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Active precursor promoting nucleation/growth of MwW zeolite and controlling its morphology

Petroleum Science 2023年第3期20卷 1922-1933页

作者： Shi-Wei Cao Peng Xiao Jjie Wang Yu Sun yun-shan shang Ya-Fen Ge Qi Liu Yan-Jun Gong Guang Moo Zhi-Hong Li State Key Laboratory of Heavy OilProcessing Key Laboratory of Catalysis of CNPCChina University of Petroleum-BejingBejing 102249China Beijing Synchrotron Radiation Facility Institute of High Energy PhysicsChinese Academy of SciencesBejing 100039China Cangzhou Risun Chemical Co.Ltd. Hebei 061000China

MWW zeolites is an important catalyst in petrochemical ***,the efficient preparation of Mww zeolites still faces challenges,and the origin of influential factors for regulating its structure properties also remains ***,we designed a nanoscale amorphous silica-alumina species denoted as active precursor(APS),and adopt the APS in the HMI mixture to synthesize MCM-22 zeolite(APS-MWW)*** reveal the distinctive role of APS in promoting the crystallization of MWW zeolites,two crystal materials(ITQ-1 and MCM-22)and one mother liquor(ML)as seeds to synthesize three types of MWW ***,when adding APS in the synthetic mixture,the HMI amount was reduced to less than a quarter and crystallization time was reduced to 36 ***-MWW sample provides a smaller particle size(2-4μm)and thinner stacked layer thickness(5-20 nm).Synchrotron radiation Small Angle X-ray Scattering(SAXS)shows each seed has a different impact on the species'fractal structure and size distribution in the mixture,which is highly related to the nucleation and growth of MWW *** shows a large number of 6 membered ring(MR)structure units which play a sig-nificant role in boosting the rapid nucleation and growth of APS-MwW *** the synthesized MWW zeolites,the APS-MWW performs the highest ethylbenzene yield in the alkylation reaction of benzene-ethylene,which is attributed to its moderate flake thickness,appropriate texture properties and more external surface *** results will provide a new perspective for producing MwW-types zeolites by using the available and effective active precursor.

关键词： MWW zeolites Active precursor Small-angle X-ray scattering Benzene-ethylene alkylation reaction

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Density peak clustering using tensor network

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Science China(Information Sciences) 2024年第3期67卷 321-322页

作者： Xiao SHI yun shang Institute of Mathematics Academy of Mathematics and Systems ScienceChinese Academy of Sciences School of Mathematical Sciences University of Chinese Academy of Sciences National Center for Mathematics and Interdisciplinary Sciences Key Laboratory of ManagementDecision and Information SystemsAcademy of Mathematics and Systems ScienceChinese Academy of Sciences

Tensor networks have been a powerful tool in simulating many-body physics and have recently gained recognition in the machine learning community due to their remarkable representation capabilities. However, using tens... 详细信息

关键词： Tensors

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Fabrication of a 25.2 T NMR magnet for an extreme condition user facility in China

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National Science Review 2024年第7期11卷 62-64页

作者： Hui Han yun shang MRI Research Institute Department of RadiologyWeill Medical College of Cornell University

An ultra-high field magnet（>20 T）is desirable for studying the characteristics of new materials under extreme magnetic conditions [1]. Additionally,such field strength will result in resonance frequencies close to or greater than 1 GHz when applied to the study of1H signals from biomolecules by nuclear magnetic resonance（NMR）,which will lead to a higher signal-to-noise ratio, better sensitivity and a higher spectral resolution due to increased chemical shift dispersion [2].

关键词： NMR double pancake high temperature superconducting magnet ultra-high field

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An artificial intelligence diabetes management architecture based on 5G

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Digital Communications and Networks 2024年第1期10卷 75-82页

作者： Ruochen Huang Wei Feng shan Lu Tao shan Changwei Zhang yun Liu Department of Geriatrics The First Affiliated Hospital of Nanjing Medical UniversityNanjing210096China Department of Information The First Afliated Hospital of Nanjing Medical UniversityNanjing210096China Department of Medical Informatics School of Biomedical Engineering and InformaticsNanjing Medical UniversityNanjing211166China Department of Outpatient The First Affiliated Hospital of Nanjing Medical UniversityNanjing210096China Jiangsu Key Laboratory of Wireless Communications Nanjing University of Posts and TelecommunicationsNanjing210003China

Along with the development of 5G network and Internet of Things technologies,there has been an explosion in personalized healthcare *** the 5G and Artificial Intelligence(Al)is introduced into diabetes management architecture,it can increase the efficiency of existing systems and complications of diabetes can be handled more effectively by taking advantage of *** this article,we propose a 5G-based Artificial Intelligence Diabetes Management architecture(AIDM),which can help physicians and patients to manage both acute complications and chronic *** AIDM contains five layers:the sensing layer,the transmission layer,the storage layer,the computing layer,and the application *** build a test bed for the transmission and application ***,we apply a delay-aware RA optimization based on a double-queue model to improve access efficiency in smart hospital wards in the transmission *** application layer,we build a prediction model using a deep forest *** on real-world data show that our AIDM can enhance the efficiency of diabetes management and improve the screening rate of diabetes as well.

关键词： Diabetes 5G Artificial intelligence Deep forest Smart hospital ward

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In-situ measurement via the flow-through method and numerical simulations for radon exhalation during measurements of the radon exhalation rate

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Nuclear Science and Techniques 2024年第7期35卷 192-207页

作者： Ming Xia Yong-Jun Ye shan-Wei shang Ting Yu Dai-Jia Chen School of Resources Environment and Safety Engineering University of South ChinaHengyang421001China Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy University of South ChinaHengyang421001China

Small-scale measurements of the radon exhalation rate using the flow-through and closed-loop methods were conducted on the surface of a uranium tailing pond to better understand the differences between the two *** abnormal radon exhalation behavior was observed,leading to computational fluid dynamics(CFD)-based simulations in which dynamic radon migration in a porous medium and accumulation chamber was *** on the in-situ experimental and numerical simulation results,variations in the radon exhalation rate subject to permeability,flow rate,and insertion depth were quantified and *** in-situ radon exhalation rates measured using the flow-through method were higher than those measured using the closed-loop method,which could be explained by the negative pressure difference between the inside and outside of the chamber during the *** consistency of the variations in the radon exhalation rate between the experiments and simulations suggests the reliability of CFD-based techniques in obtaining the dynamic evolution of transient radon exhalation rates for diffusion and convection at the porous medium-air *** synergistic effects of the three factors(insertion depth,flow rate,and permeability)on the negative pressure difference and measured exhalation rate were quantified,and multivariate regression models were established,with positive correlations in most cases;the exhalation rate decreased with increasing insertion depth at a permeability of 1×10^(−11) m^(2).CFD-based simulations can provide theoretical guidance for improving the flow-through method and thus achieve accurate measurements.

关键词： Radon exhalation Flow-through Numerical simulation Accumulation chamber Multivariate regression

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Human influence on the duration of extreme temperature events in Asia's hotspot regions

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Advances in Climate Change Research 2024年第2期15卷 312-326页

作者： Zi-Meng WANG Hong-yun MA Wei LI Hai-shan CHEN Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD)/Key Laboratory of Meteorological Disaster Ministry of Education(KLME)Nanjing University of Information Science and TechnologyNanjing 210044China

Observations and models indicate that human activities exert a considerable impact on the frequency and intensity of extreme temperature events,which are associated with global ***,changes in the duration of extreme temperature events and their association with human influence have not been considered in most ***,the possible relationship between the observed changes in the warm and cold spell duration(WSDI and CSDI)in hotspot regions during 1960-2014 and human influence was investigated based on the NCEP/NCAR reanalysis version 1 and Coupled Model Inter-comparison Project Phase 6(CMIP6)*** projection based on these attribution results was also *** optimal fingerprinting technique was used to compare observed changes in WSDI and CSDI to simulated changes averaged across eight CMIP6 *** show that anthropogenic(ANT)forcing contributed to the observed increase in WSDI in the three hotspot regions(West Asia,South Asia and Southeast Asia),with the majority of the changes being attributed to greenhouse gas ***,a generally weak ANT signal can be observed in the decreasing trend of CSDI and can be detected in South and Southeast *** influence of aerosol forcing remains undetected in either WSDI or CSDI,which differs from the results for frequency and intensity of extreme *** attribution results revealed that the constrained projection of WSDI is lower than the raw projection for 2015-2100 in West Asia and Southeast ***,no differences in future CSDI changes are found in Southeast Asia between the constrained and raw projections.

关键词： Extreme temperature events Duration Detection attribution Constraint projection Hotspot regions

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Mechanical properties and damage evolution characteristics of waste tire steel fiber-modified cemented paste backfill

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International Journal of Mining Science and Technology 2024年第7期34卷 909-924页

作者： Shenggen Cao Chiyuan Che yun Zhang Changhao shan Yang Liu Changzheng Zhao Shuyu Du State Key Laboratory for Fine Exploration and Intelligent Development of Coal Resources School of MinesChina University of Mining and TechnologyXuzhou 221116China College of Energy Engineering Xi’an University of Science&TechnologyXi’an 710054China

During the process of constructional backfill mining,the cemented paste backfill(CPB)typically exhibits a high degree of brittleness and limited resistance to *** this study,the mechanical and damage evolution characteristics of waste tire steel fiber(WTSF)-modified CPB were studied through uniaxial compression tests,acoustic emission(AE)tests,and scanning electron microscopy(SEM).The results showed that the uniaxial compressive strength(UCS)decreased when the WTSF content was 0.5%,1%,and 1.5%.When the WTSF content reached 1%,the UCS of the modified CPB exhibited a minimal decrease(0.37 MPa)compared to that without *** the WTSF content was 0.5%,1%,and 1.5%,peak strain of the WTSF-modified CPB increased by 18%,31.33%,and 81.33%,while the elastic modulus decreased by 21.31%,26.21%,and 45.42%,*** addition of WTSF enhances the activity of AE events in the modified CPB,resulting in a slower progression of the entire failure *** the failure,the modified CPB retained a certain level of load-bearing ***,the failure of the CPB was dominated by tensile *** the addition of WTSF,a gradual increase in the proportion of tensile cracks was observed upon loading the modified CPB sample to the pore compaction *** three-dimensional localization of AE events showed that the WTSF-modified CPB underwent progressive damage during the loading,and the samples still showed good integrity after ***,the response relationship between energy evolution and damage development of WTSF-modified CPB during uniaxial compression was analyzed,and the damage constitutive model of CPB samples with different WTSF contents was *** study provides a theoretical basis for the enhancement of CPB modified by adding WTSF,serving as a valuable reference for the design of CPB constructional backfill.

关键词： Constructional backfill Cemented paste backfill Waste tire steel fiber Acoustic emission Damage characteristics

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Intrinsically asymmetric atomic character regulates piezoelectricity in two-dimensional materials

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Frontiers of physics 2024年第3期19卷 153-162页

作者： yun-Qin Li Qi-Wen He Dai-Song Tang Xiao shang Xiao-Chun Wang School of Physics Science and Information Technology Liaocheng UniversityLiaocheng 252000China Key Laboratory of Polar Materials and Devices Ministry of EducationDepartment of ElectronicsEast China Normal UniversityShanghai 200241China Institute of Atomic and Molecular Physics Jilin UniversityChangchun 130012China

Decreasing of layer thickness causes the decrease of polarization until it disappears due to the existence of depolarization ***,the search for strong piezoelectric materials is highly desirable for multifunctional ultra-thin piezoelectric ***,we propose a common strategy for achieving strong piezoelectric materials through the electronic asymmetry induced by the intrinsically asymmetric atomic character of different chalcogen ***,in the tetrahedral lattice structures,for example,M4X3Y3(M=Pd/Ni,X/Y=S,Se or Te,X≠Y)monolayers are proved to display excellent out-of-plane ***4Se3Te3 possesses the largest piezoelectric coefficient d33 of 61.57 pm/V,which is much larger than that of most 2D *** the electronic asymmetry further increases the out-of-plane piezoelectricity of Janus M4X3Y3 ***,the out-of-plane piezoelectricity is positively correlated with the ratio of electronegativity difference(Red)and the electric dipole moment(P).This work provides alternative materials for energy harvesting nano-devices or self-energized wearable devices,and supplies a valuable guideline for predicting 2D materials with strong out-of-plane piezoelectricity.

关键词： piezoelectricity intrinsically asymmetric atomic character ratio of electronegativity difference electric dipole moment first-principles calculations

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Application of a concrete thermal pile in cooling the warming permafrost under climate change

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Advances in Climate Change Research 2024年第1期15卷 170-183页

作者： yun-Hu shang Fu-Jun NIU Guo-Yu LI Jian-Hong FANG Ze-Yong GAO State Key Laboratory of Frozen Soil Engineering Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China Da Xing'anling Observation and Research Station of Frozen-Ground Engineering and Environment Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesJagdaqi 165000China Qinghai Research Institute of Transportation Xining 810008China

Permafrost degradation caused by climate warming is posing a serious threat to the stability of cast-in-place pile foundations in warm permafrost *** cold energy can be effectively utilized by two-phase closed thermosyphons(TPCTs)to cool the ***,we installed TPCTs in a cast-in-place pile foundation to create a unique structure called a thermal pile,which effectively utilizes the TPCTs to regulate ground *** we conducted a case study and numerical simulation to exhibit the cooling performance,and optimize the structure of the thermal *** purpose of this study is to promote the application of thermal piles in unstable permafrost *** on the findings,the thermal pile operated for approximately 53%of the entire year and effectively reduced the deep ground temperature at a rate of at least-0.1℃per ***,it successfully raised the permafrost table that is 0.35 m shallower than the natural ground *** characteristics prove highly beneficial in mitigating the adverse effects of permafrost degradation and enhancing infrastructure *** the length of the condenser section and the diameter of the TPCT in a suitable manner can effectively enhance the cooling capability of the thermal pile and ensure the long-term mechanical stability of the pile foundation even under climate warming.

关键词： Heat transfer Cold energy Warm permafrost Two-phase closed thermosyphons Cast-in-place pile foundation

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Characterizing leaf-deposited particles: Single-particle mass spectral analysis and comparison with naturally fallen particles

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Environmental Science and Ecotechnology 2024年第5期21卷 318-328页

作者： Dele Chen Hua-yun Xiao Ningxiao Sun Jingli Yan shan Yin School of Agriculture and Biology Shanghai Jiao Tong University800 Dongchuan Rd.Shanghai 200240China shanghai Yangtze River Delta Eco-Environmental Change and Management Observation and Research Station Ministry of Science and TechnologyMinistry of Education800 Dongchuan Rd.Shanghai 200240China shanghai Urban Forest Ecosystem Research Station National Forestry and Grassland Administration800 Dongchuan Rd.Shanghai 200240China

The size and composition of particulate matter(PM)are pivotal in determining its adverse health *** is important to understand PM's retention by plants to facilitate its atmospheric ***,the distinctions between the size and composition of naturally fallen PM(NFPM)and leaf-deposited PM(LDPM)are not *** we utilize a single-particle aerosol mass spectrometer,coupled with a PM resuspension chamber,to analyze these *** find that LDPM particles are 6.8 e97.3%larger than *** a neural network algorithm based on adaptive resonance theory,we have identified distinct compositional profiles:NFPM predominantly consists of organic carbon(OC;31.2%)and potassium-rich components(19.1%),whereas LDPM are largely composed of crustal species(53.9e60.6%).Interestingly,coniferous species retain higher OC content(11.5e13.7%)compared to broadleaved species(0.5e1.2%),while the levoglucosan content exhibit an opposite *** study highlights the active role of tree leaves in modifying PM composition beyond mere passive capture,advocating for a strategic approach to species selection in urban greening initiatives to enhance PM *** insights provide guidance for urban planners and environmentalists in implementing nature-based solutions to improve urban air quality.

关键词： Particulate matter Dry deposition Phytoremediation Size distribution Chemical composition Source apportionment

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