Analysis on Earthquake Emergency Material Preparation Demand Based on Earthquake Risk Evaluation Taking Datong City of Shanxi Province as an Example

The earthqnake emergency material preparation demand analysis can provide the scientific basis for all levels of governments to conduct reasonable and unified configuration of the emergency preparation resources, in order to further optimize the earthquake emergency ability construction to provide reference. This paper takes Datong City of Shanxi Province as an example, using the earthquake risk evaluation method, adopting the deterministic method and probabilistic method to conduct earthquake danger analysis, combined with the earthquake emergency rescue case and the previous scholars＇ research achievements, in order to study and analyze the earthquake emergency material preparation demand in different earthquake dangers.

Advances in magnetic-assisted triboelectric nanogenerators:structures,materials and self-sensing systems

Triboelectric nanogenerators(TENG),renowned for their remarkable capability to harness weak mechanical energy from the environment,have gained considerable attention owing to their cost-effectiveness,high output,and adaptability.This review provides a unique perspective by conducting a comprehensive and in-depth analysis of magnetically assisted TENGs that encompass structures,materials,and self-powered sensing systems.We systematically summarize the diverse functions of the magnetic assistance for TENGs,including system stiffness,components of the hybrid electromagnetic-triboelectric generator,transmission,and interaction forces.In the material domain,we review the incorporation of magnetic nano-composites materials,along with ferrofluid-based TENG and microstructure verification,which have also been summarized based on existing research.Furthermore,we delve into the research progress on physical quantity sensing and human-machine interface in magnetic-assisted TENGs.Our analysis highlights that magnetic assistance extends beyond the repulsive and suction forces under a magnetic field,thereby playing multifaceted roles in improving the output performance and environmental adaptability of the TENGs.Finally,we present the prevailing challenges and offer insights into the future trajectory of the magnetic-assisted TENGs development.

Development of Mathematical Model on Preparation of Functionally Graded Material by Co-sedimentation

From the process of sedimentation the mathematical relationships among deposition Volume and powder properties as well as sedimentation parameters were deduced. Based on the formula a mathematical model was set up and simulated through the computer. At last the validity of mathematical model was supported by the representative experiment on Ti-Mo system FGM prepared by co-sedimentation.

PREPARATION OF NANOCRYSTALLINE MATERIALS OF PEROVSKITE-TYPE La_(1-x)Sr_xFeO_3 bY USINO GEL OF POLYVINYL ALCOHOL

Precursors of La_(1-x)Sr_xFeO_3(x=0.0,0.1,0.4 and 0.6)nanocrystalline materials were prepared by the mixed salts dissolved in an aqueous solution of polyvinyl alcohol(PVA).XRD,DTA and TEM were used to characterize the samples. Well-nanocrystalline perovskite-type La_(1_x)Sr_xFeO_3 could be synthesized at the temperatures as low as 400～550℃ for 2h by the calcination of these amorphous precursors,and the calcination of wet LaFeO_3 gel was investigated at 300℃ for lh and 700℃ for 0.5h.

High-Pressure Preparation of High-Density Cu_2ZnSnS_4 Materials

High-density Cu2ZnSnS4 （CZTS） materials are prepared via the mechanical alloying and high pressure sintering method using Cu2S, ZnS and SnS2 as the raw materials. The morphological, structural, compositional and electrical properties of the materials are investigated by using x-ray diffraction, scanning electron microscopy, and energy dispersive x-ray spectroscopy, as well as by the Raman scattering and the Hall EFfect measurements. The CZTS synthesized under 5 GPa and 800℃ shows a p-type conductivity, with a resistivity of 9.69 × 10^-2 Ω.cm and a carrier concentration of 1.45 × 10^20 cm-3. It is contributed to by the large grains in the materials reducing the grain boundaries, thus effectively reducing the recombination of the charge carriers.

Preparation and film-growing mechanism of hydrous zirconia coated on TiO_2

To overcome the photochemical activity of rutile used as a pigment and improve its durability in application, hydrous zirconia-coated TiO2 was prepared by the precipitation method. High-resolution transmission electron microscope （HRTEM） and X-ray photoelectron spectroscopy （XPS） were used to characterize the morphology and surface structure of hydrous zirconia-coated TiO2. The ζ-potential and ultraviolet （UV） absorption of both coated and uncoated rutile were examined. The results show that hydrous zirconia can not only improve the durability but also raise the lightness. A suitable ZrO2 content of hydrous zirconia-coated TiO2 is about 1.0wt%, and a dense film on the surface of rutile can be formed with better pigmentary properties. Based on the thermodynamic analysis, the zirconia-coating process and the film growth mechanism were discussed.

Ti/Al_2O_3 Functionally Gradient Material Prepared by the Explosive Compaction/SHS Process

Ti1Al2O3 Functionally Gradient Material (FGM) was prepared by an explosive compaction/SHS process. Ten sheets of the compounding powder were laminated and pressed to get a green body of FGM. It was then compacted explosively By burying the explosive compaction body into a stoichiometric Al/TiO2 mixture and igniting the combustion of the stoichiometric Al/TiO2 mixture, the SHS reaction of the explosive compaction body was initiated by the heat released from the combustion of the stoichiometric Al/TiO2 mixture. In this way, Ti/Al2O3 FGM was synthesized. The adiabatic temperatures of each gradient layer were calculated when the preheating temperatures were 298 K and 1173 K, respectively The microstructure, composition and properties of Ti/Al2O3 FGM and the reaction mechanism of each gradient layer were studied. It was found that Ti/Al2O3 FGM prepared by the explosive compaction/SHS process had a high density and a high microhardness. Its structure, composition and properties showed apparent gradient distribution. The structure of the standard stoichiometric ratio gradient layer of FGM was a network structure. Its reaction mode could be described as follows: Al powder melted first, then the molten Al penetrated into the TiO2 zone and reacted with TiO2, and big pores were left in the original positions of Al powder. The reaction of gradient layers with the addition of Al3O3 as diluents was similar to that of the standard stoichiometric ratio gradient layer, so were their structure and composition. However, the reaction of gradient layers with the addition of Ti as diluents was more complex and the composition deviated slightly from the designed one

A Bottom-up Strategy to Prepare New Carbon Rich Materials

Energy is the key to our future.Whether to the production,storage or use of energy,carbon materials could provide a good solution.They are closely related to people’s daily life and regarded as one of the most promising candidates for the flexible electrodes in energy storage devices.Recently,a research team from the Qingdao Institute of Bioenergy and Bioprocess Technology,Chinese Academy of Sciences prepared a

Materials design and preparation of ultrathin two-dimensional metal halide perovskites

Metal halide perovskites(MHPs)have emerged as highly promising candidates for the next generation of photonics and optoelectronic devices,owing to their prominent optical and excitonic properties,as well as the convenience of fabrication.Particularly,ultrathin two-dimensional(2D)MHPs,which are generally prepared by exfoliation,solution growth,and chemical vapor deposition method,have attracted dramatically increasing attentions owing to their combined features of ultrathin 2D morphology and superior performance of MHPs.Despite the growing interest in ultrathin 2D MHPs,there is currently a lack of a comprehensive and systematic overview of the distinct advantages offered by each growth method for producing these materials.This review critically assesses the preliminary studies on the materials design and preparation of ultrathin MHPs.Furthermore,it explores heterostructures based on ultrathin MHPs and offers insights into the challenges and opportunities that lie ahead for this enticing class of 2D materials.

Ultramicro molybdenum nitride powder prepared using high-energy mechanochemical method

Using the specially designed mechanochemical ball-mill equipment, ultramicro molybdenum nitride powders were prepared from pure molybdenum powders in ammonia atmosphere at room temperature by high-energy ball milling. The structure and the particle size of the powders were investigated by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, and transmission electron microscopy （TEM）. The results show that the mass ratio of grinding media to powder was 8：1, after milling for 30 h the Mo2N of fcc structure was obtained, and the average particle size of the powders was around 100 nm. It is found that the chemisorption of ammonia onto the fresh molybdenum surfaces created by milling was the predominant process during solid-gas reaction, and the energy input due to introduction of highly dense grain boundaries and lattice defects offered the activation energy for the transition from Mo-N chemisorption to molybdenum nitride. In addition, the change of Mo electronic undersaturation induced by the grain refining accelerated the bonding between Mo and N. The mechanism model of whole nitriding reaction was given, During the high-energy ball milling processing, the rotational speed of milling played a critical role in determining the overall reaction speed.

Fabrication of Tungsten Carbide Nanoparticles from Refluxing Derived Precursor

Tungsten carbide（WC） nanoparticles were fabricated from a novel refluxing-derived precursor. The precursor was prepared by acid hydrolysis of Na2WO4 with concentrated HCl in water followed by refl uxing with ethanol and n-Dedocane, respectively. Then it was heat-treated to 1 200 ℃ for 2 h in vacuum to obtain WC nanoparticles. X-ray studies reveal the formation of hexagonal tungsten carbide and the grain size of 24.3 nm. SEM image shows WC nanoparticles with particle size of 20-60 nm. Long time refl uxing results in alkane dehydrogenation and coke formation. The coke is the carbon source in the carbothermal reduction reaction. The novel route of two-stage refl uxing is quite general and can be applied in the synthesis of similar carbides.

New pattern Zn-Al-Mg-RE coating technics for steel structure sustainable design

Based on the advanced integrated technology of materials preparation and formation, a new pattern Zn-Al-Mg-RE anti-corrosion coating for steel structure sustainable design was manufactured by cored wires and high velocity arc spraying (HVAS) technologies. The developments of thermally sprayed coatings for steel structure protection were described. Based on Al, Zn, Zn-Al and Zn-Al-Mg coatings, the anti-corrosion properties of new-pattern Zn-Al-Mg-RE coating were evaluated through electrochemical methods including electrochemical polarization and electrochemical impedance spectroscopy (EIS) coupled with SEM and XRD. The models of Zn-Al-Mg-RE coating undergoing corrosion with the initial pinhole defect and the latter with accelerated products were also discussed. The results show that Zn-Al-Mg-RE coating exhibites excellent corrosion resistance for long-term immersion, which is helpful for the sustainable design of steel structure in aggressive corrosion conditions. And the corrosion products seem to possess certain self-sealing function.

Microstructures and Mechanical,Electrical,High-temperature Properties of Cu/Ti_2AlC FGM Fabricated by Hot-pressing

The microstructure and the electrical, thermal, friction, and mechanical properties of Cu/Ti_2AlC fabricated by hot-pressing at 900 ℃ for 1 h were investigated in the present work. Microstructural observations have shown that the plate-like Ti_2AlC grains distribute irregularly in the network of Cu grains, and well-structured, crack-free bonds between the layers. With the increase in the content of Ti_2AlC from layer A to layer D, the electrical resistivity increases from 1.381×10^（-7）Ω·m to 1.918 ×10^（-7）Ω·m, the hardness increases from about 980.27 MPa to about 2196.01 MPa, and the friction coefficient from above 0.20 reduces to about 0.15. Oxidation rate increases with the increases of temperature. Exfoliation was obviously observed on the surface of oxidation layer A. The surface of layer D was still intact and the spalling and other defects were not found. The mass decreases in the acid solution, and increases in the alkaline solution. The largest corrosion rate is found in 6.5% HNO_3 or 4% Na OH solution.

Fabrication of 2×2 Thermo-Optic Switches with Organic-Inorganic Hybrid Materials Prepared by Sol-Gel Technique

2×2 Mach-Zehnder interferometric thermo-optic switch was fabricated with organic/inorganic hybrid materials by sol-gel technique and direct UV patterning. The switching time of device was measured to be 4.2 ms and switching power 9.3 mW.

Fe/Cu gradient composite materials prepared by laser sintering

USLNG CO2 laser beam as a heat source to sinter whole P/M （powder metallurgy） green com-pact is a new technique. As reported in refs. [1--4], the advantages of the laser sintering ofCu-base and Fe-base green compact were characterized by rapid sintering rate, no contamina-tion, fine structure and good properties.