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Construction of highly dispersed Pt single sites and high-efficiencyheterocatalysis silylation of alcohols with silanes

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Nano Research 2023年第4期16卷 4643-4649页

作者： Qiulian Wei Yunqiang Sun Shan Wang Zunfu Hu Qingyun Liu Xiuwen Zheng School of Chemical and Biological Engineering Shandong University of Science and TechnologyQingdao 266510China Key Laboratory of Functional Nanomaterials and Technology in Universities of Shandong College of Chemistry and Chemical EngineeringLinyi UniversityLinyi 276000China

The construction of silicon-oxygen bonds has been highlighted as an exciting achievement in organosilicon and green chemistry,but their synthetic efficiency has great improvement potential,so it is crucial to explore and achieve an effective approach for synthesizing such compounds.In this study,we successfully prepared the highly dispersed platinum single-atom catalyst(Pt SAC/N-C)through a coordination-assisted strategy with a mixture of ligands(H2bpdc and H2bpydc),which were used for the Osilylation of alcohols with silanes.The strong coordination between Pt2+and the Pyridine N at the skeleton of UiO-67 plays a critical role in accessing the atomically isolated dispersion of Pt sites.Without the assistance of the H2bpydc ligands,the Pt/UiO-67-bpdc precursor is prone to aggregation during the pyrolysis process,resulting in the formation of Pt nanoparticles.Aided by advanced characterization techniques of high-angle annular dark-field scanning transmission electron microscopy(HAADFSTEM)and X-ray absorption fine structure(XAFS)spectroscopy,it has been demonstrated that atomically dispersed Pt was formed on the UiO-67 through a local structure of four-coordinated Pt-N4,exhibiting a high actual Pt loading content(0.6962 wt.%).In the oxidation of silanes,the Pt SAC/N-C catalyst showed a high turnover frequency(TOF)value(up to 9,920 h−1)when the catalyst loading decreased to 0.005%.Excellent performance was maintained during recycling experiments,indicating high stability of the catalyst.

关键词： high-dispersion single-atom catalysis O-silylation heterogeneous catalysis

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Numerical simulation of tectonic stress and strain rate fields in the northeastern margin of the Tibetan Plateau in association with major fault zones

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Science China Earth Sciences 2023年第10期66卷 2353-2367页

作者： Shuhong ZHOU Huai ZHANG Yunqiang Sun Caibo HU Yaolin SHI Key Laboratory of Computational Geodynamics University of Chinese Academy of SciencesBeijing100049China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Zhuhai519080China Beijing Yanshan Earth Critical Zone National Research Station University of Chinese Academy of SciencesBeijing101408China College of Transportation and Civil Engineering Fujian Agriculture and Forestry UniversityFuzhou350002China

A series of large strike-slip and thrust faults have developed in the northeastern margin of the Tibetan Plateau since the Late Cenozoic,with strong and active tectonic activity and frequent occurrences of large earthquakes.Modulation of regional tectonic stress distribution,strain fields,and seismic hazards has not been well studied.This study introduces a three-dimensional viscoelastic finite element numerical model to calculate crustal stress and strain rate fields under current tectonic loading.The preliminary results show that the direction of the horizontal principal compressive stress rate and compressive horizontal principal strain rate in the northeastern margin of the Tibetan Plateau rotate clockwise as a whole,and this rotation is more significant in the southeast direction because of the block of the Alxa and the Ordos blocks.The NE-SW horizontal principal compressive stress rate and SE horizontal tensile stress rate dominate the entire study region.The maximum value of the horizontal principal compressive strain rate at a depth of 0 km in the model is approximately 4×10^(-8)yr^(-1)near the East Kunlun fault and is smaller in the stable Alxa and Ordos blocks at approximately 1×10^(-8)yr^(-1).The calculated regional stress state is in good agreement with the actual focal mechanism solution,indicating that strike-slip and thrust stress fields dominate the northeastern margin of the Tibetan Plateau.The Altyn Tagh,East Kunlun,and Haiyuan faults demonstrate that the maximum shear strain rate gradually decreases eastward,and the decrease in the maximum shear strain rate value is absorbed by orogenic uplift and crustal shortening at its boundaries.The western section of the Altyn Tagh fault,west-to-middle sections of the East Kunlun fault,and west-to-middle sections of the Haiyuan fault will have high seismic hazards in the future.

关键词： Northeastern margin of the Tibetan Plateau Finite element model Stress and strain fields Seismic hazard

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Influence of construction-induced damage on the degradation of freeze—thawed lightweight cellular concrete

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Frontiers of Structural and Civil Engineering 2021年第3期15卷 781-792页

作者： Xin LIU Liye ZHANG Zhiwei SHAO yunqiang SHI Lizhi sun Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering Institute of Tunnel and Underground EngineeringHohai UniversityNanjing210098China Department of Civil and Environmental Engineering University of CaliforniaIrvineCA92697-2175USA

During the construction of lightweight cellular concrete(LCC),material damage frequently occurs,causing the degradation and deterioration of the mechanical performance,durability,and subgrade quality of LCC.The construction-induced damage can be more significant than those from the service environment of LCC,such as freeze-thaw(F-T)action in cold regions.However,the effect of construction-induced damage on LCC during F-T cycles is often ignored and the deterioration mechanisms are not yet clarified.In this study,we investigated the factors causing damage during construction using a sample preparation method established to simulate the damage in the laboratory setting.We conducted F-T cycle tests and microstructural characterization to study the effect of microstructural damage on the overall strength of LCC with different water contents under F-T actions.We established the relationship between the pore-area ratio and F-T cycle times,pore-area ratio,and strength,as well as the F-T cycle times and strength under different damage forms.The damage evolution is provided with the rationality of the damage equation,verified by comparing the measured and predicted damage variables.This study would serve as a guide for the construction and performance of LCC in cold regions.

关键词： lightweight cellular concrete construction-induced damage freeze-thaw action microstructure degradation mechanism

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Diatomic active sites nanozymes:Enhanced peroxidase-like activity for dopamine and intracellular H2O2 detection

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Nano Research 2022年第5期15卷 4266-4273页

作者： Shan Wang Zunfu Hu Qiulian Wei Huimin Zhang Weina Tang Yunqiang Sun Haiqiang Duan Zhichao Dai Qingyun Liu Xiuwen Zheng Key Laboratory of Functional Nanomaterials and Technology in Universities of Shandong College of Chemistry and Chemical EngineeringLinyi UniversityLinyi 276000China School of Chemical and Biological Engineering Shandong University of Science and TechnologyQingdao 266510China School of Materials Science and Engineering Linyi UniversityLinyi 276000China

Considering intracellular hydrogen peroxide(H_(2)O_(2))plays pivotal roles in the regulation of serial biological processes,the in-situ detection of intracellular H2O2 has attracted an extensive attention.In the present work,an atomically dispersed diatomic active sites Nanozymes(FeN_(3)/PtN_(4)-single-atom nanozymes(SAzyme))was prepared exhibiting enhanced peroxidase-like activity.The obvious synergistic effect between Fe-Pt heteronuclear diatomic active sites was confirmed by series of characterization and density functional theory(DFT).The peroxidase-like activity of Fe-sites could be substantially enhanced by the bonded Pt-sites via the modulation effect.As a consequence,the gap between the d-band centre(εd)of Fe 3d orbitals and the Fermi energy level was narrowed and the electronic interaction could be strengthened,leading to a lower free energy barrier and a lower activation energy as well as fortified metal-O bonding in the kinetic pathway.Therefore,the constructed FeN3/PtN4-SAzyme exhibited higher peroxidase-like activity than that of FeN4-SAzyme.The FeN3/PtN4-SAzyme-assisted oxidation of 3,3',5,5'-tetramethylbenzidine(TMB)facilitated the colorimetric detection of dopamine(DA),an important biomolecule.The linear detection range and limit of detection(LOD)of DA and H_(2)O_(2) were 1-10 μM,0.01-1.0 mM and 0.109 μM,7.97 μM,respectively.In addition,the constructed SAzymes were also applied for the in-situ detection of intracellular H2O2,expanding the application scope of the newborn SAzymes.

关键词： single-atom nanozymes heteronuclear diatomic active sites peroxidase-like dopamine intracellular H_(2)O_(2)

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Preliminary analysis of earthquake probability based on the synthetic seismic catalog

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Science China Earth Sciences 2020年第7期63卷 985-998页

作者： Yunqiang Sun Gang LUO Caibo HU Yaolin SHI School of Geodesy and Geomatics Wuhan UniversityWuhan 430079China Key Laboratory of Computational Geodynamics of Chinese Academy of Sciences College of Earth and Planetary SciencesUniversity of Chinese Academy of SciencesBeijing 100049China College of Transportation and Civil Engineering Fujian Agriculture and Forestry UniversityFuzhou 350002China

The analysis of seismic hazards relies on the statistical analysis of historical seismic data and the instrumental seismic catalog to obtain the regional earthquake recurrence interval and earthquake probability.The accuracy of analysis thus depends strongly on the completeness of the seismic data used.However,available seismic catalogs are too short or incomplete for the reliable analysis of the statistical characteristics of earthquakes.If a long-term synthetic seismic catalog can be generated using a physics-based numerical simulation,and the simulation results match the crustal deformation,seismicity,and other observations,then such a synthetic catalog helps us to further understand the characteristics of seismic activity and analyze the regional seismic hazard.In this paper,taking the northeastern Tibetan Plateau as a case study,we establish a three-dimensional visco-elastoplastic finite-element model to simulate earthquake cycles and the spatiotemporal evolution of earthquakes on the model fault system and obtain a seismic catalog on a time scale of tens of thousands of years.On the basis that the model satisfies the regional geodynamics of the northeastern Tibetan Plateau,we analyze seismicity on the northeastern Tibetan Plateau using the simulated synthetic earthquake catalog.The characteristics of earthquake recurrence at different locations and different magnitudes,and the long-term average probability of earthquake occurrence within the fault system on the northeastern Tibetan plateau are studied.The results are a reference for regional seismic hazard assessment and provide a basis for the physics-based numerical prediction of earthquakes.

关键词： Synthetic seismic catalog Seismic hazard Recurrence interval of earthquakes Earthquake probability Northeastern Tibetan Plateau

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Quality evaluation of lightweight cellular concrete by an ultrasound-based method

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Frontiers of Structural and Civil Engineering 2022年第9期16卷 1170-1182页

作者： Xin LIU Dongning sun Jinhe LIAO Zhiwei SHAO yunqiang SHI Siqing ZHANG Yunlong YAO Baoning HONG Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering Hohai UniversityNanjing 210098China Institute of Tunnel and Underground Engineering Hohai UniversityNanjing 210098China Geotechnical Research Institute Hohai UniversityNanjing 210098China Foshan Jianying Development Co. Ltd.Foshan 528041China

The accuracy of subgrade quality evaluation is important for road safety assessment.Since there is little research work devoted to testing lightweight cellular concrete(LCC)by an ultrasound-based method,the quantitative relation between ultrasonic testing results and the quality of LCC subgrade is not well understood.In this paper,the quality of LCC subgrade was evaluated with respect to compressive strength and crack discrimination.The relation between ultrasonic testing results and LCC quality was explored through indoor tests.Based on the quantitative relation between ultrasonic pulse velocity and compressive strength of LCC,a fitting formula was established.Moreover,after the LCC became cracked,the ultrasonic pulse velocity and ultrasonic pulse amplitude decreased.After determining the lower limiting values of the ultrasonic pulse velocity and ultrasonic pulse amplitude through the statistical data,it could be calculated whether there were cracks in LCC subgrade.The ultrasonic testing results showed that the compressive strength of the LCC subgrade was suitable for purpose and there was no crack in the subgrade.Then core samples were taken from the subgrade.Comparisons between ultrasonic testing results of subgrade and test results of core samples demonstrated a good agreement.

关键词： lightweight cellular concrete subgrade ultrasound testing quality evaluation crack discrimination

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MOF-derived Fe based catalysts for efficiently Advanced Oxidation Processes: From single atoms to diatomic and nanoparticles

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Progress in Natural Science:Materials International 2023年第4期33卷 534-543页

作者： Xinyi Yang Jiewen Qin Zhichao Dai Yunqiang Sun Hongmei Liu Xiuwen Zheng Zunfu Hu School of Chemistry and Chemical Engineering Linyi University Key Laboratory of Advanced Biomaterials and Nanomedicine in Universities of Shandong School of Physics and Electronic Engineering Linyi University Qilu Normal University

Sub-nanometer catalysts have drawn great attention based on their superior catalytic activity and extensive application in advanced oxidation processes(AOPs). Nonetheless, the precise regulation of the coordination environment and exploration of the peroxymonosulfate(PMS) activation mechanism remain the focus of research.Herein, we report the preparation of Fe catalysts with diverse sizes, including single atoms(SAs), double atoms(DAs), and nanoparticles(NPs) via adjusting the precursor. Sub-nanometric Fe catalysts exhibit a higher catalytic activity for Bisphenol A(BPA) degradation. It is confirmed that the catalytic activity of the Fe diatomic catalysts(Fe2–N/C) is 2.5 times that of the Fe single-atom catalysts(Fe1–N/C) and 8.3 times that of the Fe-nanoparticleloaded catalysts(FeNP–N/C). Broad pH adaptation ranges and reusability have also been proved. Based on experimental verification and density functional theory, non-free radical pathways dominate the degradation process of BPA, while free radical pathways are in an auxiliary position, accompanied by electron transfer process.It is found that the synergistic effect of Fe2–N6sites and pyridinic N adsorption centers contribute to the ultra-high catalytic activity of Fe2–N/C. This work opens up an efficient way for single atom catalysts-based advanced oxidation processes for the efficient removal of refractory organic pollutants.

关键词： Advanced oxidation processes Double reaction sites Fe diatomic catalysts High efficiency degradation Non-free radical pathways

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An adaptive representation model for geoscience knowledge graphs considering complex spatiotemporal features and relationships

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Science China Earth Sciences 2023年第11期66卷 2563-2578页

作者： yunqiang ZHU Kai sun Shu WANG Chenghu ZHOU Feng LU Hairong LV Qinjun QIU Xinbing WANG Yanmin QI State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application Nanjing 210023China Department of Automation Tsinghua UniversityBeijing 100084China School of Computer Science China University of GeosciencesWuhan 430074China Department of Electronic Engineering Shanghai Jiao Tong UniversityShanghai 200240China School of Computer Science University of Nottingham Ningbo ChinaNingbo 315100China

Geoscience knowledge graph(GKG)can organize various geoscience knowledge into a machine understandable and computable semantic network and is an effective way to organize geoscience knowledge and provide knowledge-related services.As a result,it has gained significant attention and become a frontier in geoscience.Geoscience knowledge is derived from many disciplines and has complex spatiotemporal features and relationships of multiple scales,granularities,and dimensions.Therefore,establishing a GKG representation model conforming to the characteristics of geoscience knowledge is the basis and premise for the construction and application of GKG.However,existing knowledge graph representation models leverage fixed tuples that are limited in fully representing complex spatiotemporal features and relationships.To address this issue,this paper first systematically analyzes the categorization and spatiotemporal features and relationships of geoscience knowledge.On this basis,an adaptive representation model for GKG is proposed by considering the complex spatiotemporal features and relationships.Under the constraint of a unified spatiotemporal ontology,this model adopts different tuples to adaptively represent different types of geoscience knowledge according to their spatiotemporal correlation.This model can efficiently represent geoscience knowledge,thereby avoiding the isolation of the spatiotemporal feature representation and improving the accuracy and efficiency of geoscience knowledge retrieval.It can further enable the alignment,transformation,computation,and reasoning of spatiotemporal information through a spatiotemporal ontology.

关键词： Geoscience Knowledge graph Representation model Spatiotemporal features Spatiotemporal relationships

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Hydrodynamic analysis of clastic injection and hydraulic fracturing structures in the Jinding Zn-Pb deposit,Yunnan,China

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Geoscience Frontiers 2012年第1期3卷 73-84页

作者： Guoxiang Chi Chunji Xue Hairuo Qing Wei Xue Jiangwei Zhang Yunqiang Sun Department of Geology University of ReginaReginaSK S4S OA2Canada State Key Laboratory of Geological Processes and Mineral Resources China University of GeosciencesBeijing 100083China

The Jinding Zn-Pb deposit has been generally considered to have formed from circulating basinal fluids in a relatively passive way, with fluid flow being controlled by structures and sedimentary facies, similar to many other sediments-hosted base metal deposits. However, several recent studies have revealed the presence of sand injection structures, intrusive breccias, and hydraulic fractures in the open pit of the Jinding deposit and suggested that the deposit was formed from explosive release of overpres- sured fluids. This study reports new observations of fluid overpressure-related structures from under- ground workings （Paomaping and Fengzishan）, which show clearer crosscutting relationships than in the open pit. The observed structures include： 1） sand （--rock fragment） dikes injecting into fractures in solidified rocks; 2） sand （~rock fragment） bodies intruding into unconsolidated or semi-consolidated sediments; 3） disintegrated semi-consolidated sand bodies; and 4） veins and breccias formed from hydraulic fracturing of solidified rocks followed by cementation of hydrothermal minerals. The development of ore minerals （sphalerite） in the cement of the various clastic injection and hydraulic fractures indicate that these structures were formed at the same time as mineralization. The development of hydraulic fractures and breccias with random orientation indicates small differential stress during mineralization, which is different from the stress field with strong horizontal shortening prior to miner- alization. Fluid flow velocity may have been up to more than 11 m/s based on calculations from the size of the fragments in the clastic dikes. The clastic injection and hydraulic fracturing structures are interpreted to have formed from explosive release of overpressured fluids, which may have been related to either magmatic intrusions at depth or seismic activities that episodically tapped an overpressured fluid reservoir. Because the clastic injection and hydraulic structures are genetically linked with the mi

关键词： Hydrodynamics Clastic injection Hydraulic breccia Hydraulic fracturesJinding Fluid overpressure

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A unified framework of temporal information expression in geosciences knowledge system

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Geoscience Frontiers 2023年第5期14卷 343-352页

作者： Shu Wang yunqiang Zhu Yanmin Qi Zhiwei Hou Kai sun Weirong Li Lei Hu Jie Yang Hairong Lv State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application Nanjing 210023China University of Nottingham Ningbo China Faculty of Science and EngineeringNingbo 315154China Guangzhou Institute of Geography Guangdong Academy of SciencesGuangzhou 510070China University of Chinese Academy of Sciences Beijing 100101China Department of Automation Tsinghua UniversityBeijing 100084China

Time is an essential reference system for recording objects,events,and processes in the field of geosciences.There are currently various time references,such as solar calendar,geological time,and regional calendar,to represent the knowledge in different domains and regions,which subsequently entails a time conversion process required to interpret temporal information under different time references.However,the current time conversion method is limited by the application scope of existing time ontologies(e.g.,“Jurassic”is a period in geological ontology,but a point value in calendar ontology)and the reliance on experience in conversion processes.These issues restrict accurate and efficient calculation of temporal information across different time references.To address these issues,this paper proposes a Unified Time Framework(UTF)in the geosciences knowledge system.According to a systematic time element parsing from massive time references,the proposed UTF designs an independent time root node to get rid of irrelevant nodes when accessing different time types and to adapt to the time expression of different geoscience disciplines.Furthermore,this UTF carries out several designs:to ensure the accuracy of time expressions by designing quantitative relationship definitions;to enable time calculations across different time elements by designing unified time nodes and structures,and to link to the required external ontologies by designing adequate interfaces.By comparing the time conversion methods,the experiment proves the UTF greatly supports accurate and efficient calculation of temporal information across different time references in SPARQL queries.Moreover,it shows a higher and more stable performance of temporal information queries than the time conversion method.With the advent of the Big Data era in the geosciences,the UTF can be used more widely to discover new geosciences knowledge across different time references.

关键词： Unified Time Framework(UTF) Time ontology Geosciences knowledge system Time conversion Time scale Big data

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