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chemical treatments of the nanocrystalline porous TiO_2 electrodes

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Chinese Science Bulletin 2000年第21期45卷 1956-1959页

作者： ZHANG Dongshe, LIU Yao, WANG Weibo & XIAO XuruiLaboratory of Photochemistry, Center for Molecular Science, Institute of Chemistry. Chinese Academy of Sciences, Beijing100080, China.Correspondence should he addressed to Xiao Xurui Laboratory of Photochemistry Center for Molecular Science Institute of Chemistry Chinese Academy of Sciences Beijing China

Two types of nanocrystalline porous TiO2 electrodes were prepared by the hydrothermal and painting methods. The incident photon-to-current efficiency and photoelectrical conversion efficiency were both improved by chemical treatments of titanium tetrachloride and titanium isopropoxide. The surface roughness, quantities of adsorbed dye, photocurrent-voltage curves, IR spectra and UV-visible absorption spectra were measured, and the mechanism of chemical treatments was discussed.

关键词： nanocrystalline porous TiO2 film dye sensitization chemical treatment solar cell.

chemical states of the atoms in magnetic multilayers Ta/NiO_x/Ni_(81)Fe_(19)/Ta and Co/AlO_x/Co

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Chinese Science Bulletin 2002年第4期47卷 276-279页

作者： YU Guanghua, ZHU Fengwu & CHAI ChunlinDepartment of Materials Physics, University of Science and Technology, Beijing 100083, China Department of Materials Physics University of Science and Technology Beijing China

Ta/NiOx/Ni81Fe19/Ta and Co/AlOx/Co multilay-ers were prepared by rf reactive and dc magnetron sputter-ing. The exchange coupling field (Hex) and the coercivity (Hc) of NiOx/Ni81Fe19 as a function of the ratio of Ar to O2 during the deposition process were studied. The composition and chemical states at the interface region of NiOx/NiFe were also investigated using the X-ray photoelectron spectroscopy (XPS) and peak decomposition technique. The results show that when the ratio of Ar to O2 is equal to 7 and the argon sputtering pressure is 0.57 Pa, the x value is approximately 1 and the valence of nickel is +2. At this point, NiOx is anti-ferromagnetic NiO and the corresponding Hex is the largest. As the ratio of Ar/O2 deviates from 7, the Hex will decrease due to the presence of magnetic impurities such as Ni+3 or metallic Ni at the interface region of NiOx/NiFe, while the Hc will increase due to the metallic Ni. Al layers in Co/AlOx/Co multilayers were also studied by angle-resolved XPS. Our finding is

关键词： NiOx/NiFe exchange coupling Co/AlOx/Co X-ray pho-toelectron spectroscopy (XPS) chemical states.

Ageing behaviour of a polyethylene blend:influence of chemical defects and morphology on charge transport

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High Voltage 2020年第3期5卷 270-279页

作者： Somyot Tantipattarakul Alun S.Vaughan Thomas Andritsch Tony Davies High Voltage Laboratory University of SouthamptonSouthamptonSO171BJUK Maintenance Division Electricity Generating Authority of ThailandNonthaburiThailand

Abstract:The properties of novel cable insulation systems will rely critically upon the morphology of the ***,a blend of high and low-density polyethylene(PE)was processed in order to generate three sets of samples with different *** influence of thermo-oxidative ageing at 120℃ was then *** resulting chemical changes included the introduction of unsaturation and oxygen-containing groups and were determined by antioxidant consumption and oxygen *** chemical defects were found to be concentrated in the fraction of each system that was molten at 120°C and,consequently,served to inhibit recrystallisation following *** resulting spatial distribution of charge trapping sites was therefore strongly dependent on *** electrical conductivity of each system varied non-monotonically with ageing:short times reduced the conductivity;a rapid increase in conductivity over five orders of magnitude occurred beyond a critical ageing *** the pronounced structural differences between the morphologically distinct sets of samples,all exhibited comparable conductivity values beyond this threshold,implying that while charge transport is strongly influenced by chemical factors,crystallinity is relatively *** experimental finding appears at odds with theoretical studies of the electronic states in crystalline and amorphous PE.

关键词： charge chemical conductivity

Improving the removal of fine particles by chemical agglomeration during the limestone-gypsum wet flue gas desulfurization process

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Journal of Environmental Sciences 2019年第6期31卷 35-44页

作者： Lei Zhou Yong Liu Lvyuan Luo Zhulin Yuan Linjun Yang Hao Wu Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education Southeast University School of Energy and Mechanical Engineering Nanjing Normal University

Coal-fired power plants are considered a major source of fine particle emissions in *** to improve the removal efficiency of fine particles during the limestone-gypsum wet flue gas desulfurization(WFGD) process, a novel technology using chemical agglomeration to abate the emission of fine particles is presented herein. The relationship between fine particle emission and the proportion of fine particles in the desulfurization slurry was ***, the influence of chemical agglomeration on fine particle size distribution, both in the flue gas and slurry was experimentally investigated. When chemical agglomeration agents were added to the desulfurization slurry, the fine particle removal performance as well as the effects of the operation parameters was also explored via the simulated experimental *** results revealed that the fine particles in both the desulfurization slurry and flue gas were significantly enlarged after the addition of the agglomeration agents. This was more marked in the submicron particles. Thus, the proportion of fine particles(chemical agglomeration technique reduced the fine particle emission of the WFGD system by ～30%, while a desulfurization efficiency >90% was maintained.

关键词： Removal performance chemical agglomeration Size distribution WFGD Fine particle emission

Controlled synthesis of high-quality W-Y2O3 composite powder precursor by ascertaining the synthesis mechanism behind the wet chemical method

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Journal of Materials Science & Technology 2020年第1期36卷 118-127页

作者： Zhi Dong Nan Liu Weiqiang Hu Zongqing Ma Chong Li Chenxi Liu Qianying Guo Yongchang Liu State Key Lab.of Hydraulic Engineering Simulation and Safety School of Materials Science and EngineeringTianjin UniversityTianjin300072China

As an emerging preparation technology,wet chemical method has been employed widely to produce lots of alloy materials such as W and Mo based alloys,owing to its unique technical *** the synthesis mechanism behind wet chemical method is indispensable for controlled synthesis of highquality W-Y2 O3 composite powder *** co-deposition mechanism of yttrium and tungsten component behind the wet chemical method of preparing yttrium-doped tungsten composite nanopowder was investigated systematically in this work.A series of co-deposited composite powders fabricated under different acidity conditions were used as research targets for investigating the effect of surface composition and structure on co-deposition *** was found that white tungstic acid has more W-OH bonds and much higher co-deposition efficiency with Y^3+ions than yellow tungstic *** is illustrated that the coordination reaction between W-OH bonds on tungstic acid particles and Y^3+ions brings the co-deposition of yttrium and tungsten component into *** displacing H^+ions in W-OH bonds,Y^3+ions can be adsorbed on the surface of or incorporated into tungstic acid particles in form of ***,to control and regulate Y2 O3 content in powder precursor accurately,H^+ion concentration in wet chemical reaction should be in range of 0.55-2.82 mol L^-1 to obtain white tungstic ***,H^+ion concentration also has prominent effect on the grain size and morphology of reduced powder *** optimal value should be around 1.58 mol L^-1,which can lead to minimum W grain size(about 17 nm) without bimodal *** chemical mechanism proposed in this work could produce great sense to preparation of high-quality precursor for sintering high-performance Y2 O3 dispersion strengthened W based *** work may also shed light on the approach to exploit analogous synthesis mechanism in other alloy systems.

关键词： W-Y2O3 Wet chemical method W-OH bond Ligand Co-deposition mechanism

Hybrid Laser Ablation and chemical Modification for Fast Fabrication of Bio-inspired Super-hydrophobic Surface with Excellent Self-cleaning,Stability and Corrosion Resistance

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Journal of Bionic Engineering 2019年第1期16卷 13-26页

作者： Zhen Yang Xianping Liu Yanling Tian Key Laboratory of Mechanism Theory and Equipment Design Ministry of EducationTianjin UniversityTianjin 300350China School of Engineering University of WarwickCoventry CV4 7ALUK

Although laser ablation is considered as a facile technique to fabricate bio-inspired super-hydrophobic surfaces,the issue is that the initial laser treated metallic surfaces show super-hydrophilic *** will take a long period to reach super-hydrophobic state under ambient *** is reported that these super-hydrophobic surfaces could be easily damaged by thermal heating effect or interaction with other liquids,causing uncontrolled loss of *** this study,a stable super-hydrophobic aluminum surface was rapidly fab-ricated via the hybrid laser ablation and surface chemical modification of(heptadecafluoro-1,1,2,2-tetradecyl)triethoxysilane(AC-FAS).Surface morphology and chemistry were systematically investigated to explore the generation mechanism of *** water contact angle of the treated surfaces can reach up to 160.6°±1.5°with rolling angle of 3.0°±1.0°,exhibiting perfect self-cleaning capability,long-term stability,and excellent chemical stability in acidic as well as alkaline *** potentiodynamic polarization tests implied that the super-hydrophobic surfaces showed better anti-corrosion *** hybrid laser ablation and surface chemical modification are very time-saving and low-cost,which offers a rapid way for quantity production of super-hydrophobic surface on aluminum material.

关键词： bioinspiration nanosecond laser super-hydrophobic chemical stability corrosion resistance self-cleaning long-term stability

Metalorganic chemical vapor deposition of InN quantum dots and nanostructures

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Light(Science & Applications) 2021年第8期10卷 1409-1420页

作者： Caroline E.Reilly Stacia Keller Shuji Nakamura Steven P.DenBaars Materials University of CaliforniaSanta BarbaraCA 93106USA Electrical and Computer Engineering University of CaliforniaSanta BarbaraCA 93106USA

Using one material system from the near infrared into the ultraviolet is an attractive goal,and may be achieved with(ln,AI,Ga)***Ⅲ-N material system,famous for enabling blue and white solid-state lighting,has been pushing towards longer wavelengths in more recent *** a bandgap of about 0.7 eV,InN can emit light in the near infrared,potentially overlapping with the part of the electromagnetic spectrum currently dominated byⅢ-As andⅢ-P *** has been the case in these otherⅢ-V material systems,nanostructures such as quantum dots and quantum dashes provide additional benefits towards optoelectronic *** the case of InN,these nanostructures have been in the development stage for some time,with more recent developments allowing for InN quantum dots and dashes to be incorporated into larger device *** review will detail the current state of metalorganic chemical vapor deposition of InN nanostructures,focusing on how precursor choices,crystallographic orientation,and other growth parameters affect the *** optical properties of InN nanostructures will also be assessed,with an eye towards the fabrication of optoelectronic devices such as light-emitting diodes,laser diodes,and photodetectors.

关键词： optoelectronic quantum chemical

When traditional ground support techniques aren’t enough–chemical injections can solve complex problems

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International Journal of Mining Science and Technology 2020年第1期30卷 119-122页

作者： Cody Hildreth Frederick Cybulski Colton Cook Stephen C.Tadolini Minova Americas GeorgetownKY 40324USA Arch Coal Inc.SharplesWV 25183USA

Broken and jointed ground is extremely hazardous and requires unique stabilization techniques to protect workers and critical *** techniques,even the most advanced pre-load to create roof compression,can leave large gaps of unconfined and separated *** roof can also be susceptible to water inflows which only exacerbate the support *** types of conditions existed on long-term development main entry accessing several future longwall *** geotechnical assessment identified well defined jointing systems that also permitted water to flow between the roof separations,which"lubricated"the roof material and minimized any frictional *** injections of polyurethane materials,Minova Carbopur WS,was placed beyond the bolted horizon to move the water to the rib lines and reinforce the fractured and broken *** injection materials permitted the effective use of bolting patterns and helped ensure long-term stability of critical *** paper describes the evaluation techniques,design patterns,basis for chemical selection and application,and results and recommendations.

关键词： chemical injection Polyurethane Water stoppage

Smart machine learning or discovering meaningful physical and chemical contributions through dimensional stacking

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npj Computational Materials 2019年第1期5卷 379-386页

作者： Lee A.Griffin Iaroslav Gaponenko Shujun Zhang Nazanin Bassiri-Gharb School of Electrical Engineering Georgia Institute of TechnologyAtlantaGAUSA G.W.Woodruff School of Mechanical Engineering Georgia Institute of TechnologyAtlantaGAUSA Department of Quantum Matter Physics University of GenevaGenevaSwitzerland ISEM Australian Institute for Innovative MaterialsUniversity of WollongongWollongongAustralia School of Materials Science and Engineering Georgia Institute of TechnologyAtlantaGAUSA

Despite remarkable advances in characterization techniques of functional materials yielding an ever growing amount of data,the interplay between the physical and chemical phenomena underpinning materials’functionalities is still often poorly *** reduction techniques have been used to tackle the challenge of understanding materials’behavior,leveraging the very large amount of data ***,we present a method for applying physical and chemical constraints to dimensional reduction analysis,through dimensional *** to traditional,uncorrelated techniques,this approach enables a direct and simultaneous assessment of behaviors across all measurement parameters,through stacking of data along specific dimensions as required by physical or chemical *** proposed method is applied to the nanoscale electromechanical relaxation response in(1−x)PMN-xPT solid solutions,enabling a direct comparison of electric field-and chemical composition-dependent contributors.A poling-like,and a relaxation-like behavior with a domain glass state are identified,and their evolution is tracked across the phase *** proposed dimensional stacking technique,guided by the knowledge of the underlying physics of correlated systems,is valid for the analysis of any multidimensional dataset,opening a spectrum of possibilities for multidisciplinary use.

关键词： stacking chemical relaxation