可调式过电压保护装置在阳煤电网电粉线的应用分析

介绍了技术应用线路的运行工况,对可调式过电压保护装置进行了技术分析,并详细阐述了可调式过电压保护器在电粉线的安装应用情况及效果。

Visible-Light Activities of Erbium Doped BiVO4 Photocatalysts

Er-doped BiVO4 composite photocatalyst was hydrothermal synthesized and characterized by X-ray powder diffraction, scanning electron microscopy, energy-dispersive X-ray Spectroscopy, X-ray photoelectron spectroscopy, and UV-Vis diffuse reflectance spectra techniques. The activity of the catalyst was determined by oxidative decomposition of methyl orange in aqueous solution under visible-light irradiation. X-ray photoelectron spectroscopy and energy-dispersive X-ray Spectroscopy analysis revealed that the doped Er existed in the form of Er2O3. It also showed that the Er doping can enhance the visible-light absorption abilities of catalysts and their visible-light-driven photocatalytic activities in comparison with those of pure BiVO4.

Characterization of ultrafine copper powder prepared by novel electrodeposition method

The auto-evolved ultrafine copper powders were synlhesized via a novel electrodeposition route performed by ultrasonic dispersion of the electrolyte. The properties of the samples obtained were characterized by X-ray powder diffractometry （XRD）, transmission electron microscopy （TEM）, scanning electron microscopy （SEM） and laser size distribution analyzer （SL） respectively. The formation mechanisms of the powders and the efficiency of the elctrodeposition were discussed. The results show that the as-prepared powders are high-purity copper nanoparticles with the fcc structure taking a mixture of fishbone-like and irregular shapes When the concentration of Cu^2＋ increases from 0.03 to 0.09 mol/L, the average size of copper particles increases from 0.92 to 1.80 μm, and current efficiency of electrodeposition linearly changes from 66.5% to 91.3%.

Development of a pentaethylenehexamine-modified solid support adsorbent for CO_2 capture from model flue gas

A novel solid support adsorbent for CO2capture was developed by loading pentaethylenehexamine(PEHA)on commercially available mesoporous molecular sieve MCM-41 using wet impregnation method.MCM-41 samples before and after PEHA loading were characterized by X-ray powder diffraction,N2adsorption/desorption,thermal gravimetric analysis and scanning electron microscope to investigate the textural and thermo-physical properties.CO2adsorption performance was evaluated in a fixed bed adsorption system.Results indicated that the structure of MCM-41 was preserved after loading PEHA.Surface area and total pore volume of PEHA loaded MCM-41 decreased with the increase of loading.The working adsorption capacity of CO2could be significantly improved at 60%of PEHA loading and 75°C.The effect of the height of adsorbent bed was investigated and the best working adsorption capacity for MCM-41-PEHA-60 reached 165 mg·(g adsorbent)-1at 75°C.Adsorption/desorption circle showed that the CO2working adsorption capacity of MCM-41-PEHA kept stable.

Dissolution mechanism and solubility of hemimorphite in NH_3-(NH_4)_2SO_4-H_2O system at 298.15 K

The dissolution mechanism of hemimorphite in NH3-（NH4）2SO4-H2O system at 298.15 K was investigated by X-ray powder diffraction （XRD）, scanning electron microscopy （SEM）, Fourier transform infrared spectroscopy （FTIR） and X-ray photoelectron spectroscopy （XPS） analysis. The results show that hemimorphite is soluble in NH3-（NH4）2SO4-H2O system and its residue exists in the form of an amorphous SiO2 layer on the hemimorphite surface. The XPS data also indicate that the Si 2p3/2 and O ls spectra of the hemimorphite are broadened and shift to higher binding energies and their binding energies are closer to silica with an increase of total ammonia and time. Solubility of hemimorphite in NH3-（NH4）2SO4-H2O system was measured by means of isothermal solution method at 298.15 K based on the study of the dissolution mechanism of hemimorphite. The results show that the solubility of zinc in solution increases firstly and then decreases with the increase of cr（NH3） （total ammonia concentration） at different NH3/NH4^＋ ratios. The solubility of silicon in solution decreases from 0.0334 mol/kg in ct（NH3）-4.1245 mol/kg NH3-（NH4）2SO4-H2O solution to 0.0046 mol/kg in cT（NH3）=7.6035 mol/kg NH3-（NH4）2SO4-H2O solution.

Influence of Synthesis Parameters with Low Seed Addition on the Crystallinity of ZSM-5

ZSM-5 zeolite microparticles （MPs） were synthesized under hydrothermal condition using a low crystal seed addition approach without template. The synthesis parameters such as the seed addition amount, the SiOJA1203 ratio, the aluminum source, the feeding addition method, aging, and crystallization were investigated. The structure, morphology and composition of the as-synthesized ZSM-5 zeolite MPs were characterized by X-ray powder diffraction （XRD）, scanning electron microscopy （SEM）, laser particle size distribution （PSD） measurements, and inductively coupled plasma-atomic emission spectrometry （ICP-AES）. The SIO2/A1203 ratio of ZSM-5 zeolite MPs was in the range of 20~80. The low seed addition was beneficial to improving the crystallinity and shortening the crystallization time, and the suitable amount of seed was 0.25% （SIO2）. The ZSM-5 zeolite MPs synthesized with aluminium nitrate nonahydrate used as the aluminum source exhibited a relatively high crystallinity. An appropriate aging time could eliminate the effect of feeding addition method and effectively adjust particle size. The particle size of ZSM-5 zeolite obtained at an aging time of 20 h was around 2.0 I.tm. Prolonging the aging time appropriately could also shorten the high-temperature crystallization time. The suitable aging time was 24 h, and the relative crystallinity of ZSM-5 zeolite could reach up to 99% after crystallization for 24 h at 180 ℃

Influence of synthesis parameters on the properties of LiFePO4/C cathode material

The influence of sintering temperature, carbon content and dispersive agent in bail-milling was investigated on the properties of LiFePO4/C prepared using Fe2O3, NH4H2PO4, Li2CO3 and glucose via solid state reaction. X-ray powder diffraction, scanning electron microscopy and charge-discharge test were applied to the characterization of the LiFePO4/C samples synthesized under different conditions. Sintering temperature affects the crystallite/ particle size and degree ofcrystallinity of LiFePO4, formation of Fe2P and maintenance of carbon in LiFePO4/C. Car- bon maintenance is favored by low sintering temperature, and 700 ℃ is optimum for synthesis of LiFePO4/C with superior electrochemical performance. A higher carbon content in the range of 4.48%-11.03% results in a better rate capability for LiFePO4/C. The dispersive agent used in ball-milling impacts the existent state of carbon in the final product which subsequently determines its charge-discharge behavior. The sample prepared at 700 ℃ by using acetone as the dispersive agent in ball-milling exhibits an excellent rate capability and capacity retention without any fade at 0.1 C, 1C and 2C, with corresponding average discharge capacities of 153.8, 128.3 and 121.0 mA·h·g-1. rest2ectivelv, in the first 50 cvcles.

Molten Salt Synthesis of (K_(0.47)Na_(0.47)Li_(0.06))NbO_3 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.

Synthesis of Macro-Mesostructured γ-Al_2O_3 with Large Pore Volume and High Surface Area by a Facile Secondary Reforming Method

Through improving the aging process during synthesis of the support, γ-Al2O3 with large pore volume and high surface area was synthesized by a facile secondary reforming method. The synthesis parameters, such as the reaction temperature, the first aging temperature and the second aging temperature, were investigated. The textural properties of γ-Al2O3 were characterized by means of N2 adsorption-desorption isotherms, X-ray powder diffractometry （XRD）, scanning electron microscopy （SEM）, Fourier transform infrared （FTIR） spectroscopy and thermogravimetry （TG）. The experimental results indicated that AACH and amorphous A1OOH were the precursors of alumina, which were formed via precipitation from solutions after reaction of aluminum sulphate with ammonium hydrogen carbonate. The precursor nanocrystallites grew and re-assembled during the secondary reforming process, which resulted in an increased pore size and pore volume and a decreased bulk density. The as-synthesized γ-Al2O3 materials featured meso/macroporosity, large pore volume （2.175 cm^3/g）, high surface area （237.8 m^2/g）, and low bulk density （0.284 g/mL）.

Preparation and characterization of sulfated TiO_2 with rhodium modification used in esterification reaction and decomposition of methyl orange

A unique Rh/TiO2 solid acid catalyst modified with H2S04 was synthesized and evaluated in the esterification reaction of propylene glycol methyl ether and decomposition of methyl orange （MO） in aqueous phase under halogen lamp irradiation. For this purpose, rhodium （Rh） nanoparticles were loaded on S02-/Ti02 via the photo-deposition method. It was found that S024-/Rh-Ti02 exhibited stronger catalytic activity than S02-/ Ti02. The new catalysts were characterized by X-ray powder diffraction （XRD）, Brunauer-Emmett-Teller （BET）, Transmission electron microscopy （TEM） and high-resolution （HRTEM）, X-ray photoelectron spec- troscopy （XPS） and Fourier Transform infrared spectroscopy （FrlR）. Results from XRD and BET show that S02-/Rh-Ti02 has higher specific surface area and smaller pore size than S02-fri02. The distribution of loaded Rh was found to be uniform with a particle size of 2-4 nm. Data from XPS reveal that Rh primarily exists as Rh~ and Rh3 ＋ in Rh-Ti02 and SO^-/Rh-TiO~. These valence forms of Rh likely contribute to the en- hanced catalytic activity. Furthermore, FT-IR spectra of the catalysts show an abundance of surface hydroxyl groups, which help the formation of hydroxyl radicals and the enhancement of surface acid density. The results show that more acid sites are formed on the sulfated Rh-Ti02, and these acidic sites are largely responsible for improving the catalytic performance. This superior SO]-/Rh-Ti02 catalyst has potential applications in reactions reouirinz efficient acid catalysts, includinz esterification reactions and waste water treatment.

Effects of temperature variation on Li_xFe PO_4/C(0

Li Fe PO4/C was prepared via solid state reaction and characterized with X-ray powder diffraction and charge–discharge test. As-prepared Li Fe PO4/C has a triphylite structure and exhibits an excellent rate capability and capacity retention. Electrochemical impedance spectroscopy(EIS) was applied to investigate LixFe PO4/C(0<x<1) electrode on temperature variation. The valid equivalent circuit for EIS fitting was determined which contains an intercalation capacitance for Li+ ion accumulation and consumption in the electrode reaction. The surface layer impedance needs to be included in the equivalent circuit when Li Fe PO4/C is deeply delithiated at a relatively high temperature. EIS examination indicates that a temperature rise leads to a better reversibility, lower charge transfer resistance, higher exchange current density J0 and greater Li+ ion diffusion coefficient for the LixFe PO4/C electrode process. The Li+ ion concentration in LixFe PO4/C is potential to impact the Li+ ion diffusion coefficient, and a decrease in the former results in an increase in the latter.

Facile synthesis of Zn_2GeO_4 nanorods toward improved photocatalytic reduction of CO_2 into renewable hydrocarbon fuel

Zn2GeO4 nanorods were prepared by a surfactant-assisted solution phase route.The as-prepared products were characterized by X-ray powder diffraction(XRD),scanning electron microscopy(SEM),high-resolution transmission electron microscopy(HRTEM),inductively coupled plasma atomic emission spectrometer(ICP-AES),UV-vis diffuse reflection spectroscopy and photoluminescence(PL) spectroscopy.The possible formation mechanism of Zn2GeO4 nanorods was discussed.It was supposed that the CTA+ cations preferentially adsorb on the planes of Zn2GeO4 nanorods,leading to preferential growth along the c-axis to form the Zn2GeO4 rods with larger aspect ratio and higher surface area,which showed the improved photocatalytic activity for photoreduction of CO2.The photoluminescence(PL) property of Zn2GeO4 nanorods was investigated through the emission spectra.

Comparative study of the mechanical properties,micro-structure,and composition of the cranial and beak bones of the great spotted woodpecker and the lark bird

Woodpeckers are well able to resist head injury during repeated high speed impacts at 6-7 m s-1 with decelerations up to 1000 g.This study was designed to compare the mechanical properties,microstructures and compositions of cranial bone and beak bone of great spotted woodpecker(Dendrocopos major) and the Mongolian sky lark(Melanocorypha mongolica).Microstructures were observed using micro-computed tomography and scanning electron microscopy and their compositions were characterized by X-ray powder diffraction and Fourier-transform infrared spectroscopy.Under high stress,the cranial bone and the beak of the woodpecker exhibited distinctive mechanical features,which were associated with differences in micro-structure and composition,compared with those of the lark.Evolutionary optimization of bone micro-structure has enabled functional adaptation to the woodpecker's specific lifestyle.Its characteristic micro-structure efficiently avoids head impact injury and may provide potential clues to the prevention of brain injury using bio-inspired designs of shock-absorbing materials.

Growth of silicon nanowires in aqueous solution under atmospheric pressure

A new method for growing silicon nanowires is presented. They were grown in an aqueous solution at a temperature of 85℃ under atmospheric pressure by using sodium methylsiliconate as a water-soluble silicon precursor. The structure, morphology, and composition of the as-grown nanowires were characterized by scanning electron microscopy, transmission electron microscopy, and energy dispersive X-ray spectrometry. It was also confirmed by X-ray powder diffraction and Raman spectroscopy that the silicon nanowire has a hexagonal structure. It was possible to grow the crystalline silicon nanowires at low temperature under atmospheric pressure because potassium iodide, which was used as a gold etchant, sufficiently increased the surface energy and reactivity of gold as a metal catalyst for the reaction of the Si precursor even at low temperature.

Surface Na2CO3 etching induced activity enhancement of 2D BiOI photocatalyst working under visible light

The visible light photocatalytic activity of two-dimensional （2D） BiOl microplates was intensively enhanced through simply dipping in Na2CO3 solutions at room temperature. The X-ray powder diffrac- tion （XRD） and scanning electron microscopy （SEM） investigations suggest that little amount of （BiO）2CO3 phase was formed on the surface of 2D BiOI via the in situ chemical conversion. The concen- tration of Na2CO3 solutions affected the structure, morphology, light absorption and surface element component of 2D BiOl. The surface loaded （BiO）2CO3 mainly trapped the photoinduced electrons of BiOI, improved the separation efficiency of photocharges and finally raised the photocatalytic activity of BiOl under visible light （λ 〉 420 nm）. Furthermore, the product of the as-prepared （BiO）2CO3/BiOI displayed excellent stability in the repeated experiment. This study provides a facile way to improve the photocatalytic activity of BiOX （X = CI, Br, I） by means of surface treatment with Na2CO3 solutions.

Squared-like BiOCl nanosheets synthesized by ethylene glycol-assisted solvothermal method and their photocatalytic performance

Bismuth oxychloride(Bi OCl) with morphology of squared-like nanosheet is synthesized by solvothermal method using ethylene glycol aqueous reaction solution. The product is characterized by X-ray powder diffraction(XRD), scanning electron microscopy(SEM), energy dispersive spectroscopy(EDS), transmission electron microscopy(TEM) and ultraviolet-visible(UV-Vis) diffuse reflection spectroscopy, respectively. The layered structure, the hydrogen bonding between hydroxyl groups and their selective adsorption cause the formation of the squared-like nanosheets. The photocatalytic degradation activity of the as-prepared Bi OCl is tested by the degradation of methyl orange under UV light irradiation. Repeating the degradation process four times under the same condition, the results show that the squared-like Bi OCl nanosheets present high photocatalytic activity and stability.