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Velocity distribution and scaling properties of wall bounded flow

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2010年第7期11卷 505-510页

作者： zhao-cun liu Key Laboratory o finland Waterway Regulation of Communications Industry Chongqing Jiaotong University Chongqing 400074 China Key Laboratory of Waterway Engineering of Communication Ministry and Chongqing City Chongqing Jiaotong UniversityChongqing 400074 China

The scaling and similarity of wall bounded turbulent flow were studied. The properties of such flows and the relationship between a power law and a logarithmic type of velocity distribution were investigated. Based on the physical mechanism involved, our results show that the power law and the logarithmic distribution are only different forms with the same hypothesis and hold only in the outer flow zone. Thus, a universal explanation for various empirical formulae of velocity distribution was obtained. Manning’s formula was studied to explain theoretically the experiential result that the roughness coefficient is only a comprehensive parameter of the whole system without a corresponding physical factor. The physical mechanism of the velocity distribution of parallel to wall bounded flow was explored, the results show that the parameters in the formula of velocity distribution are indices of the system responding to flowing environmental factors to represent general case of boundary roughness and the flowing state, corresponding physical mechanism is vortex motion.

关键词： Velocity distribution Scaling Turbulence

Relationship between nutrient pollutants and suspended sediments in upper reaches of Yangtze River

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Water Science and Engineering 2015年第2期8卷 121-126页

作者： Xiao-qing Wang zhao-cun liu Ji-lun Miao Ning Zuo Southwest Research Institute of Water Transport Engineering Chongqing Jiaotong University

In order to study the relationship between nutrient pollutants and suspended sediments（SS） in the upper reaches of the Yangtze River and two tributaries, water samples were collected from September 1, 2010 to September 30, 2011 at the Zhutuo, cuntang, Beibei, Wulong, Qingxichang,Wanxian, and Fengjie cross-sections. In the laboratory, the SS concentration and the concentration of SS whose particle size was smaller than0.02 mm were measured. The phosphorus（P）, nitrogen（N）, and permanganate index（CODMn） concentrations in the natural water sample, the settled water sample, and two types of filtered water samples obtained through filter membranes with pore sizes of 0.02 mm and 0.45 mm were monitored synchronously. The results show that there are strong relationships between the P and CODMnconcentrations and the SS concentration. P mainly exists in particulate form, while N mainly exists in dissolved form. SS whose particle size is smaller than 0.02 mm accounts for a high proportion of sediments in the Yangtze River and has a strong effect on water quality. At the seven cross-sections, the amounts of P, N, and CODMnin particulate form in the wet season are higher than in the dry season and the adsorption amounts of P, N, and CODMnper unit mass of sediment are higher in the dry season than in the wet season.

关键词： Suspended sediment Phosphorus Nitrogen Permanganate index

Low-cost and fluoride-free synthesis of MFI zeolite nanosheets with enhanced stability for benzene alkylation with ethanol

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Journal of Energy Chemistry 2025年第1期100卷 458-468页

作者： Peng Zhu cun liu Yiren Yu Guoshu Gao Yumeng zhao Xiongfu Zhang Guodong liu Guohui Yang State Key Laboratory of Fine Chemicals School of Chemical EngineeringDalian University of TechnologyDalian 116024 State Key Laboratory of Catalysis Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023LiaoningChina

Zeolite nanosheets with a short b-axis thickness are highly desirable in lots of catalytic reactions due to their reduced diffusion resistance. Nevertheless, conventional synthesis methods usually require expensive structure-directing agents(SDAs), pricey raw materials, and eco-unfriendly fluorine-containing additives. Here, we contributed a cost-effective and fluoride-free synthesis method for synthesizing high-quality MFI zeolite nanosheets through a Silicalite-1(Sil-1) seed suspension and urea cooperative strategy, only with inexpensive colloidal silica as the Si source. Our approach was effective for synthesizing both Sil-1 and aluminum-containing ZSM-5 nanosheets. By optimizing key synthesis parameters,including seed aging time, seed quantity, and urea concentration, we achieved precise control over the crystal face aspect ratio and b-axis thickness. We also revealed a non-classical oriented nanosheet growth mechanism, where Sil-1 seeds induced the formation of quasi-ordered precursor particles, and the(010)crystal planes of these particles facilitated urea adsorption, thereby promoting c-axis-oriented *** obtained ZSM-5 nanosheets exhibited exceptional catalytic performance in the benzene alkylation with ethanol, maintaining stability for over 500 h, which is 5 times longer than traditional ZSM-5 catalysts. Furthermore, large-scale production of ZSM-5 nanosheets was successfully carried out in a 3 L highpressure autoclave, yielding samples consistent with those from laboratory-scale synthesis. This work marks a significant step forward in the sustainable and efficient production of MFI nanosheets using inexpensive and environmentally friendly raw materials, offering the broad applicability in catalysis.

关键词： MFI zeolite ZSM-5 Nanosheets Scale-up synthesis Aromatic alkylation

Removal of arsenic from water by silver nanoparticles and Fe-Ce mixed oxide supported on polymeric anion exchanger

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Journal of Environmental Sciences 2025年第5期151卷 540-549页

作者： Li Li Su-juan Yu Rong-gang Zheng Qing-cun Li Rui liu Jing-fu liu State Key Laboratory of Environmental Chemistry and Ecotoxicology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China Hubei Key Laboratory of Environmental and Health Effects of Persistent Toxic Substances Institute of Environment and HealthJianghan UniversityWuhan 430056China University of Chinese Academy of Sciences Beijing 100049China Department of Ecology and Resources Engineering He Tao CollegeInner Mongolia 015000China

By encapsulating nanoscale particles of goethite(α-FeO(OH)),hydrous ceric oxide(CeO_(2)·H_(2)O,HCO)and silver nanoparticles(AgNPs)in the pores of polystyrene anion exchanger D201,a novel nanocomposite FeO(OH)-HCO-Ag-D201 was prepared for the effective removal of arsenic from *** isotherm study shows that FeO(OH)-HCO-Ag-D201 has excellent adsorption performance for As(III)and As(V),with an increased adsorption capacity of As(III)to 40.12 mg/g compared to that of 22.03 mg/g by the composite adsorbent without AgNPs(FeO(OH)-HCO-D201).The adsorption kinetics data showed that the sorption rate of FeO(OH)-HCO-Ag-D201 for As(III)is less than that for As(V),and the adsorption of As(III)and As(V)were consistent with the pseudo-second-order model and the pseudofirst-order model,*** or basic conditions are favored for the adsorption of As(III/V)by FeO(OH)-*** with nitrate/chloride/bicarbonate,sulfate/silicate/phosphate showed more remarkable inhibition of arsenic removal by FeO(OH)-HCO-Ag-D201,whereas natural organic matter showed no interference to the arsenic *** As(V)adsorption involved different interactions such as electrostatic attraction and surface complexation,while the adsorption of As(III)involved the part oxidization of As(III)to As(V)and the simultaneous adsorption of As(III)and As(V).In addition to the Ce(IV)in CeO_(2)·H_(2)O acted as an oxidant,the synergistic effect ofα-FeO(OH)and AgNPs also contributed to the oxidization of As(III)to As(V).Moreover,the reusable property suggested that this FeO(OH)-HCO-Ag-D201 nanocomposite has great potential for arsenic-contaminated water purification.

关键词： FeO(OH)-HCO-Ag-D201 Arsenic removal Synergistic effect Oxidation Electrostatic attraction Surface complexation

An efficient conversion model between acceleration and pseudo-acceleration response spectra considering effects of magnitude,distance,and site class

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Earthquake Engineering and Engineering Vibration 2025年第1期24卷 15-30页

作者： liu Zheng zhao Yan-Gang Zhang Haizhong Key Laboratory of Urban Security and Disaster Engineering of Ministry of Education Beijing University of TechnologyBeijing 100124China Faculty of Agriculture Yamagata University1-23Wakaba-machiTsuruoka-shiYamagata 997-8555Japan

Both acceleration and pseudo-acceleration response spectra play important roles in structural seismic ***,only one of them is generally provided in most seismic ***,many studies have attempted to develop conversion models between the acceleration response spectrum(SA)and the pseudo-acceleration response spectrum(PSA).Our previous studies found that the relationship between SA and PSA is affected by magnitude,distance,and site ***,we developed an SA/PSA model incorporating these ***,this model is suitable for cases with small and moderate magnitudes and its accuracy is not good enough for cases with large *** paper aims to develop an efficient SA/PSA model by considering influences of magnitude,distance,and site class,which can be applied to cases not only with small or moderate magnitudes but also with large *** this purpose,regression analyses were conducted using 16,660 horizontal seismic records with a wider range of *** magnitude of these seismic records varies from 4 to 9 and the distances vary from 10 to 200 *** ground motions were recorded at 338 stations covering four site *** comparing them with existing models,it was found that the proposed model shows better accuracy for cases with any magnitudes,distances,and site classes considered in this study.

关键词： acceleration response spectrum pseudo-acceleration response spectrum magnitude distance site class

An improved method to evaluate trap depth from thermoluminescence

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Journal of Rare Earths 2025年第2期43卷 262-269页

作者： Shiyou Zhang Fangyi zhao Shengqiang liu Zhen Song Quanlin liu The Beijing Municipal Key Laboratory of New Energy Materials and Technologies School of Materials Science and EngineeringUniversity of Science and Technology Beijing

Rare earth-doped inorganic compounds contribute mostly to the family of persistent luminescent materials due to the versatile energy levels of rare earth *** of the key research aims is to match the trap level stemming from the doped rare earth ion or intrinsic defects to the electronic structure of the host,and therefore thermoluminescence measurement becomes a radical technology in studying trap depth,which is one of the significant parameters that determine the properties of persistent luminescence and photostimulated ***,the results of trap depth obtained by different thermoluminescence methods are quite different so that they are not ***,we analyzed different thermoluminescence methods,selected and improved the traditional peak position method of Tm/500 to be E=（-0.94Inβ+30.09）*** the experimental heating rate（β） is needed additionally,but the accuracy is improved greatly in most *** convenient and accurate method will accelerate the discovery of novel rare earth-doped materials.

关键词： Persistent luminescence Photostimulated luminescence Rare earths Thermoluminescence Trap depth

Engineering nanoparticle structure at synergistic Ru-Na interface for integrated CO_(2)capture and hydrogenation

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Journal of Energy Chemistry 2025年第1期100卷 779-791页

作者： Hanzi liu Ling Cen Xinlin Xie Lei liu zhao Sun Zhiqiang Sun Hunan Engineering Research Center of Clean and Low-Carbon Energy Technology School of Energy Science and EngineeringCentral South UniversityChangsha 410083HunanChina

The development of dual functional material for cyclic CO_(2)capture and hydrogenation is of great significance for converting diluted CO_(2)into valuable fuels,but suffers from kinetic limitation and deactivation of adsorbent and ***,we engineered a series of RuNa/γ-Al_(2)O_(3)materials,varying the size of ruthenium from single atoms to clusters/*** coordination environment and structure sensitivity of ruthenium were quantitatively investigated at atomic *** findings reveal that the reduced Ru nanoparticles,approximately 7.1 nm in diameter with a Ru-Ru coordination number of 5.9,exhibit high methane formation activity and selectivity at 340°*** Ru-Na interfacial sites facilitate CO_(2)migration through a deoxygenation pathway,involving carbonate dissociation,carbonyl formation,and ***-situ experiments and theoretical calculations show that stable carbonyl intermediates on metallic Ru nanoparticles facilitate heterolytic C–O scission and C–H bonding,significantly lowering the energy barrier for activating stored CO_(2).

关键词： CO_(2)capture Hydrogenation Ru-Na interface Dual functional material Reaction mechanism

Carbon Dots-Modified Hollow Mesoporous Photonic Crystal Materials for Sensitivityand Selectivity-Enhanced Sensing of Chloroform Vapor

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Nano-Micro Letters 2025年第4期17卷 381-398页

作者： Junchen liu Ji liu Zhipeng Li liupeng zhao Tianshuang Wang Xu Yan Fangmeng liu Xiaomin Li Qin Li Peng Sun Geyu Lu Dongyuan zhao State Laboratory On Integrated Optoelectronics College of Electronic Science and EngineeringJilin UniversityChangchun 130012People’s Republic of China Department of Chemistry and Laboratory of Advanced Materials Shanghai Key Laboratory of Molecular Catalysis and Innovative MaterialsState Key Laboratory of Molecular Engineering of PolymersCollaborative Innovation Center of Chemistry for Energy Materials(2011-iChEM)College of Chemistry and MaterialsFudan UniversityShanghaiPeople’s Republic of China School of Engineering and Built Environment Griffith UniversityNathanQLD 4111Australia

Chloroform and other volatile organic pollutants have garnered widespread attention from the public and researchers,because of their potential harm to the respiratory system,nervous system,skin,and ***,research on chloroform vapor sensing is still in its early stages,primarily due to the lack of specific recognition *** we report a mesoporous photonic crystal sensor incorporating carbon dots-based nanoreceptor(HMSS@CDs-PCs)for enhanced chloroform *** colloidal PC packed with hollow mesoporous silica spheres provides an interconnected ordered macro-meso-hierarchical porous structure,ideal for rapid gas sensing utilizing the photonic bandgap shift as the readout *** as-synthesized CDs with pyridinic-N-oxide functional groups adsorbed in the hollow mesoporous silica spheres are found to not only serve as the chloroform adsorption sites,but also a molecular glue that prevents crack formation in the colloidal *** sensitivity of HMSS@CDs-PCs sensor is 0.79 nm ppm^(-1)and an impressively low limit of detection is 3.22 ppm,which are the best reported values in fast-response chloroform vapor sensor without multi-signal *** positive response time is 7.5 s and the negative response time 9 ***,relatively stable sensing can be maintained within a relative humidity of 20%-85%RH and temperature of 25-55℃.This study demonstrates that HMSS@CDs-PCs sensors have practical application potential in indoor and outdoor chloroform vapor detection.

关键词： Carbon dots Photonic crystal sensors Sensitivity-enhanced sensing Selectivity-enhanced sensing Chloroform vapor sensing

Upcycling of polyphenylene oxide into 2,6-dimethyl aniline via depolymerization and amination over a Pt/CeO_(2) catalyst

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Science China Chemistry 2025年第2期68卷 520-525页

作者： Shengchao Jia Wenke zhao Xiaohui liu Yong Guo Yanqin Wang State Key Laboratory of Green Chemical Engineering and Industrial Catalysis Research Institute of Industrial CatalysisSchool of Chemistry and Molecular EngineeringEast China University of Science and TechnologyShanghai 200237China Shanghai Key Laboratory of Functional Materials Chemistry School of Chemistry and Molecular EngineeringEast China University of Science and TechnologyShanghai 200237China

Upcycling of plastic waste into N-containing compound is a novel and attractive strategy for its disposal and will opens up a promising direction for the production of value-added ***,an efficient strategy for the depolymerization-amination of polyphenylene oxide(PPO)into 2,6-dimethyl aniline is developed over a simple Pt/CeO_(2) *** C–O linkages of PPO can be selectively broken,producing 2,6-dimethyl phenol and then hydrogenated and aminated to 2,6-dimethyl cyclohexylamine over the Pt/CeO_(2) ***,2,6-dimethyl aniline was produced with high selectivity through the dehydrogenation of 2,6-dimethyl cyclohexylamine in the same *** can be used as the hydrogen-acceptor in the dehydrogenation step and enhance the selectivity of target *** N-containing compound,2,6-dimethyl aniline,is obtained and separated after HCl ***,the Pt/CeO_(2) catalyst exhibit remarkable stability and can sustainably catalyze the synthesis of 2,6-dimethyl aniline in several cycles.

关键词： PPO depolymerization-amination 2,6-dimethyl aniline Pt/CeO_(2)