Research Progress and Prospects of Magnetic Nanomaterials

Nanomaterials are one of the research and development hotspots in the field of cutting-edge new materials,and also an important strategic emerging industry.Magnetic nanomaterials have broad application prospects in fields such as chemical engineering,new materials,electronic information,and biomedicine.This article introduces the application progress and preparation methods of magnetic nanomaterials,and puts forward suggestions for further optimizing the preparation process of magnetic nanomaterials and developing new magnetic materials with better performance.

2D multifunctional devices:from material preparation to device fabrication and neuromorphic applications

Neuromorphic computing systems,which mimic the operation of neurons and synapses in the human brain,are seen as an appealing next-generation computing method due to their strong and efficient computing abilities.Two-dimensional (2D) materials with dangling bond-free surfaces and atomic-level thicknesses have emerged as promising candidates for neuromorphic computing hardware.As a result,2D neuromorphic devices may provide an ideal platform for developing multifunctional neuromorphic applications.Here,we review the recent neuromorphic devices based on 2D material and their multifunctional applications.The synthesis and next micro–nano fabrication methods of 2D materials and their heterostructures are first introduced.The recent advances of neuromorphic 2D devices are discussed in detail using different operating principles.More importantly,we present a review of emerging multifunctional neuromorphic applications,including neuromorphic visual,auditory,tactile,and nociceptive systems based on 2D devices.In the end,we discuss the problems and methods for 2D neuromorphic device developments in the future.This paper will give insights into designing 2D neuromorphic devices and applying them to the future neuromorphic systems.

Vascular endothelial growth factor protein and gene delivery by novel nanomaterials for promoting liver regeneration after partial hepatectomy

Partial hepatectomy(PH)can lead to severe complications,including liver failure,due to the low regenerative capacity of the remaining liver,especially after extensive hepatectomy.Liver sinusoidal endothelial cells(LSECs),whose proliferation occurs more slowly and later than hepatocytes after PH,compose the lining of the hepatic sinusoids,which are the smallest blood vessels in the liver.Vascular endothelial growth factor(VEGF),secreted by hepatocytes,promotes LSEC proliferation.Supplementation of exogenous VEGF after hepatectomy also increases the number of LSECs in the remaining liver,thus promoting the reestablishment of the hepatic sinusoids and accelerating liver regeneration.At present,some shortcomings exist in the methods of supplementing exogenous VEGF,such as a low drug concentration in the liver and the reaching of other organs.Moreover,VEGF should be administered multiple times and in large doses because of its short half-life.This review summarized the most recent findings on liver regeneration and new strategies for the localized delivery VEGF in the liver.

The Microparticles SiOx Loaded on PAN-C Nanofiber as Three-Dimensional Anode Material for High-Performance Lithium-Ion Batteries

Three-dimensional C/SiOx nanofiber anode was prepared by polydimethylsiloxane(PDMS)and polyacrylonitrile(PAN)as precursors via electrospinning and freeze-drying successfully.In contrast to conventional carbon cover-ing Si-based anode materials,the C/SiOx structure is made up of PAN-C,a 3D carbon substance,and SiOx load-ing steadily on PAN-C.The PAN carbon nanofibers and loaded SiOx from pyrolyzed PDMS give increased conductivity and a stable complex structure.When employed as lithium-ion batteries(LIBs)anode materials,C/SiOx-1%composites were discovered to have an extremely high lithium storage capacity and good cycle per-formance.At a current density of 100 mA/g,its reversible capacity remained at 761 mA/h after 50 charge-dis-charge cycles and at 670 mA/h after 200 cycles.The C/SiOx-1%composite aerogel is a particularly intriguing anode candidate for high-performance LIBs due to these appealing qualities.

New Nano Polymer Materials for Composite Exterior-Wall Coatings

A triethylenetetramine epoxy mixture was synthesized through the reaction of a low-molecular-weight liquid epoxy resin with triethylenetetramine(TETA).Then triethyltetramine(TETA)was injected dropwise into a pro-pylene glycol methyl ether(PM)solution for chain extension reaction.A hydrophilic andflexible polyether seg-ment was introduced into the hardener molecule.The effects of TETA/DGEPG,reaction temperature and reaction time on the epoxy conversion of polyethylene glycol diglycidyl ether(DGEPG)were studied.In addition,several alternate strategies to add epoxy resin to the high-speed dispersion machine and synthesize MEA DGEBA adduct(without catalyst and with bisphenol A diglycidyl ether epoxy resin)were compared.It was found that the higher the molecular weight of triethylenetetramine,the longer the chain segment of the surface active molecule.When the equivalence ratio of amine hydrogen and epoxy group is low,the stability of lotion is good.When the ratio of amine hydrogen to epoxy group is large,the content of triethylenetetramine is small.The main objective of this study is the provision of new data and knowledge for the development of new materials in the coating and electronic industry.

Preparation of Nano-porous Materials(Ⅰ) by Polymerization of Amphiphile Self-assemblies

The polymerization of amphiphilic self assemblies is a promising method to synthesize nano structured materials with novel properties. These materials have many attractive features for their application in biomedical area and materials science, such as catalysis, separation, surface modification, and therapeutics areas. A general review on the polymerization of lipids and surfactant self assemblies to amphiphilic self assemblies is given in this paper with 49 references. The polymerization and the subsequently resulted structure of lipids in different morphologies are summarized. The polymerization of polymerizable surfactants(surfmers) in emulsion and liquid crystalline phases are also discussed. The potential application of new nano porous materials is briefly described.

Carbon dioxide catalytic conversion to nano carbon material on the iron–nickel catalysts using CVD-IP method

The over-consumption of fossil fuels resulted in the large quantity emission of carbon dioxide （CO2）, which was the main reason for the climate change and more extreme weathers. Hence, it is extremely pressing to ex- plore efficient and sustainable approaches for the carbon-neutral pathway of CO2 utilization and recycling. In our recent works with this context, we developed successfully a novel ＂chemical vapor deposition integrated process （CVD-IP）＂ technology to converting robustly CO2 into the value-added solid-form carbon materials, The monometallic FeNi0-Al2O3 （FNi0） and bimetallic FeNix-Al2O3 （FNi2, FNi4, FNi8 and FNi20） samples were synthesized and effective for this new approach. The catalyst labeled FNi8 gave the better performance, exhibited the single pass solid carbon yield of 30%. These results illustrated alternative promising cases for the CO2 capture utilization storage （CCUS）, by means of the CO2 catalytic conversion into the solid-form nano carbon materials.

Tuning the particle size and morphology of high energetic material nanocrystals

Morphology controlled synthesis of nanoparticles of powerful high energetic compounds(HECs) such as l,3,5-trinitro-l,3,5-triazinane(RDX) and 1,3,5,7-tetranitro-l,3,5,7-tetrazocane(HMX) were achieved by a simple solvent—antisolvent interaction(SAI) method at 70 ℃.The effects of different solvents on particle size and morphology of the prepared nano-HECs were studied systematically.Particle size and morphology of the nano-HECs was characterized using field emission scanning electron microscopy(FE-SEM) imaging.X-ray diffraction(XRD) and Fourier transform infrared(FTIR) spectroscopy studies revealed that RDX and HMX were precipitated in their most stable polymorphic forms,i.e.a and P,respectively.Thermogravimetric analysis coupled with differential scanning calorimetry(TGA-DSC) studies showed that the thermal response of the nanoparticles was similar to the respective raw-HECs.HEC nanoparticles with spherical and rod shaped morphology were observed under different solvent conditions.The mean particle size also varied considerably with the use of different solvents.

Computational Analysis of the Effect of Nano Particle Material Motion on Mixed Convection Flow in the Presence of Heat Generation and Absorption

The present study is concerned with the physical behavior of the combined effect of nano particle material motion and heat generation/absorption due to the effect of different parameters involved in prescribed flow model.The formulation of the flow model is based on basic universal equations of conservation of momentum,energy and mass.The prescribed flow model is converted to non-dimensional form by using suitable scaling.The obtained transformed equations are solved numerically by using finite difference scheme.For the analysis of above said behavior the computed numerical data for fluid velocity,temperature profile,and mass concentration for several constraints that is mixed convection parameterλt,modified mixed convection parameterλc,Prandtl number Pr,heat generation/absorption parameterδ,Schmidt number Sc,thermophoresis parameter Nt,and thermophoretic coefficient k are sketched in graphical form.Numerical results for skin friction,heat transfer rate and the mass transfer rate are tabulated for various emerging physical parameters.It is reported that in enhancement in heat,generation boosts up the fluid temperature at some positions of the surface of the sphere.As heat absorption parameter is decreased temperature field increases at position X=π/4 on the other hand,no alteration at other considered circumferential positions is noticed.

Construction and Properties of Structure-and Size-controlled Micro/Nano-energetic Materials

The recent research progress of structure- and size-controlled micro/nano-energetic materials is reviewed, which properties are fundamentally different from those of their corresponding bulk materials. The development of the construction strategies for achieving zero-dimensional (0D), one-dimensional (1D), two-dimensional (2D), and three-dimensional (3D) micro/nanostructures from energetic molecules is introduced. Also, an overview of the unique properties induced by micro/nanostructures and size effects is provided. Special emphasis is focused on the size-dependent properties that are different from those of the conventional micro-sized energetic materials, such as thermal decomposition, sensitivity, combustion and detonation, and compaction behaviors. A conclusion and our view of the future development of micro/nano-energetic materials and devices are given.

Graphene oxide assisted facile hydrothermal synthesis of LiMn_(0.6)Fe_(0.4)PO_4 nanoparticles as cathode material for lithium ion battery

Assisted by graphene oxide（GO）,nano-sized LiMn0.6Fe0.4PO4 with excellent electrochemical performance was prepared by a facile hydrothermal method as cathode material for lithium ion battery.SEM and TEM images indicate that the particle size of LiMn0.6Fe0.4PO4（S2）was about 80 nm in diameter.The discharge capacity of LiMn0.6Fe0.4PO4 nanoparticles was 140.3 mAh-g^1 in the first cycle.It showed that graphene oxide was able to restrict the growth of LiMn0.6Fe0.4PO4 and it in situ reduction of GO could improve the electrical conductivity of LiMn0.6Fe0.4PO4 material.

Synthesis and Characterization of Storage Energy Materials Prepared from Nano-crystalline Cellulose/Polyethylene Glycol

This paper gives a brief report of the synthesis of a new kind of solid-solid phase change materials （SSPCMs）, nano-crystalline cellulose/polyethylene glycol （NCC/PEG）. These PCMs have very high ability for energy storage, and their enthalpies reach 103.8 J/g. They are composed of two parts, PEG as functional branches for energy storage, and NCC as skeleton. The flexible polymer PEG was grafted onto the surface of rigid powder of NCC by covalent bonds. The results of DSC, FT-IR were briefly introduced, and some comments were also given.

Preparation of nano-PANI@MnO_2 by surface initiated polymerization method using as a nano-tubular electrode material:The amount effect of aniline on the microstructure and electrochemical performance

In this study,nano-polyanline and manganese oxide nanometer tubular composites（nano-PANI@MnO2）were prepared by a surface initiated polymerization method and used as electrochemical capacitor electrode materials; and the effect of aniline amount on the microstructure and electrochemical performance was investigated. The microstructures and surface morphologies of nano-PANI@MnO2 were characterized by X-ray diffraction,scanning electron microscopy and fourier transformation infrared spectroscope. The electrochemical performance of these composite materials was performed with cyclic voltammetry,charge–discharge test and electrochemical impedance spectroscopy,respectively. The results demonstrate that the feed ratio of aniline to MnO2 played a very important role in constructing the hierarchically nano-structure,which would,hence,determine the electrochemical performance of the materials. Using the templateassisted strategy and controlling the feed ratio of aniline to MnO2,the nanometer tubular structure of nanoPANI@MnO2 was obtained. A maximum specific capacitance of 386 F/g was achieved in aqueous 1 mol/L Na NO3 electrolyte with the potential range from 0 to 0.6 V（vs. SCE）.

Investigation of nano-talc as a filling material and a reinforcing agent in high density polyethylene (HDPE)

An experiment of producing high density polyethylene (HDPE) nano-composite filled with 4wt.% talc was presented. Acting as filler and a reinforcing agent in the HDPE, talc powder, sized at around 5 μm, was surface-treated with aluminum diethylene glycol dinitrate coupling agent before adding to the HDPE. Analyses of the reinforced HDPE nano-composite show significant improvement in its mechanical properties including, tensile strength (>26 MPa), break elongation (<1.1%), flexural strength (>22 MPa), and friction coefficients<0.11. The results demonstrate that, after surface-treated, talc can be used as a promising filling material and a reinforcing agent in making HDPE nano-composite.

A Computerized System for the Measurement of Nanomaterial Field Emission and Ionization

We have developed a computerized system for measuring field electron emission （FE） and field ionization （FI）, which has a three-electrode configuration with emitters biased up to 25 kV, and is programmed by the Labview software. The current-voltage curves of nano-tip tungsten and carbon nanotube （CNT） arrays were measured. The electron emission of CNTs proceeded with a turn-on field of 1.24 V/μm and a threshold field of 1.85 V/μm. Compared to the field emission, field ionization turned on at 3.5 V/μm. Raman spectroscopy and scanning electron microscopy （SEM） measurements showed degradation of the CNTs after FE/FI testing. The measurement of a W-tip revealed strong electron emission and instability behavior at a field strength higher than 7.0 V/μm.

Experimental Research on Toluene Degradation in Plasma as the Driving Force of Nanomaterials

Plasma technology has some shortcomings, such as higher energy consumption and byproducts produced in the reaction process. However non-thermal plasma associated with catalyst can resolve these problems. So this kind of technology was paid more and more attention to treat waste gas. In this paper, we make use of this technology to decompose toluene under different electric field and packed materials. At the same time, the mechanism of toluene decomposition using plasma and catalyst is discussed. The experimental results show toluene decomposition increases with electric field strength increasing and flow velocity and initial concentration decreasing. There are four conditions in plasma: without packed materials (1);with packed materials (2);with BaTiO3 in the surfaces of packed materials (3);and with nanometer Ba0.8Sr0.2Zr0.1Ti0.9O3 (4). Toluene decomposition represents a obvious trend, that is, η(4) > η(3) > η(2) > η(1). The best decomposition efficiency of toluene arrives at 95%.

Preparation of nano-structured Ag solid materials and application to surface-enhanced Raman scattering

Silver nano-particles with average diameter of about 60 nm were compacted in a high-strength mold under different pressures at 523 K to produce nano-structured Ag solid materials. The structure and characteristic of the nano-structured Ag solid materials (NSS-Ag) were studied using X-ray diffraction (XRD), scanning electron microscope (SEM) and Raman spectrometer. The NSS-Ag could be used as highly efficient surface-enhanced Raman scattering (SERS) active substrates. The common probe molecules Rhodamine 6G (R6G, 1×10-10 mol/L) were used to test the SERS activity on these substrates at very low concentrations. It is found that the SERS enhancement ability is dependent on the density of NSS-Ag. When the relative density of NSS-Ag is 83.87%, the materials reveal great SERS signal.

Melting Characteristics of a Phase Change Material Mixed with Nano Particles of Cobalt Oxide Bounded in a Trapezoidal Structure

A novel trapezoidal design for storage of heat energy through melting of phase-change material(PCM)is investigated.Latent heat thermal energy storage system(LHTES)is a promising option to diminish mis-match between energy consumption and supply.For this purpose,Paraffin:Rubitherm-35(RT35)material is successively melted in aluminum structure which is heated from one side and the other sides are kept adiabatic.Melting of PCM is observed experimentally and melt fronts are photographed for various time lengths.The fluid-solid module in COMSOL Multiphysics 5.4 has been utilized.The transient heat conduction with enthalpy function is hired.Simulations are carried out for enhancement of thermal conductivity through addition of nano-entities of cobalt oxide Co3O4.Themelting time is notably reduced with inclusion of nano-entities to enhance thermal conductivity.The time spans for melt start and total melt in case of pure PCM are 375 and 4500(s)respectively whereas for the nano mix case,these are 150 and 3000 s.Thus 33%shorter time length is noticed for charging of the PCM trapezoidal matrix with nano entities of Co3O4 aremixed.The results fromsimulation and lab observations depict similar patterns and are in quite close comparison.

Carbon Nano Material Synthesis from Polyethylene by Chemical Vapour Deposition

Three different types of Polyethylene family, High Density Polyethylene, (HDPE), Low Density polyethylene (LDPE) and Linear Low Density polyethylene (LLDPE) polymers having different molecular weight and density;were pyrolyzed in the temperature range of 550°C - 1050°C under H2, N2 and Ar gases. Taguchi Optimization technique was applied to find out the best operating conditions to get maximum yield of carbon nano material (CNM). For Taguchi op- timization, experimental set up was done in two different temperature ranges i.e. 550°C - 750°C and 850°C - 1050°C. CNMs synthesized were characterized by SEM, TEM, Micro Raman and XRD analysis. HDPE was found to yield maximum CNM. Its pyrolysis at 750°C under hydrogen atmosphere for 2h gave carbon nano beads and some carbon nano tubes. Whereas under same conditions at 1050°C more multi wall carbon nano tubes (MWCNT) were produced, with some carbon nano beads. XRD data confirmed the graphitic nature of carbon-nanotube. The intensities of G-band and D-band of Raman spectra suggested that CNM has more defect sites and spectra were similar for CNM obtained in both the temperature ranges. The TGA analysis of CNM obtained at 550°C - 750°C, indicated that they are not amor- phous carbon and CNM obtained at 850°C - 1050°C decomposed at 624°C - 668°C;suggesting that CNT synthesized at this temperature range were more crystalline than what was obtained at the 550°C - 750°C.