纸质包装材料中甲醛、乙醛向食品模拟物改性聚苯醚的迁移行为

为了解纸质包装材料中甲醛、乙醛向食品模拟物改性聚苯醚( Tenax)中的迁移行为,建立了一步提取衍生化、超高效液相色谱测定纸质包装材料和Tenax中的甲醛和乙醛的方法。本方法在甲醛和乙醛的测定范围内,线性相关系数R2>0.9999,甲醛检出限为0.03 mg/m2,乙醛检出限为0.04 mg/m2,测定纸样和Tenax的加标回收率为90.1%~108.6%。采用本方法研究不同温度和时间下两种纸质包装材料中甲醛、乙醛向Tenax中的迁移规律。研究表明,甲醛、乙醛迁移行为随时间变化趋势大致相同,均呈现迁移率随迁移时间延长先迅速增大,后又减小达到一个常数;甲醛和乙醛迁移率受温度的影响不同,达到平衡后,甲醛在30℃下迁移率最高,乙醛在70℃和50℃下迁移率高;甲醛和乙醛向Tenax中的迁移率差异较大,达到平衡后,乙醛的迁移率远高于甲醛。     

紫外荧光光谱法测定焦炉气中的痕量总硫

采用紫外荧光光谱法测定焦炉气制取液化天然气的原料气中痕量总硫,考察了样品引入速率、进样量、气体流量、燃烧温度、取样方式和进样方式等条件对分析结果的影响。总硫检出限为15μL·m-3,测定结果与气相色谱法和微库仑法的结果相吻合,测定值的相对标准偏差(n=7)小于10%。     

Synthesis and characterization of novel chalcones linked 3-[1-(3-chlorophenyl)-3-(pyren-1-yl)]-1H-pyrazole moiety

Russian Journal of General Chemistry - New series of pyrenyl–pyrazole based chalcones have been synthesized and characterized via the condensation of...     

Synchrotron FTIR analysis of drug treated ovarian A2780 cells: an ability to differentiate cell response to different drugs?

Recently a new di-gold(I) organometallic complex [1,3-(Ph(3)PAu)(2)-C(6)H(4)] (KF0101) has been synthesised and found to exhibit cytotoxic activity in vitro. Subsequently it has been demonstrated that KF0101 shows little or no cross-resistance against a number of the cisplatin resistant ovarian cancer cell lines in vitro suggesting a different mode of action for the drug. In this study, syncrotron radiation infrared microspectroscopy (SR-IRMS) has been used on drug treated single A2780 cells in order to determine if this different mode of action can be identified spectroscopically. The aim of the study was to establish: (i) if single cell SR-IRMS could be used to give insight into the cellular response on treatment with different cytotoxic agents relative to non-treated cells (control) and (ii) that if the cytotoxic drugs elicit a different biochemical response these responses could be distinguished from each other. The most striking features obtained after Principal Components Analysis (PCA) of Resonant Mie Scattering (RMieS) corrected single cell spectra of drug treated ovarian A2780 cells are: (i) The spectra obtained for the control are quite heterogeneous and several hundred spectra are required to adequately define the nature of the control; (ii) after drug treatment at the IC50 level for 24 h with cisplatin, KF0101, methotrexate, paclitaxel or 5-fluorouracil the cell spectra, as represented on a PCA scores plot, generally concentrate in certain well defined areas of the control, there are however a small number of spectra that fall outside of the area defined by the control; and (iii) a differentiation between cell spectra obtained on treatment with different drugs is observed which fits well with different in vitro cell culture behaviour and a flow cytometry cell cycle analysis of the control and drug treated cells. Inspection of the loading plots shows that PC1 is essentially the same for all plots and reflects changes in cell biochemistry related to the cell cycle. PC2, however, on comparison of the control versus cisplatin or cisplatin versus KF0101 is indicative of differences induced by drug treatment and has been termed as cell cycle-plus behaviour. These data are shown to be consistent with that obtained using bench-top IRMS by averaging a number of single cell spectra and carrying out a PCA, but SR-IRMS offers more insight into how the drug is affecting the cell population. More importantly, this approach enables the influence of the cell cycle on both the control and drug treated samples to be taken into consideration when evaluating the drug-cell interaction.     

流动肥皂膜气体界面及其在柱状汇聚激波作用下演化的实验研究

在Richtmyer-Meshkov(RM)不稳定性实验研究中,形成两种不同密度流体的初始扰动界面是前提和关健.本文提出了一种流动肥皂膜气体界面生成方法,其工作原理是由细丝构成的导流框从激波管实验段穿过,肥皂液从导流框的上端注入并在重力作用下在导流框中形成流动肥皂膜,膜的两测可以分别充入不同密度的气体从而形成稳定的气体...     

互叶白千层不同部位油细胞分布及显微拉曼光谱研究

为避免复杂的制样提取过程,在天然状态下获得植物样品油细胞中精油的成分,用显微拉曼光谱仪,得到互叶白千层同一植株不同部位的油细胞的分布及油细胞中的主成分。对各部位的显微镜观察发现在软枝干中不存在油细胞或者很少,老叶中的油细胞没有新叶中的多。在老叶油细胞上获得的谱峰中,1 675和726 cm-1为4-萜烯醇的特征峰, 归属为C═C伸缩振动和环的变形振动;1 700和754 cm-1为γ-松油烯的特征峰,归属为C═C伸缩振动和环的变形振动;1 609 cm-1为α-松油烯的特征峰,归属为C═C伸缩振动;1 522,1 156和1 011 cm-1为β-胡萝卜素的的特征峰,分别归属为C═C伸缩振动、C-C伸缩振动和C-C面内摇摆振动。在新叶油细胞上获得的谱峰中,745 cm-1为顺香桧烯水合物的特征峰,归属为环变形振动;1 609 cm-1为α-松油烯的特征峰;1 525,1 160和1 008 cm-1为β-胡萝卜素的的特征峰;老叶与新叶油细胞中的主成分不完全相同,老叶中油细胞精油为γ-松油烯-4-萜烯醇-α-松油烯型,而新叶中油细胞中的精油为顺香桧烯水合物-α-松油烯型。老叶、新叶的共有物为：α-松油烯、β-胡萝卜素。β-胡萝卜素及顺香桧烯水合物为首次在互叶白千层中发现。利用该方法可迅速的确定植株油细胞的主成分,为互叶白千层精油提取提供有益参考。     

基于成像差分吸收光谱技术和压缩感知理论的烟囱烟羽断层重建研究

烟羽断层重建质量受两方面条件限制：其中一个限制条件是遥感设备的时间分辨率。以往的研究多使用多轴差分吸收光谱仪（MAX-DOAS）进行CT重建,受采集数据速度的限制,重建图像的时间分辨率较低。另一个限制条件是,采集到的数据量有限,是典型的不完全角度重建。过去多使用代数迭代重建算法或统计迭代重建算法,重建图像受测量误差的影响比较大,分辨率较低且伪影较多。构造了基于成像差分吸收光谱技术（IDOAS）的光谱数据采集系统,与多轴差分吸收光谱仪构造的系统相比,数据采集的时间分辨率提高了160多倍,基本解决了时间分辨率的问题。提出了一种基于压缩感知理论和低三阶导数模型的烟羽断层重建算法--投影凸函数集低三阶导数法,简称为POCS-LTD。在投影的过程中,使用代数重建算法使重建图像符合投影方程;在全变分迭代的过程中使用了优化算法,将低三阶导数模型的全变分归一化值作为优化算法的迭代方向,前次迭代运算结果与本次投影运算的差值的模作为迭代步长。对重建算法进行了数值模拟,并以重建图像的接近度和一致性相关因子为指标,对重建结果进行了分析。数值模拟表明,算法具有良好的抗误差能力,与传统的低三阶导数法相比,本文提出的算法将重建接近度减小了80%以上。使用烟羽数据采集系统进行了外场实验,用POCS-LTD算法对外场实验的数据进行了烟羽重建,重建图像显示烟羽图像清晰,伪影得到了较好的抑制。介绍的烟羽断层数据采集系统和烟羽断层重建算法,提高了烟羽断层重建图像的时间分辨率,减少了重建图像的伪影,扩大了光谱测量技术的应用范围。     

过硫酸胺与N－［（3－二甲氨基）丙基］丙烯酰胺氧化还原引发体系的研究

N-[(3-DimetLylamino)-propyll acrylamide(DMAPAA) and N-[(3dimetliylamino)-propyl] methacrylamide(DMAPMA) were synthesized by the reaction of 3-dimethylamino-propylamine with acryloyl and methacryloyl chloride respectively at 0-5℃ temperature. The kinetics of the aqueous solution polylmerization of acrylamide(AAm) by using ammonium persulfate(APS) combined with DMAPAA or DMAPMA was investigated. The rate equations were given as:respectively. The overall activation energies of the polymerization were determined as low as 35.0kJ/mol and 41.0kJ/mol respectively. Based on the end-group analysis results, the reaction mechanism of DMAPAA or DMAPMA with APS was proposed to be similar to the initiation reation of persulfate/tertiary aliphatic amine redox system,and the resulting aminomethyl radicals were responsible for initiation of vinyl polymerization as well as sulfate radical.     

带积分环节的隶属度函数中心自适应模糊控制器设计

自适应变论域模糊控制是改变模糊控制性能的主要方法之一,针对自适应变论域模糊控制器的稳定性设计这一难题,将输入和输出的隶属度函数分别用论域值表示成解析形式;针对典型模糊控制系统没有考虑积分环节带来的稳态误差问题,设计一种积分器,并从减小控制规则数目的角度出发设计了针对积分环节的控制规则库;引进Lyapunov函数,设计了输入隶属度函数论域值的自适应律和输出隶属度函数中心取值的自适应律,最后针对Duffing非线性系统仿真,结果表明设计的变论域模糊控制器是可行的。     

具有功能性反应函数为的捕食系统

本文给出了具有功能性反应函数为 x的捕食系统x=γx-δ x y-αx2 ,y=-sy+β x y-εy2的全局相图 .得到了两种群持续共存和捕食者种群必将灭绝的条件 .讨论了此系统唯一正平衡点的 Hopf分支 ,并证明了该点可以成为二阶不稳定细焦点 ,从而得到该系统有出现至少三个极限环的可能 .