Preparation of Cu/ZnO/Al2O3 catalysts in a solvent-free routine for CO hydrogenation

The synthesis of methanol and dimethyl ether (DME) from CO hydrogenation has been investigated on Cu-based catalysts. A series of Cu/ZnO/Al₂O₃ catalysts were prepared using a solvent-free routine which involved a direct blend of copper/zinc/aluminum salts and citric acid, followed by calcination at 450 °C. The calcination processes were monitored using thermogravimetry differential scanning calorimetry (TG-DSC). Catalysts were further characterized using N₂ adsorption, scanning electronic microscopy (SEM), X-ray diffraction (XRD), N₂O oxidation followed by H₂ titration, and temperature-programmed reduction with H₂ (H₂-TPR). The reduction processes were also monitored with in-situ XRD. The physicochemical properties of catalysts depended strongly on the types of precursor salts, and catalysts prepared using Al acetate and Cu nitrate as starting materials had a larger surface area, larger exposed metallic copper surface area, and lower reduction temperature. The CO hydrogenation performances of these catalysts were compared and discussed in terms of their structures. Catalysts prepared with copper nitrate, zinc and aluminum acetates exhibited the highest catalytic activity.     

Molten Salt Synthesis of （K0.47Na0.47Li0.06） NbO3 Lead-Free Piezoelectric Ceramics

(K0.47Na0.47Li0.06)NbO3 (KNLN) lead-free ceramics were prepared by molten salt synthesis (MSS) method using k2CO3-Na2CO3 eutectic mixtures as the flux. The microstructure and piezoelectric properties when sintered at 980-1 030 ℃ were investigated. The calcined powders were examined by X-ray diffraction. The microstructure of the calcined powders and sintered bodies was observed using a scanning electron microscope (SEM).The piezoelectric constant d33 was measured using a quasi-static piezoelectric d33 meter. The planar coupling coefficient Kp was calculated by resonance-antiresonance method. The experimental data for each sample's performance indicators were the average values of 8 specimens. The relative densities of sintered specimens are above 97%, and the dielectric loss is below 0.03. It was found that (K0.47Na0.47Li0.06)NbO3 prepared by MSS is compact and lead-free. The piezoelectric constant d33 is 216 pC·N-1 and the planar electromechanical coupling factor Kp is 0.352.     

Effects of La^3＋on microwave dielectric properties of（Pb0.5Ca0.5）（Fe0.5Ta0.5）O3ceramics

This work investigated the microwave dielectric properties of A-site substitution by rare earth La3+in(Pb0.5Ca0.5)(Fe0.5Ta0.5)O3(PCFT) system.A single perovskite phase was obtained only when the doping content was 2%.Suitable La3+ doping improved microwave dielectric performances.Excessive La3+doping caused the formation of secondary phase,which resulted in the decreasing of permittivity εrand quality factor Qfvalues.Especially,when the doping content is 2%-5%,permittivity εrwas above 75 and Qfvalues were 6...     

mpg-C3N4/BiVO4异质结光催化剂的制备及其降解复方磺胺甲恶唑的效果研究

采用水热合成法制备了典型的手里剑型钒酸铋晶体（BiVO₄）,利用硬模板法制备了介孔氮化碳材料（mpg-C₃N₄）,运用超声分散的方法将二者复合,制得mpg-C₃N₄/BiVO₄异质结光催化剂。文章考察了其在可见光条件下降解复方磺胺甲恶唑的效果,并探讨了影响降解效果的因素。     

关于T凸函数的不等式

In this paper, the Tφ-convex functions were introduced as a generalizations of convex functions. Then the characteristics of the Tφ-convex functions were discussed. Furthermore, some new inequalities for the Tφ-convex functions were derived.     

果胶@生物炭-Fe3O4的制备及其对Cu2+的吸附性能

以木屑为原料,高温热解制备生物炭。以聚乙烯醇为粘结剂,采用混合法将生物炭与果胶复合,并负载磁性,经烘干定型制备果胶包覆的磁性生物炭材料（果胶@生物炭-Fe₃O₄）。采用扫描电镜（SEM）、X射线衍射（XRD）及N₂吸附-脱附（BET）等方法对果胶@生物炭-Fe₃O₄进行表征,结合吸附实验分析其对Cu²⁺的吸附特性。结果表明,当生物炭、果胶、Fe₃O₄质量比为5：1：1,溶液pH值为6,吸附24 h,果胶@生物炭-Fe₃O₄对Cu²⁺吸附效果最好;二级动力学方程能较好地描述果胶@生物炭-Fe₃O₄对Cu²⁺的吸附过程,Freundlich模型能较好地拟合其吸附行为;SEM结果显示该材料具有不规则的孔隙结构;XRD分析显示纳米Fe₃O₄是其主要的晶体结构;BET测得其比表面积为25.654 m²·g^-1,平均孔径为20.18 nm。     

EF-H2O2-FeOX法深度处理畜牧业养殖废水技术研究

利用EF-H_2O_2-FeO_X法深度处理畜牧业养殖废水,结果表明,当pH值为3,电压为24 V,反应时间为45 min,电解质投加量为0.8 g/L,PAM投加量为2.5 mg/L时,对畜牧业养殖废水的深度处理效果最佳,COD的去除率可以达到99.1%。此方法具有成本低、设备简单、效果好等优点,在畜牧业养殖废水的深度处理领域具有广阔的应用前景。     

圆柱形GaAs/Al_xGa_(1-x)As量子环中类氢施主杂质态的电场效应

在有效质量近似理论下,利用变分法研究了外电场下圆柱形GaAs/Al_xGa_(1-x)As量子环中类氢施主杂质束缚能。讨论了施主杂质束缚能与量子环尺寸(径向厚度、高度)、杂质位置以及外电场间的变化规律。结果表明:随着量子环径向厚度(高度)的增大,中心施主杂质束缚能先增大后减小,显示有一极大值;施加的电场明显地改变了量子环中电子波函数的分布,导致施主杂质束缚能相应的改变;施主杂质束缚能随杂质位置的变化呈现出规律性。     

Coordination compounds in biology The chemistry of vitamin B12 and model compounds

Vitamin B₁₂ is an important coordination compound in biology. It is an interesting biomolecule in the sense that no other vitamin contains a metal ion. This is the only naturally occurring organometallic compound found in biology. An intriguing aspect of vitamin B₁₂ is the great stability of the metal-carbon bond. A great deal of new and interesting inorganic chemistry has been uncovered while studying systems pertinent to B₁₂. In this article some salient features of this unique molecule (B₁₂) and its model compounds are presented.     

Transport properties on La0.7Sr0.3MnO3/Al2O3/Fe tunnel junctions

Manganese oxide La_0.7Sr_0.3MnO₃ produced on (001) LaAlO₃ substrate by means of sol-gel spincoating method was used as the base electrode of LaSrMnO/Al₂O₃/Fe tunnel junctions. The I-V characteristic in the high bias region of this system was shown to be similar to that of the conventional tunnel junctions. Anomalous temperature dependence of tunneling resistance was observed to be a positive temperature coefficient of resistance. This phenomenon was attributed to the high voltage applied and was simply elucidated from the density states vs. energy diagram. Project(199031) supported by the Science Foundation of Zhejiang Province.     

PF/EP/Nano-SiO2 composite paint for resistor

Phenolic resin(PF) and nano-SiO₂ were used to improve the curing property and high humidity resistance of epoxy resin (EP) and methyl nadic anhydride (MNA) resistor paint, respectively. Hydrogen bonds, formed between phenolic resin and nano-SiO₂ in alcohol, made nano-SiO₂ disperse easily in EP/MNA paint through phenolic resin without being treated by supersonic vibration. When the mass ratio of PF to EP in paint is 3:7, the formed composite paint film can be cured in 2 min at 170 °C. When the mass ratio of nano-SiO₂ to PF in paint is 3:100, the property of high humidity resistance of the composite paint is the best, meeting the requirement of varying ratio of resistance less than 0.1% after experiment on high humidity resistance. SEM analysis shows the surface of the composite paint film is smooth, glassy, tight and homogeneous, without acicular air holes.     

Co/Pt多层膜的铁磁共振研究

Out-of-plane angular dependence of ferromagnetic resonance spectra was measured in sputtered Co/Pt multilayers and analyzed with the Landau-Lifshitz-Gilbert equation. The effective demagnetizing field 4πMeff is found to increase with decreasing tPt and decreasing 1/tco, which can be considered as a result of interplay between the interlayer coupling and a lowdimensional effect. The g factor increases with increasing tpt and decreasing tCo, indicating contribution of spin-polarization of Pt atoms and additional contribution of orbital moment of Co atoms. The in-plane resonance line-width increases with decreasing too and increases with increasing tPt.     

Effects of HfO2 buffer layers on the dielectric property and leakage current of Ba0.6Sr0.4TiO3 thin films by pulsed laser deposition

Ba0.6Sr0.4TiO3 （BST） thin films with and without HfO 2 buffer layer were fabricated on Pt/Ti/SiO2/Si substrates by pulsed laser deposition. Dependences of HfO 2 thickness on the dielectric property and leakage current of BST thin films were focused. The dielectric constant of BST thin films increased and then decreased with the increase of HfO 2 thickness, while the dielectric relaxation was gradually improved. The loss tangent and leakage current under positive bias decreased with the HfO 2 thickness increasing. The leakage current analysis based on the Schottky emission indicated an improvement of the BST/Pt interface with HfO 2 buffer layer. The loss tangent, tunability and figure of merit of optimized HfO 2 buffered BST thin film achieved 0.009 8, 21.91% （E max = 200 kV/cm）, 22.40 at 10 6 Hz, respectively.     

Estimation of the J-resistance curve for Cr2Ni2MoV steel using the modified load separation parameter S_（pb） method

Based on load separation theory, the load separation parameter Spb method is an effective approach for estimating the J-resistance curve from records of load versus displacement directly, using one sharp cracked specimen and an additional reference blunt cracked specimen. However, the effect of the reference blunt cracked specimen on J-resistance determination was not explicitly considered in past work. In this paper, a modified load separation parameter Spb method was developed to eliminate this effect, and then a unique estimation of instantaneous crack length for one sharp cracked specimen could be obtained. Furthermore, a forced blunting calibration method was also adopted to determine the instantaneous crack length in the load inseparable region, referring to a normalization method. Experiments on steam turbine rotator steel Cr2Ni2MoV were carried out to estimate J-resistance curves using an unloading compliance method. By removing unload and reload data from load-displacement records, the J-resistance curve for the same sharp cracked specimen was estimated using the modified separation parameter Spb method. The results indicate that the modified Spb method completely eliminates the effect of the reference blunt cracked specimen on the instantaneous crack length determination of the sharp cracked specimen. However, different J-resistance curves in a small range of crack extension are present when different blunting coefficients are used in the blunting line equation. The J-resistance curve obtained from the modified Spb method agrees well with that obtained from the compliance method.     

Preparation and application of supported amorphous alloy catalyst CoP/TiO2

A new supported amorphous catalyst CoP/TiO2 was prepared by chemical reduction and characterized by ICP, XRD, TEM, BET and DSC Its application in decomposing PH3 to high purity phosphor and its catalytic activity were studied. The decomposition rate is over 95% at 450 ℃. For comparison, unsupported CoP amorphous catalyst was prepared by the same method. The result suggests that CoP/TiO2 exhibits higher thermal stability and catalytic activity than CoP, which is attributed to the high dispersion of CoP alloy particles on the support-TiO2.     

Dual structure of composite right/left-handed transmission line

A dual structure of composite right/left handed （CRLH） transmission line （TL） is analyzed in which an inductance LR is in parallel with a capacitance CL and a shunt capacitance CR is in series with an inductance LL. Both the distributed and lumped cases are considered. The dispersion diagram and transmission properties of the dual CRLH TL are given and compared with those of a standard CRLH TL. Contrary to the frequency response of a standard CRLH TL, a dual CRLH TL has a left-handed （negative phase shift） band at higher frequencies and a right-handed （positive phase shift） band at lower frequencies. A novel dual-band balun is presented as an application.     

Characterization of DC magnetron sputtering deposited thin films of TiN for SBN/MgO/TiN/Si structural waveguide

INTRODUCTION Monocrystalline SBN (Strontium barium nio-bium, SrxBa1?xNb2O6, denoted SBNx?100, where 0.25≤x≤0.75) solid solution, is currently being inves-tigated as potential material for many micro-device applications, such as piezoelectric infrared detectors, piezoelectric, electro-optic modulators, and holo-graphic storage (Koch et al., 1998), because SBN has one of the largest known linear electro-optic coeffi-cients (r33=1300 pm/V for SBN75), two orders of magnitude larger th…     

柠檬酸含量对溶胶凝胶自燃烧法制备的钡铁氧体磁性能的影响

BaFe12O19 powders with nanocrystaUine sizes were produced by sol-gel auto-combustion method. The precursors were prepared under the molar ratios of citric acid to the metal nitrate of 0.5, 1.0 and 1.5. Appropriate ethylene diamine （C2H8N2） was added in order to adjust pH of 7. The ions distribution of citric acid at different pH explains the effect of citric acid in the starting solution. The XRD patterns of the as-burnt powders and annealing powders show different phases for different citric acid content. In addition, the lattice constants （a, c） derived from X-ray diffraction pattern were changed from 0.58881 nm to 0.58997 nm and 2.32057 nm to 2.32296 nm respectively. The data from VSM indicated that the powder with high citric acid content took on good magnetic properties. Pure single BaFe12O19 of the specific maximum magnetization M（1 T）≈ 49.73 Am^2/kg, the specific remanent magnetization Mr ≈ 30.77 Am^2/kg and the coercive force He≈ 467 kA/m was produced when the molar ratios of citric acid to the metal nitrate was 1.5.     

硼对金属间化合物Ni3Fe氢气诱发环境氢脆的影响

In this paper the tensile properties of both ordered and disordered Ni-24Fe and Ni-24Fe-0.03%B （wt%） alloys in gaseous hydrogen was investigated. The result shows that the ductility of the disordered Ni3Fe is significantly larger than that of ordered material in gaseous hydrogen. However, the ductility of ordered Ni3Fe doped with 0.03%B is nearly the same as that of disordered one indicating the obvious suppressing effect of boron on the H2-induced embrittlement. Based on the segregation behavior of boron in Ni3A1, it is proposed that the suppressing effect of boron in Ni3Fe on the H2-induced embrittlement is attributed to the segregation of boron on grain boundaries, thereby reducing the hydrogen diffusivity along the grain boundaries.