Illumination and Voltage Dependence of Electrical Characteristics of Au/0.03 Graphene-Doped PVA/n-Si Structures via Capacitance/Conductance-Voltage Measurements

Au/n-Si （MS） structures with a high dielectric interlayer （0.03 graphene-doped PVA） are fabricated to investigate the illumination and voltage effects on electrical and dielectric properties by using capacitance-voltage （C-V） and conductance-voltage （G/w-V） measurements at room temperature and at 1 MHz. Some of the main electrical parameters such as concentration of doping atoms （ND）, barrier height （ ФB（ C - V） ）, depletion layer width （WD） and series resistance （Rs） show fairly large illumination dispersion. The voltage-dependent profile of surface states （Nss） and resistance of the structure （Ri ） are also obtained by using the dark-illumination capacitance （Cdark- Cm） and Nicollian-Brews methods, respectively, For a clear observation of changes in electrical parameters with illumination, the values of ND, WD, ФB（O- V） and Rs are drawn as a function of illumination intensity. The values of ND and WD change almost linearly with illumination intensity. On the other hand, Rs decreases almost exponentially with increasing illumination intensity whereas ФB（C - V） increases. The experimental results suggest that the use of a high dielectric interlayer （0.03 graphene-doped PVA） considerably passivates or reduces the magnitude of the surface states. The large change or dispersion in main electrical parameters can be attributed to generation of electron-hole pairs in the junction under illumination and to a good light absorption. All of these experimental results confirm that the fabricated Au/0.03 graphene-doped PVA/n-Si structure can be used as a photodiode or a capacitor in optoelectronic applications.

Phyllanthuse emblica polyphenols:Optimization of high-voltage pulsed electric field assisted extraction,an antioxidant and anti-inflammatory effects in vitro

Background:The polyphenols extraction of Phyllanthus emblica is primarily carried out using organic solvents,and assisted by physical fields such as ultrasound and microwave for extraction.High voltage pulsed electric field technology(PEF)is a non-thermal processing technology that has high efficiency and minimal damage to thermosensitive substances.PEF has been applied to plant extraction in many studies,however,the extraction of polyphenols from Phyllanthus emblica using the PEF has still not been reported;Objective:This study explores the optimal extraction process of polyphenols from Phyllanthus emblica using the PEF,and investigates its relaxation and anti-wrinkle based on anti-oxidation and anti-inflammatory experiment,in order to develop a Phyllanthus emblica extract with substantial efficacy;Materials and Methods:The method of Phyllanthus emblica extract using PEF is established,and compared with a traditional extraction method.The experimental conditions,such as electric field intensity(0.5–6.0 kV/cm),pulse times(20−120),extraction time(0–60 min)and material concentration(0.5%∼3%),are investigated and optimized using orthogonal experiments;Results:the polyphenols in the Phyllanthus emblica extract were highest at the electric field intensity of 5 kV/cm,120 pulses,extraction time of 30 min,and 2%material concentration.The PEFcontained more polyphenols than the conventional water extraction and ultrasound-assisted extraction.The Phyllanthus emblica extract had substantial antioxidant and anti-inflammatory effects,with a good clearance effect on DPPH(IC50 of 1.82%)and ABTS(IC50 of 1.80%)radicals.At the Phyllanthus emblica extract concentration of 1.25%,inflammatory factors(TNF-α)were reduced by 47.08%;and Conclusion:The PEF is a leading-edge and promising method for preparing Phyllanthus emblica extracts.

Numerical simulation of high voltage electric pulse comminution of phosphate ore

Numerical simulation of the electrical field distribution helps in-depth understanding of the mechanisms behind the responses and the benefits of the high voltage pulse comminution. The COMSOL Multiphysics package was used to numerically simulate the effect of ore compositions in this study. Regarding phosphate ore particles shape and composition, the effects of mineral composition, particle size, particle shape and electrodes distance were investigated on the electrical field intensity and distribution. The results show that the induced electrical field is significantly dependent on the electrical properties of minerals,the feed particle size and the location of conductive minerals in ores. The angle of material contact surface with the discharge electrode is also an important factor in the intensity of electrical field. Moreover,it is found that the specific liberation effect at the disintegration of phosphate ore by electrical pulses is due to the locality of the electrical field at the interface of mineral components of the phosphate ore aggregates with different permittivities. However, the intensity of the electrical field increases with sharpening the contact angle. Besides, the electrical discharge in the samples is converted to the electrohydraulic discharge across the surrounding water by changing the distance between the discharge electrode and sample surface.

Structure Design and Properties of Three-Layer Particleboard Based on High Voltage Electrostatic Field(HVEF)

In this study,the effects of three different particle sizes of wood wastes(A=–8+12 mesh;B=–12+20 mesh;C=–20+30 mesh)and factory shavings(D)on the properties of particleboard were investigated.According to the test results,three-layer particleboard was designed.Particleboard face layers made with mixture of A,B,and C.The core layer made with D.The ratio of core layer to face layers is 50:50.Three-layer particleboard were fabricated with 12%urea-formaldehyde(UF)resins and three different high voltage electrostatic field intensities(0 kv,30 kv,60 kv).The internal bond(IB)strength,modulus of rupture(MOR),modulus of elasticity(MOE),thickness swelling(TS),and water absorption(WA)of particleboard were evaluated.The density distribution of the three-layer particleboard were examined by vertical density profiles(VDP),and the bonding mechanism and functional groups changes in the particles were analyzed by FTIR analysis.The results showed that HVEF treatment intensity play a remarkable role in properties of particleboard.The particleboard with higher electrostatic field intensities treatment has higher MOE,MOR,IB,and TS.Under HVEF treatment(60 kv),the MOR,modulus of MOE,and IB of three-layer particleboard were 23.61 N/mm^(2),2787.09 N/mm^(2),and 0.86 N/mm^(2),respectively.FTIR indicated that the surface activity of wood particles was increased electric field treatment.

Hydrophobic Poplar Prepared via High Voltage Electric Field(HVEF)with Copper as Electrode Plate

In order to improve hydrophobic characteristics which will affect the service performance of fast-growing poplar due to growing bacteria in the humid environment.In this study,a simple method was proposed to treat poplar via the high voltage electric field(HVEF)with copper as the electrode plate.Scanning electron microscope(SEM),Fourier transforms infrared spectroscopy(FTIR),X-ray diffraction(XRD)and contact angle tester were adopted to evaluate the surface morphology,surface group of poplar,crystallinity and wettability under HVEF.It was found by SEM that a large number of copper particles were uniformly attached to the surface of poplar.In all three sections,the weight percentage of the Cu element was accounting for more than half.The diffraction peaks of copper-containing compounds appeared in the(XRD).FTIR analysis confirmed that the reaction between copper and poplar took place.The surface contact angle of three sections of poplar increased in the following order:cross section<radial section<tangential section(increased by 34°,45°and 53°,respectively).An environmentfriendly and efficient method of HVEF treating fast-growing wood with copper as the electrode plate can promote its outdoor application.

Relationship Between Electric Properties and Temperature of ZrB_2-SiC Composite Ceramic Heating Element

ZrB2 -SiC composite ceramic has been successfully introduced as heating element in super high temperature .field. This paper further investigated the microstructure of ZrB2 - SiC composite ceramic heating element and the relationship between electric properties and temperature. SEM photos show that the heating element consists of SiC grains and ZrBz grains smaller than 10 μm. The voltage and current gradually increase and the furnace tempera- ture rises lineally with heating time prolonging. The electric resistance increases linearly with the temperature rising. The service temperatltre of the heating element can reach 1 800 ℃ and 2 150 ℃ in air and argon at- mosphere, respectively.

Effect of La_2O_3 on electrical friction and wear properties of Cu-graphite composites

Sliding friction and wear experiments using Cu-La2O3-graphite composites against Cu-5 wt.%Ag alloy ring were conducted at a constant sliding speed of 10 m/s, a current density of 10 A/cm2 and a load of 2.5 N/cm2. These composites with different La2O3 and graphite contents were fabricated by hot-pressing. Physical and mechanical properties of the composites were examined. Morphologies of the worn surface of composites were observed using optical microscopy. X-ray photoelectron spectroscopy spectra were used to study compositions of the lubricating film. The results showed that with the increasing addition of La2O3, hardness, flexural strength and electrical resistivity increased, but the relative density dropped. The friction coefficient increased with the increasing addition of La2O3. Composite containing 3 vol.% of La2O3 and 37 vol.% of graphite showed the best wear resistance. The main wear mechanisms of composites were abrasive wear, oxidative wear and adhesive wear.