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Preparation and photochromism of Keggin-type molybdphosphoric acid/silica mesoporous composite thin films

Science China Chemistry 2007年第3期50卷 318-326页

作者： ZHANG XueAo wu WenJian MAN YaHui tian tian tian XiaoZhou WANG JianFang College of Aerospace and Material Engineering National University of Defense TechnologyChangsha 410073China

Using tetraethoxysilane and 3-aminopropyltriethoxysilane as the silica sources, amino-functionalized organic/inorganic hybrid mesoporous silica thin films with 2-dimensional hexagonal structure have been synthesized by evaporation induced self-assembly process in the presence of cetyltrimethyl ammonium bromide templates under acid conditions. The Keggin-type molybdphosphoric acid (PMo) is incorporated into the mesoporous silica thin films with amino-groups by wetness impregnation, and the PMo/silica mesoporous composite thin films are obtained. The results of X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), and Fourier transform infrared (FTIR) spectra indicate the PMo molecules maintain Keggin structure and are homogeneously distributed inside mesopores. The composite thin films possess excellent reversible photochromic properties, and change from colorless to blue under ultraviolet irradiation. The photochromic mechanism of the composite thin films is studied by ultraviolet-visible (UV-vis), electron spin resonance (ESR) and X-ray photoelectron spectroscopy (XPS) spectra. It is shown that intervalence charge transfer (IVCT) and ligand-to-metal charge transfer (LMCT) are the main reasons of photochromism. PMo anions interact strongly with amino-groups of the mesoporous suface via hydrogen bond and electrostatic force. After ultraviolet irradiation, the charge transfer occurs by reduction of heteropolyanions accompanying the formation of heteropolyblues with multivalence Mo(VI, V), and the bleaching process of composite thin films is closely related to the presence of oxygen.

关键词： molybdphosphoric acid silica mesoporous composite thin films preparation photochromism

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Feedbacks between vegetation restoration and local precipitation over the Loess Plateau in China

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Science China Earth Sciences 2021年第6期64卷 920-931页

作者： Baoqing ZHANG Lei tian Xining ZHAO Pute wu Key Laboratory of Western China’s Environmental Systems(Ministry of Education) College of Earth and Environmental SciencesLanzhou UniversityLanzhou730000China Institute of Green Development for the Yellow River Drainage Basin Lanzhou UniversityLanzhou730000China Institute of Soil and Water Conservation Northwest A&F UniversityYangling712100China

The implementation of large-scale vegetation restoration over the Chinese Loess Plateau has achieved clear improvements in vegetation fraction,as evidenced by large areas of slopes and plains being restored to grassland or ***,such large-scale vegetation restoration has altered land-atmosphere exchanges of water and energy,as the land surface characteristics have *** variations could affect regional climate,especially local *** evaluating this feedback is an important scientific question in *** study constructs a coupled land-atmosphere model incorporating vegetation dynamics,and analyzes the spatio-temporal changes of different land use types and land surface parameters over the Loess *** considering the impacts of vegetation restoration on the water-energy cycle and on land-atmosphere interactions,we quantified the feedback effect of vegetation restoration on local precipitation across the Loess Plateau,and discussed the important underlying *** achieve a quantitative evaluation,we designed two simulation experiments,comprising a real scenario with vegetation restoration and a hypothetical scenario without vegetation *** enabled a comparison and analysis of the net impact of vegetation restoration on local *** results show that vegetation restoration had a positive effect on local precipitation over the Loess *** show that precipitation on the Loess Plateau increased significantly,at a rate of 7.84 mm yr^(-2),from 2000 to *** simulations show that the contribution of large-scale vegetation restoration to the precipitation increase was about 37.4%,while external atmospheric circulation changes beyond the Loess Plateau contributed the other 62.6%.The average annual precipitation under the vegetation restoration scenario over the Loess Plateau was 12.4%higher than that under the scenario without vegetation *** above research re

关键词： Coupled land-atmosphere modeling Vegetation restoration Water balance Hydrometeorology Ecohydrology

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Cycling performance of layered oxide cathode materials for sodium-ion batteries

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International Journal of Minerals,Metallurgy and Materials 2024年第7期31卷 1720-1744页

作者： Jinpin wu Junhang tian Xueyi Sun Weidong Zhuang School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China Beijing Key Laboratory for Green Recovery and Extraction of Rare and Precious Metals University of Science and Technology BeijingBeijing 100083China

Layered oxide is a promising cathode material for sodium-ion batteries because of its high-capacity,high operating voltage,and simple *** performance is an important criterion for evaluating the application prospects of ***,facing challenges,including phase transitions,ambient stability,side reactions,and irreversible anionic oxygen activity,the cycling performance of layered oxide cathode materials still cannot meet the application ***,this review proposes several strategies to address these ***,bulk doping is introduced from three aspects:cationic single doping,anionic single doping,and multi-ion ***,homogeneous surface coating and concentration gradient modification are *** addition,methods such as mixed structure design,particle engineering,high-entropy material construction,and integrated modification are ***,a summary and outlook provide a new horizon for developing and modifying layered oxide cathode materials.

关键词： sodium-ion battery layered oxide materials cycling performance bulking doping surface coating concentration gradient mixed structure high-entropy

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Application and prospective of 3D printing in rock mechanics: A review

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International Journal of Minerals,Metallurgy and Materials 2021年第1期28卷 1-17页

作者： Yong-tao Gao tian-hua wu Yu Zhou Key Laboratory of Ministry for Efficient Mining and Safety of Metal Mines University of Science and Technology BeijingBeijing 100083China School of Civil and Resource Engineering University of Science and Technology BeijingBeijing 100083China

This review aims to discuss the application and development of three-dimensional printing(3DP) technology in the field of rock mechanics and the mechanical behaviors of 3D-printed specimens on the basis of various available printing *** review begins with a brief description of the concepts and principles associated with 3DP, and then systematically elaborates the five major applications of 3DP technology in the field of rock mechanics, namely, the preparation of rock(including pre-flawed rock) specimens, preparation of joints, preparation of geophysical models, reconstruction of complex rock structures, and performance of bridging experimental testing and numerical ***, the mechanical performance of 3D-printed specimens created using six different printing materials, such as polymers, resin,gypsum, sand, ceramics, and rock-like geological materials, is reviewed in ***, some improvements that can make these 3D-printed specimens close to natural rocks and some limitations of 3DP technology in the application of rock mechanics are *** prospects that are required to be investigated in the future are also ***, a brief summary is *** review suggests that 3DP technology, especially when integrated with other advanced technologies, such as computed tomography scanning and 3D scanning, has great potential in rock mechanics field.

关键词： three-dimensional printing(3DP) rock mechanics 3DP material rock analogue 3DP geotechnical model numerical simulation

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Production of Graphene Nanospheres by Annealing of Graphene Oxide in Solution

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Nano Research 2011年第7期4卷 705-711页

作者： Jian Zheng hongtao Liu Bin wu Yunlong Guo Ti wu Gui Yu Yunqi Liu Daoben Zhu Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic Solids Institute of Chemistry Chinese Academy of Sciences Beijing 100190 China Graduate University of Chinese Academy of Sciences Beijing 100039 China

We report a simple method to produce graphene nanospheres （GNSs） by annealing graphene oxide （GO） solution at high-temperature with the assistance of sparks induced by the microwave absorption of graphite flakes dispersed in the solution. The GNSs were formed by rolling up of the annealed GO, and the diameters were mostly in the range 300-700 nm. The GNS exhibited a hollow sphere structure surrounded by graphene walls with a basal spacing of 0.34 nm. Raman spectroscopy and X-ray photoelectron spectroscopy of the GNSs confirmed that the GO was efficiently reduced during the fabrication process. The resulting GNSs may open up new opportunities both for fundamental research and applications, and this method may be extended to the synthesis of other nanomaterials and the fabrication of related nanostructures.

关键词： Graphene nanosphere self-assembly microwave anneal

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Target-responsive DNAzyme hydrogel for portable colorimetric detection of lanthanide(Ⅲ)ions

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Science China Chemistry 2017年第2期60卷 293-298页

作者： Yishun Huang Xuemeng wu tian tian Zhi Zhu Hui Lin Chaoyong Yang Key Laboratory of Spectrochemical Analysis & Instrumentation Ministry of EducationCollaborative Innovation Center of Chemistry for Energy MaterialsKey Laboratory for Chemical Biology of Fujian ProvinceState Key Laboratory of Physical Chemistry of Solid SurfacesCollege of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005China

Lanthanide elements(Ln)play an important role in industry and *** a result of the increasing consumption of lanthanides,environmental emission of Ln has become detrimental to the health of flora and *** methods for trace lanthanides detection mainly rely on sophisticated *** this article,a Ln^(3+)dependent DNAzyme was incorporated into a hydrogel to generate Ln^(3+)sensitive DNAzyme hydrogel for portable colorimetric *** enzyme strand and its substrate strand act as crosslinker and functional unit of the hydrogel with polyacrylamide chains as the scaffold and gold nanoparticles(AuNPs)as the indicator of hydrogel *** ions in the Ln^(3+)series can trigger the cleavage of substrate strand by activating the enzyme strand,thereby decreasing the crosslink ratio and leading to collapse of the *** release of the encapsulated AuNPs turns the supernatant wine *** this colorimetric method,Ln^(3+)can be detected with high sensitivity,with a limit of detection(LOD)of 20 nM for Ce^(3+).The hydrogel responds specifically to any Ln^(3+)ion and works well with the spiked lake sample without the need of instruments and skilled *** results suggest that the lanthanide responsive hydrogel can be used for portable and sensitive detection of Ln^(3+)contamination in the field.

关键词： lanthanides DNAzyme colorimetric detection hydrogel

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Use of the epitaxial MTBs as a 1D gate(Lg=0.4 nm)for the construction of scaling down two-dimensional field-effect transistors

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Journal of Semiconductors 2024年第10期45卷 1-2页

作者： Youla Yang Daixuan wu He tian tian-Ling Ren School of Integrated Circuit Tsinghua UniversityBeijing 100083China School of Instrument Science and Technology Xi'an Jiaotong UniversityXi'an 710049China

In recent years,there has been a significant increase in research focused on the growth of large-area single *** et al.[1]recently achieved the growth of large-area monolayers of transition-metal chalcogenides through assisted *** quality of molecular beam epitaxy(MBE)-grown two-dimensional(2D)materials can be greatly enhanced by using sacrificial species deposited simultaneously from an electron beam evaporator during the growth *** technique notably boosts the nucleation rate of the target epitaxial layer,resulting in large,homogeneous monolayers with improved quasiparticle lifetimes and fostering the development of epitaxial van der Waals ***,micrometer-sized silver films have been formed at the air-water interface by directly depositing electrospray-generated silver ions onto an aqueous dispersion of reduced graphene oxide under ambient conditions[2].

关键词： silver epitaxial dimensional

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Metabolic fate of dietary sialic acid and its infuence on gut and oral bacteria

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Systems Microbiology and Biomanufacturing 2022年第1期2卷 41-49页

作者： Jianrong wu Zhang Leilei Mengdan Qiang hongtao Zhang Xiaobei Zhan Key Laboratory of Carbohydrate Chemistry and Biotechnology Ministry of EducationSchool of BiotechnologyJiangnan UniversityNo.1800 Lihu AveWuxi 214122JiangsuChina

In recent years,the biological functions of human milk oligosaccharides and the potential toxic efects of red meat on human health have attracted considerable *** acid is an important carbohydrate in milk and red meat,corresponding to sialylated oligosaccharides and N-glycolylneuraminic acid(NeuGc,one type of sialic acid).Herein,we reviewed the metabolic fate of dietary sialic acid in the body and their efects on gut and oral *** summary,dietary NeuAc monomer is directly excreted through urine after being assimilated through the intestines and is not utilized by the human body;in contrast,dietary NeuGc from red meat is easily utilized by the human body and can be incorporated into the brain and other *** can be partially utilized by the human body,but they do not afect the cognitive development and growth of *** sialic acid may mainly regulate the growth and metabolism of gastrointestinal microbiota and human health and development through the gut–brain axis.

关键词： Sialic acid Metabolic fate Oral bacteria Gut microbiota Red meat

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Effect of fructooligosaccharides on the colonization of Lactobacillus rhamnosus AS 1.2466^(T) in the gut of mice

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Food Science and Human Wellness 2023年第2期12卷 607-613页

作者： Zhihua Niu Meijuan Zou Tingting Bei Na Zhang Dongyao Li Miaoshu Wang Chen Li hongtao tian College of Food Science and Technology Hebei Agricultural UniversityBaoding 071000China College of Biochemistry and Environmental Engineering Baoding UniversityBaoding 071000China New Hope Tensun(Hebei)Dairy Co. LtdBaoding 071000China Hebei Technology Innovation Center of Probiotic Functional Dairy Product Baoding 071000China National Engineering Research Center for Agriculture in Northern Mountainous Areas Baoding 071000China

Lactobacillus rhamnosus and fructooligosaccharides(FOS)have been widely studied so ***,the effects of *** on the intestinal microecological environment at the species level and the effect of different proportions of FOS on *** colonization in different parts of mice intestine are still *** study results indicated that the specific bands of enterobacterial repetitive intergenic consensus polymerase chain reaction(ERIC-PCR)in the ***(LR)group significantly increased at 7 *** the number of bands was similar to the natural recovery(NR)group,the brightness of few bands significantly enhanced in the later stage of ***,Southern-blot maps showed strong signals,indicating that the ERIC-PCR fingerprint could accurately reflect the changes in the mouse gut microbiota ***,the high-throughput results confirmed that the Lactobacillus and Akkermansia had different changes at different periods,but all of them showed an upward trend,while the Klebsiella were inhibited,thereby maintaining the intestinal microecology ***,FOS exerted a positive effect on *** colonization in the gut.

关键词： Intestinal microbiota Synbiotics Fructooligosaccharides Lactobacillus rhamnosus

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Robust inference in linear mixed model with skew normal-symmetric error

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Frontiers of Mathematics in China 2017年第6期12卷 1483-1500页

作者： Mixia wu Ye tian Aiyi LIU College of Applied Sciences Beijing University of Technology Beijing 100124 China Biostatistics and Bioinformatics Branch Eunice Kennedy Shriver National Institute of Child Health and Human Development Bethesda MD 20892 USA

Linear mixed effects models with general skew normal-symmetric （SNS） error are considered and several properties of the SNS distributions are obtained. Under the SNS settings, ANOVA-type estimates of variance components in the model are unbiased, the ANOVA-type F-tests are exact F-tests in SNS setting, and the exact confidence intervals for fixed effects are constructed. Also the power of ANOVA-type F-tests for components are free of the skewing function if the random effects normally distributed. For illustration of the main results, simulation studies on the robustness of the models are given by comparisons of multivariate skew-normal, multivariate skew normal-Laplace, multivariate skew normal-uniform, multivariate skew normal-symmetric, and multivariate normal distributed errors. A real example is provided for the illustration of the proposed method.

关键词： Skew normal-symmetric (SNS) ANOVA-type F-test mixed effect

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