Preparation of the Supported Heteropolyacids Catalyst by Ultrasound-plasma Treatment

Novel catalysts of phosphotungstic heteropolyacids （PW12） supported on neutral alumina were prepared by assistance of ultrasound and plasma treatment. The prepared catalysts were characterized by FT-IR pyridine adsorption （Py-IR）, temperature programmed desorption of Pyridine （Py-TPD）, BET and X-ray diffraction （XRD）, and their catalytic performances were evaluated by the cationic polymerization of tetrahydrofuran. The results indicate that plasma treatment remarkably increases the surface acidity of the prepared catalyst while ultrasonic treatment induces PW12 to uniformly disperse on the support surface and expose more active sites for the acid catalytic reaction. A higher catalytic activity （69.7%） is obtained on the novel catalyst, which significantly outstripped that on the conventional sample （57.5%）.

Plasma Treatment of Ni Catalyst for Partial Oxidation of Methane

The 10%Ni/Al_2O_3 catalyst for partial oxidation of methane was treated byDBD (dielectric barrier discharge) plasma in a continuous system under atmospheric pressure and roomtemperature by flowing He. It was found that 10%Ni/Al_2O_3 catalyst treated by plasma presents ahigher catalytic activity and an enhanced stability than the catalysts prepared without plasmatreatment. The methane conversion over the catalyst treated by plasma is 3%-5% higher than thecatalysts untreated by plasma. Moreover, the enhanced dispersion of the catalyst can be achieved byplasma treatment, which can improve the interaction between active species and supports, catalyticactivity and the resistance to carbon deposition.

Plasma Treatment of Natural Jute Fibre by RIE 80 plus Plasma Tool

Plasma treatment can be used to modify the structure of natural fibre like jute for a variety of applications. Environmentally friendly jute fibre was treated with argon and oxygen plasma. The treated samples were characterized by X-ray diffraction （XRD）, Fourier transform infrared spectroscopy （FTIR） and optical microscope. The macromolecular and microstructural changes in cellulose confirmed the change by plasma treatment. The XRD results confirmed that the crystal size and the crystallinity of the plasma treated fibre increased. Argon plasma treated fibre had a smooth and compact surface, compared to oxygen plasma treated fibre. The maximum stain （i.e. stress） concentrated in the oxygen plasma treated fibre. Optical micrographs showed the oxygen plasma treated fibre tended to rupture due to higher strain （i.e., stress） compared to fibre with argon plasma treatment. FTIR results also provided the evidence of change in the chemical constituents with plasma treatment.

Investigation of AlGaN/GaN fluorine plasma treatment enhancement-mode high electronic mobility transistors by frequency-dependent capacitance and conductance analysis

This paper reports fluorine plasma treatment enhancement-mode HEMTs （high electronic mobility transistors） EHEMTs and conventional depletion-mode HEMTs DHEMTs fabricated on one wafer using separate litho-photography technology. It finds that fluorine plasma etches the AlGaN at a slow rate by capacitance-voltage measurement. Using capacitance-frequency measurement, it finds one type of trap in conventional DHEMTs with TT = （0.5 - 6） ms and DT ： （1 - 5）×10^13 cm^-2. eV^-1. Two types of trap are found in fluorine plasma treatment EHEMTs, fast with TW（f）= （0.2 - 2） μs and slow with TT（s） = （0.5 - 6） ms. The density of trap states evaluated on the EHEMTs is Dw（f） ： （1 - 3） × 10^12 cm^-2. eV^-1 and DT（s） =（2 - 6） × 10^12 cm-2. eV-1 for the fast and slow traps, respectively. The result shows that the fluorine plasma treatment reduces the slow trap density by about one order, but introduces a new type of fast trap. The slow trap is suggested to be a surface trap, related to the gate leakage current.

Sterilization of Cotton Fabrics Using Plasma Treatment

Microbial contamination induces surface deformations and strength degradation of cotton fabrics by invading deeply into the fibers. In this study, the sterilization effects of low pressure plasmas on bacteria-inoculated cotton fabrics were investigated. Oxygen plasma treatment completely sterilized the cotton fabrics inoculated with various concentrations of staphylococcus aureus. Also, the influence of plasma treatment on physical properties of fabrics was examined. It was found that the plasma treatment did not affect ultimate tensile strength and surface morphology of the fabrics because it took advantage of relatively low plasma temperature.

Environmental and economic vision of plasma treatment of waste in Makkah

An environmental and economic assessment of the development of a plasma-chemical reactor equipped with plasma torches for the environmentally friendly treatment of waste streams by plasma is outlined with a view to the chemical and energetic valorization of the sustainability in the Kingdom of Saudi Arabia（KSA）. This is especially applicable in the pilgrimage season in the city of Makkah, which is a major challenge since the amount of waste was estimated at about 750 thousand tons through Arabic Year 1435 H（2015）, and is growing at a rate of 3%–5% annually. According to statistics, the value of waste in Saudi Arabia ranges between 8 and 9 billion EUR. The Plasma-Treatment Project（PTP） encompasses the direct plasma treatment of all types of waste（from source and landfill）, as well as an environmental vision and economic evaluation of the use of the gas produced for fuel and electricity production in KSA, especially in the pilgrimage season in the holy city Makkah. The electrical power required for the plasmatreatment process is estimated at 5000 kW（2000 kW used for the operation of the system and 3000 kW sold）, taking into account the fact that：（1） the processing capacity of solid waste is 100 tons per day（2） and the sale of electricity amounts to 23.8 MW at 0.18 EUR per kWh.（3） The profit from the sale of electricity per year is estimated at 3.27 million EUR and the estimated profit of solid-waste treatment amounts to 6 million EUR per year and（4） the gross profit per ton of solid waste totals 8 million EUR per year. The present article introduces the first stage of the PTP, in Makkah in the pilgrimage season, which consists of five stages：（1） study and treatment of waste streams,（2） slaughterhouse waste treatment,（3） treatment of refuse-derived fuel,（4）treatment of car tires and（5） treatment of slag（the fifth stage associated with each stage from the four previous stages）.

Electrical and Optical Characterization of DBD and Its Application to Plasma Treatment of PET Fibers

A newly developed atmospheric pressure dielectric barrier discharge （DBD） plasma treatment system （PLA-PLA） was used in this study. The discharge is characterized by electrical analysis and optical emission spectroscopy （OES）. The characters of the discharge were found to change systematically with an increase of applied voltage and variation of flow ratio of O2/Ar in the plasma. The OES analysis revealed that the relatively weak spectrum line can be detected beyond a certain applied power value. It is also found that the emission intensity of main species in the discharge spectrum will be enhanced with the increase of applied power. To improve the wettability, poly （ethylene terephtalate） （PET） fiber was treated in this system. The surface morphology and properties of fiber after plasma treatment were investigated by both scanning electron microscope （SEM） and contact angle measurement.

improvement of electrical properties of Cu/SiCOH low-k film integrated system by O2 plasma treatment

This paper investigates the effect of O2 plasma treatment on the electric property of Cu/SiCOH low dielectric constant （low-k） film integrated structure. The results show that the leakage current of Cu/SiCOH low-k integrated structure can be reduced obviously at the expense of a slight increase in dielectric constant k of SiCOH films. Bythe Fourier transform infrared （FTIR） analysis on the bonding configurations of SiCOH films treated by O2 plasmar it is found that the decrease of leakage current is related to the increase of Si-O cages originating from the linkage of Si dangling bonds through O, which makes the open pores sealed and reduces the diffusion of Cu to pores.

Plasma treatment for enhancement of the sorption capacity of carbon fabric

In this work we carried out an experimental investigation into enhancement of the sorption capacity of carbon fabric using plasma treatment methods.Carbon fabric is based on viscose fiber and is hydrophobic by nature.Enhancement of the fabric sorption capacity is required for its application in medicine.For this purpose,two plasma treatment methods were considered,i.e.atmospheric nonequilibrium radiofrequency(RF)discharge and a vacuum RF plasma source with an external magnetic field.Samples treated by atmospheric discharge demonstrated aging effects during the first week after treatment.The sorption capacity of samples treated by the RF plasma source was stable over the same period and reached values as high as 0.95.Parameters of the beam created by the vacuum RF plasma source were analyzed and dependences of the fabric sorption capacity and specific surface area on plasma treatment time were investigated.We found that sorption capacity reached its maximum value after 30 min of treatment and did not change significantly if processing was continued,while the specific surface area reached its maximum after 3 min of treatment and quickly decreased after that.It was found that the micropore structure of the fabric remained almost the same during plasma treatment.The volume of mesopores in a unit of the fabric mass(specific volume)doubled during the first 5 min of treatment and returned to initial values after 30 min of treatment.The sorption capacity continued to increase even when the specific surface area decreased after reaching its peak value.This indicates the important role of surface functional groups formed on carbon fibers during plasma treatment.This is consistent with the results of x-ray photoelectron spectroscopy analysis showing changes in surface oxidation during plasma treatment.

Plasma Treatment of Aluminum Using a Surface Barrier Discharge Operated in Air and Nitrogen: Parameter Optimization and Related Effects

This paper presents the results of aluminum surface treatment by diffuse coplanar surface barrier discharge. The goals are to study the effectiveness of the plasma treatment and the dependence of its efficiency on operation parameters, such as sample-to-electrode distance, treatment time or gas atmosphere. Three types of aluminum materials （bricks, sheets and thin films） were tested to ensure the reliability of the treatment. The changes in the surface properties were characterized by the surface free energy, atomic force microscopy, attenuated total reflectance Fourier transform infrared spectroscopy （ATR FTIR） and X-ray photoelectron spec- troscopy （XPS）. The influence of aging effect on the treatment was also measured and discussed.

Effects of microwave oxygen plasma treatments on microstructure and Ge-V photoluminescent properties of diamond particles

The microstructure and Ge-V photoluminescent properties of diamond particles treated by microwave oxygen plasma are investigated.The results show that in the first 5 min of microwave plasma treatment,graphite and disordered carbon on the surface of the particles are etched away,so that diamond with regular crystal plane,smaller lattice stress,and better crystal quality is exposed,producing a Ge-V photoluminescence(PL)intensity 4 times stronger and PL peak FWHM(full width at half maximum)value of 6.6 nm smaller than the as-deposited sample.It is observed that the cycles of‘diamond is converted into graphite and disordered carbon,then the graphite and disordered carbon are etched’can occur with the treatment time further increasing.During these cycles,the particle surface alternately appears smooth and rough,corresponding to the strengthening and weakening of Ge-V PL intensity,respectively,while the PL intensity is always stronger than that of the as-deposited sample.The results suggest that not only graphite but also disordered carbon weakens the Ge-V PL intensity.Our study provides a feasible way of enhancing the Ge-V PL properties and effectively controlling the surface morphology of diamond particle.

In vacuo XPS investigation of surface engineering for lithium metal anodes with plasma treatment

Lithium(Li)metal is an attractive anode material with high capacity(3860 mAh g^(−1))and low potential(−3.04 V vs.standard hydrogen electrode)that shows highly promising for applications requiring high energy density.However,the low electrochemical potential of Li metal makes it extremely reactive and inevitably forming a native oxidized layer in the ambient environment and repeatedly being consumed when exposed to liquid electrolytes.It is therefore beneficial to replace the poorly controlled native passivation layer with a tailored artificial SEI to improve interface management between Li and electrolyte and enhance the stability of Li metal battery.Here,we use an integrated glovebox-atomic layer deposition(ALD)-X-ray photoelectron spectroscopy(XPS)setup to in-situ investigating the pristine Li surface and the surface composition after Ar,H_(2)O_(2),N_(2)and NH_(3)plasma treatment processes.We find that the pristine Li foil is naturally being covered with a native oxidized layer,which is mainly composed of LiOH,Li_(2)O and Li_(2)CO_(3).These investigated plasmas can efficiently remove the oxidized layer from the Li metal surface,in which metallic Li surface is obtained after Ar or H2 plasma treatments,where Ar plasma is more efficient.While O_(2)plasma treatment produces a Li_(2)O layer,and N_(2)or NH_(3)plasma treatment leads to a Li3N(including a certain amount of LiON)layer on the Li surface.When employing the representative metallic Li(by Ar plasma treatment),Li_(2)O layer coated Li(by O_(2)plasma treatment)and Li3N layer coated Li(by N_(2)plasma treatment)foils as electrodes in symmetric Li metal batteries,the Li3N coated Li electrode exhibits much higher stability than that of metallic and Li_(2)O layer coated Li foils.Improved electrochemical performance has also been achieved in LiMn_(2)O_(4)(LMO)||Li full cells using Li anode with Li3N protective coating layer.Our work reveals the detailed process of surface engineering of Li metal anodes with plasma treatments by in vacuo XPS,which may also be extended to other gas-treatment or plasma-treatment for stabilization of high energy density Li metal anodes and other metal-based anodes.

Effects of O_2 Plasma Treatment on the Chemical and Electric Properties of Low-k SiOF Films

With the progress of ULSI technology, materials with low dielectric constant are required to replace Si02 film as the interlayer to scale down the interconnection delay. Fluorinated Si oxide thin films (SiOF) are a promising material for the low dielectric constant and the process compatibility in existing technology. However, SiOF films are liable to absorb moisture when exposed to air. By treating the SiOF films with O2 plasma, it was found that the moisture resistibility of SiOF films was remarkably improved. The mechanism of the improvement in stability of dielectric constant was investigated. The results show that: 1) F atoms dissociated from the films and the bond angle of Si-O-Si decreased. 2) The plasma treatment enhanced the strength of Si-F bonds by removing unstable =SiF2 structures in the films. Resistibility of SiOF films in moisture was improved.

Effect of CHF_3 Plasma Treatment on the Characteristics of SiCOH Low-k Film

The characteristics of SiCOH low dielectric constant film treated by a trifluromethane （CHF3） electron cyclotron resonance （ECR） plasma was investigated. The flat-band voltage VFB and leakage current of the Cu/SiCOH/Si structure, and the hydrophobic property of the SiCOH film were obtained by the measurements of capacitance-voltage, current-voltage and water contact angle. The structures of the SiCOH film were also analyzed by Fourier transform infrared spectroscopy and atomic force microscopy. The CHF3 plasma treatment of the SiCOH film led to a reduction in both the fiat-band voltage VFB shift and leakage current of the Cu/SiCOH/Si structure, a decrease in surface roughness, and a deterioration of the hydrophobic property. The changes in the film＇s characteristics were related to the formation of Si-F bond, the increase in Si-OH bond, and the C：F deposition at the surface of the SiCOH film.

Surface Modification of Electrospun Poly(L-lactide)/Poly(ε-caprolactone)Fibrous Membranes by Plasma Treatment and Gelatin Immobilization

Biopolymer fibers have great potential for technical applications in biomaterials.The surface properties of fibers are of importance in these applications.In this study,electrospun poly(L-lactide)(PLLA)/poly(ε-caprolactone)(PCL)membranes were modified by cold plasma treatment and coating gelatin to improve the surface hydrophilic properties.The morphologies of the fibers were observed by scanning electron microscopy(SEM).Atomic force microscopy(AFM)was employed to show the surface characteristics of the fibers.The chemical feature of the fibrous membrane surfaces was examined by X-ray photoelectron spectroscopy(XPS).The surface wettability of the fibrous membrane was also characterized by water contact angle measurements.All these results show that plasma treatment can have profound effects on the surface properties of fibrous membranes by changing their surface physical and chemical features.Gelatin-PLLA/PCL membrane has great potential in applications of tissue engineering scaffolds.

Colour Reflectance Investigation of Decolourized Sulfur Dyed Cotton Knitted Fabric via Ozone Plasma Treatment

Ozone plasma treatment is accessible to be applied on shading adjustment and colour fading because of the capacity of ozone production. It is a green process that treats dyed cotton fabric under dry condition so as to avoid chemical pollutants. This study means to explore colour reflectance of decolourized sulfur dyed cotton texture using ozone plasma treatment. Sulfur dyed cotton textures with various colour depths (0.5%, 1.5%, 2.5%) were set up to be treated different plasma parameters, including ozone air concentrations (10%, 30%, 50%, 70%), water contents in terms of weight percentage (35%, 45%) of fabric and ozone air plasma treatment periods (10 mins, 20 mins, 30 mins). The colour fading result is assessed by the colour reflectance in percentage (R%) utilizing spectrophotometer under CIE standard illuminant D65. The valid colour fading based on high percentage of reflectance was demonstrated from plasma treatment under higher ozone air concentration (50% and 70% ozone in air) and longer time length of plasma treatment (20 mins and 30 mins). The level of water content contained in the cotton fabrics is appeared to have noteworthy relationship with the degree of decolourization.

Effect of Glow-Discharge Air Plasma Treatment on Wettability of Synthetic Polymers

Main aim of this study was focused on characterization of the effect of microwave air plasma treatment on wettability of synthetic polymer surfaces. Wettability of solid polymer surfaces polyethylene, polypropylene, polystyrene (PE, PP, PS) was followed as a function of plasma treatment time. For evaluation the equilibrium contact angles of wetting as well as dynamic contact angles of wetting were determined by means of sessile drop and Wilhelmy plate methods. Free surface energy (SFE) of studied samples were calculated from the experimentally determined contact angles using Fowkes and van Oss, Chaudhury and Good (vOCG) approaches. It was found that with prolonged treatment time the total surface free energy of PE was two times increased from 23 mJ/m2 to 45 mJ/m2 after 360 s plasma treatment time (calculated for W and EG as wetting liquids). Similar effect was found for all studied polymers. With respect to the dispersive and polar components of the total surface free energy the vigorous effect was found for polar component, for which it was increased from 7 mJ/m2 to 20 mJ/m2.

Effect of Cold Plasma Treatment on the Mechanical Properties of RTM Composites

Cold plasma technology was used to treat the surface of carbon fibers braided by PET in this paper and SEM was used to analyze the fracture microstructure of composite interlaminar shear stress (ILSS). The result shows that the surface polarity of carbon fibers was modified by cold plasma treatment, which increases the impregnation of PET braided carbon fibers during the process of resin flowing, improves the interfacial properties of RTM composites, and therefore enhances the mechanical properties of the KTM composites.

Effect of Low-Pressure Nitrogen DC Plasma Treatment on the Surface Properties of Biaxially Oriented Polypropylene, Poly (Methyl Methacrylate) and Polyvinyl Chloride Films

In this study, commercial biaxially oriented polypropylene （BOPP）, polyvinyl chlo- ride （PVC） and poly （methyl methacrylate） （PMMA） films were treated with nitrogen plasma over different exposure times in a Pyrex tube surrounded by a DC variable magnetic field. The chemi- cal changes that appeared on the surface of the samples were investigated using Fourier transform infrared （FT4R） spectroscopy and attenuated total reflectance Fourier transform infrared （ATR- FTIR） spectroscopy after treatment for 2 min, 4 min and 6 rain in a nitrogen plasma chamber. Effects of the plasma treatment on the surface topographies and contact angles of the untreated and plasma treated films were also analyzed by atomic force microscopy （AFM） and a contact angle measuring system. The results show that the plasma treated films become more hydrophilic with an enhanced wettability due to the formation of some new polar groups on the surface of the treated films. Moreover, at higher exposure times, the total surface energy in all treated films increased while a reduction in contact angle occurred. The behavior of surface roughness in each sample was completely different at higher exposure times.

Effect of Cold Plasma Treatment on Seed Germination and Growth of Wheat

This study investigated the effect of cold helium plasma treatment on seed germina- tion, growth and yield of wheat. The effects of different power of cold plasma on the germination of treated wheat seeds were studied. We found that the treatment of 80 W could significantly improve seed germination potential （6.0%） and germination rate （6.7%） compared to the control group. Field experiments were carried out for wheat seeds treated with 80 W cold plasma. Com- pared with the control, plant height （20.3%）, root length （9.0%） and fresh weight （21.8%） were improved significantly at seedling stage. At booting stage, plant height, root length, fresh weight, stem diameter, leaf area and leaf thickness of the treated plant were respectively increased by 21.8%, 11.0%, 7.0%, 9.0%, 13.0% and 25.5%. At the same time, the chlorophyll content （9.8%）, nitrogen （10.0%） and moisture content （10.0%） were higher than those of the control, indicating that cold plasma treatment could promote the growth of wheat. The yield of treated wheat was 7.55 t-ha-1, 5.89% more than that of the control. Therefore, our results show that cold plasma has important application prospects for increasing wheat yield.