对甲氧基苯乙酸的合成新工艺研究

研究对甲氧基苯乙酸新的合成方法,即苯甲醚在三氯化铝催化下与草酰氯单乙酯发生Friede1-Crafts酰化反应得到对甲氧基苯乙酮酸乙酯,后者不经纯化直接与水合肼发生Wolff-Kishner-Huang反应得到目标产物,总产率为55.4%,其结构经IR、1HNMR和MS证实.     

主成分分析法在冬枣果实贮藏特性分析中的应用

在常温贮藏条件下,测定冬枣果实可溶性固形物、Vc、有机酸、可溶性糖、叶绿素含量及呼吸速率、失重率、果实硬度,应用主成分分析法分析果实贮藏过程中这8个指标的综合变化情况,确定了代表果实品质指标94.83%综合信息的2个重要主成分,列出了2个重要主成分的函数式,构建了综合评价模型。结果表明:鄂北冬枣果实可贮藏12 d,果实品质较好,以后果实综合指标迅速下降,与实际情况相近。该分析法可用于评判冬枣果实的贮藏特性及最佳贮藏寿命。     

碳化钨和天然沸石复合材料在水溶液中的电催化活性(英文)

Tungsten carbide and zeolite nanocomposite was prepared by combining a mechanochemical approach with a reduction and carbonization approach,using natural zeolite and ammonia metatungstate as precursors.The sample was characterized by X-ray diffraction and scanning electron microscope.The results showed that the crystal phase of the sample is composed of zeolite,monotungsten carbide and bitungsten carbide.The mass percentage and the crystallite diameter of tungsten carbide change along with the reacted time.Its electrocatalytic activity was measured with a microelectrode system with three electrodes.The results show that its electrocatalytic property is related to its crystal phase and the mass percentage of tungsten carbide,and its electrocatalytic activity is connected with the property of electrolyte,in which it is measured.Synergistic effect between tungsten carbide and zeolite is found during electrocatalysis.     

添加剂影响湿法脱硫过程中石灰石溶解的实验研究

通过实验筛选出了促进石灰石溶解的最佳添加剂配方,考虑了所有的过程参数(添加剂的添加浓度、pH值、搅拌速率、反应温度)对石灰石溶解的影响。溶解实验结果表明,石灰石的溶解速率随添加剂浓度的增加而增加。在未加入添加剂时,反应温度和搅拌速度的提高以及较低的pH值都可以提高石灰石的溶解速率;添加剂的加入,可以在原先的基础上进一步促进石灰石的溶解。在温度为323 K、搅拌速率为500 r/min、pH值为5.5、添加剂浓度为2×10-4实验条件下,有添加剂存在时石灰石溶解的活化能为8.89 kJ/mol,无添加剂时石灰石溶解的活化能为14.68 kJ/mol,进一步说明添加剂可以有效促进石灰石的溶解。     

响应面法优化野菊花蒙花苷的提取工艺及大悟县不同区域野菊花中蒙花苷含量的测定

为了探究湖北省大悟县不同地区分布的野菊花中蒙花苷的含量,本研究在单因素实验的基础上,采用Box-Behnken法设计了4因素3水平的响应面试验,对影响蒙花苷得率的主要因素进行了优化,并以最优工艺测定了湖北省孝感市大悟县不同区域野菊花样品中的蒙花苷含量。工艺优化结果表明,溶质质量分数、液料比、提取温度、提取时间是影响蒙花苷得率的四个主要因素。其中,提取温度对蒙花苷得率的影响最大,随后依次是提取时间、液料比和溶质质量分数。蒙花苷最优提取工艺为:乙醇质量分数54%、液料比150:1 (mL/g)、提取温度80 ℃、提取时间60 min,蒙花苷对应得率为2.75%±0.03%,与模型预测值2.80%无显著性差异。且该工艺条件还展现出稳定性好（RSD<5%）、精密度高（RSD<5%）、加标回收率优良（>80%）等特点,适用于实际野菊花样本中蒙花苷含量的测定。含量结果表明,大悟县不同地区野菊花样品中蒙花苷含量差异较大,介于0~2.75%之间,其中第027、037、060、094号取样地蒙花苷含量较高,均超过2.5%。本研究可为野菊花食材或药材的质量评价提供可靠方法,也可为高蒙花苷含量野菊花优良品种的种植和选育提供重要依据。     

复合有机过滤板替代陶瓷过滤板可行性探讨

陶瓷过滤机是一种普遍采用的高效、节能、环保型固液分离设备。简述了陶瓷过滤机的工作原理,指出目前普遍使用的陶瓷过滤板存在易堵塞、难清洗、覆膜边角处易损坏漏气、清洗时会爆板等突出问题,介绍了新研制的可克服陶瓷过滤板所存在问题的新型复合有机过滤板的性能特点。通过试验表明复合有机过滤板在提高处理能力方面具有明显的优势,增产能力达14.85%,但在滤饼的脱水效果方面略逊于陶瓷过滤板,滤饼含水率较陶瓷过滤板的高0.57个百分点。可见,复合有机过滤板有利于提高陶瓷过滤机的工作效率和企业的经济效益,具有广阔的推广应用前景。     

多波长分光光度法同时测定Fe、Cu、Cr、Ni

研究多波长分光光度法对Fe、Cu、Cr、Ni 4 种金属同时定量分析.考察了通常存在的Ca、Mg、Zn对测定的干扰,确定了4 种金属的最佳吸收波长,并在特定波长下测定摩尔吸光系数,建立了完整的线性方程.采用本方法对配制的Fe、Cu、Cr、Ni 混合溶液进行测定,验证其线性方程的准确性,结果表明其相对误差在±5 %以内.考虑不同样品金属离子的含量不同,对多波长分光光度法进行了测定下限的研究.结果表明:采用本方法Fe、Cu、Cr、Ni 的测定下限分别为5×10-4 mg/mL、1×10-3 mg/mL、5×10-3 mg/mL、5×10-3 mg/mL, 在此浓度以上的样品均可获得可靠的定量分析结果. 最后对实际电镀污泥中Fe、Cu、Cr、Ni 的含量进行测定,分析测定结果与原子吸收分光光度法是一致的.      

WC@TiO2核壳结构纳米复合材料制备与电催特征

Monotungsten carbide and titania nanocomposite with core-shell(WC@TiO2)structure was prepared by a new approach of spray drying and reduction-carbonization reaction,with titania nanopowder and ammonium metatungstate as precursors,methane as carbon source,and hydrogen as reduction gas.The sample was characterized by X-ray diffraction,scanning electron microscope,high resolution transmission electron microscope and X-ray energy dispersion spectroscopy.The results show that its crystal phase is composed of brookite,tungsten and monotungsten carbide.The morphology of the sample particle is irregular sphere-like,with a diameter smaller than 100 nm.Its chemical components are titanium,tungsten,carbon and oxygen.Monotungsten carbide nanoparticles lie on the surface of titania core and form an incomplete shell around titania core in the nanocomposite.The measurement with a microelectrode system of three electrodes shows that the sample is electrocatalytic active to nitrophenol in basic solution at room temperature.Its peak potential is at0.988 V(vs saturated calomel electrode (SCE)),which is more negative than the peak potential,0.817 V(vs SCE),of mesoporous monotungsten carbide, and its peak current is 8.809μA,which is higher than the peak current,4.058μA,of mesoporous monotungsten carbide.The hydrogen generation potential of the sample is at1.199 V(vs SCE),which is more negative than that of pure nanosized monotungsten carbide at1.100 V(vs SCE).These results show that the presence of titania in the sample can lower the peak potential of nitrophenol electrocatalysis and its hydrogen generation potential,and increase its peak current of nitrophenol electrocatalysis in basic solution at room temperature.This indicates a synergistic effect of titania and monotungsten carbide in electrocatalysis.     

基于移动IPv6的AAA接入认证的应用研究

论文首先对AAA架构及其移动IPv6应用扩展进行阐述,给出基于移动IPv6的AAA解决方案,在此基础上对AAA实体间的消息进行了优化,并根据需要对接入路由器进行了AAA功能的扩展,从而实现了对移动节点的访问控制,并且减少了移动节点的切换延迟。