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Synthesis of new Squarains Used as Organic Electroluminescent Materials

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Chinese Chemical Letters 1997年第5期8卷 403-406页

作者： liu, n Lu, ZY Xie, MG Jiang, Q SICHUAn UnIV DEPT CHEMCHENGDU 610064PEOPLES R CHINA

Two types of eight kinds of new squarains were designed and synthesized. Their structures were elucidated by IR,nMR,MS and elementary analysis. Their luminescent properties were determined,which indicated that they ca... 详细信息

关键词： OC Cl

nitrogen addition promotes soil carbon accumulation globally

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Science China Life Sciences 2025年第1期68卷 284-293页

作者： Xuemei Yang Suhui Ma Erhan Huang Danhua Zhang Guoping Chen Jiangling Zhu Chengjun Ji Biao Zhu Lingli liu Jingyun Fang Institute of Ecology College of Urban and Environmental Sciencesand Key Laboratory for Earth Surface Processes of the Ministry of EducationPeking University Ministry of Education Key Laboratory for Transboundary Ecosecurity of Southwest China School of Ecology and Environmental ScienceYunnan University State Key Laboratory of Vegetation and Environmental Change Institute of BotanyChinese Academy of Sciences

Soil is the largest carbon(C) reservoir in terrestrial ecosystems and plays a crucial role in regulating the global C cycle and climate *** nitrogen(n) deposition has been widely considered as a critical factor affecting soil organic carbon(SOC) storage, but its effect on SOC components with different stability remains unclear. Here, we analyzed extensive empirical data from 304 sites worldwide to investigate how SOC and its components respond to n addition. Our analysis showed that n addition led to a significant increase in bulk SOC(6.7%), with greater increases in croplands(10.6%) and forests(6.0%) compared to grasslands(2.1%). Regarding SOC components, n addition promoted the accumulation of plant-derived C(9.7%–28.5%) over microbial-derived C(0.2%), as well as labile(5.7%) over recalcitrant components(–1.2%), resulting in a shift towards increased accumulation of plant-derived labile C. Consistently, n addition led to a greater increase in particulate organic C(11.9%) than mineral-associated organic C(3.6%), suggesting that n addition promotes C accumulation across all pools, with more increase in unstable than stable pools. The responses of SOC and its components were best predicted by the n addition rate and net primary productivity. Overall, our findings suggest that n enrichment could promote the accumulation of plant-derived and non-mineral associated C and a subsequent decrease in the overall stability of soil C pool, which underscores the importance of considering the effects of n enrichment on SOC components for a better understanding of C dynamics in soils.

关键词： meta-analysis nitrogen enrichment soil organic carbon carbon accumulation carbon stability

Invariant and energy analysis of an axially retracting beam

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Chinese Journal of Aeronautics 2016年第4期29卷 952-961页

作者： Yang Xiaodong liu Ming Zhang Wei Roderick V.n.Melnik Beijing Key Laboratory of nonlinear Vibrations and Strength of Mechanical Engineering College of Mechanical Engineering Beijing University of Technology M2neT Laboratory The MS2Discovery Interdisciplinary Research Institute Wilfrid Laurier University

The mechanism of a retracting cantilevered beam has been investigated by the invariant and energy-based analysis. The time-varying parameter partial differential equation governing the transverse vibrations of a beam with retracting motion is derived based on the momentum theorem. The assumed-mode method is used to truncate the governing partial differential equation into a set of ordinary differential equations (ODEs) with time-dependent coefficients. It is found that if the order of truncation is not less than the order of the initial conditions, the assumed-mode method can yield accurate results. The energy transfers among assumed modes are discussed during retraction. The total energy varying with time has been investigated by numerical and analytical methods, and the results have good agreement with each other. For the transverse vibrations of the axially retracting beam, the adiabatic invariant is derived by both the averaging method and the Bessel function method. (C) 2016 Chinese Society of Aeronautics and Astronautics. Production and hosting by Elsevier Ltd. This is an open access article under the CC BY-nC-nD license.

关键词： Adiabatic invariants Asymptotic analysis Retracting beam Time-varying systems Transient dynamics

Synthesis and Properties of Layered Oxides LiCo_(1-x)ni_xO_2

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Journal of Materials Science & Technology 1997年第5期13卷 405-408页

作者： Lin, Q Chen, n Ye, W liu, RM Luo, JS GEn RES InST nOnFERROUS MET BEIJING 100088PEOPLES R CHINA

The mechanism of LiCo1－xnixO2(x=0, 0.5, 1) synthesis from carbonates or hydrates was studied by thermogravimetric analysis and X-ray diffraction to identify the medium and final products. The synthesis process from carbonates can be divided into two steps. Below 300℃cobalt carbonate and/or nickel carbonate decompose forming oxides. Over 300℃ Li2CO3 decomposes and reacts with Co and/or ni oxides gradually, as a result Co++ and/or ni++ areoxidized to Co+++ and/or ni+++, finally LiCo1-xnixO2 forms. The proportion of cobalt tonickel in the starting mixture and atmosphere during synthesis affects the structure of ***1-xnixO2(x≤0.5) can be synthesized in air or oxygen and characterized by solid solutionof LiCoO2 and LiniO2. LiniO2 can be obtained only from hydrates and in oxygen *** and LiCo0.5ni0.5O2 have higher first charge capacity than that of LiCoO2. Their discharge capacity reaches a level with that of LiCoO2 and has reasonable reversibility.

关键词： Lithium batteries

Hierarchically electrospun nanofibers and their applications:A review

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nano Materials Science 2021年第3期3卷 213-232页

作者： Muhammad Badmus Jing liu nüWang norbert Radacsi Yong Zhao School of Engineering Institute for Materials and ProcessesUniversity of EdinburghRobert Stevenson RoadEdinburghEH93FBUnited Kingdom Key Laboratory of Bioinspired Smart Interfacial Science and Technology of Ministry of Education School of ChemistryBeihang UniversityBeijing100191PR China

Electrospinning is a popular method for generating long and continuous nanofibers due to its simplicity and ***,conventional electrospun products have weak strength and low availability,which restrict their functionality in complex *** morphology introduces additional and distinctive structural layers onto electrospun *** requires either an extra fabrication step or controlling electrospinning parameters to achieve the desired *** morphology can improve the properties of electrospun nanofibers while also mitigating the undesired *** review discusses the primary and secondary hierarchical structures of electrospun *** structures were found to enhance the functionality of nanomaterials and improve pore connectivity and surface areas of electrospun nanofibers.A further advantage is the ability to impart multiple functionalities on *** a better understanding of some of the dominant hierarchical structures,nanomaterials applications in drug delivery,tissue engineering,catalysis,and energy devices industries can be improved.

关键词： Hierarchical structures Electrospun nanofibers Hollow fibers Core-shell fibers

Fabrication of carbon-supported Al2O3 nanoparticles via spontaneous cross-linking to enhance selective hydrogenation of furfural

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Journal of Energy Chemistry 2025年第1期100卷 612-620页

作者： Weiwei Yu Xinbao Zhang Hongyu Chen Yanan Wang Shaoguo Li Fucun Chen Zhenni liu Xiujie Li Xiangxue Zhu State Key Laboratory of Catalysis Dalian Institute of Chemical Physics Chinese Academy of Sciences

Selective hydrogenation of furfural to furfuryl alcohol is a great challenge in the hydrogenation field due to thermodynamic preference for hydrogenation of C=C over C=***,a novel Al2O3/C-u hybrid catalyst,composed of n-modified dendritic carbon networks supporting Al2O3nanoparticles,was successfully prepared via carbonizing the freeze-dried gel from spontaneous cross-linking of alginate,Al3+and *** obtained carbon-supported Al2O3hybrid catalyst has a high ratio （31%） of Al species in pentahedral-coordinated *** introduction of urea enhances the surface n content,the ratio of pyrrolic n,and specific surface area of catalyst,leading to improved adsorption capacity of C=O and the accessibility of active *** the furfural hydrogenation reaction with isopropyl alcohol as hydrogen donor,Al2O3/C-u catalyst achieved a 90%conversion of furfural with 98.0% selectivity to furfuryl alcohol,outperforming that of commercial γ-***,Al2O3/C-u demonstrates excellent catalytic stability in the recycling tests attributed to the synergistic effect of abundant weak Lewis acid sites and the anchoring effect of the carbon network on *** work provides an innovative and facile strategy for fabrication of carbon-supported Al2O3hybrid catalysts with rich AlVspecies,serving as a high selective hydrogenation catalyst through MPV reaction route.

关键词： Selective hydrogenation Furfural Furfuryl alcohol Cross-linking Carbon supported Al 2 O 3 MPV route

An Axiom System of Probabilistic Mu-Calculus

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Tsinghua Science and Technology 2022年第2期27卷 372-385页

作者： Wanwei liu Junnan Xu David n.Jansen Andrea Turrini Lijun Zhang College of Computer Science National University of Defense TechnologyChangsha 410073China State Key Laboratory of Computer Science Institute of SoftwareChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100039China Institute of Intelligent Software Guangzhou 511458China

Mu-calculus(a.k.a.μTL)is built up from modal/dynamic logic via adding the least fixpoint operatorμ.This type of logic has attracted increasing attention since Kozen’s seminal work.PμTL is a succinct probabilistic extension of the standardμTL obtained by making the modal operators *** of this logic,such as expressiveness and satisfiability decision,have been studied *** consider another important problem:the axiomatization of that *** extending the approaches of Kozen and Walukiewicz,we present an axiom system for Pμ*** addition,we show that the axiom system is complete for aconjunctive formulas.

关键词： PμTL axiom system aconjunctive formula tableau approach

Discovery of a new family member of arsenic–vanadium polyoxometalates with high catalytic performance for one-pot coupling of CO2, epoxides and amines

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Tungsten 2025年第1期7卷 80-87页

作者： Fang-Qian Wang Yin Zhang Wei-Wei Wang Mei-Qian Fu Hong-Bing Mo Wei-Dong Yu Chao liu Jun Yan College of Chemistry and Chemical Engineering Central South University Junior Education Department Changsha Normal University School of Science Hunan University of Technology and Business

Arsenic-vanadium polyoxometalates（POMs） represent a family of tremendous potential catalysts owing to their peculiar physical and chemical *** in CO2conversion,using POMs to catalyze the conversion of CO2and epoxide into chemical intermediates is the research ***,A new family number of arsenic-vanadium POMs,[n（CH3）4]4[As8V12O38（H2O）]·2H2O({As8V12O38}),was reported and characterized by single-crystal X-ray diffraction,fourier transform infrared spectroscopy,X-ray photoelectron spectroscopy,*** from other allotropicity,{As8V12O38}shows a different structure pattern with an I-43d *** obtained {As8V12O38} was employed as a catalyst for the *** initial catalytic reaction confirmed that {As8V12O38} can catalyze the formation of epoxy carbonate by using 1.01 kPa CO2and epoxide at 70℃.Furtherly,when added amine in the catalytic system,oxazolidinone could be obtained by high yields,which provides an efficient way to convert CO2into profitable ***,a possible catalytic reaction mechanism was proposed by using different characterization analyses.{As8V12O38} first catalyzes the epoxide and CO2to form an epoxy carbonate and then catalyzes epoxy carbonate and benzylamine into oxazolidinone.

关键词： Arsenic CO2 conversion Oxazolidinone Polyoxometalates Vanadium

Biochemical Characterization of Uracil-DnA Glycosylase from Pyrococcus furiosus

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Chemical Research in Chinese Universities 2012年第3期28卷 477-482页

作者： L1n Li-bo liu Yu-fen liu Xi-peng liu Jian-hua Key Laboratory of Microbial Metabolism School of Life Sciences&BiotechnologyShanghai Jiaotong UniversityShanghai 200240P.R.China

We report the characterization of a uracil-DnA glycosylase（UDG） from the hyperthermophilic archaea Pyrococcus furiosus（P, furiosus）. P. furiosus UDG（PfUDG） has high sequence similarity to the families IV and V UDGs（thermostable UDG family and PaUDG-b family）. PfUDG excises uracil from various DnA substrates with the following order： U/T=U/C〉U/G=U/AP=U/-〉U/U=U/I=U/A. The optimal temperature and pH value for uracil exci- sion by PfUDG are 70 ℃ and 9.0, respectively. The removal of U is inhibited by the divalent ions of Fe, Ca, Zn, Cu, Co, ni and Mn, as well as a high concentration of naC1. The phosphorothioates near uracil strongly inhibit the exci- sion of uracil by PfUDG. Interestingly, pfuDnA（Pyrococcusfuriosus DnA） polymerase, which tightly binds the ura- cil-carrying oligonucleotide, does not inhibit the excision by ***, suggesting PfUDG in vivo functions as the re- pair enzyme to excise uracil damage in genome.

关键词： Pyrococcus furiosus(P furiosus) Uracil DnA glycosylase(UDG) Pyrococcus furiosus DnA polymeras Uracil repair in hyperthermophile