热解-还原法制备单分散Fe3O4亚微空心球

在用模板法水解FeCl3制备单分散聚(苯乙烯-共-丙烯酸)/Fe2O3[P(St-co-AA)/Fe2O3]核壳粒子的基础上, 于N2环境下热解内核直接得到了单分散的磁性Fe3O4亚微空心球. 用透射电镜(TEM)、场发射扫描电镜(FESEM)、X射线衍射(XRD)、振动样品磁强计(VSM)表征并测试了空心微球的结构形貌、成分以及静磁性能. 结果表明, P(St-co-AA)/Fe2O3核壳粒子在热处理过程中, 由于内核热解生成的有机小分子将Fe2O3 壳层同时还原为Fe3O4, 从而生成了粒径和壁厚均匀的单分散Fe3O4亚微空心球. 该空心微球在室温下的饱和磁化强度、剩余磁化强度和矫顽力分别为50.91 A·m2·kg-1、3.97 A·m2·kg-1和2.33 kA·m-1.     

Solid-phase extraction of iron(III) with an ion-imprinted functionalized silica gel sorbent prepared by a surface imprinting technique

A new Fe(III)-imprinted amino-functionalized silica gel sorbent was prepared by a surface imprinting technique for selective solid-phase extraction (SPE) of Fe(III) prior to its determination by inductively coupled plasma atomic emission spectrometry (ICP-AES). Compared with non-imprinted polymer particles, the ion-imprinted polymers (IIPs) had higher selectivity and adsorption capacity for Fe(III). The maximum static adsorption capacity of the ion-imprinted and non-imprinted sorbent for Fe(III) was 25.21 and 5.10 mg g⁻¹, respectively. The largest selectivity coefficient of the Fe(III)-imprinted sorbent for Fe(III) in the presence of Cr(III) was over 450. The relatively selective factor (α_r) values of Fe(III)/Cr(III) were 49.9 and 42.4, which were greater than 1. The distribution ratio (D) values of Fe(III)-imprinted polymers for Fe(III) were greatly larger than that for Cr(III). The detection limit (3σ) was 0.34 μg L⁻¹. The relative standard deviation of the method was 1.50% for eight replicate determinations. The method was validated by analyzing two certified reference materials (GBW 08301 and GBW 08303), the results obtained is in good agreement with standard values. The developed method was also successfully applied to the determination of trace iron in plants and water samples with satisfactory results.     

Methane Combustion Over Fe, Co and Ni Modified Manganese Oxide Catalysts

Fe-Mn, Co-Mn and Ni-Mn composite oxide catalysts based on high specific surface area MnO₂ precursor were prepared and applied to catalytic combustion of CH₄. Results were compared with that of unmodified MnOx and 1wt.% Pd/-Al₂O₃. Below 450°C, manganese oxide catalysts show higher activity than Pd/-Al₂O₃, while the modified manganese oxide catalysts exhibit higher activity than the unmodified one below 420°C. All catalysts were characterized by means of N₂-BET, XRD, TG-DTA and H₂-TPR. Due to the interaction between Fe, Co or Ni oxides and manganese oxide, the activity of the oxygen species of the modified catalysts is improved, which leads to the increase of their CH₄ combustion activity.     

Exploring high pressure structural transformations,electronic properties and superconducting properties of MH2 (M = Nb,Ta)

The high-pressure structures and properties of MH₂ (M = Nb, Ta) are explored through an ab initio evolutionary algorithm for crystal structure prediction and first-principles calculations. It is found that NbH₂ undergoes a phase transition from a cubic Fm$\overline{3}$m structure with regular NbH₈ cubes to an orthorhombic Pnma structure with fascinating distorted NbH₉ tetrakaidecahedrons at 48.8 GPa, while the phase transition pressure of TaH₂ from a hexagonal P6₃mc phase with slightly distorted TaH₇ decahedron to an orthorhombic Pnma phase with attractive distorted TaH₉ tetrakaidecahedrons is about 90.0 GPa. Besides, the calculated electronic band structure and density of states demonstrate that all of these structures are metallic. The Poisson’s ratio, electron localization function, and Bader charge analysis suggest that these phases possess dominant ionic bonding character with the effective charges transferring from the metal atom to H. From our electron–phonon calculations, the calculated superconducting critical temperature T_c of the Pnma-NbH₂ is 6.903 K at 50 GPa. Finally, via the quasi-harmonic approximation method, the phase diagrams at pressure up to 300 GPa and temperature up to 1000 K of MH₂ (M = Nb, Ta) are established, where the transition pressure of Fm$\overline{3}$m-NbH₂ → Pnma-NbH₂ and P6₃mc-TaH₂ → Pnma-TaH₂ were found to decrease with increasing temperature.     

Preparation and Characterization of Nanotitanium Dioxide Coating Film Doped with Fe^3＋ Ions on Porous Ceramic

The nanotitanium dioxide （TiO2） photocatalytic and porous ceramic filtering technique is one of the advanced methods to effectively treat organic wastewater. The TiO2 sol doped with Fe^3＋ ions was prepared by sol-gel processing. The influences of the process conditions of coating nanophotocatalytic material- Fe^3＋-TiO2 film on the surface of porous ceramic filter by dipping-lift method on the performance of porous ceramic filter were studied. The porous ceramic filters have two functions at the same time, filtration and photocatalytic degradation. The results of this study showed that the pH and viscosity of the sol, amount of Fe^3＋ ions doped as well as the coating times greatly affect the quality of coating film, the performance parameters and the photocatalytic activity of the porous ceramic filter. When the pH of the sol is 3-4, the viscosity is about 6 mPa.S, the amount of doped Fe^3＋ ions is about 2.0 g/L, the porous ceramic filter has been shown to have the best filtering performance and photocatalytic activity. In this condition, the porosity of porous ceramic is about 42.5%, the pore diameter is 8-10μm. The degradation of methyl-orange is 74.76% under lighting for 120 rain.     

Bacterial response to eukaryotic cells. Analysis of differentially expressed proteins using nano liquid chromatography-electrospray ionization tandem mass spectrometry

Host-bacteria interactions have mostly been investigated with regard to the host response or to activities of pathogenic bacteria. In contrast, we aim to identify reactions of non-pathogenic bacteria that result from their contact with host cells of the gastrointestinal tract. In a proteomic approach, the response of non-pathogenic human Escherichia coli bacteria on gut epithelial cells (rat IEC-6) was investigated in an in vitro co-culture model. For this purpose, a sensitive analytical procedure was developed based on the identification of two-dimensional polyacrylamide gel electrophoresis separated proteins by online nanoLC-electrospray ionization MS/MS using a quadrupole time-of-flight tandem mass spectrometer for accurate mass determination. We demonstrate here the efficiency of this technique by the identification of a total of 43 differentially expressed proteins, out of which 25 were up-regulated and 18 were down-regulated. They represent a wide range of molecular weight and different metabolic and physiological functions.     

FT合成沉淀Fe／Cu／K催化剂有效因子的计算Ⅰ．工业颗粒催化剂有效因子的计算

用包括水抑制作用的动力学方程，根据建立的反应扩散模型和ＦＴ合成化学计量关系，计算了工业原颗粒ＦＴ合成沉淀Ｆｅ／Ｃｕ／Ｋ催化剂在工业操作条件下的有效因子。根据不同的产物组成，建立了三种化学计量关系式，比较了气相反应和气液反应的有效因子，确立了ＦＴ合成沉淀Ｆｅ／Ｃｕ／Ｋ催化剂有效因子的计算方法。在ＦＴ合成反应条件下，产物蜡充满了催化剂的微孔，各组分在蜡中的扩散系数要比纯气相中的扩散系数小得多。在工况操作条件下（５２３Ｋ，２．５ＭＰａ，５００ｈ￣（－１），尾气循环比３．０），工业原颗粒（ｄ＿ｐ＝２．５ｍｍ，ｌ＿ｐ＝５～１０ｍｍ）催化剂的实际有效因子是纯气相反应的一半左右，计算的平均有效因子分别为０．４０和０．４２。     

Preparation of a sulfonated fused-silica capillary and its application in capillary electrophoresis and electrochromatography

In the present paper, two new methods, sol-gel and chemical bonding methods, were proposed for preparation of sulfonated fused-silica capillaries. In the sol-gel method, a fused-silica capillary was coated with the sol solution obtained by hydrolysis of 3-mercaptopropyltrimethoxysilane (MPTS) and tetramethoxysilane, and followed by age; while in the chemical bonding method, a capillary was chemically bonded directly with MPTS. Then, both the resulting capillaries were oxidized with an aqueous solution of hydrogen peroxide solution (H2O2) (30%, m/m) to obtain the sulfonated capillaries. The electroosmotic flow (EOF) for the sulfonated capillaries was found to remain almost constant within the studied pH range, and greater than that of the uncoated capillary. However, the coating efficiency of the capillary prepared by chemical bonding method was higher than that by sol-gel method, by comparing their magnitude of the EOF, the degree of disguise of the silanol and reproducibility of preparation procedure. The effects of the electrolyte's concentration and the content of methanol (MeOH) on the EOF were also studied. Especially, the study of the apparent pH (pH*) on the EOF in a water-MeOH system was reported. Finally, capillary electrophoretic separation of seven organic acids was achieved within 6.5 min under optimal condition using the chemically bonded sulfonated capillary. Moreover, separation of four alkaloids on the sulfonated capillary was compared with that on uncoated capillary in different conditions. Ion-exchange mechanism was found to play a key role for separation of these four basic analytes on the sulfonated capillary.     

Fe_3(CO)_9(μ_3-S)_2的P(SR)Cl_2和P(SR′)_3取代物的合成和结构研究

用P(SR)Cl_2和P(SR′)_3作n-酸配体,分别与Fe_3(CO)_9(μ_3-S)_2进行取代反应,得到6种新的一取代产物Fe_3(CO)_8(μ_3-S)_2L和3种新的二取代产物Fe_3(CO)_7(μ_3-S)_2L_2,并对它们进行了IR、~1H NMR和MS表征,测定了其中一种取代物Fe_3(CO)_8(μ_3-S)_2[P(SC_6H_5)Cl_2]的分子和晶体结构。