Metal oxide semiconductors realized using solution processes have received a great deal of attention because of their low cost and simple fabrication. One major problem associated with the solution ...approach is the presence of undesired impurity species introduced by precursor solutions. Here, we investigated the effects of impurities on the electrical properties and device performance of metal oxide semiconductor thin-film transistors. It was found that chlorine residues inhibit the formation of the oxide framework and impede electron transport in a chloride precursor-derived metal oxide. To minimize the impurity concentration and produce high-quality oxide semiconductors, we used perchloric acid to remove excess chlorine species in a facile redox reaction. After the removal of chlorine species, the oxygen lattice concentration increased from 53 to 62%, and the field-effect mobility of indium oxide thin-film transistors was improved by >20-fold. Furthermore, devices treated with perchloric acid showed superior electrical stability under bias stress tests, corresponding to an improved oxide quality.
•Self-sustainable oxychlorination process in Fe-Al coatings is inhibited effectively in Ni-Al coatings.•The formation of gaseous tungsten oxide is greatly inhibited by unaluminised Ni film ...barrier.•Interdiffusion is largely alleviated due to the smaller indiffusion coefficient in Ni-Al coating.
Fe-Al and Ni-Al coatings were prepared by aluminizing ferritic-martensitic steels without and with pre-electroplating a Ni film, respectively. The corrosion behaviour of two aluminide coatings in marine environment, where high temperature oxidation and corrosion occur under the synergistic effect of solid NaCl and water vapour, were investigated. The results indicated that Ni-Al coatings showed superior corrosion resistance to Fe-Al coatings, the improved performance is mainly due to the beneficial influence of the Ni-plating layer on inhibiting self-sustainable oxychlorination, tungsten outward diffusion and interdiffusion behaviour. The detrimental effects of Fe on breakaway oxidation of Fe-Al coatings are discussed.
Ni-Al aluminide coating was deposited by electroplating of Ni and subsequent aluminisation while Ti-Al aluminide coating was deposited by aluminisation directly on Ti-based alloy. The corrosion ...performance of two coated samples with uncoated sample in marine environment in the presence of NaCl and water vapour at 700 °C were studied. Ni-Al coated sample showed the best corrosion resistance. Ti-Al coated sample showed severer corrosion in marine environment compared with that in static air due to self-sustainable oxychlorination process. The detrimental effect of Ti and beneficial effect of Ni-plating on self-sustainable oxychlorination in marine environment are discussed.
•The corrosion behaviour of Ti-Al coating was facilitated under the synergetic effect of NaCl and H2O(g) .•The corrosion product Na2TiO3 was detected in Ti-Al coating during self-sustainable oxychlorination process.•The self-sustainable oxychlorination process in Ni-Al coating was greatly inhibited by pre-eletroplating Ni layer.
Nanomaterials are naturally metastable with respect to bulk solids. This raises the very important fundamental problem of their morphological stability, especially when nanoscale crystallites are ...touching or nearly touching each other, such as in thin-film devices. In some cases, nanostructuring must be preserved under operational conditions (e.g., in quantum dot LEDs, lasers, photodetectors, and nanogranular thermoelectric devices). In other cases, we use nanocrystalline particles as precursors to a material with large crystalline grains and aim to sinter them as efficiently as possible (e.g., in polycrystalline thin-film solar cells). We carried out a systematic study of sintering and grain growth in materials composed of various sub-10 nm semiconductor grains. The boundaries between individual semiconductor grains have been chemically engineered using inorganic surface ligands. We found that the early stages of sintering and grain growth of nanocrystalline semiconductors are controlled by the ion mobility at the nanocrystal surfaces, while the late stages of grain growth are controlled by the mobility of the grain boundaries. This appears to be a general phenomenon for semiconductor nanocrystals, and it leads to several interesting and counterintuitive trends. For example, III–V InAs nanocrystals are generally much more resilient against sintering and grain growth compared to II–VI CdSe nanocrystals even though bulk CdSe has significantly higher melting point temperature than InAs (1268 °C vs 942 °C). Grain growth can be dramatically accelerated when coupled to solid−solid phase transitions. These findings expand our toolbox for rational design of nanocrystal materials for different applications.
•Thermal barrier coating system with Hf-doped (Ni,Pt)Al bond coat is developed.•Trace incorporation of Hf into (Ni,Pt)Al greatly reduces oxidation rate and rumpling tendency.•Hf diffuses to surface ...and participates in oxidation, forming Hf/Ta oxide pegs in Al2O3 scale.•Two failure modes are proposed for TBCs with (Ni,Pt)Al bond coat.
Thermal cycling behavior of thermal barrier coatings deposited on Hf-doped (Ni,Pt)Al bond coats were investigated, comparing with conventional (Ni,Pt)Al at 1100 °C, to elucidate the effect of Hf addition into (Ni,Pt)Al bond coat on failure mode of TBCs. The results revealed that thermal cycling resistance of TBCs was significantly improved with addition of Hf, where relatively lower oxidation rate constant and decreased scale rumpling tendency were achieved. The effects of Hf incorporation on scale rumpling tendency and failure modes of the TBCs were discussed. Moreover, residual stress, Young’s modulus and hardness in top coat were determined with increasing thermal cycles.
·Crystallization of a SiO2-Al2O3-ZnO-CaO-ZrO2-TiO2 based glass is controlled by foreign ceramics addition.·Needle-like crystals are retarded from precipitation by Al2O3 and CeO2 addition.·Al2O3 ...addition retards the formation of needle precipitates of Zn2SiO4 and CaTiSiO5.·ZrSiO4 precipitation is suppressed by CeO2 addition.
Glass-ceramics are usually obtained through controlled crystallization. In this work, we propose a new strategy to add an appropriate amount of oxide particles to the parent glass to improve the performance of glass-ceramics. Different amounts of Al2O3 or/and CeO2 particles were added into a SiO2-Al2O3-ZnO-CaO-ZrO2-TiO2 based glass, and crystallization behavior, fracture strength, and thermal shock behavior were systematically evaluated. The results indicate that with the addition of Al2O3 or/and CeO2 particles of moderate amount, the unfavorable needle-like ZrSiO4, Zn2SiO4, and CaTiSiO5 crystals were largely inhibited when annealed at 900 °C. Accordingly, fracture strength is maintained high after heating at high temperatures. The thermal shock resistance is also enhanced drastically. The additive Al2O3 is thermodynamically favorable to react with the glass, forming particulate ZnAl2O4 instead of precipitating the needle-like crystals of Zn2SiO4 and CaTiSiO5; while CeO2 will combine with ZrO2 to form a solid solution and promote the precipitation of primary crystal CaZrTi2O7 that will not transform to ZrSiO4 with prolonging thermal exposure.
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A single-phase (Ni,Pt)Al coating with lean addition of Zr was prepared by co-electroplating of Pt-Zr composite plating and subsequent gaseous aluminization treatments. Isothermal and cyclic oxidation ...behavior of the Zr-doped (Ni,Pt)Al coating samples was assessed at 1373 K in static air in comparison with plain nickel aluminide (NiAl) and normal (Ni,Pt)Al coatings. Results indicated that Zr-doped (Ni,Pt)Al coating demonstrated a lower oxidation rate constant and reduced tendency of oxide scale spallation as well as surface rumpling, in which the enhanced oxidation performance was mainly attributed to the segregation of Zr at oxide scale grain boundaries and the improved Young’s modulus of the coating. Besides, the addition of Zr effectively delayed oxide phase transformation of Al2O3 from θ phase to α phase in the early oxidation stage and coating degradation of β-NiAl to γ'-Ni3Al in the stable oxidation stage.
•A strain JI6 from ginseng rhizosphere soil as Pseudomonas thivervalensis.•To promote the growth of ginseng significantly and control rusty root rot.•To colonize and improve microbial community in ...rhizosphere soil of ginseng.
The bacterial strain JI6, which has plant growth-promoting characteristics, was isolated from ginseng rhizosphere soil. It can produce indoleacetic acid (IAA), dissolve phosphorus, dissolve potassium and fix nitrogen and significantly promoted the growth of ginseng. The strain was identified as Pseudomonas thivervalensis by morphological, physiological and biochemical characteristics and 16S rDNA sequence analysis. The bud length of ginseng seeds treated with 109 CFU/mL JI6 suspension increased significantly by 42.76 % after 15 days. The fresh weight and the ginsenoside content of 3-year-old ginseng roots significantly increased by 38.72 % and 24.20 %, respectively with the 108 CFU/mL JI6 suspension for five months in the field. The strain JI6 can inhibit the six fungal pathogens and control rusty root rot of ginseng. For the biocontrol mechanism, the strain JI6 can colonize in ginseng rhizosphere soil. After treatment with JI6, the activitie of five ginseng defence enzymes of β-1.3 glucanase, peroxidase and phenylalanine ammonia-lyase, chitinase and superoxide dismutase and four soil enzymes of urease, phosphatase, invertase, and catalase significantly increased. The effect of strain JI6 on soil microbial community showed that the microbial diversity increased and the abundance of beneficial microorganisms elevated, while the abundance of pathogenic microorganisms decreased. This study indicate the great potential of P. thivervalensis JI6 for use as a biological agent for the control of ginseng rusty root rot.
Biofilm that colonizes on the surface of microplastics (MPs) may represent a potential health risk. The current study examined factors that influence MP-associated biofilm growth, including polymer ...type, degree of weathering, and source water quality. Weathered MPs were produced in-lab, and biofilm trials were conducted on-site at drinking water treatment facilities using a passive flow-through system. Biofilm abundance was quantified in terms of adenosine triphosphate (ATP); its composition was assessed via metagenomic sequencing. Biofilm growth was observed on MPs of all polymer types, and most prevalent on polyvinyl chloride (PVC) where ATP levels were 6 to 12 times higher when compared to other polymers. Pathogen-containing species including Salmonella enterica and Escherichia coli were observed on all polymers with relative abundance up to 13.7%; S. enterica was selectively enriched on weathered polymers in specific water matrices. These findings support the need to examine the impact of drinking water treatment to minimize potential health risks. As well they suggest the need for future studies to adopt the use of weathered polymers, as they were observed to increase biofilm growth.
Doping of alkali metals in precursor solutions demonstrates an effective strategy to achieve high efficiency Cu2ZnSn(S,Se)4 solar cells. The properties of doped films are related to alkali metal ...radius. Smaller alkali atoms are beneficial for increasing carrier concentration, whereas larger atoms are conducive to grain growth. Over 8% efficiency of K‐doped Cu2ZnSn(S,Se)4 solar cell with optimized CdS thickness is realized.
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