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Science china chemistry 2008年第5期51卷 447-451页

作者： zou bo,jiang huanfeng college of chemistry,south china university of technology,guangzhou 510640,china college of chemistry South China University of Technology Guangzhou China

A novel and green method for the synthesis of dimethyl pyridine-3,5-dicarboxylate has been developed. It is PdCl2-catalyzed heterocyclotrimerization of methyl acrylate with urea in methanol/supercritical carbon dioxid... 详细信息

关键词： PdCl2 heterocyclotrimerization dimethyl pyridine-3 5-dicarboxylate scCO2

Rh(Ⅱ)-catalyzed intermolecular carboamination of pyridines via double Csp^(2)-H bond activations

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Science china chemistry 2024年第1期67卷 374-382页

作者： Zhongfeng Luo Jingxing jiang Lifang zou Xiaoyu Zhou Junshan Liu Zhuofeng Ke Fengjuan Chen huanfeng jiang Wei Zeng Key Laboratory of Functional Molecular Engineering of Guangdong Province School of Chemistry and Chemical EngineeringSouth China University of TechnologyGuangzhou 510641China School of Materials Science and Engineering PCFM LabSun Yat-sen UniversityGuangzhou 510275China Guangdong Provincial Key Laboratory of Chinese Medicine Pharmaceutics School of Traditional Chinese MedicineSouthern Medical UniversityGuangzhou 510515China

We disclose the development of the Rh-catalyzed amine-directed remote 5,6-carboamination protocol of pyridines via dual Csp^(2)-H functionalizations.A variety of readily available 2-aminopyridines and 1,2,3-triazoles are allowed for coupling cyclization to access polyfunctionalized *** studies including DFT calculations unveil that relay carbenoidelectrophilic addition to pyridines and the sequential pyridyl Csp^(2)-H amination are involved in this *** postsynthetic utility of this methodology is showcased by versatile and site-selective modification of azaindoles.

关键词： Rh-catalysis azaindoles pyridyl Csp^(2)-H bond carboamination coupling-cyclization

Microwave peak absorption frequency of liquid

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Science china(Physics,Mechanics & Astronomy) 2008年第9期51卷 1254-1263页

作者： HAN GuangZe1 & CHEN MingDong2 1 Department of Physics,south china university of technology,guangzhou 510640,china 2 guangzhou Auto college,south china university of technology,guangzhou 510800,china Department of Physics South China University of Technology Guangzhou China guangzhou Auto college South China University of Technology Guangzhou China

Microwave-assisted extraction is a new effective method which has practical ap-plications in many fields. Microwave heating is one of its physical mechanisms,and it also has the characteristic of selectivity. When the applied microwave fre-quency equals a certain absorption frequency of the material (or specific compo-nent),the material will intensively absorb microwave energy. This is also known as resonant absorption,and the frequency is called the peak absorption frequency which depends on the physical structure of the material. In this work,dynamic hy-drogen bond energy was included in molecular activation energy; with the liquid cell model,the expression of interaction energy between dipolar molecules was derived. The rotational relaxation time was gotten from the Eyring viscosity formula. Then based on the relationship between dielectric dissipation coefficient and re-laxation time,the expression of microwave peak absorption frequency as a func-tion of the material physical structure,rotational inertia and electrical dipole mo-ment of molecules was established. These theoretical formulas were applied to water and benzene,and the calculated results agree fairly well with the experi-mental data. This work can not only deepen the study of the interaction between microwave and material,but also provide a possible guide for the experiment of microwave-assisted extraction.

关键词： microwave-assisted extraction microwave heating relaxation time liquid viscosity peak absorption fre-quency

Pressure effects on metal/covalent-organic frameworks:structural and optical properties

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Science china chemistry 2024年第9期67卷 2890-2903页

作者： Yixuan Wang Yunfeng Yang Xinyi Yang bo zou Synergetic Extreme Condition High-Pressure Science Center State Key Laboratory of Superhard MaterialsCollege of PhysicsJilin UniversityChangchun 130012China

Metal-organic frameworks(MOFs)and covalent organic frameworks(COFs)with highly ordered porous structure,tunable bandgap,large specific surface area and structural diversity,provide an appealing platform for the development of stimulus response,sensing,imaging and *** various tuning methods,pressure engineering using the diamond anvil cell is a highly powerful in-situ technique,which can efficiently modulate the structural and optical properties of MOFs/*** is beyond the realization of traditional chemical *** review outlines the research progress in the experimentoriented discovery of new phases or unique properties under high pressure,including phase transition,abnormal compression,photoluminescence(PL)discoloration and ***,the improvement of PL quantum yield in MOFs could be achieved by pressure-treated engineering and hydrogen-bonding cooperativity *** also propose and establish the relationship between structure and optical properties under high ***,the challenge and outlook of the current fields are *** hope that this review will supply guidance for comprehending the development of high-pressure MOF/COF-related research fields,and offer novel strategies for designing more high-performance MOF/COF materials to ultimately expand their applications.

关键词： metal/covalent-organic frameworks pressure engineering phase transition abnormal compressive behaviors piezochromic behaviors emission enhancement

A STUDY OF THE INFLUENCE OF INTERFACIAL DAMAGE ON STRESS CONCENTRATIONS IN INTRAPLY HYBRID COMPOSITES

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Acta Mechanica Solida Sinica 2001年第2期14卷 161-168页

作者： Zeng Qingdun Lin Xuehui (college of Traffic and Communications, south china university of technology,guangzhou 510640, china) Coll. of Traffic and Communications South China University of Technology Guangzhou 510640 China

In the axial tensile failure process of intraply hybridcomposites, the breakage of some fibers may lead to interfacialdamage, thus directly influencing the local stress concentrationsnear the sites of breakage. A modified shear-lag model, in which theinterfacial damage is considered, is proposed. Based on the model,the influence of interfacial shear strength on the stressconcentrations and the lengths of interfacial damage zone is firststudied. The present results also provide an important theoreticalbasis for investigating the failure mechanism and hybrid effects forsuch kind of composites.

关键词： intraply hybrid composites interfacial damage stress concentration

Cl^(-)ions accelerating interface charge transfer in a Si/In_(2)S_(3) Faradaic junction photocathode for solar seawater splitting

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Science china chemistry 2024年第9期67卷 2923-2929页

作者： Jun Luo Ruotong Bao Hongzheng Dong Ye Fu Dongjian jiang bo Wang Yuzhan Zheng Qiong Wang Wenjun Luo Zhigang zou Eco-materials and Renewable Energy Research Center(ERERC) Jiangsu Key Laboratory for Nano TechnologyNational Laboratory of Solid State MicrostructuresCollege of Engineering and Applied SciencesNanjing UniversityNanjing 210093China National Laboratory of Solid State Microstructures and Department of Physics Nanjing UniversityNanjing 210093China

Photoelectrocatalytic seawater splitting is a promising low-cost method to produce green hydrogen in a large *** effects of Cl^(-)ions in seawater on the performance of a photoanode have been reported in previous ***,few researches have been done on the roles of Cl^(-)ions in a ***,for the first time,we find that Cl^(-)ions in the electrolyte improve the photocurrent of a Si/In_(2)S_(3) photocathode by 50% at-0.6 V_(RHE).An in-situ X-ray photoelectron spectroscopy(XPS)characterization combined with the time-of-flight secondary-ion mass spectrometry by simulating photoelectrochemical conditions was used to investigate the interface charge transfer *** results suggest that there is an In_(2)^(+3)S_(3-x)(OH)_(2x)layer on the surface of In_(2)S_(3) in the phosphate buffer solution(PBS)electrolyte,which plays a role as an interface charge transfer mediator in the Si/In_(2)S_(3) *** In_(2)^(+3)S_(3-x)(OH)_(2x)surface layer becomes In_(2)^(+3)S_(3-x)(Cl)_(2x)in the PBS electrolyte with NaCl and accelerates the charge transfer rate at the In_(2)S_(3)/electrolyte *** results offer a new concept of regulating interface charge transfer mediator to enhance the performance of photoelectrocatalytic seawater splitting for hydrogen production.

关键词： solar hydrogen production interface charge transfer mechanism coupled electron and ion transfer in-situ XPS characterization In_(2)^(+3)S_(3-x)(OH)_(2x)surface layer

RBF neural network and active circles based algorithm for contours extraction

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Progress in Natural Science:Materials International 2007年第6期17卷 681-686页

作者： Zhou Zhiheng, Zeng Delu and Xie Shengli(college of Electronic & Information Engineering, south china university of technology, guangzhou 510640, china) college of Electronic & Information Engineering South China University of Technology Guangzhou 510640 China

For the contours extraction from the images, active contour model and self-organizing map based approach are popular nowadays. But they are still confronted with the problems that the optimization of energy function will trap in local minimums and the contour evolutions greatly depend on the initial contour selection. Addressing to these problems, a contours extraction algorithm based on RBF neural network is proposed here. A series of circles with adaptive radius and center is firstly used to search image feature points that are scattered enough. After the feature points are clustered, a group of radial basis functions are constructed. Using the pixels’ intensities and gradients as the input vector, the final object contour can be obtained by the predicting ability of the neural network. The RBF neural network based algorithm is tested on three kinds of images, such as changing topology, complicated background, and blurring or noisy boundary. Simulation results show that the proposed algorithm performs contours extraction greatly.

关键词： contours extraction RBF neural network dynamic clustering.

Arbuscular mycorrhizal fungi and endophytic fungi differentially modulate polyamines or proline of peach in response to soil flooding

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Pedosphere 2024年第2期34卷 460-472页

作者： Shengmin LIANG Yingning zou bo SHU Qiangsheng WU Ministry of Education Engineering Research Center of Ecology and Agricultural Use of WetlandHubei Key Laboratory of Waterlogging Disaster and Agricultural Use of WetlandCollege of Horticulture and GardeningYangtze UniversityJingzhou 434025China

Symbiotic fungi are involved in plant flooding tolerance,while the underlying mechanism is not yet *** polyamines(PAs)and proline are also associated with stress tolerance,it is hypothesized that the enhancement of stress resistance by symbiotic fungi is associated with changes in PAs and/or *** aim of this study was to analyze the effect of inoculation with Funneliformis mosseae and Serendipita indica on plant growth,PAs,and proline and the metabolisms in peach(Prunus persica)under ***-week flooding did not affect root colonization frequence of ***,while it promoted root colonization frequence of *** flooding,plants inoculated with *** and *** maintained relatively higher growth rates than uninoculated *** mosseae promoted root ornithine(Orn)contentration and arginine(Arg)and Orn decarboxylase activities under flooding,which promoted putrescine(Put),cadaverine(Cad),and spermidine(Spd)***,*** decreased contentrations of Arg,Orn,and agmatine and Arg decarboxylase activities,thus decreasing PA contentrations under *** were negatively correlated with the expression of PA uptake transporter genes,PpPUT1 and PpPUT2,in *** transporter genes of ***(FmTPO)and ***(SiTPO)were regulated by flooding,of which FmTPO1 was positively correlated with Put,Cad,and Spd,along with positive correlations of Spd with SiTPO1,SiTPO2,and *** flooding,*** decreased proline concentration,while *** increased proline concentration and correlated with expression of a△^(1)-pyrroline-5-carboxylate synthetase gene,*** was thus concluded that *** modulated polyamine accumulation,while *** induced proline accumulation to tolerate flooding.

关键词： △^(1)-pyrroline-5-carboxylate synthetase flooding tolerance Funneliformis mosseae ornithine aminotransferase root colonization Serendipita indica spermidine transporter

Microstructure and Properties of Low Temperature Composite Chromized Layer on H13 Tool Steel

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Journal of Materials Science & technology 2005年第2期21卷 251-255页

作者： Cuilan WU, Chengping LUO and Ganfeng zou college of Mechanical Engineering, south china university of technology, guangzhou 510641, china Coll. of Mech. Eng. South China Univ. of Technol. Guangzhou 510641 China

Low temperature composite chromizing is a process composed of a plain ion-carbonitriding or ion-nitriding at 550-580℃, followed by a low-temperature chromizing in a salt-bath of 590℃. The microstructure and properties of the low temperature composite chromized layer on H13 tool steel were investigated using metallography, X-ray diffraction, microanalysis, hardness and wear tests. It was found that this low temperature process was thermo-dynamically and kinetically possible, and the composite chromized layer on H13 steel, with a thickness of 3-6 μm, consisted of three sub-layers (bands), viz. the outer Cr-rich one, the intermediate (black) one, and the inner, original white layer. After chromizing, the former diffusion layer was thickened. The results of X-ray diffraction showed that the composite chromized layer contained such nitrides and carbides of chromium as CrN, Cr2N, (Cr, Fe)23C6, and (Cr, Fe)7C3, as well as plain α-(Fe, Cr). A high surface microhardness of 1450-1550 HV0.025, which is much higher than that obtained by the conventional ion carbonitriding and ion nitriding, was obtained. In addition, an excellent wear resistance was gained on the composite chromized layer.

关键词： H13 tool steel Low temperature composite chromizing Nitride and carbide of chromium Microhardness Wear resistance

Recovery of cyanophycin granule polypeptide from activated sludge: carbon source dependence and aggregation-induced luminescence characteristics

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Frontiers of Environmental Science & Engineering 2024年第2期18卷 25-34页

作者： Kui zou Hongyuan Liu bo Feng Taiping Qing Peng Zhang college of Environment and Resources Xiangtan UniversityXiangtan 411105China

In the sewage treatment process,facilitating the conversion of pollutants into value-added resources holds great potential for reducing the amount of greenhouse gas emissions and promoting economic *** granule polypeptide(CGP),a recently discovered high value-added biopolymer present in activated sludge,has provided new avenues for the recovery of ***,the mechanisms that regulate CGP synthesis and the characteristics of this biopolymer in activated sludge remain unclear thus *** study investigated the synthesis of CGP,polyhydroxyalkanoates(PHA),and alginate-like exopolysaccharides(ALE)in various microbial aggregates under different carbon sources feeding *** results showed that the CGP yields was superior that of PHA and ALE when subjected to identical carbon source feeding ***,biofilm was more conducive to CGP accumulation than floc *** with glucose and methanol,sodium acetate significantly enriched the CGP synthetase-encoding gene(cphAabundance=~17419),resulting in the highest CGP yield(average 107.1 mg/g MLSS)in both biofilm and floc *** study is the first to reported the characteristic fluorescence of CGP(Ex/Em=~360/450 nm)caused by the aggregated luminescence of arginine on the side ***,this study highlights the potential application of CGP as a fluorescent material and offers insights into CGP recovery from activated sludge in wastewater treatment plants.

关键词： Cyanophycin Polyhydroxyalkanoate Alginate-like exopolysaccharides Bioresource recovery Aggregation-induced luminescence