有机物料对滨海盐渍土重金属根际效应的影响Ⅰ.土壤内源Zn形态分布

研究了排水条件下施用腐熟有机物料、种稻改良滨海盐渍土内源Ｚｎ形态分布．结果表明，单淹水使土中各形态Ｚｎ一定程度上向生物有效性较低的Ｚｎ形态转化，有效态Ｚｎ降低．土壤盐分量不同，明显影响无定形氧化铁结合态、紧结有机态以及硅酸盐矿物态Ｚｎ变化．种稻不施有机物料，根际交换态和硅酸盐矿物态Ｚｎ亏缺；碳酸盐结合态、氧化锰结合态和无定形氧化铁结合态Ｚｎ富集．根际Ｚｎ形态转化强度大于非根际，其有效态Ｚｎ量接近临界值并高于非根际．有机物料利于根际内外土壤中硅酸盐矿物态Ｚｎ的转化，低盐土壤根际更强烈．随有机物料用量增加，促使根际硅酸盐矿物态、碳酸盐结合态及氧化锰结合态Ｚｎ向交换态、紧结有机态和无定形氧化铁结合态Ｚｎ转化，低盐土壤较明显．

Crystallographic and electrochemical characteristics of melt-spun Ti-Zr-Ni-La alloys

Ti-based icosahedral quasicrystalline phase (I-phase) exhibited excellent hydrogen storage property for special structure. Unfortunately, the application as the negative electrode material of the nickel-metal hydride batteries was limited due to the poor electrochemical kinetics. Meanwhile, rare-earth element was beneficial to the electrochemical properties of Ti, Zr-based alloy.

Ti- Zr- Ni基准晶合金的热力学和电化学贮氢性能

对急冷凝固方法、熔融纺丝法、机械合金化法等制备Ti-Zr-Ni基准晶合金的方法进行探讨,综述了几种Ti-Zr-Ni基准晶合金的热力学和电化学贮氢性能

热处理工艺对Mg-RE-Zn-Zr系合金显微组织及力学性能的影响

通过气体保护制备了Mg-RE-Zn-Zr[RE=Ce-40La(wt%)的富铈稀土]合金,并对合金进行了热处理,测试了不同状态下合金的硬度、抗拉强度及伸长率等力学性能,采用光学显微镜、X射线衍射仪及扫描电镜对合金显微组织、拉伸断口进行了分析。结果发现,采用T6热处理工艺后,合金的晶粒尺寸明显细化,硬度、抗拉强度、屈服强度和伸长率显著提高,分别提高了11%,24%,7.3%和102%

Synthesis and characterization of (Zn,Cd)TiO3 by a modified sol-gel method

Ilmenite-type (Zn1-xCdx)TiO3 (0 <= x <= 0.15 and 0.8 <= x <= 1.0) was synthesized by a modified sol-gel route including the Pechini process via two-step heat treatments. The thermal stability of (Zn1-xCdx)TiO3 depended on the amount of cadmium content. The as-synthesized (Zn1-xCdx)TiO3 (0 <= x <= 0.15 and 0.8 <= x <= 1.0) showed higher thermal stability than that of ZnTiO3. The variation of the dielectric constant of all synthesized (Zn1-xCdx)TiO3 samples for all measurement frequencies showed a similar tendency.

Constructing channel structures based on the assembly of p-sulfonatocalix[4]arene nanocapsules and [M(bpdo)(3)](2+)(M = Cu, Zn)

Novel channel structures based on [M(bpdo)(3)](2+) and p-sulfonatocalix[4]arene nanocapsules have been established; these are sustained exclusively by charge-assisted pi...pi interactions and sorption experiments show the porous materials have selective guest sorption properties.

Studies on the magnetism of cobalt ferrite nanocrystals synthesized by hydrothermal method

Fe-Co/CoFe2O4 nanocomposite and CoFe2O4 nanopowders were prepared by the hydrothermal method. The structure of magnetic powders were characterized by X-ray diffraction diffractometer (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), thermal gravity analysis (TGA) and differential thermal analysis (DTA) analysis, X-ray photoelectron spectrometry (XPS), and Fourier transform infrared spectra (FTIR) techniques, while magnetic properties were determined by using a vibrating sample magnetometer (VSM) at room temperature.

快速凝固 Ti-Zr-Ni 合金的电化学贮氢性能

采用铜辊快速凝固方法制备了Ti45Zr30Ni25和Ti50Zr25Ni25合金,并对合金作为镍-氢二次电池负极的动力学和电化学性能进行了研究。结果表明,Ti45Zr30Ni25为非晶相合金,Ti50Zr25Ni25合金由准晶相和非晶相组成。两合金电极的最大放电容量分别为129和132mAh/g。在240mA/g电流密度下,高倍率放电性能(HRD)分别为62.7%和63.3%。合金电极的交换电流密度分别为205.1和375.6mA/g,氢在合金中的扩散系数分别为5.4×10-11和5.8×10-11cm2·s-1

Electrochemical hydrogen storage in (Ti1-xVx)(2)Ni (x=0.05-0.3) alloys comprising icosahedral quasicrystalline phase

For (Ti1-xVx)(2)Ni (x = 0.05,0.1,0.15,0.2 and 0.3) ribbons, synthesized by arc-melting and subsequent melt-spinning techniques, an icosahedral quasicrystalline phase was present, either in the amorphous matrix or together with the stable Ti2Ni-type phase. With increasing x values, the maximum discharge capacity of the alloy electrodes increased until reached 271.3 mAh/g when x = 0.3. The cycling capacity retention rates for these electrodes were approximately 80% after a preliminary test of 30 consecutive cycles of charging and discharging.

The microstructures and mechanical properties of cast Mg-Zn-Al-RE alloys

The microstructures and mechanical properties of cast Mg-Zn-Al-RE alloys with 4 wt.% RE and variable Zn and At contents were investigated. The results show that the alloys mainly consist of alpha-Mg, Al2REZn2, Al4RE and tau-Mg-32(Al,Zn)(49) phases. and a little amount of the beta-Mg17Al12 phase will also be formed with certain Zn and At contents. When increasing the Zn or At content, the distribution of the Al2REZn2 and Al4RE phases will be changed from cluster to dispersed, and the content of tau-Mg-32(Al,Zn)(49) phase increased gradually. The distribution of the Al2REZn2 and Al4RE phases, and the content of beta- or tau-phase are critical to the mechanical properties of Mg-Zn-Al-RE alloys.

Crystallographic and electrochemical characteristics of Ti-Zr-Ni-Pd quasicrystalline alloys

Ti45Zr35Ni20-xPdx (x = 0, 1, 3, 5 and 7, at%) alloys were prepared by melt-spinning. The phase structure and electrochemical hydrogen storage performances of melt-spun alloys were investigated. The melt-spun alloys were icosahedral quasicrystalline phase, and the quasi-lattice constant increased with increasing x value. The maximum discharge capacity of alloy electrodes increased from 79 mAh/g (x = 0) to 148 mAh/g (x = 7). High-rate dis-chargeability and cycling stability were also enhanced with the increase of Pd content. The improvement in the electrochemical hydrogen storage characteristics may be ascribed to better electrochemical activity and oxidation resistance of Pd than that of Ni.

Perovskite-Like Mixed Oxides (LaSrMn1-x Ni (x) O4+delta, 0 a parts per thousand currency sign x a parts per thousand currency sign 1) as Catalyst for Catalytic NO Decomposition: TPD and TPR Studies

Catalytic NO decomposition on LaSrMn1-x Ni (x) O4+delta (0 a parts per thousand currency sign x a parts per thousand currency sign 1) is investigated. The activity of NO decomposition increases dramatically after the substitution of Ni for Mn, but decreases when Mn is completely replaced by Ni (x = 1.0). The optimum value is at x = 0.8. These indicate that the catalytic performance of the samples is contributed by the synergistic effect of Mn and Ni. O-2-TPD and H-2-TPR experiments are carried out to explain the change of activity. The former indicates that only when oxygen vacancy is created, could the catalyst show enhanced activity for NO decomposition; the latter suggests that the best activity is obtained from catalyst with the most matched redox potentials (in this work, the biggest Delta T and Delta E values).

Nonenzymatic glucose sensor based on renewable electrospun Ni nanoparticle-loaded carbon nanofiber paste electrode

A novel nonenzymatic glucose sensor was developed based on the renewable Ni nanoparticle-loaded carbon nanofiber paste (NiCFP) electrode. The NiCF nanocomposite was prepared by combination of electrospinning technique with thermal treatment method. The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images showed that large amounts of spherical nanoparticles were well dispersed on the surface or embedded in the carbon nanofibers. And the nanoparticles were composed of Ni and NiO, as revealed by energy dispersive X-ray spectroscopy (EDX) and X-ray powder diffraction (XRD). In application to nonenzymatic glucose determination, the renewable NiCFP electrodes, which were constructed by simply mixing the electrospun nanocomposite with mineral oil, exhibited strong and fast amperometric response without being poisoned by chloride ions. Low detection limit of 1 mu M with wide linear range from 2 mu M to 2.5 mM (R = 0.9997) could be obtained.

Theoretical studies on the reaction mechanism of oxidation of primary alcohols by Zn/Cu(II)-phenoxyl radical catalyst

The catalytic mechanism for the oxidation of primary alcohols catalyzed by the two functional models of galactose oxidase (GOase), M-II L (M = Cu, Zn; L = N,N'-bis(3,5-di-tert-butyl-2-hydroxyphenyl)1-2-diiminoquinone)), has been studied by use of the density functional method B3LYP The catalytic cycle of Cu- and Zn-catalysts consists of two parts, namely, substrate oxidation (primary alcohol oxidation) and O-2 reduction (catalyst regeneration). The catalytic mechanisms have been studied for the two reaction pathways (route 1 and route 2). The calculations indicate that the hydrogen atom transfer within the substrate oxidation part is the rate-determining step for both catalysts, in agreement with the experimental observation.