％ＮＨ４Ｈ２ＰＯ４以改进基体，更好地进行灰化；用加钙标准曲线修正基体干扰。以此法测定人发标准样ＢＢＷ０９１０１，测定值为０．０９８±０．００４，与标准值０．０９５±０．０１２μｇ／ｇ相符，误差＜４％。     

氢化纳米硅薄膜的光声光谱研究

分析了纳米硅薄膜材料从可见光到近红外范围的光声光谱，并与微晶硅和非晶硅材料进行了对比．纳米硅的光吸收系数比后两者都高（特别是在１．４～１．９ｅＶ之间，高出近一个数量级），其原因是纳米硅薄膜中大量晶粒对光子的散射、晶粒界面缺陷的吸收及载流子吸收的影响，此外，纳米硅光声谱中Ｕｒｂａｃｈ边宽且缓，反映出这种材料很高的无序程度．     

磁场对磁流体红外吸收的影响

测量了３种磁流体在施加外磁场前后的红外反射吸收谱，发现磁流体的红外吸收第数随磁粉浓度的增加而增加；在外磁场作用下吸收系数降低，钡铁氧体和锰锌体磁液随外磁场增强吸收系数单调下降并趋向一渐近值，Ｆｅ－Ｎｉ超微粒磁流体的吸收系数随磁场的变化出现异常。采用链状结构模型和理论可解释上述现象。