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Optimal design of self-propagating high temperature one-dimensional nano-SnO_2 synthesis

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Acta Metallurgica Sinica(English Letters) 2011年第4期24卷 321-325页

作者： Nian LIU guodonq zhang Department of Materials Engineering and Center for Electron Microscopy Wuhan UniversityWuhan 430072 China

The success in synthesizing high purity SnO2 nanobelts via self-propagating high tem- perature synthesis was achieved. According to the experimental results, a relationship between the residual heat of the reaction system at 2848 K and SnO2 nanobelts yield was identified. The most appropriate formula for this self-propagating high tempera- ture synthesis method is turned out to be composed of Sn powder and thermite with weight ratio of 1：1.

关键词： Optimal design Self-propagating high temperature synthesis Nano-Sn02

Preparation and gas sensing performances of palladium surface-modified flower-like SnO_2 nanopowders

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Particuology 2013年第6期11卷 743-747页

作者： Wanli Jiao Lei zhang School of Material Science and Engineering Shandong University of Technology

Flower-like SnO2 nanopowders prepared by a hydrothermal method were surface modified with palla- dium via impregnation. The crystal structure, morphology, and surface chemistry states of the samples were characterized by means of X-ray diffraction （XRD）, scanning electron microscopy （SEM）, and X-ray photoelectron spectroscopy （XPS）, respectively. The gas sensing performances were also investigated. For a hydrothermal temperature of 220 ℃, flower-like SnO2 nanoparticles consist of nanorods with diameters of 40 nm and lengths of 100 nm. The XPS and XRD results reveal that palladium exists in the Pd0 chemical state but the crystal is too small to be detected. The 0.3 wt% Pd modified SnO2 sensor shows better sensi- tivity, up to 21, for 70 μL/L ethanol gas at an optimal working temperature of 250 ℃. The quick response time （3 s） and fast recovery time （-20 s） are the main characteristics of this sensor.

关键词： SnO2 nanopowders Flower-like structure Hydrothermal method Impregnation Palladium gas sensing

Yolk-shell nanostructural Ni_(2)P/C composites as the high performance electrocatalysts toward urea oxidation

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Chinese Chemical Letters 2021年第7期32卷 2222-2228页

作者： Yi zhang Chundong Wang School of Optical and Electronic Information Wuhan National Laboratory for OptoelectronicsHuazhong University of Science and TechnologyWuhan 430074China Key Laboratory of green Chemical Process of Ministry of Education Key Laboratory of Novel Reactor and Green Chemical Technology of Hubei ProvinceSchool of Chemical Engineering and PharmacyWuhan Institute of TechnologyWuhan 430073China Key Laboratory of Nanodevices and Applications Suzhou Institute of Nano-Tech and Nano-BionicsChinese Academy of SciencesSuzhou 215123China

Highly active and low-cost catalytic electrodes for urea oxidation reaction(UOR)are always crucial for exploration of urea fuel ***,novel york-shell-structural Ni_(2)P/C na nosphere hybrids(Ni_(2)P/C-YS)are rationally constructed via a hydrothermal method and subsequent phosphidation treatment under different temperature ranging from 250℃to 450℃for UOR *** the in-situ constructed hollow york-shell structure,the coupling of conductive carbon materials and active Ni_(2)P allows numerous interfaces facilitating the electron transfer and thereby accelerating the catalytic *** results demonstrate that Ni_(2)P/C-YS-350 nanocomposite can boost the UOR process with a low potential of 1.366 V *** at a current density of 50 mA/cm^(2) in alkaline electrolyte and afford the superior durability with negligible potential decay after 23 *** study presents that the carbon coated Ni_(2)P hybrid with the optimized crystallinities and hollow york-shell configurations can be a promising candidate for application in urea fuel cells.

关键词： Ni_(2)P/C Yolk-shell Electrocatalysts Urea oxidation Nanosphere

On limit fractional Volterra hierarchies

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Communications in Theoretical Physics 2024年第1期76卷 7-16页

作者： Lixiang zhang Chuanzhong Li School of Mathematics and Statistics Ningbo UniversityNingbo315211China College of Mathematics and Systems Science Shandong University of Science and TechnologyQingdao266590China

For the limit fractional Volterra(LFV)hierarchy,we construct the n-fold Darboux transformation and the soliton ***,we extend the LFV hierarchy to the noncommutative LFV(NCLFV)hierarchy,and construct the Darboux transformation expressed by quasi determinant of the noncommutative ***,we establish the relationship between new and old solutions of the NCLFV ***,the quasi determinant solutions of the NCLFV hierarchy are obtained.

关键词： limit fractional Volterra hierarchy noncommutative limit fractional Volterra hierarchy Darboux transformation soliton solution quasi determinant solution

Interspecific competition effects on phosphorus accumulation by Hydrilla verticillata and Vallisneria natans

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Journal of Environmental Sciences 2011年第8期23卷 1274-1278页

作者： Xiufeng zhang Zhengwen Liu Institute of Hydrobiology of Jinan University Guangzhou 510632 China. State Key Laboratory of Lake Science and Environment Nanjing Institute of Geography and LimnologyChinese Academy of Sciences Nanjing 210008 China

The competition between submersed plants has been recognized as an important factor influencing the structure of plant communities in shallow lakes. The ability of different species to take up and store nutrients from the surrounding ambience varies, and hence plant community structure might be expected to affect the cycling of nutrients in lake ecosystems. In this study, the uptake of phosphorus by Hydrilla verticillata and Vallisneria natans was studied and compared in monoculture and competitive mixed-culture plantings. Results showed that for both studied species the phosphorus concentrations of different tissues and of whole plants was unaffected by competition. However, the quantity of phosphorus accumulated by whole plants of 1-1. verticillata was significantly higher in mixture culture than in monoculture, while that of V. natans was lower in the mixed culture. The results indicated that 11. verticillata has a competitive advantage over V. natans, when the two species are grown in competition, and is able to accumulate a greater quantity of phosphorus.

关键词： interspecific competition submersed plants phosphorus storage

New model for load-sharing k-out-of-n:g system with different components

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Journal of Systems Engineering and Electronics 2008年第4期19卷 748-751,842页

作者： Tang Yinghui zhang Jing School of Mathematics & Software Science Sichuan Normal Univ. Chengdu 610066 P. R. China

On the basis of capacity flow model, a new model is developed for a load-sharing k-out-of-n： g system consisting of different components, to describe the increase of the same component＇s failure rates under different loads. All components have exponential life distributions and are nonrepairable in the system. Reliability of load- sharing 2-out- of-3： g system is calculated and some special cases for the system are discussed. The calculation and discussions show that the model is right and practical.

关键词： load-sharing k-out-of-n: g system system reliability

DYNAMIC AND VERIFIABLE SECRET SHARINg AMONg WEIgHTED PARTICIPANTS

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Journal of Systems Science & Complexity 2007年第4期20卷 481-485页

作者： Yanshuo zhang Zhuojun LIU Beijing Electronic Science and Technology Institute Beijing 100070 China Key Laboratory of Mathematics Mechanization CAS Beijing 100080 China

A secret sharing scheme permits a secret to be shared among participants in such a way that only qualified subsets of participants can recover the secret. Secret sharing is useful in management of cryptographic keys. Based on identity, we analyze the secret sharing scheme among weighted participants. Then we present a dynamic scheme about secret sharing among weighted participants. At last, we analyze the secret sharing scheme among weighted participants, which can make all weighted participants verifiable and dynamic.

关键词： Chinese Remainder Theorem dynamic secret sharing verifiable weighted

Uncertainty in Projection of Climate Extremes:A Comparison of CMIP5 and CMIP6

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Journal of Meteorological Research 2021年第4期35卷 646-662页

作者： Shaobo zhang Jie CHEN State Key Laboratory of Water Resources&Hydropower Engineering Science Wuhan University299 Bayi RoadWuchang DistrictWuhan 430072 Hubei Provincial Key Lab of Water System Science for Sponge City Construction Wuhan UniversityWuhan 430072

Climate projections by global climate models(gCMs)are subject to considerable and multi-source *** study aims to compare the uncertainty in projection of precipitation and temperature extremes between Coupled Model Intercomparison Project(CMIP)phase 5(CMIP5)and phase 6(CMIP6),using 24 gCMs forced by 3 emission scenarios in each phase of *** this study,the total uncertainty(T)of climate projections is decomposed into the greenhouse gas emission scenario uncertainty(S,mean inter-scenario variance of the signals over all the models),gCM uncertainty(M,mean inter-model variance of signals over all emission scenarios),and internal climate variability uncertainty(V,variance in noises over all models,emission scenarios,and projection lead times);namely,T=S+M+*** results of analysis demonstrate that the magnitudes of S,M,and T present similarly increasing trends over the 21 st *** magnitudes of S,M,V,and T in CMIP6 are 0.94-0.96,1.38-2.07,1.04-1.69,and 1.20-1.93 times as high as those in *** CMIP5 and CMIP6 exhibit similar spatial variation patterns of uncertainties and similar ranks of contributions from different sources of *** uncertainty for precipitation is lower in midlatitudes and parts of the equatorial region,but higher in low latitudes and the polar *** uncertainty for temperature is higher over land areas than oceans,and higher in the Northern Hemisphere than the Southern *** precipitation,T is mainly determined by M and V in the early 21 st century,by M and S at the end of the 21 st century;and the turning point will appear in the 2070 *** temperature,T is dominated by M in the early 21 st century,and by S at the end of the 21 st century,with the turning point occuring in the 2060 *** relative contributions of S to T in CMIP6(12.5%-14.3%for precipitation and 31.6%-36.2%for temperature)are lower than those in CMIP5(15.1%-17.5%for precipitation and 38.6%-43.8%for temperature).By contrast,the re

关键词： climate projection uncertainty uncertainty contribution Coupled Model Intercomparison Project(CMIP)phase 5(CMIP5)and phase 6(CMIP6) extreme precipitation and temperature

Moments of integral-type downward functionals for single death processes

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Frontiers of Mathematics in China 2020年第4期15卷 749-768页

作者： Jing WANg Yuhui zhang School of Mathematical Sciences Beijing Normal UniversityLaboratory of Mathematics and Complex SystemsMinistry of EducationBeijing 100875China School of Mathematics and Statistics Yili Normal UniversityYili 835000China

We get an explicit and recursive representation for high order moments of integral-type downward functionals for single death ***,main results are applied to more general integral-type downward functionals.

关键词： Single death process integral-type functional moment