N-[(2,2–propinyldiferrocenyl)methinyl]benzoyl hydrazone and its bivalent transition metal complexes

Transition Metal Chemistry -     

Synthesis of monodisperse poly(chloromethylstyrene-co-divinylbenzene) beads and their application in separation of biopolymers

The monodisperse, porous poly(chloromethylstyrene-co-divinylbenzene) beads of 7.9 microm were prepared by a single-step swelling and polymerization method. The seed particles prepared by dispersion polymerization exhibited good absorption of the monomer phase. Based on this media, a weak cation-exchange (WCX) stationary phase for HPLC was synthesized by a new chemically modified method. The prepared resin has advantages of biopolymer separation, high column efficiency, low column backpressure, high protein mass recovery, and good resolution for proteins. The dynamic protein-loading capacity of the synthesized WCX packings was 18.2 mg/g. Five proteins were separated in 3.0 min using the synthesized WCX stationary phase. The experimental results show that the obtained WCX resin has very weak hydrophobicity. The WCX resin was also used for the rapid separation and purification of lysozyme from egg white in 5.0 min with only one step. The purity and specific bioactivity of the purified lysozyme were found to be more than 93% and 70 245 U/mg, respectively.     

Synthesis of Polyacrylaminothiourea Chelating Fiber and Properties of Concentration and Separation of Trace Noble Metal Ions from Samples

A novel polyacrylaminothiourea chelating fiber was synthesized simply and rapidly from nitrilon (an acrylonitrile-based synthetic fiber), which was applied to preconcentrate and separate of trace amount of Au(Ⅲ）,Pt(Ⅳ）,Pd(Ⅳ） and Ir (Ⅳ） ions from solution of samples.The analyzed ions can be quantitatively concentrated by the fiber up to a flow rate of 20.0mL/min at pH2, and can also be desorbed with 15 mL of 4mol/L HCl 3% thiourea from the fiber column with recoveries of 96.5%-100%.The chelating fiber can be reused for ten times,the recoveries of these ions are still over 92%,and hundred to thousand times of excess of Fe(Ⅲ）,Al（Ⅲ）,Ca(Ⅱ），Mg（Ⅱ）,Ni(Ⅱ）,Mn（Ⅱ),Cu(Ⅱ），Zn(Ⅱ），and Cd(Ⅱ） cause no interference on the determination of the analyzed ions by inductively-coupled plasma atomic emission spectrometry (ICP-AES).The static saturation adsorption capacities of the fiber for the analytes are in the range of 1.15-2.80mmol/g.The relative standard deviations for the determination of 20.0ng/mL each of Au(Ⅲ）,Pt(Ⅳ）,Pd(Ⅳ）and Ir(Ⅳ） are in the range of 0.7%-3.0%.The recoveries for test from standard additions to real solution samples are between 96% and 100%.The concentration of each ion in powder sample detected by the method is in good agreement with the certified value.     

A High-Order Finite Difference Scheme for 3D Unsteady Convection Diffusion Reaction Equations北大核心CSCD

针对三维非稳态对流扩散反应方程,构造了一种高精度紧致有限差分格式,对空间的离散采用四阶紧致差分方法,对时间的离散采用Taylor级数展开和余项修正技术,所提格式在时间上的精度为二阶、在空间上的精度为四阶。利用Fourier稳定性分析法证明了该格式是无条件稳定的。最后给出数值算例验证了理论结果。     

探究苯与酸性高锰酸钾溶液的褪色反应

人教版高中教材《化学2》明确指出苯不能使酸性高锰酸钾溶液褪色。但在实验中多次发现苯与酸性高锰酸钾溶液混合后放置一段时间能够褪色。为探讨这一问题，设计了以光照或黑暗、加酸或不加酸为条件，利用紫外-可见分光光度计对放置不同时间后的混合液体进行测试，并对反应后生成的沉淀物进行XRD表征的实验方案。通过对实验数据的综合分析提出了苯与酸性高锰酸钾溶液褪色反应的可能反应机理。     

对苯二酚在碳纳米管修饰玻碳电极的电化学行为及电化学动力学研究

碳纳米管(Carbon Nanotubes,CNT)自1991年发现以来,因其结构所具有的高比表面,高电导率,稳定的化学性质与超常的机械强度已成为世界范围内的研究热点,并应用于催化、气体储藏和电极材料等领域。用CNT修饰的电极具有良好的电化学性能并且已经取得了很好的实验结果[1],因此研究碳     

Gas chromatographic/mass spectrometric and microbiological analyses on irradiated chicken

Ionizing radiation is widely used as treatment technique for food preservation. It involves among others reduction of microbial contamination, disinfestations, sprout inhibition and extension of shelf life of food. However, the commercialization of irradiated food requires the availability of reliable methods to identify irradiated foodstuffs. In this paper, we present results on the application to irradiated chicken of this method, based on the detection, in muscle and skin samples, of the peaks of ions 98 Da and 112 Da, in a ratio approximately 4:1, typical of radiation induced 2-dodecylcyclobutanones (2-DCB). Aim of the work was also to study the time stability of the measured parameters in samples irradiated at 3 and 5 kGy, and to verify the efficacy of the treatment from a microbiological point of view. Our results show that, one month after irradiation at 3 kGy, the method is suitable using the skin but not the muscle, while the measured parameters are detectable in both samples irradiated at 5 kGy. The microbial population was substantially reduced even at 3 kGy.     

KN03／MCM-48催化酯交换法合成碳酸二丙酯

对KNO，／MCM-48用于丙醇和碳酸二甲酯进行酯交换合成碳酸二丙酯的催化性能进行了考察．用X射线衍射（XRD）、红外光谱（IR）和X射线荧光法研究了催化剂的结构特征和表面性质．XRD结果表明，随着K负载量的增加，载体特征峰强度逐渐减弱，但仍保留MCM-48的晶体结构．随着焙烧温度的升高，KNO3逐渐分解成K2O．分别考察了活性组分负载量、焙烧温度、焙烧时间和催化剂的用量以及反应时间对反应的影响．结果表明，KNO3／MCM-48催化剂对碳酸二丙酯的合成具有很高的催化活性．在反应温度363K，反应时间6h，催化剂用量5％，丙醇与碳酸二甲酯摩尔比为4的条件下，碳酸二甲酯的转化率可达99．9％，产物碳酸二丙酯选择性93．4％，产率93．3％．     

Split least‐squares finite element methods for non‐Fickian flow in porous media

In this article, we introduce two least‐squares finite element procedures for parabolic integro‐differential equations arising in the modeling of non‐Fickian flow in porous media. By selecting the least‐squares functional properly the presented procedure can be split into two independent subprocedures, one subprocedure is for the primitive unknown and the other is for the flux. The optimal order convergence analysis is established. Numerical examples are given to show the efficiency of the introduced schemes. © 2012 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2013     

Correlation between Boron Isotope of Coral Acropora and pH Value of Seawater Surface

A water circulation system with the almost same element composition and socket type was adopted in coral Acropora culture under different seawater pH value conditions and the data of the relationship between boron isotopic compositions of coral and seawater pH value by thermoelectric ionization mass spectrometer were obtained. According to the correlations between α_carb-3 of coral and the pH value of cultured seawater, α_carb-3 was not a constant but related to pH value, indicating that B(OH)₃ also incorporated carbonate. Therefore, the theoretical formula could not be used to calculate the seawater pH value from the δ¹¹B_carb value of the measured marine biological carbonate. The empirical equations obtained experimentally would be an alternative method to calculate the seawater pH value. In addition, the mixed precipitation of CaCO₃ and Mg(OH)₂ was found in aquaculture tanks with high pH value, and the δ¹¹B of the solid was significantly higher than that of cultured seawater. The result indicated that the presence of Mg(OH)₂ had a significant effect on the boron isotope fractionation, which deserved our attention.