AAS测定纸巾中的铅和镉

本文采用原子吸收光谱法测定纸巾中铅、镉的含量。结果表明，不同纸巾中的污染元素铅、镉的含量不同。同时还对一种纸巾的铅、镉元素进行了回收实验，回收率在92％-104％之间。     

鸡精和味精中铅、镉含量的测定

采用原子吸收法测定了鸡精和味精中污染元素铅、镉的含量。结果表明,不同品牌的鸡精和味精所含铅、镉的量不同。该方法简便、快速、准确、实用。测定的线性范围为铅0.00～10.00 μg·mL-1,镉0.00～4.00 μg·mL-1。铅和镉的精密度试验的相对标准偏差分别为3.15%和4.26%,并进行了回收实验,回收率铅在96.7%～102.1%,镉在91.9%～107.6%之间。     

三维鱼体参数化建模

因水下环境复杂,鱼类三维模型获取非常困难,基于三维鱼类数据驱动的很多自动化研究工作无法开展。为此,提出一种三维鱼体参数化建模方法。首先,用专业建模师构建的标准鱼体模板注册扫描仪采集三维鱼体数据,构建拓扑结构一致的三维鱼体网格数据集;其次,用主成分分析法对数据集中的三维鱼体网格模型进行建模分析,建立鱼体的参数化表示模型;最后,采集草鱼数据进行相关实验。实验结果表明,注册得到的三维鱼体模型与真实扫描鱼体模型顶点之间的平均均方根误差仅为0.691 3 mm,在可接受范围。通过改变三维鱼体参数化表示模型中的权参数,快速生成了大量三维鱼体数据,从而解决了三维鱼体数据获取困难的问题。     

巯基棉分离富集—火焰原子吸收光谱法测定钠盐试剂中的痕量镉

偏硼酸钠，无水乙酸钠，无水碳酸钠，磷酸氢二钠等试剂中的痕量镉，经巯基棉分离和富集后，以火焰原子吸收光谱法进行测定。方法简便，快速，测定的相对标准偏差均小于４．６１％。     

Theoretical simulation of a polarization splitter based on dual-core soft glass PCF with micron-scale gold wire

A polarization splitter based on dual-core soft glass photonic crystal fiber(PCF) filled with micron-scale gold wire is proposed. The characteristics of the polarization splitter are studied by changing the structural parameters of the PCF and the diameter of the gold wire with the finite element method(FEM). The simulation results reveal that the coupling length ratio of the soft glass-based PCF is close to 2 and the corresponding curve is more flat than that of the silica-based PCF.The broadband bandwidth is 226 nm in which the extinction ratio is lower than-20 d B by the soft glass-based PCF, i.e.,from 1465 nm to 1691 nm which is competitive in the reported polarization splitters, and the bandwidth is just 32 nm by the silica-based PCF. The insertion loss by our polarization splitter is just 0.00248 d B and 0.43 d B at the wavelength of 1.47 μm and 1.55 μm. The birefringence is obviously increased and the coupling length is decreased by filling gold wire into the soft glass-based or the silica-based PCF. Also the birefringence based on the silica-based PCF is much larger than that based on the soft glass-based PCF whether or not the gold wire is introduced. The fabrication tolerance of the polarization splitter is also considered by changing the structural parameters. The polarization splitter possesses broad bandwidth, low insertion loss, simple structure and high fabrication tolerance.     

硫酸羟胺及亚硝酸钠对高碳钢表面锌系磷化涂层的组织和摩擦性能的影响

研究了在锌系磷化液中添加环保型促进剂-硫酸羟胺与常规促进剂-亚硝酸钠以便在高碳钢表面形成锌系磷化涂层．用X射线衍射分析了磷化涂层的相结构的变化,结果发现,形成的磷化膜主要由Zn₃Fe(PO₄)₂·4H₂O(H膜)和Zn₂Fe(PO₄)₂·4H₂O(P膜)组 成．运用扫描电镜分析了磷化涂层的显微组织与磷化时间之间的变化规律．四球摩擦实验结果表明,与亚硝酸钠相比,在锌系磷化液中添加硫酸羟胺能有效降低润滑后的磷化涂层的摩擦系数．     

味觉化学之甜味化学

甜,是一种令人愉快的味道,让人产生幸福的感觉,生物本质是甜味分子与甜味受体相互作用,经过复杂的传递过程然后激活大脑奖赏区释放神经递质多巴胺。从化学结构角度上看,甜味分子可分为:糖类(糖、糖衍生物、糖醇、糖苷),氨基酸类(二肽、蛋白质),磺酰胺类等,甜度值与分子结构密切相关。本文从分子结构层面阐述各类甜味分子及其甜度。     

超高效液相色谱-串联质谱法快速测定植物油中黄曲霉毒素B1

2.500g植物油样品用10 mL甲醇(7+3)溶液提取,以6 000r·min~(-1)转速离心10min,在-20℃冷冻30min后,上清液经0.22μm有机滤膜过滤,采用超高效液相色谱-串联质谱法快速测定滤液中黄曲霉毒素B_1的含量。以Accucore aQ色谱柱为固定相,以不同体积比的含5mmol·L~(-1)乙酸铵的0.1%(体积分数)甲酸溶液和甲醇的混合液为流动相进行梯度洗脱,串联质谱分析中采用电喷雾正离子源和选择离子监测模式。黄曲霉毒素B_1的质量浓度在0.50～10.00μg·L~(-1)内与其对应的峰面积呈线性关系,检出限(3S/N)为0.02μg·kg~(-1)。以空白样品为基体进行加标回收试验,所得回收率为86.0%～96.6%,回收量的相对标准偏差(n=6)为5.6%～8.4%。     

10种治疗胃病中成药中5种必需微量元素含量分析

通过检测10种临床常用治疗胃病中成药中人体必需微量元素含量从而探讨微量元素含量与中成药药效的关系。采用微波消解法消解样品,电感耦合等离子体-质谱法(ICP-MS)进行测定。10种治疗胃病中成药中人体必需微量元素Mn、Fe、Se、Cu、Zn含量丰富。检测结果为研究治疗胃病的中成药中元素含量与药物疗效二者关系的研究提供有用的数据,还可以为此类药物的临床应用及药物质量评价提供有意义的信息。     

Photonic crystal fiber polarization filter with two large apertures coated with gold layers

A novel photonic crystal fiber(PCF) polarization filter is designed and fabricated; it consists of two large apertures coated with gold. The asymmetric structure separates the resonance position in the vertical direction well. Due to the metal layer covering, loss is greatly improved. Finite element method is applied for numerical simulation. The influences of varying gold thickness and varying the diameters and the center positions of the larger apertures on filtering performance are evaluated. Theory of coupling between surface plasma and core mode is introduced. By modulating the parameters, we realize a single polarization filter at 1.31 μm and 1.55 μm. The basal mode loss in the y direction can reach 1408.80 dB/cm at 1.31 μm and 1911.22 dB/cm at 1.55 μm respectively, but basal mode loss in the x direction is relatively small, 0.82 dB/cm and 1.87 dB/cm. In addition, two kinds of broadband polarization filters are proposed. If the fiber length is set to 200 μm,the extinction ratio is greater than 20 dB with width of 570 nm and 490 nm. The filter has simple structure and excellent performance.