改性磁性壳聚糖微球对Cu2+、Cd2+和Ni2+的吸附性能

Fe3O4/ chitosan magnetic microspheres of 50 to 80 滋m were prepared using the inverse phase emulsion dispersion and chemical crosslinking technology, and then modified with ethylenediamine for use in the adsorption of heavy metal ions. The adsorption properties of the modified Fe3O4/chitosan toward Cu2+, Cd2+ and Ni2+ were investigated. It was found that the adsorption capacities of Cu2+ and Ni2+ increased with pH, and a maximum adsorption for Cd2+ occurred at pH=3. The saturated adsorption capacities calculated by Langmuir isotherms were 54.3 mg·g-1 for Cu2+, 20.4 mg·g-1 for Cd2+, and 12.4 mg·g-1 for Ni2+, respectively. The adsorption kinetics were well described by pseudo-second-order equation models. The experimental results showed that the Fe3O4/chitosan modified with ethylenediamine presented higher adsorption selectivity for Cu2+ than for Cd2+ and Ni2+ in all studied pH ranges.     

磷钼酸铵-孔雀绿-PVA分光光度法测定钽粉中磷

提出了以磷钼酸铵-孔雀绿-PVA三元络合物体系测定金属钽粉中磷的方法,该体系表观摩尔吸光系数ε=8.19×104L.mol-1.cm-1,加标回收率为:99.3%~105%,方法的RSD为:5.9%。有效地解决了目前高纯钽粉中磷的分析难题,方法已应用于实际产品的分析中。     

Debye type dielectric relaxation and the glass transition of alcohols

Many hydrogen-bonded liquids, especially glass-forming cases, display a dielectric relaxation behavior that differs qualitatively from that of other simple liquids. The majority of models aimed at explaining this unusual dielectric behavior associate the prominent Debye process with structural relaxation, viscous flow, and the glass transition. We perform dielectric and calorimetric studies of glass-forming mixtures of 2-ethylhexylamine and 2-ethyl-1-hexanol across the entire composition range. The kinetic glass transition temperature derived from the large dielectric Debye peak decreases, whereas that of the much smaller and asymmetrically broadened peak increases upon addition of amine. Only the latter feature coincides with the calorimetric glass transition results, implying that molecular structure and dielectric polarization fluctuate on time scales that can differ by orders of magnitude in many hydrogen-bonding liquids.     

Highly Efficient One-Pot Synthesis of 2-Arylmethyl N-Substituted Anilines via Yb（OTf）3 Catalyzed Three-Component Reaction

An efficient method has been developed for one-pot three-component coupling reactions of various aldehydes, 1-cyclohexen-2-one, and primary or secondary amines in the presence of a catalytic amount of Yb（OTf）3 under mild conditions to afford the corresponding 2-arylmethyl N-substituted anilines in good yields. In addition, the catalyst was easily recovered and could be reused for at least four cycles without any loss of activity.     

ICP-AES法同时测定TiNi形状记忆合金中杂质Co、Cu、Cr、Fe、Nb

研究建立了ICP—AES同时测定TiNi形状记忆合金中Co、Cu、Cr、Fe、Nb5元素的方法。进行了必要的条件试验，选择了分析线及其他仪器工作参数；考察了方法检出限、H2SO4酸度及基体钛、镍对测定的影响、工作曲线线性。进行了准确度和精密度试验，各元素的加标回收率为Co98．4％。99．6％、Cu98．0％～103％、Cr98.9％～99．6％、Fe94．6％～95．8％、Nb99．8％。102％。5种元素的相对标准偏差范围为4．2％-10％。     

亚烷基卡宾与甲醛环加成反应机理的理论研究

用二阶微扰理论研究了单重态亚烷基卡宾与甲醛发生的三种环加成反应的机理 ，采用MP2/6－31G~*方法计算了势能面上各驻点的构型参数、振动频率和能量。根 据能量数据可以预言环加成反应（1）的a途径将是单重态亚烷基卡宾与甲醛环加成 反应的主要反应通道，该反应由两步组成：（I）亚烷基卡宾与甲醛生成了一富能 中间体（INT1a），是一无势垒的放热反应，（II）中间体异构化为产物亚烷基环 乙烷，其势垒为24.1 kJ·mol~(-1)(MP2/6-31G~*)。     

用X-射线衍射法测定聚对苯二甲酸乙二醇酯/聚对苯二甲酸丁二醇酯共混体系的结晶度

Based on Hermans and Weidinger postulate that the crystalline fraction is proportional to crystalline intensity Ic and that the amorphous fraction is proportional to amorphous intensity Ia, it is. Suggseteet that for PBT/PET blends we assume that the intensity at 18. 2° is completely originated from amorphous scattering. The separation between the peaks at 17. 2° and 20. 8° is 3. 6°m, which is regarded as large enough to justify this assumption. Thus , it is possible to draw an acceptable demaraction line between the crystalline and amorphous scattering. The degree of crystallinity Xc is given by X_c-I_c/(I_c+KI_a),coefficient K is available by the values of Ic plotted against the values of Ia.For PBT/PET blends,we obtain that K is 0.95 and that correlation coefficient is 0.92 According to the method revieved above,we investi-gated the crystallinity of PBT/PET blends prepared by different ways.     

多组分体系同时定性定量测定的逐步回归分析法

阐述了逐步回归分析法用于多组分体系同时定性定量分析的原理、实验及数据处理方法。分析了硝基酚类人工样、未知样及合成样。该法可用于仅知可能含有的组分范围的样品分析。     

Formation and Structure of [Al_(13)(μ_3-OH)_6(μ_2-OH)_6(μ_2-OH)_(12)(H_2O)_(24)]Cl_(15)·13H_2O

1 INTRODUCTION At present, the polyaluminium compounds are mainly studied by single-crystal X-ray diffraction method to obtain the components, structures and exis- tence forms of aluminium in hydrolysis system, and then hydrolysis courses and mechanisms of each hydrolytic polyaluminium cation could be further dis- closed[1～5]. Generally, the single crystals suitable for X-ray diffraction are obtained from the crystallization of polyaluminium cations into sulfates or selenates. Following …     

UPLC-Q-TOF MS分析海洋鱼类血清皮质醇

皮质醇浓度是反映肾上腺皮质功能的重要指标之一,海洋鱼类血清中的皮质醇激素含量随应激强度呈现规律性变化,从而被广泛用来衡量应激水平的重要指标[1].