Characteristics of inductively coupled plasma(ICP)and helicon plasma in a single-loop antenna

Large area uniform plasma sources,such as high-density magnetized inductively coupled plasma(ICP)and helicon plasma,have broad applications in industry.A comprehensive comparison of ICP and helicon plasma,excited by a single-loop antenna,is presented in this paper from the perspectives of mode transition,hysteresis behavior,and density distribution.The E-H mode transition in ICP and the E-H-W mode transition in helicon plasma are clearly observed in the experiments.Besides,the considerable variation of hysteresis behavior from inverse hysteresis to normal hysteresis by the influence of the magnetic field is explored.The bi-Maxwellian and Maxwellian electron energy distribution functions in each discharge are used to explain this phenomenon,which is essentially related to the transition from a nonlocal kinetic property to a local kinetic property of electrons.In addition,we notice that the plasma density,in the radial direction,is peaked in the center of the tube in ICP,but a complicated distribution is formed in helicon plasma.In the axial direction,the maximum plasma density is still in the center of the antenna in ICP,whereas the highest plasma density is located downstream,far away from the antenna,in helicon plasma.It is believed that the reflected electrons in the sheath and pre-sheath by the upper metallic endplate and downstream propagated helicon wave will be responsible for this plasma density profile in helicon plasma.Due to the constrained electron motion in the magnetic field,an extremely uniform density distribution will be obtained with an appropriate axial magnetic field in the wave discharge mode.

The low temperature growth of stable p-type ZnO films in HiPIMS

In this study,the influence of substrate temperature on properties of Al-N co-doped p-type ZnO films is explored.Benefitting from the high ionization rate in high-power impulsed magnetron sputtering,the concentration of ionized nitrogen N+and ionized zinc Zn+were increased,which promoted the formation of ZnO films and lowered the necessary substrate temperature.After optimization,a co-doped p-type ZnO thin film with a resistivity lower than 0.35Ωcm and a hole concentration higher than 5.34×10^(18)cm^(-3)is grown at 280°C.X-ray diffraction results confirm that Al-N co-doping does not destruct the ZnO wurtzite structure.X-ray photoelectron spectroscopy demonstrates that the presence of Al promotes the formation of acceptor(No)defects in ZnO films,and ensures the role of Al in stabilizing p-type ZnO.

等离子体放电催化处理污染水的研究进展

等离体子体处理废液技术具有处理范围广、快速、高效、无二次污染等优点,在工业界得到广泛的应用。在等离子体处理技术的应用领域,针对相对成本高这一限制,选择合适的催化剂与低温等离子体结合可以降低成本,是比较有发展前景的技术。等离子体协同催化技术可以在充分利用等离体子激发产生的物理和化学效应的同时,利用催化剂有效降低活化能,既提高污染物的降解效率,又提高了等离子体的能量利用率。本文就等离子体同催化剂的协同效应对污染物的降解进展进行了分析,从等离子体的类型、反应器、催化的种类、降解的机理以及对污染物降解效率的评估等这几个方面进行了阐述。文章对未来的研究趋势提出展望,为研究者在理论研究基础上尽早实现等离子体和催化剂处理污水技术的实际工业化提供技术支持。

Fabrication and characterization of iron and iron carbide thin films by plasma enhanced pulsed chemical vapor deposition

A new pulsed chemical vapor deposition（PCVD） process has been developed to fabricate iron（Fe） and iron carbide(Fe1-xCx) thin films at low temperature range from 150 ℃ to 230 ℃.The process employs bis（1,4-di-tert-butyl-1,3-diazabutadienyl）iron（Ⅱ） as iron source and hydrogen gas or hydrogen plasma as the coreactant.The films deposited with hydrogen gas are demonstrated polycrystalline with body-centered cubic Fe.However,for the films deposited with hydrogen plasma,the amorphous phase of iron carbide is obtained.The influence of the deposition temperature on iron and iron carbide characteristics have been investigated.

High power impulse magnetron sputtering and its applications

High power impulse magnetron sputtering（HiPIMS） has attracted a great deal of attention because the sputtered material is highly ionized during the coating process,which has been demonstrated to be advantageous for better quality coating.Therefore,the mechanism of the HiPIMS technique has recently been investigated.In this paper,the current knowledge of HiPIMS is described.We focus on the mechanical properties of the deposited thin film in the latest applications,including hard coatings,adhesion enhancement,tribological performance,and corrosion protection layers.A description of the electrical,optical,photocatalytic,and functional coating applications are presented.The prospects for HiPIMS are also discussed in this work.

Structure-Property Relationship of Conjugated Polymers Utilizing Isomerized Fused Benzothiadiazole-Based Building Blocks

Only a few fused benzothiadizole(BTz)based conjugated polymers have been applied in organic field-effect transistors(OFETs),and their performances were low,mainly due to the lack of available building blocks and in-depth study of the relationship between structure and performance.Herein,we report two isomeric fused BTz-based building blocks(M1 and M2)and their copolymers PBTzVBTz-T and PBTzVBTz-TT,PTVT-T and PTVT-TT.DFT study showed all polymers had nearly planar backbone geometries,and PBTzVBTz-TT exhibited the most linear backbone.PTVT-T and PTVT-TT exhibited red-shift absorption spectra and deeper LUMO level than those of PBTzVBTz-T and PBTzVBTz-TT.Thin film microstructure study demonstrated PBTzVBTz-TT and PTVT-TT had edge-on molecular orientation,while the others had the mixed molecular orientation of edge-on and face-on.Furthermore,PBTzVBTz-TT had the longest coherence length in thin film.All these features of PBTzVBTz-TT resulted in its highest carrier mobility of 0.1 cm^(2)·V^(–1)·s^(–1) among these polymers.

Chlorinated Conjugated Polymer Based on Chlorine- and Cyano-substituted (E)-1,2-Di(thiophen-2-yl)ethane for Ambipolar and n-Type Organic Thin-film Transistors

Chlorinated conjugated polymers are rarely reported in ambipolar and n-type organic thin-film transistors(OTFTs),mainly due to the lack of chlorinated strong electron-deficient building blocks.Herein,we report three new chlorine(Cl)-and cyano(CN)-substituted(E)-1,2-di(thiophen-2-yl)ethane building blocks and their copolymers P2Cl1CNTVT-DPP,P4Cl1CNTVT-DPP and P2Cl2CNTVT-DPP.

Biomarkers in oral immunotherapy

Food allergy(FA)is a global health problem that affects a large population,and thus effective treatment is highly desirable.Oral immunotherapy(OIT)has been showing reasonable efficacy and favorable safety in most FA subjects.Dependable biomarkers are needed for treatment assessment and outcome prediction during OIT.Several immunological indicators have been used as biomarkers in OIT,such as skin prick tests,basophil and mast cell reactivity,T cell and B cell responses,allergen-specific antibody levels,and cytokines.Other novel indicators also could be potential biomarkers.In this review,we discuss and assess the application of various immunological indicators as biomarkers for OIT.

Papiliotrema flavescens colonized in biochars inhibits wheat crown rot and Fusarium head blight

Biochar,a known soil amendment,has been found to alleviate plant or soil-borne diseases.However,the related mechanisms are poorly understood,especially from the perspective of microbes colonizing in raw biochar.In this study,laboratory studies,including isolation,adsorption,antifungal test,were employed to investigate biological characteristic of a fungus isolated from aging biochars(peanut shell biochar,rice husk biochar and bamboo biochar),as well as antimicrobial mechanisms on Fusarium species which cause wheat crown rot and Fusarium head blight(FHB).Furthermore,the field trial was conducted to investigate the effect of this fungus on spikelet disease rate and crop yield.The results were as follows:the isolated fungus was identified as Papiliotrema flavescens(P.flavescens),which was confirmed from ambient air,and its properties were characterized,such as the optimal growth pH and the growth curve.The mixed action of 1×10^(6)cells/mL P.flavescens and 1×10^(6)cells/mL Bacillus subtilis(B.subtilis)had the best antifungal effect,reaching an antifungal rate of 86.5%.The P.fla-vescens exerted antifungal effects through potential competition among nutrition,space,and parasitism,not from producing antifungal substances.Results from the field trial showed that the presence of P.flavescens could reduce the spike disease rate by 43.2%and increase the yield by 34.5%.In summary,the present study provides novel evidence about microbes from aging biochars that can prevent wheat crown rot and FHB.