Metal-organic framework-derived porous carbon for the advanced aqueous zinc-ion hybrid capacitor

Aqueous zinc ion hybrid capacitors(ZIHCs)are considered one of the most promising electrochemical energy storage systems due to their high safety,environmental friendliness,low cost,and high power density.However,the low energy density and the lack of sustainable design strategies for the cathodes hinder the practical application of ZIHCs.Herein,we design the N and O co-doped porous carbon cathode by annealing metal-organic framework(ZIF-8).ZIF-8 retains the original dodecahedral structure with a high specific surface(2814.67 m^(2)/g)and I_(G)/I_(D) ratio of 1.0 during carbonization and achieves self-doping of N and O heteroatoms.Abundant defect sites are introduced into the porous carbon to provide additional active sites for ion adsorption after the activation of carbonized ZIF-8 by KOH treatment.The ZIHCs assembled with modified ZIF-8 as the cathode and commercial zinc foil as the anode show an energy density of 125 W∙h/kg and a power density of 79 W/kg.In addition,this ZIHCs device achieves capacity retention of 77.8%after 9000 electrochemical cycles,which is attributed to the diverse pore structure and plentiful defect sites of ZIF-8-800(KOH).The proposed strategy may be useful in developing high-performance metal-ion hybrid capacitors for large-scale energy storage.

氯化钠/纳米疏水二氧化硅超细干粉制备及灭火性能研究

选用氯化钠为基体制备金属火灾超细干粉灭火剂。应用反溶剂法对其改性,使纳米疏水二氧化硅吸附在氯化钠晶体表面,其中分散剂为PEG-1000。结果表明,纳米疏水二氧化硅的添加有利于细化氯化钠颗粒,但过量的添加会起反作用,最佳用量为3 wt%左右,平均粒径为2.18μm。镁片灭火实验证明超细复合干粉的灭火性能明显好于传统氯化钠灭火剂(商用D类灭火剂),纳米疏水二氧化硅最佳添加量为3 wt%,此时灭火时间仅需传统灭火剂的一半。最后利用FDS5.0模拟干粉颗粒与燃烧火焰作用过程,模拟结果表明干粉覆盖对火焰具有一定的抑制效果,并分析了复合干粉灭火机理。

Determination and Analysis of Heavy Metals Contents in Edible Fungi

[Objective] This study aimed to understand the status of heavy metal contamination in edible fungi, thereby providing some scientific basis for the safety of edible fungi. [Method] The heavy metal contamination status in four kinds of edible fungi, i.e., shitake mushroom, mushroom, agaric and needle mushroom, from Guiyang City and Tongren City, Guizhou Province was evaluated by flame atomic absorption spectrophotometry. [Result] Cu, Mn, Cr and Ni were detected in the four kinds of edible fungi from Guiyang and Tongren; the Cr contents in the four kinds of edible fungi from Guiyang and Tongren all exceeded the national standard, and the Cu contents all met the national standard; The Ni contents in agaric and needle mushroom from Guiyang, and the Ni contents in the four kinds of edible fungi from Tongren, all exceeded the national standard; the enrichment capacity of the four kinds of edible fungi for the four kinds of heavy metal elements ranked as Cu＇s Mn＇s Cr＇s Ni＇s; among the four kinds of edible fungi, mushroom showed the strongest enrichment capacity for the four kinds of heavy metal elements. [Conclusion] The heavy metal contamination in the four kinds of edible fungi was all severe in Guiyang and Tongren, especially in Tongren. There has been currently no national standard for Mn content in edible fungi, which needs to be developed as soon as possible.

Preparation and properties of flame-sprayed Mo-FeB-Fe cermet coatings

The powders of Mo2FeB2 cermet were prepared with Mo powders, Fe-B alloy powders and Fe powders as raw materials. Mo2FeB2 cermet coatings were prepared on Q235 steel by reactive thermal spraying （RTS） method and heated at 1 000 ℃ in vacuum oven of 1 kPa for 5 h. The properties of coatings were investigated. The results indicate that Fe2B appears after milling for 15 h in the powder at room temperature, a part of ternary borides （Mo2FeB2） are generated in powder sintered at 900 ℃. The coatings are composed of the major phases Mo2FeB2 and a-Fe, a little of Fe203, FeO and some pores. The bonding strength between the substrate and the ceramic coating is 32.73 MPa, the thermal-shock times is about 43 and the wear resistance is enhanced by approximately 5.28 times compared with that of the substrate, respectively. The comprehensive properties of Mo2FeB2 cermet coatings can be imoroved further after vacuum heat-treatment at 1 000 ℃ for 5 h.

Thermal stability,crystallization behavior,Vickers hardness and magnetic properties of Fe-Co-Ni-Cr-Mo-C-B-Y bulk metallic glasses

Thermal stability,crystallization behavior,Vickers hardness and magnetic properties of the Fe41Co7-xNixCr15Mo14C15B6Y2（x=0,1,3,5） bulk metallic glasses were investigated.The Fe41Co7-xNixCr15Mo14C15B6Y2（x=0,1,3,5） metallic glasses were fabricated by copper mold casting method.The thermal stability and crystallization behavior of the metallic glass rods were investigated by differential scanning calorimetry and isothermal experiments.Hardness measurements for samples annealed at different temperatures for different time were carried out at room temperature by the Vickers hardness tester,and magnetic measurements were performed at different temperatures by the vibrating sample magnetometer.It is shown that the addition of Ni does not play a positive role for enlarging ΔTx and GFA from parameter γ（=Tx/（Tg＋Tl））,and it can,however,increase the activation energy in the initial stage of crystallization by changing the initial crystallization behavior.The minor addition of Ni can refine the crystal grain obtained from the full crystallization experiment.The primary crystallization causes the decrease of hardness in these alloys,and as the crystallization continues,the hardness in all samples increases instead due to the precipitation of carbide and boride.The annealing temperature has an obvious effect on magnetic properties of these alloys,and the minor addition of Ni can effectively prevent the alloy annealed at high temperature to transform from paramagnetic to ferromagnetic state.

Integrated interpretation of dual frequency induced polarization measurement based on wavelet analysis and metal factor methods

In mineral exploration, the apparent resistivity and apparent frequency （or apparent polarizability） parameters of induced polarization method are commonly utilized to describe the induced polarization anomaly. When the target geology structure is significantly complicated, these parameters would fail to reflect the nature of the anomaly source, and wrong conclusions may be obtained. A wavelet approach and a metal factor method were used to comprehensively interpret the induced polarization anomaly of complex geologic bodies in the Adi Bladia mine. Db5 wavelet basis was used to conduct two-scale decomposition and reconstruction, which effectively suppress the noise interference of greenschist facies regional metamorphism and magma intrusion, making energy concentrated and boundary problem unobservable. On the basis of that, the ore-induced anomaly was effectively extracted by the metal factor method.

Evaluation of diffusion and phase transformation at Ag/Al bimetal produced by cold roll welding

Aluminum and silver strips were cold welded by rolling and a bimetallic strip was produced. To create cold weld between A1 and Ag, mating surfaces were specially prepared and various rolling thickness reductions were applied. The minimum critical thickness reduction to begin cold weld was specified as 70% which equals 0.1630 critical rolling shape factors. The bimetallic strips were treated by diffusion annealing at 400 ~C and various annealing time. The A1/Ag interface of strips was observed by scanning electron microscope to investigate the formation of hard and brittle probable phases. The effect of anneal time on diffusion distance and phase transformation was also analysed by EDS analysis and line scan. A diffusion region along the interface in the Ag side was observed and its width increased with prolonging annealing time. Some 8 phases were detected close to the interface after anneal treating for 3 h and 8 phase was thicker and more continuous by increasing annealing time. The microhardness measurement showed that in spite of formation of 8 phase due to diffusion annealing, the interface hardness was reduced.

Computer Simulation on Metallic Card Clothing Garnett Wire Teeth's Temperature Field & Structure Field in the Process of Quenching Treatment

The quenching process of garnett wire teeth of metallic card clothing heated by flame was researched by use of 3-D finite element method and the equation of boundary condition was established by making use of a model of artificial neural network. The transient temperature field, phase transformation in the heating process, the quenching microstructures and the hardness distribution on quenched garnett wire teeth of metallic card clothing were simulated. The result shows that the maximum error of the hardness between the simulative value and the actual measuring value is 8.0% on only one testing point and errors are all less than 3.0% on other testing points.

Correlation between catalytic activity of supported gold catalysts for carbon monoxide oxidation and metal–oxygen binding energy of the support metal oxides

The effect of a wide variety of metal oxide （MOx） supports has been discussed for CO oxidation on nanoparticulate gold catalysts. By using typical co‐precipitation and deposition–precipitation methods and under identical calcination conditions, supported gold catalysts were prepared on a wide variety of MOx supports, and the temperature for 50%conversion was measured to qualita‐tively evaluate the catalytic activities of these simple MOx and supported Au catalysts. Furthermore, the difference in these temperatures for the simple MOx compared to the supported Au catalysts is plotted against the metal–oxygen binding energies of the support MOx. A clear volcano‐like correla‐tion between the temperature difference and the metal–oxygen binding energies is observed. This correlation suggests that the use of MOx with appropriate metal–oxygen binding energies （300–500 kJ/atom O） greatly improves the catalytic activity of MOx by the deposition of Au NPs.

Comparison between sequential and single extraction procedures for metal speciation in fresh and dried Sedum Plumbizincicola

Sequential and single extraction procedures were applied to both fresh and dried Sedum Plumbizincicola leaves and stems.The extractants, different from those of soil, sediment or sewage sludge metal fractions, were water, 80%(v/v) ethanol, 1 mol/L Na Cl,2% HAc and 0.6 mol/L HCl. Zn, Cd and Cu in the extracts and samples were measured by flame atomic adsorption spectrometry. In sequential extraction procedures, water soluble form and ethanol soluble form are the main fractions for Zn, while water soluble form and Na Cl soluble form for Cd, and comparatively uniform distribution for Cu with the residue form most and HCl soluble form second. Single extraction procedures are used to compare the extraction efficiencies of the five reagents to screen appropriate extractants and operating conditions for liquid extraction to deal with large amount of harvested metal-contained biomass, which will pose a threat to the environment if treated improperly. The sequences of extraction efficiencies are HCl>Na Cl≈HAc>Water≈Ethanol for Zn and HCl≈Na Cl≈HAc>Water>Ethanol for Cd. As for Cu, all the five extractants cannot effectively extract Cu, but HCl achieves a higher efficiency(>70% in fresh samples, and 45%-60% in dried samples). Besides, extraction efficiencies for most extractants in fresh samples are higher than those in dried samples, and extraction efficiencies of stems and leaves for the five extractants are close. The two extraction procedures can obtain high degree of accuracy with the relative standard deviation(RSD)lower than 10%, and metal recoveries are controlled between 80%-120% with most of 90%-110%.

Ethanol sensing properties of Bi_(3.15)Nd_(0.85)Ti_3O_(12) films at low operating temperatures

Bi3.15Nd0.85Ti3O12 (BNdT) films were deposited on Pt/Ti/SiO2/Si(100) substrates by a metal organic decomposition (MOD)method, and annealed by a rapid thermal annealing process in oxygen atmosphere and in air, respectively. The crystalline structuresand morphologies of BNdT films were characterized by X-ray diffraction and field-emission scanning electron microscopy, and thegas sensing properties were measured by monitoring its resistance at different gas concentrations. The results indicate that the BNdTfilms annealed in air are of porous microstructure and rough surface, and the annealing atmosphere has great influence on gas sensingproperties. At an operating temperature of 100 °C, the BNdT films annealed in air are of high response value to 1×10?6 gaseousethanol, and the detecting limit is as low as 0.1×10?6. The corresponding response and recovery time is about 10 and 6 s, respectively.The results can offer useful guidelines for fabricating high performance ethanol sensors.

The Use of Multiwalled Carbon Nanotubes Mini Column for Preconcentration of Trace Metal Ions in Tap Water of Khartoum City and Their Determination by Flame Atomic Absorption Spectrometry （FAAS）

The adsorption behavior of multiwalled carbon nanotubes （MWNTs） toward heavy elements has been investigated systemically, and a new method has been developed for the determination of trace elements in water samples based on preconcentration with mini-column packed with MWNTs prior to its determination by flame atomic absorption spectrometry （FAAS） The recommended parameters of proposed method influencing the preconcentration of the analytes, such as pH of the sample, sample flow rate and volume, elute solution and interfering ions, have been used. Under the optimized conditions, the calibration graphs were linear with the correlation coefficient range 0.9981-0.9995. According to the results, the metals were found 0.019-0.051, 0.011-0.031, 0.00-0.081, 0.00-0.0002, 0.007-0.0925, 0.00-0.0104 μg/L in water samples for Pb, Mn, Zn, Cd, Fe, Cu respectively. The percentage relative standard deviation （%RSD） for five replicate samples were 〈 5% in all cases. The method has been successfully applied to the determination of trace elements in some environmental samples with satisfactory results.

Investigation of structural and magnetic properties of Ni implanted rutile

In this paper,the structural and magnetic properties of Ni metal implanted TiO 2 single crystals are discussed.Ni nanocrystals (NCs) have been formed in TiO 2 after ion implantation.Their crystalline sizes were increased with increasing post-annealing temperature.Metallic Ni NCs inside the TiO 2 matrix are stable up to an annealing temperature of 1073 K.The Ni NCs forming inside TiO 2 are the major contribution of the measured ferromagnetism.

Effect of acupuncture plus thunder-fire moxibustion on MMP-3, TIMP-1 and TGF-β1 in rats with knee osteoarthritis

Objective： To observe the effect of acupuncture plus thunder-fire moxibustion on the expressions of matrix metalloproteinase-3 （MMP-3）, tissue inhibitor of metalloproteinase-1 （TIMP-1） and transforming growth factor-β1 （TGF-β1） in cartilage of knee osteoarthritis （KOA） rats, and to explore the mechanism of acupuncture plus thunder-fire moxibustion in the treatment of KOA. Methods： Thirty Sprague-Dawley （SD） rats were randomly divided into a blank control group, a model group and an acupuncture-moxibustion group by random digits table, 10 rats in each group. Rats in the model group and the acupuncture-moxibustion group were injected with papain in the right posterior knee joint to prepare the models. The levels of MMP-3 and TIMP-1 in rat synovium of each group were measured by enzyme-linked immunosorbent assay （ELBA） after 2 weeks of treatment. The level of TGF-β1 was determined by Motic B5 Micro-camera system. Results： The levels of MMP-3 and TIMP-1 in the cartilage of the model group were significantly higher than those in the blank control group （all P〈0.01）; the levels of MMP-3 and TIMP-1 in the acupuncture-moxibustion group were lower than those in the model group, and the between-group differences were statistically significant （all P〈0.05）. The levels of MMP-3 and TIMP-1 in the acupuncture-moxibustion group were higher than those in the blank control group, and the differences were statistically significant （all P〈0.05）. The level of TGF-β1 in cartilage tissues of the model group was significantly lower than that in the blank control group （P〈0.01）; the level of TGF-β1 in the acupuncture-moxibustion group was higher than that in the model group （P〈0.05）, but it was lower than that in the blank control group, and the between-group difference was statistically significant （P〈0.05）. Conclusion： Acupuncture plus thunder-fire moxibustion can effectively recover the abnormal expressions of MMP-3 and TIMP-1 in KOA model rats and somewhat up-regulate TGF-β1, which may be one of its mechanisms of acupuncture plus thunder-fire for KOA.

The concept and realization of nanostructure fabrication using free-standing metallic wires with rapid thermal annealing

Free-standing metallic nanostructures are considered to be highly relevant to many branches of science and technology with applications of three dimensional metallic nanostructures ranging from optical reflectors,actuators,and antenna,to free-standing electrodes,mechanical,optical,and electrical resonators and sensors.Strain-induced out-of-plane fabrication has emerged as an effective method which uses relaxation of strain-mismatched materials.In this work,we report a study of the thermal annealing-induced shape modification of free-standing nanostructures,which was achieved by introducing compositional or microstructural nonuniformity to the nanowires.In particular gradient,segmented and striped hetero-nanowires were grown by focused-ion-beam-induced chemical vapor deposition,followed by rapid thermal annealing in a N2 atmosphere.Various free-standing nanostructures were produced as a result of the crystalline/grain growth and stress relief.