Microstructure and Mechanical Performance of Cu-SnO_2-rGO based Composites Prepared by Plasma Activated Sintering

A novel chemical technique combined with unique plasma activated sintering（PAS） was utilized to prepare consolidated copper matrix composites（CMCs） by adding Cu-SnO2-rGO layered micro powders as reinforced fillers into Cu matrix. The repeating Cu-SnO2-rGO structure was composed of inner dispersed reduced graphene oxide（r GO）, SnO2 as intermedia and outer Cu coating. SnO2 was introduced to the surface of rGO sheets in order to prevent the graphene aggregation with SnO2 serving as spacer and to provide enough active sites for subsequent Cu deposition. This process can guarantee rGO sheets to suffi ciently disperse and Cu nanoparticles to tightly and uniformly anchor on each layer of rGO by means of the SnO2 active sites as well as strictly control the reduction speed of Cu^2＋. The complete cover of Cu nanoparticles on rGO sheets thoroughly avoids direct contact among rGO layers. Hence, the repeating structure can simultaneously solve the wettability problem between rGO and Cu matrix as well as improve the bonding strength between rGO and Cu matrix at the well-bonded Cu-SnO2-rGO interface. The isolated rGO can effectively hinder the glide of dislocation at Cu-rGO interface and support the applied loads. Finally, the compressive strength of CMCs was enhanced when the strengthening effi ciency reached up to 41.

Development,modeling and application of piezoelectric fiber composites

Piezoelectric materials are capable of actuation and sensing and have been used in a wide variety of smart devices and structures.Active fiber composite and macro fiber composite are newly developed types of piezoelectric composites,and show superior properties to monolithic piezoelectric wafer due to their distinctive structures.Numerous work has focused on the performance prediction of the composites by evaluation of structural parameters and properties of the constituent materials with analytical and numerical methods.Various applications have been explored for the piezoelectric fiber composites,including vibration and noise control,health monitoring,morphing of structures and energy harvesting,in which the composites play key role and demonstrate the necessity for further development.

Synthesis of BiVO_4-g-C_3N_4 Composite Photocatalyst with Improved Visible Light-induced Photocatalytic Activity

The novel visible light-induced carbon nitride（g-C3N4） and Bi VO4 composite photocatalysts were obtained through a simple mixing-calcination method. The physical and photophysical properties of the Bi VO4-g-C3N4 composites were investigated by X-ray diffraction（XRD）, Fourier transform infrared（FTIR） spectroscopy, UV-vis diffuse reflection spectroscopy, high-resolution transmission electron microscopy（HRTEM）, photoluminescent（PL） spectroscopy, and BET surface area measurements. Photocatalytic oxidation ability of the prepared samples was examined by studying the degradation of rhodamine B（Rh B） as a target pollutant under visible-light irradiation. The composite photocatalysts exhibited an enhanced photocatalytic performance in degrading Rh B. The optimal g-C3N4 content of the composite photocatalysts was determined for the photodegradation activity. The improved photocatalytic activity of the as-prepared composite photocatalyst may be attributed to the enhancement of photo-generated electron-hole separation at the interface.

Properties of Al/Conductive Coating/α-PbO2-CeO2-TiO2/β-PbO2-WC-ZrO2 Composite Anode for Zinc Electrowinning

The properties of Al/conductive coating/α-PbO2-CeO2-TiO2/β-PbO2-WC-ZrO2 composite anode for zinc electrowinning were investigated. The electrochemical performance was studied by Tafel polarization curves（Tafel）, electrochemical impedance spectroscopy（EIS） and corrosion rate obtained in an acidic zinc sulfate electrolyte solution. Scanning electron microscopy（SEM）, X-ray diffraction（XRD）, and energy dispersive X-ray spectroscopy（EDXS） were used to observe the microstructural features of coating. Anodes of Al/conductive coating/α-PbO2-CeO2-TiO2/β-PbO2, Al/conductive coating/α-PbO2-CeO2-TiO2/β-PbO2-WC, Al/conductive coating/α-PbO2-CeO2-TiO2/β-PbO2-ZrO2, and Pb-1%Ag anodes were also researched. The results indicated that the Al/conductive coating/α-PbO2-CeO2-TiO2/β-PbO2-WC-ZrO2 showed the best catalytic activity and corrosion resistant performance; the intensity of diffraction peak exhibited the highest value as well as a new PbWO4 phase; the content of WC and ZrO2 in coating showed the highest value as well as the finest grain size.

Pressure relief-dipping-microwave assisted polymerization of melamine-L-aspartic acid resin at activated carbon for purification of L-threonine fermented crude product

L-threonine(L-Thr) obtained by fermentation often contains vestigial hydrosoluble Pb(Ⅱ), Fe(Ⅱ), L-glutamic acid(L-Glu) etc., which affect the product quality. Poly melamine and L-aspartic acid(L-Asp) resin functional coconut shell activated carbon composite(PMA/AC) was prepared by a pressure relief-dipping-microwave assisted polymerization method for the simultaneous removals. The adsorption capacities of Pb(Ⅱ), Fe(Ⅱ) and L-Glu could reach to 82.34 mg·g^(-1), 57.82 mg·g^(-1) and 102.58 mg·g^(-1) at conditions of pH 5.0, 45 °C and 4 h with an initial concentration of 0.01 mol·L^(-1), respectively. The present PMA/AC was successfully used to the simultaneous removals of vestigial Pb(Ⅱ), Fe(Ⅱ) and L-Glu from the fermented crude product solution of L-Thr. Moreover, the PMA/AC was carefully characterized by FE-SEM, IR et al. analysis techniques, the results show that abundant PMA particles evenly distributed at the inner and outside surface of AC with a size of(50 ± 20) nm.

Immobilization of Agaricus Bisporus Laccase on Ceramic-Chitosan Composite Support and Their Properties:Potential for Oily Wastewater Treatment

Laccase was immobilized on the ceramic-chitosan composite support by using glutaraldehyde as the cross-linking reagent. The immobilization conditions and characterization of the immobilized enzyme were investigated. The immobilization of laccase was successfully realized when 3.0 mL of 1.25 mg/mL of laccase at a pH value of 4.0 reacted with 0.15 g of ceramic-chitosan composite support(CCCS) at 4 ℃ for 24 h. The immobilized enzyme exhibited a maximum activity at pH 3.0. The optimal temperatures for immobilized enzyme were 25 ℃ and 50 ℃. The K_m value of immobilized laccase for ABTS was 66.64 μmol/L at a pH value of 3.0 at 25 ℃. Compared with free laccase, the thermal, operating and storage stability of immobilized laccase was improved after the immobilization.

Mineralogical and Active Mechanical Excitation Characteristics of Filled Fly Ash Cementitious Materials

To reveal the influence of mechanical activation on the performance of fly ash, the microanalysis（the energy spectroscopy, XRD and SEM）, the distribution size of particle of fly ash and cement paste intensity of various age for different grinding time were studied. The relationships of the activity and the composition of fly ash, microstructure and the distribution of particle size by mechanical activation of fly ash were obtained. The internal glass beads with activity were released by grinding fly ash for a certain time. The particle specific surface area was improved and the hydration reaction of the interface and the surface active center was increased by grinding. The granularity distributing of fly-ash trended towards optimization. The polar molecules or ions were easier to intrude into the internal cavity of the vitreous body. The active silica and alumina of fly ash were rapidly depolymerized. Each performance index of fly ash was increased before grinding for 20 min. Cement paste intensity of various age increased along with the grinding time, and the early strength increase range was big, but the later period intensity increase range hastened slightly. The internal part of vitreous of fly ash was destroyed if the fly ash continued to be ground and the activity of fly ash was reduced. It is suggested that Guozhuang＇s fly ash should be ground for 20 min.

Research Progress of Chinese Medicine Used in Treating COVID-19

The outbreak of COVID-19 has brought great health threat to human beings all over the world,it also brings great challenges to the development of medicine.Several traditional Chinese medicines have good effects on treating pneumonia patients in COVID-19.In this article,the active composition,pharmacological mechanism and clinical practice of these traditional Chinese medicines were reviewed.This will be of positive significance to the further research and clinical application of traditional Chinese medicine for treating COVID-19 pneumonia.

Optimization of the Active Composition of the Wind Farm Using Genetic Algorithms

The article presents the results of research on the possibilities of using genetic algorithms for solving the multicriteria optimization problem of determining the active components of a wind farm.Optimization is carried out on two parameters:efficiency factor of wind farm use(integrated parameter calculated on the basis of 6 parameters of each of the wind farm),average power deviation level(average difference between the load power and energy generation capabilities of the active wind farm).That was done an analysis of publications on the use of genetic algorithms to solve multicriteria optimization problems.Computer simulations were performed,which allowed us to analyze the obtained statistical data and determine the main optimization indicators.That was carried out a comparative analysis of the obtained results with other methods,such as the dynamic programming method;the dynamic programming method with the general increase of the set loading;the modified dynamic programming method,neural networks.It is established that the average power deviation for the genetic algorithm and for the modified dynamic programming method is located at the same level,33.7 and 28.8 kW,respectively.The average value of the efficiency coefficient of wind turbine used for the genetic algorithm is 2.4%less than for the modified dynamic programming method.However,the time of finding the solution by the genetic algorithm is 3.6 times less than for the modified dynamic programming method.The obtained results provide an opportunity to implement an effective decision support system in energy flow management.

Liquid crystal elastomer composites for soft actuators

Liquid crystal elastomers are active materials that combine the anisotropic properties of liquid crystals with the elasticity of polymer networks.The LCEs exhibit remarkable reversible contraction and elongation capabilities in response to external stimuli,rendering them highly promising for diverse applications,such as soft robotics,haptic devices,shape morphing structures,etc,However,the predominant reliance on heating as the driving stimulus for LCEs has limited their practical applications.This drawback can be effectively addressed by incorporating fllers,which can generate heat under various stimuli.The recent progress in LCE composites has significantly expanded the application potential of LCEs.In this minireview,we present the design strategies for soft actuators with LCE composites,followed by a detailed exploration of photothermal and electrothermal LCE.composites as prominent examples.Furthermore,we provide an outlook on the challenges and opportunities in the feld of LCE composites.

Carbon nanotubes/TiO_2 nanotubes composite photocatalysts for efficient degradation of methyl orange dye

A series of carbon nanotubes/TiO2 nanotubes （CNTs/TNTs） composite photocatalysts were successfully prepared by incorporation of CNTs in HNO3 washing process. These photocatalysts were characterized by XRD, N2 physical adsorption, UV-vis diffuse reflectance spectroscopy, TEM and Raman spectroscopy, respectively, and their photocatalytic activities were tested by using methyl orange （MO） as a model compound. Also, the effects of amount of CNTs incorporated, calcination temperature and amount of catalyst on the photocatalytic activity of the composite photocatalyst were systematically investigated. The results show that the CNTs/TNTs composite exhibits much higher photocatalytic activity than that of the TNTs or CNTs alone.

Effect of activators on the properties of nickel coated diamond composite powders

Nickel coated diamond composite powders were fabricated via a newly developed direct electrodeposition technique. The effects of activators on the coating of diamond were firstly investigated and diamond grinding wheels were then prepared from Ni-coated diamond composite powders with different activators. The microstructural characterizations of this composite powders were finally conducted by scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction, and the mechanical and tribological properties of as-prepared diamond grinding wheels were also measured. There are changes in microstructures and properties of the composite powders with activators. The activator concentration also has an influence on the morphologies and phase structures of the Ni coating on diamond particles.The composite powders with more compact coating of nickel can be prepared by adding 1 g dm^（-3） or more AgNO_3 as an activator to electrodeposit nickel on diamond. The mechanical and tribological properties of diamond grinding wheels were significantly improved when the coating phase structure of Ni crystal grew with（111） plane orientation on the surface of diamond particles. The wheels made from nickel coated diamond composite powders possessed the advantages of easy preparation and outstanding tribological properties. Therefore, Ni coated diamond composite powders exhibit a great potential to be extensively applied in diamond cutting and grinding tools.

Study on photocatalytic activity of MoS2/ZnO composite in visible light

A series of MoS_2/ZnO compound photocatalysts with different mass ratios were successfully prepared by hydrothermal method. The X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS), scanning electron microscope(SEM) and UV-vis absorption were used to characterize the prepared MoS_2/ZnO photocatalysts. It was proved that the combination of Mo S2 and Zn O can increase the content of oxygen vacancies on surface of Zn O, thus improving the light absorption capacity in visible light region and reducing the band gap of Zn O. And the photocatalytic performance of Zn O was improved. Experimental results show that the MoS_2/ZnO(3 wt%) compound has the highest degradation rate for methylene blue(MB) under visible light, which means that it has the best photocatalytic activity among all the prepared samples.

Synthesis of ZrC Nanoparticles in the ZrO_2–Mg–C–Fe System Through Mechanically Activated Self-Propagating High-Temperature Synthesis

ZrC nanoparticles in the matrix of Fe were produced by the mechanically activated self-propagating hightemperature method using ZrO2/C/Mg/Fe powder mixtures. The effects of milling time, Fe content, and combustion temperature as well as the formation route for synthesizing ZrC powder particles were studied. The samples were characterized by XRD, SEM, TEM, and DTA. The XRD results revealed that, after 18 h of mechanical activation, ZrO2/ZC/Mg/Fe reacted with the self-propagating combustion（SHS） mode at 870 °C producing the ZrC–Fe nanocomposite. It was also found that both mechanical activation and Fe content played key roles in the ZrC synthesis temperature. With a Fe content of（5–40） wt%, the SHS reaction proceeded favorably and both the ZrC formation temperature and the adiabatic temperature（Tad） decreased. The Mg O content was removed from the final products using a leaching test process by dissolving in hydrochloric and acetic acids.