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Enhancing stability by tuning element ratio in 2D transition metal chalcogenides

Nano Research 2021年第6期14卷 1704-1710页

作者： Zhenjia Zhou Tao Xu Chenxi Zhang Shisheng Li Jie Xu Litao Sun Libo Gao National Laboratory of Solid State Microstructures School of PhysicsCollaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing210093China SEU-FEI Nano-Pico Center Key Laboratory of MEMS of Ministry of EducationSchool of Electronic Science and EngineeringSoutheast UniversityNanjing210096China International Center for Young Scientists(ICYS) National Institute for Materials Science(NIMS)TsukubaIbaraki3050044Japan

Two-dimensional(2D)transition metal chalcogenides(TMCs)are known to be susceptible to the atmosphere,which greatly obscures the intrinsic physical and chemical *** quantitative origin of the instability on the atomic scale has not been well investigated due to the lack of environmentally stable TMCs ***,we find the stability of the grown TMCs is strongly relevant to their initial element ratios,and thus the stoichiometric bonded TMCs have favorable stability,benefitted from the TMCs with controllable *** this study,the degree of structural degradation has been quantitatively defined by the reduced element ratio of chalcogen to metal through the time-dependent characterizations,and the non-stoichiometric ratios in TMCs reveal the atomic lattices with point defects like additive bonds or vacancies *** study not only provides a potential view to fabricate environmentally stable TMCs based devices,but also will bring an effective feasibility of stacking stable vertical heterostructures.

关键词： transition metal chalcogenides stability point defects stoichiometric ratio two-step vapor deposition

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Low-temperature growth of stoichiometric aluminum nitride films prepared by magnetic-filtered cathodic arc ion plating

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Rare Metals 2016年第7期35卷 520-525页

作者： Wan-Qi Qiu Zhong-Wu Liu Ke-Song Zhou School of Materials Science and Engineering South China University of Technology New Materials Research Department Guangzhou Research Institute of Nonferrous Metals

A1N films were prepared on Si（100） and quartz glass substrates with high deposition rate of 30 nm-min-I at the temperature of below 85 ℃ by the magnetic-filtered cathodic arc ion plating （FCAIP） method. The as-deposited A1N films show very smooth surface and almost no macrodroplets. The films are in amorphous state, and the formation of A1N is confirmed by Nls and A12p X-ray photoelectron spectroscopy （XPS）. The XPS depth profile analysis shows that oxygen is mainly absorbed on the A1N surface. The A1N film has A1 and N concentrations close to the stoichiometric ratio with a small amount of A1203. The prepared A1N films are highly transparent over the wave- length range of 210-990 nm. The optical transmission spectrum reveals the bandgap of 6.1 eV. The present technique provides a good approach to prepare large-scale A1N films with controlled structure and good optical properties at low temperature.

关键词： A1N film stoichiometric ratio Binding energy Ion plating Filter

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Effect of slope position on leaf and fine root C,N and P stoichiometry and rhizosphere soil properties in Tectona grandis plantations

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Journal of Forestry Research 2023年第6期34卷 1997-2009页

作者： Qingqing Zhang Zaizhi Zhou Weiwei Zhao Guihua Huang Gaofeng Liu Xiaofei Li Junduo Wu Research Institute of Tropical Forestry Chinese Academy of ForestryGuangzhou 510520People’s Republic of China Experimental Center of Tropical Forestry Chinese Academy of ForestryPingxiang 532600People’s Republic of China

Little is known about C-N-P stoichiometries and content in teak(Tectona grandis)plantations in South China,which are mostly sited on hilly areas with lateritic soil,and the effect of slope position on the accumulation of these elements in trees and rhizosphere *** we analyzed the C,N,P content and stoichiometry in leaves,fine roots and rhizosphere soils of trees on the upper and lower slopes of a 12-year-old teak *** Kraft classification system of tree status was used to sample dominant,subdominant and mean trees at each slope *** results showed that the C,N and P contents in leaves were higher than in fine roots and rhizosphere *** lowest C/N,C/P and N/P ratios were found in rhizosphere soils,and the C/N and C/P ratios in fine roots were higher than in *** accumulation in leaves,fine roots and rhizosphere soils were significantly influenced by slope position and tree class with their interaction mainly showing a greater effect on rhizosphere *** C content and C/N ratio,fine root C and P contents,and C/N and C/P ratios all increased distinctly with declining slope *** contents of organic matter(SOM),ammonium(NH4+-N),nitrate-nitrogen(NO3--N)and available potassium(AK)in rhizosphere soils were mainly enriched on upper slopes,but exchange calcium(ECa),available phosphorus(AP),and pH were relatively *** in the C,N and P stoichiometries in trees were mainly attributed to the differences in rhizosphere soil properties.N and P contents showed significant positive linear relationships between leaf and rhizosphere soil,and C content negative linear correlation among leaves,fine roots and rhizosphere *** properties of rhizosphere soils,particularly C/N and NH4+-N,had significant effects on the leaf nutrients in trees on the upper ***,rhizosphere soil properties mainly influenced fine root nutrients on the lower slope,and soil AK was the major influencing ***,these

关键词： Tectona grandis stoichiometric ratio Rhizosphere soil Dominant trees Nutrient accumulation

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Phosphorus Speciation and Nutrient Stoichiometry in the Soil-Plant System During Primary Ecological Restoration of Copper Mine Tailings

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Pedosphere 2018年第3期28卷 530-541页

作者： WANG Yupeng SHEN Zhangjun ZHANG Zhen Anhui Province Key Laboratory of Farmland Ecological Conservation and Pollution Prevention Anhui Agricultural University School of Life Science Hefei Normal University

The effects of plant vegetation on phosphorus （P） speciation, pH, total carbon concentration, total nitrogen concentration, and alkaline phosphatase activities were investigated to explore the P uptake strategy of plants in low-P soil and to determine the nutrient stoichiometric ratio changes in the rhizosphere of plants （Imperata cylindrica, Miscanthus floridulus, Zoysia sinica, Artemisia lavandulaefolia, Indigofera pseudotinctoria, and Conyza canadensis） which had grown for approximately 15 years in copper mine tailings, East China. The results showed that the average pH values in the rhizosphere decreased by 0.06 1.37 compared with those in the non-rhizosphere. The alkaline phosphatase activities of the rhizosphere were significantly higher than those in the non-rhizosphere. The mean concentrations of aluminum （A1）- and iron （Fe）-bound P and Ca2-P （CaHPO4） in the rhizosphere of all plants were 5.4% to 87.7%, 49.2% to 214.2%, and 86.6% to 147.6% higher than those in the non-rhizosphere, respectively. Except for Cas-P （CasH2（PO4）6） and Cal0-P （Cal0（PO4）6（OH）2） in the rhizosphere, all kinds of inorganic P forms were negatively correlated with pH. Significant correlation was also observed among the concentrations of dominant forms of inorganic P, C, and N and alkaline phosphatase activities in the rhizosphere. Among the studied species, I. pseudotinetoria showed the most significant effect on enhancing soil available P concentration. The stoichiometric ratios of C：P and N：P were apparently higher in the rhizosphere than the non-rhizosphere, whereas these ratios were far below the ratios commonly observed in Chinese soils. These results indicated that the plant growth effectively affected P fractions possibly by changing pH, C and N concentrations, and alkaline phosphatase activity, in the rhizosphere in copper mine railings.

关键词： alkaline phosphatase available P leguminous plant phytoremediation plant community rhizosphere stoichiometric ratio

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Elevational patterns of carbon,nitrogen and phosphorus in understory bryophytes on the eastern slope of Gongga Mountain,China

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Journal of Plant Ecology 2019年第4期12卷 781-786页

作者： Zhe Wang Chunyan Pi Xiaoming Li Weikai Bao College of Life Sciences Shanghai Normal UniversityShanghai 200234China CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization&Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province Chengdu Institute of BiologyChinese Academy of SciencesChengdu 610041China

Aims The nutrient uptake,requirement and releasing rates of bryophytes are very different from those of ***,it is diffi-cult to make a quantitative evaluation of bryophytes’roles in nu-trient cycling and their specific eco-physiological adaptations due to lack of knowledge of their concentrations and stoichiometric ratios of carbon(C),nitrogen(N)and phosphorus(P).To fill this gap,the present study aims to investigate:(i)what are the elevational trends of C,N and P concentrations and stoichiometric ratios of bryophytes?(ii)whether C,N and P concentrations and stoichio-metric ratios of bryophytes differ between different bryophyte types(in terms of the growth form and living substrate)?and(iii)how do the exponent scalings of N and P of bryophytes change along the elevational gradient?Methods We measured and calculated the C,N,P concentrations and stoi-chiometric ratios of bryophytes from four elevations on the eastern slope of Gongga Mountain(22 species in total).Differences in these traits among elevations,and between different bryophyte types were *** log-log allometric regression parameters of N and P at each elevation were also determined and *** Findings The C,N and P concentrations of bryophytes showed decreasing trends with increasing *** specifically,erect bryo-phytes possessed higher C and N concentrations than those of pros-trate species,and terricolous species had higher P concentration than that of corticolous and saxicolous *** from different elevations had an invariant allometric regression slope for P versus *** research at a larger scale is in need for a more generalized law of bryophytes.

关键词： allometric scaling growth form living substrate stoichiometric ratio subalpine

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The Integration of Water and Fertilizer Regulated Soil Nutrients and Enzyme Activities of Greenhouse Tomato ( Solanum lycopersicum ) by Moistube Irrigation

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PHYTON-INTERNATIONAL JOURNAL OF EXPERIMENTAL BOTANY 2024年第11期93卷 2813-2836页

作者： Yang, Haijian Zhang, Mingzhi Xiao, Na Li, Yuan Huanghe Sci & Technol Univ Fac Engn Zhengzhou 450063 Peoples R China Shaanxi Normal Univ Northwest Land & Resources Res Ctr Xian 710119 Peoples R China

Moistube irrigation was driven by the gradient of water potential inside and outside the pipe wall, which has the advantages of continuous irrigation during the crop growth period. However, the response mechanism of soil nutrients and enzyme activities of greenhouse tomatoes under the integration of water and fertilizer by moistube irrigation is still unclear. In order to explore the changes in soil nutrients and enzyme activities of greenhouse tomatoes regulated by irrigation and fertilization in moistube irrigation greenhouse, a completely randomized experimental design was conducted to explore the effects of different irrigation amounts (I, controlling the working pressure head of moistube to achieve different irrigation amount gradients, capillary working pressure was 1 (I1), 2 (I2), 3 (I3) m) and fertilization amounts (F, single fertilization amount was 100 (F1), 200 (F2), 300 (F3) kg/hm 2 ) on soil nutrients, enzyme activities and yield of greenhouse tomato. It was found that with the increase of I, the total organic carbon content (TOC), soil beta-glucosidase (BG), leucine amino peptidase (LAP), N-acetylglucosaminidase (NAG), and alkaline phosphatase (AP) activities enzyme of greenhouse tomato soil increased fi rst and then decreased. When the I increased from I1 to I3, the soil total nitrogen (TN) decreased by 5.07% and 4.91%, respectively, and the soil total phosphorus (TP) by 4.37% and 4.22%, respectively. With the increase of fertilizer amounts, the TOC of tomato soil increased fi rst and then decreased, the activities of BG, LAP, NAG and AP in soil increased fi rst and then decreased, and the contents of TN and TP in soil decreased by 4.79% and 4.68%, 12.32% and 10.47%, respectively. The yield of tomatoes treated with I2 was signi fi cantly higher than that of I1 and I3 by about 13.99% and 1.29%, respectively. The tomato yield of F2 treatment was signi fi cantly higher than that of F1 and F3 treatments by about 22.57% and 1.72%, respectively. Based on th

关键词： Soil nutrient material extracellular enzyme stoichiometric ratio yield

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