The In Situ Synthesis of Fe(OH)3 Film on Fe Foam as Efficient Anode of Alkaline Supercapacitor Based on a Promising Fe3+/Fe0 Energy Storage Mechanism

Herein, a simple in situ charge/discharge activation strategy is proposed to synthesize Fe(OH)3 film on Fe foam as an efficient anode of supercapacitors. The physical characteristics of electrodes are characterized and the electrochemical energy storage performances are investigated. Importantly, it is demonstrated the as‐synthesized Fe(OH)3@Fe foam electrode adopted a novel Fe³⁺/Fe⁰ redox reaction mechanism for energy storage in alkaline electrolytes. Compared with previously reported Fe³⁺/Fe²⁺ mechanisms, the Fe³⁺/Fe⁰ redox couple shows a more promising application value (e.g., higher theoretical‐specific capacitance, excellent conductivity of its reduction state). As for supercapacitor anodes, the electrode achieves high areal capacitance of 5.55–3.94 F cm⁻² at a current range of 20–200 mA cm⁻² and shows good stability for high‐rate and long‐term cycling. The assembled single supercapacitor device gives a high energy density of 11.64–7.43 Wh m⁻² at a power density of 157–1461 W m⁻². More importantly, the as‐adopted in situ activation strategy may also have potential value for synthesizing other transition metal oxide‐based products.     

利用P-MBE方法在(400)Si衬底上生长ZnO薄膜

利用等离子体辅助分子束外延(P-MBE)方法在(400)Si衬底上生长ZnO薄膜。为改善生长后样品的质量,把样品解理成三块后,在不同温度下氧气气氛中退火。通过X射线衍射(XRD)谱和光致发光(PL)谱进行表征,讨论了用P-MBE方法在Si基上生长的ZnO的室温光致发光发光峰的可能原因。     

(Au)核(Ag)壳纳米微粒-火焰原子吸收光谱法测定过氧化氢

在90 ℃水浴条件下,以粒径为10 nm的纳米金做晶种,用柠檬酸三钠还原硝酸银,制备了平均粒径为30 nm的（Au）核（Ag）壳纳米微粒,用高速离心纯化除去过量的柠檬酸三钠获得了较纯的（Au）核（Ag）壳纳米微粒。在pH 3.8的HAc-NaAc缓冲溶液中,Fe2＋催化H2O2反应产生的羟基自由基可氧化（Au）核（Ag）壳纳米微粒生成银离子。离心后,离心液中的银离子可用火焰原子吸收光谱法在328.1 nm波长处测量。随着H2O2浓度增大,离心液中银离子浓度增加,其吸光度值增加。H2O2浓度在2.64～42.24 μmol·L-1范围内与上清液中银离子的原子吸收值ΔA呈良好的线性关系,回归方程为ΔA=0.014c-0.013 1, 相关系数为0.998 4,检出限为0.81 μmol·L-1 H2O2。当用于水样中H2O2的测定,获得了满意的结果。     

Growth of Semi-Insulating GaN Using N2 as Nucleation Layer Carrier Gas Combining with an Optimized Annealing Time

Semi-insulating （SI） GaN is grown using N2 as the nucleation layer （NL） carrier gas combined with an optimized annealing time by metalorganic chemical vapour deposition. Influence of using 1-12 and N2 as the NL carrier gas is investigated in our experiment. It is found that the sheet resistance of unintentionally doped GaN can be increased from 10^4 Ω/sq to 10^10 Ω/sq by changing the NL carrier gas from 1-12 to N2 while keeping the other growth parameters to be constant, however crystal quality and roughness of the tilm are degraded unambiguously. This situation can be improved by optimizing the NL annealing time. The high resistance of GaN grown on NL using N2 as the carrier gas is due to higher density of threading dislocations caused by the higher density of nucleation islands and small statistic diameter grain compared to the one using 1-12 as carrier gas. Annealing the NL for an optimized annealing time can decrease the density of threading dislocation and improve the tilm roughness and interface of AlGaN/GaN without degrading the sheet resistance of as-grown GaN signiticantly. High-quality SI GaN is grown after optimizing the annealing time, and AlGaN/GaN high electron mobility transistors are also prepared.     

Incorporation of Siderophore Binding Sites in a Dipodal Fluorescent Sensor for Fe(III)

A new fluorescent probe 3, has been developed for the detection of Fe(III) in water based samples. The design of 3 involved the incorporation of Fe(III) binding sites observed in naturally occurring Siderophores into a synthetic sensing assembly. The probe, containing two Schiff base receptors connected to a mesitylene platform, was prepared in two steps. The dipodal sensor displayed good selectivity for Fe(III) when tested against other physiological and environmentally important metal ions, in HEPES buffered solution at pH 7.0, through a quenching of the fluorescent intensity. Stern-Volmer analysis of this quenching interaction indicated a 1:1 (host : guest) binding stoichiometry between the probe and Fe(III). The association constant, K _a calculated using the Benesi-Hildebrand equation was found to be 3.8 × 10⁴ M⁻¹. Crucially, the sensor was capable of measuring Fe(III) competitively in solutions containing both Fe(III) and Cu(II). Thus, the adoption of Fe(III) binding sites found in nature, into synthetic luminescent assemblies has proven an effective design strategy for the development of new Fe(III) probes. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Vector magnetization of a Cr monolayer on an Fe(110) film

The non-collinear magnetic moment distribution at the Cr/Fe(110) interface of an Fe(110) thin film covered by a Cr monolayer is revealed by means of periodic Anderson model calculations. It is shown that the Cr surface has two magnetically non-equivalent sites with magnetic moments canted to each other. The Fe atoms in the subsurface monolayer also acquire two magnetically non-equivalent sites with magnetic moments canted to each other. Non-collinearity is shown to be a ground state for the Cr/Fe(110) multilayer.     

Growth of SiO2 on InP substrate by liquid phase deposition

We have grown silicon dioxide (SiO₂) on indium phosphorous (InP) substrate by liquid phase deposition (LPD) method. With inserting InP wafer in the treatment solution composed of SiO₂ saturated hydrofluorosilicic acid (H₂SiF₆), 0.1 M boric acid (H₃BO₃) and 1.74 M diluted hydrochloric acid (HCl), the maximum deposition rate and refractive index for the as-grown LPD-SiO₂ film were about 187.5 Å/h and 1.495 under the constant growth temperature of 40 °C. The secondary ion mass spectroscope (SIMS) and energy dispersive X-ray (EDX) confirmed that the elements of silicon, oxygen, and chloride were found in the as-grown LPD-SiO₂ film. On the other hand, the effects of treatment solution incorporated with the hydrogen peroxide (H₂O₂) that can regulate the concentration of OH⁻ ion were also shown in this article. The experimental results represented that the deposition rate decreases with increasing the concentration of hydrogen peroxide due to the reduced concentration of SiO₂ saturated H₂SiF₆ in treatment solution.     

CHx(x=2~4)在Fe(110)表面吸附的DFT研究

采用密度泛函理论与周期平板模型相结合的方法,对物种CHx(x=2~4)在Fe(110)表面的top,hcp,SB和LB位的吸附模型进行了结构优化、能量计算,得到了各物种较有利的吸附位;并对最佳吸附位进行密立根电荷和总态密度分析。结果表明：CH4在Fe(110)表面的最稳定吸附位都是SB位,吸附能别是-38.14 kJ•mol-1,CH3在Fe(110)表面的最稳定吸附位都是top位,吸附能别是-171.78 kJ•mol-1,而CH2在Fe(110)表面的最稳定吸附位hcp的吸附能是-342.43 kJ•mol-1;CH3 和CH2两物种与金属表面成键,属于化学吸附。     

CHx(x=2~4)在Fe(110)表面吸附的DFT研究

采用密度泛函理论与周期平板模型相结合的方法,对物种CHx(x=2~4)在Fe(110)表面的top,hcp,SB和LB位的吸附模型进行了结构优化、能量计算,得到了各物种较有利的吸附位;并对最佳吸附位进行密立根电荷和总态密度分析。结果表明：CH4在Fe(110)表面的最稳定吸附位都是SB位,吸附能别是-38.14 kJ•mol-1,CH3在Fe(110)表面的最稳定吸附位都是top位,吸附能别是-171.78 kJ•mol-1,而CH2在Fe(110)表面的最稳定吸附位hcp的吸附能是-342.43 kJ•mol-1;CH3 和CH2两物种与金属表面成键,属于化学吸附。     

H2S在Fe(100)面吸附的第一性原理研究

基于密度泛函理论第一性原理, 在广义梯度近似下, 研究了表面覆盖度为0.25 ML (monolayer)时硫化氢分子在Fe(100)面吸附的结构和电子性质, 并与单个硫原子吸附结果进行了对比. 结果表明: 硫化氢分子吸附在B2位吸附能最小为-1.23 eV, 最稳定, B1位吸附能最大为-0.01 eV, 最不稳定; 并对硫化氢分子在B1位和B2位吸附后的电子态密度进行了分析, 也表明了吸附在B2位稳定, 且吸附在B2位后硫化氢分子几何结构变化不大; 将硫化氢中硫原子吸附与单个硫原子吸附的电子性质进行了比较, 发现前者吸附作用非常微弱; 同时对吸附后的Fe(100)面进行了对比, 单个硫原子吸附的Fe(100)面电子态密度出现了一系列峰值且离散分布, 生成了硫化亚铁, 表明在硫化氢环境下, 主要是硫化氢析出的硫原子发生了吸附. 关键词： 第一性原理 Fe(100)表面 吸附能 硫化氢     

Magnetic properties of hard magnetic (Fe,Cr)3Sn2 intermetallic compound

By high‐throughput screening Fe–Sn–Cr, (Fe,Cr)₃Sn₂ (Fe_53.5Cr_6.5Sn₄₀) with high potential as new hard magnetic compound is discovered. To produce the compound in large amounts a special procedure is needed. By quantitative microscopy and magnetometry promising intrinsic properties, J_s ～ 0.9 T, K₁ ～ 1.7 MJ/m³, T_C ～ 612 K, are found with K₁ increasing with temperature.

     

火焰原子吸收光谱法直接测定红细胞中Cu,Zn,Fe的含量

本文采用沈阳分析仪器厂产４０２型原子吸收分光光度计，在标准溶液中加入ＮａＣｌ溶液作为基体改进剂，用火焰原子吸收光谱法直接测定红细胞中Ｃｕ、Ｚｎ、Ｆｅ的含量，不仅消除基体干扰，而且提高了测定Ｃｕ和Ｚｎ的灵敏度，Ｃｕ、Ｚｎ、Ｆｅ的平均回收率为１０１％、１０３％及９９％；相对标准偏差分别为４．６％、２．２％及９．６％。     

Removal of lead from aqueous solutions by using the natural and Fe(III)-modified zeolite

In the present study, the sorption of lead by the natural and Fe(III)-modified zeolite (clinoptilolite) is described. The characterization of the natural zeolite-rich rock and the Fe(III)-modified form was performed by chemical analysis, point of the zero charge (pH_pzc), X-ray powder diffraction, applying the Rietveld/RIR method for the quantitative phase analysis, and scanning electron microscopy. The effects of sorbents dose and the initial lead concentrations on its sorption by two sorbents were investigated. For both sorbents, it was determined that at lower initial concentrations of lead, ion exchange of inorganic cations in zeolites with lead, together with uptake of hydrogen dominated, while at higher initial lead concentrations beside these processes, chemisorption of lead occurred. Significantly higher sorption of lead was achieved with Fe(III)-modified zeolite. From sorption isotherms, maximum sorbed amounts of lead, under the applied experimental conditions, were 66 mg/g for the natural and 133 mg/g for Fe(III)-modified zeolite. The best fit of experimental data was achieved with the Freundlich model (R² ≥ 0.94).     

Growth, morphology, and crystalline structure of ultrathin Fe films on Cu3Au(100)

The growth mode, morphology, and crystalline structure of Fe films on Cu₃Au(100) are studied for different growth temperatures (300 and 160 K), using in situ scanning tunneling microscopy and low energy electron diffraction. Multilayer growth is found to be predominant for both growth temperatures. Only in films of 3–4 monolayers (ML) grown at 300 K is a mixed mode of layer-by-layer growth and island growth observed. An fcc-to-bcc structural transformation, accompanied by a distinct change in the surface topography, starts at about 3.5 ML and 5.5 ML for the growth temperatures of 300 and 160 K, respectively. For both growth temperatures bcc-like Fe in Fe/Cu₃Au(100) assumes, most likely through a Bain path, a surface plane with the (100) rather than the (110) orientation found in the Fe/Cu(100) system. Both the surface morphology and the onset thickness of the fcc–bcc structural transformation are shown to be strongly affected by the growth temperature.     

Y(Fe,M)12化合物的电子结构与磁性(M=Nb,Si)

采用新近发展的全势能线性缀加平面波((L)APW) 局域轨道(lo)和广义梯度近似(GGA)密度泛函方法计算了Y(Fe,M)12化合物(M=Nb,Si)的电子结构,得到了相应的总态密度和局域态密度,并分析了替代原子与替代晶位不同引起态密度的变化。根据计算结果预测的居里温度变化与实验结果基本一致。     

Nd(Fe,Si)11Cx化合物的全电子计算(x=0,2)

采用基于第一原理的全势能线性缀加平面波加局域轨道((L)APW lo)方法对Nd(Fe,Si)11Cx化合物(x=0,2)的电子结构进行了计算,得到了化合物态密度和磁矩等信息.计算结果表明NdFe9Si2化合物中Si原子主要与4b和32i位Fe原子产生杂化,导致Fe原子磁矩减小.NdFe9Si2C2化合物C原子使32i位Fe原子磁矩进一步降低,同时减弱了Si原子的影响,使得4b位Fe原子磁矩增大.     

Quenched Fe moment in the collapsed tetragonal phase of Ca_(1-x)Pr_x Fe_2As_2

We report 75As NMR studies on single crystals of rare-earth doped iron pnictide superconductor Ca1-xPrxFe2As2 . In both cases of x = 0.075, 0.15, a large increase of νq upon cooling is consistent with the tetragonal-collapsed tetragonal structure transition. A sharp drop of the Knight shift is also seen just below the structure transition, which suggests the quenching of Fe local magnetism, and therefore offers important understanding of the collapsed tetragonal phase. At even low temperatures, the 1/75T1 is enhanced and forms a peak at T ≈ 25 K, which may be caused by the magnetic ordering of the Pr3+ moments or spin dynamics of mobile domain walls.     

Growth of Fe on Ge(1 1 1) at room temperature studied by X-ray photoelectron diffraction

The growth of ultrathin Fe films of various coverages on Ge(1 1 1) at room temperature using molecular beam epitaxy (MBE) was studied via X-ray photoelectron diffraction (XPD or XPED) together with low energy electron diffraction (LEED) and X-ray photoelectron spectroscopy (XPS). All experimentally observed XPD patterns suggested local order structures of the Fe layers for all thicknesses studied. The short-range order of the resulting structures was found to be enhanced for thinner layers whereas the long-range order was gradually lost with increasing Fe thicknesses. At a very low coverage of 0.8 Å Fe and Ge tend to react to the partly ordered structure in which Fe atoms were located in local environments similar to those for higher Fe coverages. Comparison of theoretical and experimental XPD patterns, along with XPS results, showed that intermixing between Fe and Ge occurred during the pseudomorphic growth with a stacking fault near the interface for all Fe coverages under study. Nevertheless, small percentage of domains without the stacking fault was also found to coexist with those with the stacking fault by performing a quantitative analysis of a reliability factor R of the Fe2p pattern for 5.4 Å. The orientation changes of the Ge2p and Ge3d XPD patterns with Fe thickness were unambiguously explained in terms of their different dependencies on the overlayer thickness due to the different inelastic mean free path lengths used in the simulations. Also, Fe got increasingly enriched in the grown layers with increased Fe coverage. The resulting structures and intermixing are discussed in detail.