Preparation and characterization of nanostructured Bi<Subscript>2</Subscript>Se<Subscript>3</Subscript> and Sn<Subscript>0.5</Subscript>-Bi<Subscript>2</Subscript>Se<Subscript>3</Subscript>

Nanostructured Bi₂Se₃ and Sn_0.5-Bi₂Se₃ were successfully synthesized by hydrothermal coreduction from SnCl₂·H₂O and the oxides of Bi and Se. The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and field emission scanning electron microscope (FESEM). Bi₂Se₃ powders obtained at 180°C and 150°C consist of hexagonal flakes of 50–150 nm in side length and nanorods of 30–100 nm in diameter and more than 1 μm in length. The product obtained at 120°C is composed of thin irregular nanosheets with a size of 100–200 nm and several nanometers in thickness. The major phase of Sn_0.5-Bi₂Se₃ synthesized at 180°C is similar to that of Bi₂Se₃. Sn_0.5-Bi₂Se₃ powders are primarily nanorod structures, but small amount of powders demonstrate irregular morphologies.     

Magnetic properties and crystallization kinetics of Zn<Subscript>0.5</Subscript>Ni<Subscript>0.5</Subscript>Fe<Subscript>2</Subscript>O<Subscript>4</Subscript>

Precursor of nanocrystalline Zn0.5Ni0.5Fe2O4 was obtained by grinding mixture of ZnSO4·7H2O,NiSO4·6H2O,FeSO4·7H2O,and Na2CO3·10H2O under the condition of surfactant polyethylene glycol(PEG)-400 being present at room temperature,washing the mixture with water to remove soluble inorganic salts and drying it at 373 K.The spinel Zn0.5Ni0.5Fe2O4 was obtained via calcining precursor above 773 K.The precursor and its calcined products were characterized by differential scanning calorimetry(DSC) ,Fourier transform infrared(FT-IR) ,X-ray diffraction(XRD) ,and vibrating sample magnetometer(VSM) .The result showed that Zn0.5Ni0.5Fe2O4 obtained at 1073 K had a saturation magnetization of 74 A·m2·kg-1.Kinetics of the crystallization process of Zn0.5Ni0.5Fe2O4 was studied using DSC technique,and kinetic parameters were determined by Kissinger equation and Moynihan et al.equation.The value of the activation energy associated with the crystallization process of Zn0.5Ni0.5Fe2O4 is 220.89 kJ·mol-1.The average value of the Avrami exponent,n,is equal to 1.59±0.13,which suggests that crystallization process of Zn0.5Ni0.5Fe2O4 is the random nucleation and growth of nuclei reaction.     

Synthesis and electrochemical performances of LiCoO<Subscript>2</Subscript> recycled from the incisors bound of Li-ion batteries

A new LiCoO₂ recovery technology for Li-ion batteries was studied in this paper. LiCoO₂ was peeled from the Al foil with dimethyl acetamide (DMAC), and then polyvinylidene fluoride (PVDF) and carbon powders in the active material were eliminated by high temperature calcining. Subsequently, Li₂CO₃, LiOH·H₂O and LiAc·2H₂O were added into the recycled powders to adjust the Li/Co molar ratio to 1.00. The new LiCoO₂ was obtained by calcining the mixture at 850°C for 12 h in air. The structure and morphology of the recycled powders and resulting samples were studied by XRD and SEM techniques, respectively. The layered structure of LiCoO₂ synthesized by adding Li₂CO₃ is the best, and it is found to have the best characteristics as a cathode material in terms of charge-discharge capacity and cycling performance. The first discharge capacity is 160 mAh·g⁻¹ between 3.0–4.3 V. The discharge capacity after cycling for 50 times is still 145.2 mAh·g⁻¹.     

疏水性硼酸镧纳米棒的制备及其在菜籽油中的摩擦磨损性能(英文)

采用水热法合成油酸修饰的硼酸镧纳米棒(OA/La BO3·H2O),利用X射线衍射和扫描电镜等测试技术对其微观结构进行表征,并在四球摩擦试验机上考察其在菜籽油中的摩擦磨损性能。结果表明,所制备的OA/La BO3·H2O为直径约50 nm、长达500 nm的疏水性纳米棒。OA/La BO3·H2O能显著提高菜籽油的抗磨减摩性能;当OA/La BO3·H2O的添加量为1%(质量分数)时,菜籽油的抗磨减摩性能最佳。     

Electrochemical properties of carbon-coated LiFePO<Subscript>4</Subscript> and LiFe<Subscript>0.98</Subscript>Mn<Subscript>0.02</Subscript>PO<Subscript>4</Subscript> cathode materials synthesized by solid-state reaction

Olivine structured LiFePO4/C (lithium iron phosphate) and Mn2+-doped LiFe0. 98Mn0. 024/C powders were synthesized by the solid-state reaction. The effects of manganese partial substitution and different carbon content coating on the surface of LiFePO4 were considered. The structures and electrochemical properties of the samples were measured by X-ray diffraction (XRD), cyclic voltammetry (CV), charge/discharge tests at different current densities, and electrochemical impedance spectroscopy (EIS). The electrochemical properties of LiFePO4 cathodes with x wt. ％ carbon coating (x=3, 7, 11, 15) at γ=0. 2C, 2C (1C=170 mAh·g-1) between 2. 5 and 4. 3 V were investigated. The measured results mean that the LiFePO4 with 7 wt. ％ carbon coating shows the best rate performance. The discharge capacity of LiFe0. 98Mn0. 02PO4/C composite is found to be 165 mAh·g 1 at a discharge rate, γ=0. 2C, and 105 mAh·g-1 at γ=2C, respectively. After 10cycles, the discharge capacity has rarely fallen, while that of the pristine LiFePO4/C cathode is 150 mAh·g-1 and 98 mAh·g-1 at γ=0. 2 and 2C, respectively. Compared to the discharge capacities of both electrodes above, the evident improvement of the electrochemical performance is observed, which is ascribed to the enhancement of the electronic conductivity and diffusion kinetics by carbon coating and Mn2+-substitution.     

Nanocrystalline ZrO<Subscript>2</Subscript> preparation and kinetics research of phase transition

The precursor of nanocrystalline ZrO2 was synthesized by solid-state reaction at low heat using ZrOCl2·8H2O,and Na2CO3·10H2O as raw materials.The nanocrystalline ZrO2 was obtained by calcining the precursor.The precursor and its calcined products were characterized using TG/DTA,FT-IR,XRD,and SEM.The results showed that the precursor dried at 353 K was a zirconyl carbonate compound.When the precursor was calcined at 673 K for 150 min,highly crystallization ZrO2 with tetragonal structure (space group P42/nmc (137)) was obtained with a crystallite size of 24 nm.However,when the precursor was calcined at 1023 K for 150 min,highly crystallization ZrO2 with monoclinic structure (space group P21/c (14)) was obtained with a crystallite size of 20 nm.The mechanism and kinetics of the thermal process of the precursor were studied using DTA and XRD techniques.Based on the Kissinger and Arrhenius equation,the values of the activation energies associated with the thermal process of the precursor were determined to be 26.80 and 566.73 kJ·mol-1 for the first and third steps,respectively.The mechanism of ZrO2 phase transition from tetragonal to monoclinic structure is the random nucleation and growth of nuclei reaction.     

Photocatalytic activity of La-doped ZnO nanostructure materials synthesized by sonochemical method

ZnO nanostructure materials doped with different La contents were synthesized by sonochemical method. The products were characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM),transmission electron microscopy(TEM), Raman spectroscopy, and Fourier transform infrared spectroscopy(FTIR). In this research, XRD patterns of pure ZnO and La-doped ZnO are specified as hexagonal wurtzite ZnO structure with no detection of La2O3 phase. SEM and TEM characterization revealed the flower shape of pure ZnO built-up from petals of hexagonal prisms with hexagonal pyramid tips. Upon doping with La, the flower-shaped ZnO is broken into individual 1D prism-like nanorods. Photocatalytic activities of the as-synthesized products were determined by measuring the degradation of methylene blue(MB) under ultraviolet–visible(UV) light irradiation.Among them, the 2.0 mol% La-doped ZnO shows better photocatalytic properties than any other products.     

Fabrication and magnetic properties of NiFe<Subscript>2</Subscript>O<Subscript>4</Subscript> nanorods

NiFe₂O₄ nanorods have been successfully synthesized via thermal treatment of the rod-like precursor fabricated by Ni-doped α-FeOOH, which was enwrapped by the complex of citric acid and Ni²⁺. The morphology evolution during the calcination of the precursor nanorods was investigated with transmission electron microscopy (TEM), and the phase and the magnetic properties of samples were analyzed through X-ray diffraction (XRD) and vibrating sample magnetometer (VSM). The results indicated that the diameter of the NiFe₂O₄ nanorods obtained ranged between 30 and 50 nm, and the length ranged between 2 and 3 μm. As the calcination temperature was up to 600°C, the coercivity, saturation magnetization, and remanent magnetization of the samples were 36.1 kA·m⁻¹, 27.2 A·m²·kg⁻¹, and 5.3 A·m²·kg⁻¹, respectively. The NiFe₂O₄ nanorods prepared have higher shape anisotropy and superior magnetic properties than those with irregular shapes.     

Electrochemical properties of spinel compound LiNi_（0.5）Mn_（1.2）Ti_（0.3）O_4 as cathode materials for lithium ion batteries

The electrochemical properties of spinel compound LiNi0.5Mn1.2Ti0.3O4 were investigated in this study.The chemicals LiAc·2H2O,Mn(Ac)2·2H2O,Ni(Ac)2·4H2O,and Ti(OCH3)4 were used to synthesize LiNi0.5Mn1.2Ti0.3O4 by a simple sol-gel method.The discharge capacity of the sample reached 134 mAh/g at a current rate of 0.1C.The first and fifth cycle voltammogram almost overlapped,which showed that the prepared sample LiNi0.5Mn1.2Ti0.3O4 had excellent good cycle performance.There were two oxidation peaks at 4.21 V and 4.86 V,and two reduction peaks at 4.55 V and 3.88 V in the cycle voltammogram,respectively.By electrochemical impedance spectroscopy and its fitted result,the lithium ion diffusion coefficient was measured to be approximately 7.76 × 10?11 cm2/s.     

Thermal activation currents of biocompatible nanocrystalline calcium hydroxyapatite Ca<Subscript>10</Subscript>(PO<Subscript>4</Subscript>)<Subscript>6</Subscript>(OH)<Subscript>2</Subscript>

Nanocrystalline stoiochiometric calcium hydroxyapatite, Ca₁₀(PO₄)₆(OH)₂ (NCHA), a counterpart of the inorganic osseous tissue component, is synthesized under biomimetic conditions. Methods of physico-chemical analysis (XRD, IRS, derivatography, DSC, ESCA, SEM, TEM) are used to identify the products of synthesis. The temperature dependence of thermally stimulated currents (TSCs) of NCHA is studied in the temperature range of 300–600 K and the effect of the dispersion degree on TSCs is analyzed.     

Performance and capacity fading reason of LiMn<Subscript>2</Subscript>O<Subscript>4</Subscript>/graphite batteries after storing at high temperature

Spinel LiMn₂O₄ was synthesized by a solid-state method. A 204468-size battery was fabricated and stored at 55°C. The structure and morphology of the LiMn₂O₄ cathode were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM) technique. Energy dispersive spectroscopy (EDS) was used to analyze the surface component of the carbon anode. The discharge capacities of LiMn₂O₄ stored for 0, 24, 48, and 96 h are 106, 98, 96, and 92 mAh·g⁻¹, respectively. The cyclic performance is improved after storage. The capacity retentions of LiMn₂O₄ stored for 0, 24, 48, and 96 h are 83.8%, 85.8%, 86.9%, and 88.6% after 180 cycles. The intensity of all the LiMn₂O₄ diffraction peaks is weakened. Mn is detected from the carbon electrode when the battery is stored for 96 h. Cyclic voltammograms and electrochemical impedance spectroscopy (EIS) were used to examine the surface state of the electrode after storage. The results show that the resistance and polarization of LiMn₂O₄/electrolyte is increased after storage, which is responsible for the fading of capacity.     

Zur Korrosion von unlegiertem Stahl und Aluminium in wäßrigen Lösungen von Ammoniak und Kohlensäure — 1. Mitteilung: Korrosionsprodukte

Corrosion of unalloyed steel and aluminium in aqueous solution of ammonia and carbonic acid-1. Communication:Corrosion products Two new corrosion products were detected in testing of pure iron, rimming unalloyed steel, aluminium (99,9) and Al-Mg 1,5 in aerated aequous solutions of 130 g/l NH₃ and 80/l Co₂ at 60°. On iron and unalloyed steel the compound (NH₄)₂Fe₂(OH)₄(CO)₃ · H₂O was formed and on aluminium or Al-Mg 1,5 NH₄Al(OH)₂CO₃ · H₂. Both compounds were synthesized and compared by X-ray diffraction, IR spectrum, thermoanalysis, and chemical analysis with published literature. For NH₄Al(OH)₂CO₃ · H₂O the unit cell was calculated which changes somewhat with for the corrosion product are a = 6,64 Å; b = 11,99 Å; c = 5,76 Å. Orthorhombic lattice, aspect C*c*, or (a*) = 13.29 Å; C* = 11,99 Å (hexagonal lattice, pseudohexagonal?). The measured density = 2.03 g · the calculated 2,29 g · cm for Z = 4. The infrared spectrum was partly newly coordinated. Between aluminium metal and NH₄Al(OH)₂CO₃H₂O epitaxial relations are possible, which could explain the higher resistance against corrosion in comparison with steel in the test solution.     

通过水性还原法用NaBH4制备纳米铜颗粒过程中反应参数对制备过程的影响（英文）

通过水溶液还原法制备纳米铜颗粒,研究了不同反应条件对制备纳米铜的影响。制备纳米铜的最优条件是:当溶液 pH为12、温度为 313K、1%的明胶作为分散剂时,将0.4mol/L NaBH4加入含有 1.2mol/L 氨水的0.2mol/L CuSO4溶液中。此外,进行了一系列实验来模拟反应进程。结果表明,氨水能改变反应进程。当溶液 pH为10时,氨水将Cu2+转化为铜氨络合物,然后被 NaBH4还原为铜颗粒。当溶液pH为12时,氨水将Cu2+转化为氢氧化铜,然后被 NaBH4还原为铜颗粒。     

Effect of heat treatment of titanium substrates on the properties of IrO<Subscript>2</Subscript>-Ta<Subscript>2</Subscript>O<Subscript>5</Subscript> coated anodes

The Ti substrates of IrO 2 -Ta 2 O 5 coated anodes were treated by solid-solution and aging, stress relieving annealing, and recrystallization annealing, and the coatings were prepared by thermal decomposition of a mixture of H 2 IrCl 6·6H 2 O dissolved in hydrochloric acid and TaCl 5 dissolved in alcohol. Scanning electron microscopy (SEM), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and accelerated life test (ALT) were employed to study the microstructure and electrochemical properties of the anodes. Compared with the anode without heat treatment, the anodes with heat treatment are of higher electrochemical activity and longer accelerated life; especially, the anode with recrystallization annealing treatment has the best electrochemical properties and the longest accelerated life.     

Synthesis of LiFePO<Subscript>4</Subscript>/C as cathode material by a novel optimized hydrothermal method

Olivine LiFePO 4 , as a cathode material for lithium ion batteries, was prepared by a novel optimized hydrothermal method; afterwards, the product mixed with glucose was two-step (350℃ and 700℃) calcinated under high-purity N 2 atmosphere to obtain the LiFePO 4 /C composite. The study on the hydrothermal preparation method, which focused on the influences of molar ratios, initial pH value, reaction temperature, and duration, was made to promote the resultant performances and to investigate the relations between the performances and the reaction conditions. The resultant samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and electrochemical tests, which include charge-discharge, electrochemical impedance spectroscopy, and cyclic voltammetry. The result shows that the optimal hydrothermal condition is to set the Li:Fe:P molar ratio at 3:1:1 and the reaction temperature at 180℃ for 5 h duration with an initial pH value of 7. The optimized sample, with an average particle size of 100 to 300 nm and a discharge capacity of 118.2 mAh·g-1 at 0.1C, exhibits a stable and narrow-gapped charge-discharge platform and small capacity losses after cycles.     

Preparation and optical properties of Y<Subscript>2</Subscript>O<Subscript>3</Subscript>/SiO<Subscript>2</Subscript> powder

Y(NO3)3 and NH3·H2O were used as a raw materials,and nano-Y2O3 powder was successfully synthesized by a precipitation method.Employing TEOS as a raw material,SiO2 powder was successfully prepared by a alkoxide-hydrolysis method,and a Y2O3/SiO2 composite powder was obtained by coating.The Y2O3,SiO2,and Y2O3/SiO2 powders were characterized using X-ray diffraction(XRD),scanning electron microscopy(SEM),and Fourier transform infrared spectrophotometer(FT-IR);the Y2O3 and Y2O3/SiO2 powders were further examined ...     

Cr doping effect in B-site of La<Subscript>0.75</Subscript>Sr<Subscript>0.25</Subscript>MnO<Subscript>3</Subscript> on its phase stability and performance as an SOFC anode

La_0.75Sr_0.25Cr _y Mn_1−y O₃ (LSCM) (y = 0.0–0.6) composite oxides were synthesized by a complexing process of combining ethylene diamine tetraacetic acid (EDTA) and citrate. X-ray diffraction (XRD), temperature-programmed reduction, electrical conductivity, I–V polarization, and impedance spectroscopy were conducted to investigate the Cr doping effect of La_0.75Sr_0.25MnO₃ on its phase stability and electrochemical performance as a solid-oxide fuel cell (SOFC) anode. The chemical and structural stabilities of the oxides increased steadily with increasing Cr doping concentration, while the electrical conductivity decreased on the contrary. At y ≥ 0.4, the basic perovskite structure under the anode operating condition was sustained. a cell with 0.5-mm-thick scandia-stabilized zirconia electrolyte and La_0.75Sr_0.25Cr _y Mn_1−y O₃ anode delivered a power density of ∼15 mW·cm⁻² at 850°C.     

Electronic structures of new tunnel barrier spinel MgAl<Subscript>2</Subscript>O<Subscript>4</Subscript>: first-principles calculations

The electronic structures of spinel MgAl2O4 and MgO tunnel barrier materials were investigated using first-principles density functional theory calculations. Our results show that similar electronic structures are found for the MgAl2O4 and MgO tunneling barriers. The calculated direct energy gaps at the Γ-point are about 5. 10 eV for MgAl2O4 and 4. 81 eV for MgO, respectively. Because of the similar feature in band structures from Γ high-symmetry point to F point (△ band), the coherent tunneling effect might be expected to appear in MgAl2O4-based MTJs like in MgO-based MTJs. The small difference of the surface free energies of Fe (2. 9 J. m-2) and MgAl2O4 (2. 27 J·m-2) on the {100}orientation, and the smaller lattice mismatch between MgAl2O4 and ferromagnetic electrodes than that between MgO and ferromagnetic electrodes, the spinel MgAl2O4 can substitute MgO to fabricate the coherent tunneling and chemically stable magnetic tunnel junction structures, which will be applied in the next generation read heads or spintronic devices.     

Synthesis of hierarchical hollow spherical CdS nanostructures by microwave hydrothermal process

Hierarchical hollow spherical CdS nanostructures were synthesized via a simple microwave hydrothermal(M-H) process using CdCl₂·H₂O and Na₂S₂O₃·5H₂O as raw materials and adding ethylenediaminetetraacetic acid (EDTA) as template. The obtained products were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), energy dispersive spectroscopy (EDS), and high-resolution transmission electron microscopy (HRTEM). Ultraviolet-visible (UV-vis) spectroscopy was used to study the optical properties of CdS. The results demonstrate that the hierarchical hollow spherical CdS with a diameter range of 400-600 nm is self-assembled by nanoparticles of 30 nm and in a wurtzite structure. EDTA and microwave play an important role on the formation of the hollow hierarchical morphology. The effect of the microwave and possible growth mechanism were discussed. UV-vis spectroscopy indicates that the CdS crystallites could be used as a potential blue light emitting material.     

Plasma-chemical polymerization in CH<Subscript>4</Subscript>-based mixtures containing various amounts of rare gases

For constant-current glow discharge in Ar + Ne + CH₄ mixtures in a pressure range of 13–250 Pa and a discharge current range of 5–100 mA, the following characteristics were determined: gas temperature; longitudinal electric field intensity; radiation line intensities of Ne (3p → 3s) and Ar (4p → 4s) transitions; intensities of H_α, H_β, and H_γ lines of Balmer series; concentrations of Ne, Ar, and H atoms in metastable and resonance states; concentration of atomic hydrogen; and growth rate of polymer films. The composition of the polymer films was analyzed with the use of infrared spectroscopy. Mathematical modeling of discharges under the selected conditions was carried out. The results of calculations were compared to the experimental data. The mechanism of processes that proceed in the glow discharge plasma is shown to depend strongly on the Ne-to-Ar concentration ratio, which results in the qualitative difference between the compositions of films that were grown at the same pressure and discharge current, as well as in the difference between the growth rates of the films.