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Regulating metal-acid double site balance on mesoporous SiO2-Al2O3 co.posite oxide for supercritical n-decane cracking

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Petroleum Science 2024年第4期21卷 2881-2891页

作者： Liu-Ling Chen Jun Zhang Chun-Guang Li Li-Qun Fei Bo Wang Chen-Qi Zhang Yi Jiao Jian-Li Wang Institute of New Energy and Low-Carbon Technology Sichuan University Engineering Research Center of co.bustion and co.ling for Aerospace Power Ministry of Education School of Chemical Engineering Sichuan University State Key Laboratory of Industrial Vent Gas Reuse Southwest Institute of Chemical Co. Ltd Science and Technology on Scramjet Laboratory Beijing Power Machinery Research Institute

The balance between metal and acid sites directly affects the preparation of high-performance cracking catalysts with high heat sink and low ***,how to co.trol acid-metal sites balance and its relationship with cracking performance are reported *** this work,a series of Pt/Al2O3-SiO2dual sites catalysts with different metal to acid active sites ratio(CM/CSA) were co.structed by ethanolassisted impregnation method and the impact on n-decane cracking under supercritical co.ditions was systematically and deeply *** results showed that the co.version and carbon deposition increased gradually with varied CM/CSAand reached the balance at CM/CSAof *** proper ratio CM/CSA（0.13） can balance the deep dehydrogenation co.ing over metal active sites and high heat sink of cracking over acid active sites,the chemical heat sink reaches amazing 1.75 MJ/kg and carbon deposition is only22.03 mg/cm2at 750℃.Meanwhile,the few metal sites at low CM/CSAand the few strong acid sites at high CM/CSAare the main factors limiting the cracking *** CM/CSAlimit the activation of C-H bond and deep dehydrogenation of co.ing precursor,resulting in relative low cracking activity and carbon deposition,while high CM/CSAlimit the activation of C-C bond and increase the deep *** this co.tribution,design and co.struction of metal-acid dual sites can not only provide the technical solution for the preparation of high heat sink and low co.ing cracking catalyst,but also deepen the understanding of the cracking path of hydrocarbon fuel.

关键词： Metal-acid dual sites balance Catalytic cracking Hydrocarbon fuels Chemical heat sink Carbon deposition

A method for support stiffness failure identification in a steel spring floating slab track of urban railway: a case study in China

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第3期25卷 206-222页

作者： Junyuan ZHENG Caiyou ZHAO Duojia SHI Ping WANG Jian WANG Bolong JIANG Xi SHENG Key Laboratoryof High-speed Railway Engineering Ministry of EducationSouthwest Jiaotong UniversityChengdu 60031China School of Civil Engineering Southwest Jiaotong UniversityChengdu 610031China 01 DYNA(Qingdao)Test&Data co. Ltd.Qingdao 266000China Rail Transit Digital co.struction and Measurement Technology National Engineering Research Center China Railway Design CorporationTianjin300308China Institute of Urban Smart Transportation&Safety Maintenance Shenzhen UniversityShenzhen 518060China

The extensive use of steel spring floating slab tracks has effectively addressed the challenge of alleviating the environmental vibrations induced by urban rail transit ***,under the co.bined action of train dynamic loads and co.plex environmental factors,problems,such as the fracture of steel spring vibration isolators and suspension vibrations induced by the uneven settlement of the base,often *** failure of isolator support stiffness is often hidden in its early stages and is challenging to identify by co.ventional detection *** the same time,it will aggravate the wheel-rail interaction,accelerate the deterioration of track structure,and even affect the driving *** study first establishes a detailed co.pled train-floating slab track-foundation analytical *** the influence of the vibration isolator support stiffness failure on the dynamic indices of the floating slab track system response is analyzed.A set of defect identification methods that can detect the number of failed steel springs,severity of damage,and their location is ***,an intelligent monitoring system for support stiffness of floating slab track is built by co.bining the density-based spatial clustering of applications with noise algorithm and statistical data analysis and is applied to a rail line in southern *** a three-year monitoring campaign,a suspension failure and a fracture of a steel spring were each successfully detected and detailed failure information was *** investigation results were co.sistent with the damage identification *** repair,the track structure dynamic response returned to the average pre-damage level and further deterioration had been *** proposed damage identification methods and monitoring system provide an approach for intelligent identification of track structure support stiffness failures.

关键词： Floating slab track Support stiffness Detailed analytical model Failure identification Monitoring system

Numerical investigation on ball-sealers transport and diversion performance in shale gas horizontal well based on semi-resolved CFDDEM

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PARTICUOLOGY 2024年第10期93卷 137-153页

作者： Huang, Yinjian Zhao, Jinzhou Ren, Lan Lin, Ran Wu, Jianfa Shen, Cheng Wu, Jianjun Li, Bing southwest Petr Univ Natl Key Lab Oil & Gas Reservoir Geol & Exploitat Chengdu 610500 Peoples R China Tianfu Yongxing Lab Chengdu 610213 Peoples R China PetroChina southwest Oil & Gas Field co Shale Gas Res Inst Chengdu 610056 Peoples R China PetroChina co.lbed Methane co.Ltd Xian 710082 Peoples R China

In the staged multi-cluster fracturing of shale gas horizontal wells, ball sealers are used to ensure uniform fluid distribution among clusters, a strategy that is both co.t-effective and operationally beneficial. Despite these advantages, co.prehending the ball sealers' dynamics within the wellbore and their plugging behavior at perforations is still challenging. This co.plexity results in prediction difficulties regarding their diversion efficiency. To address this, our study utilized a semi-resolved CFD-DEM model based on kernel approximation to simulate the behavior of medium-sized ball sealers in single and multiple cluster scenarios. Our findings from a single cluster scenario reveal that the plugging probability is co.determined by velocity gradients in the fluid ingestion area near the perforation, backflow region, and inertial forces of the ball sealers. As the critical flow rate is achieved, the plugging probability negatively co.related with fluid visco.ity and displacement, and positively co.related with the perforation flow ratio (PFR), the difference in particle-fluid density, ball sealer 's diameter, and the ball sealer 's offset from the pipeline center. Temporary plugging co.trol efficiency was used to evaluate the flow balance effect among multiple clusters. The results indicate that an increased number of ball sealers enhances the fault tolerance during the temporary plugging process. Nevertheless, excessive ball sealers might undermine the temporary plugging co.trol efficiency, as perforations with lower fluid inflow rates are unexpectedly plugging. Higher differences in fluid injection rates between clusters led to increased efficiency in temporary plugging co.trol. Premature deployment of ball sealers cannot effectively plug perforations with marginally higher fluid inflow rates, but instead accidently plug intermediate clusters with lower fluid inflow rates. These findings offer a theoretical basis for optimizing the design of ball sealers. (c

关键词： Gas shale Horizontal wells Ball sealer Semi-resolved CFD-DEM Diversion DEM SIMULATION PARTICLES FLOW MODEL EFFICIENCY

Effects of Different Light Qualities on the Growth Characteristics of Populus trinervis

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Phyton-International Journal of Experimental Botany 2024年第5期93卷 1043-1056页

作者： Jiaqi Li Zhensheng Qiao Dan Zong Chengzhong He Key Laboratory for Forest Genetics and Tree Improvement and Propagation in Universities of Yunnan Province Southwest Forestry UniversityKunmingChina Key Laboratory of Biodiversity co.servation in southwest China State Forestry AdministrationSouthwest Forestry UniversityKunmingChina Key Laboratory for Forestry Resources co.servation and Utilization in the southwest Mountains of China Ministry of EducationSouthwest Forestry UniversityKunmingChina

Populus trinervis is native to China and plays an irreplaceable role in maintaining the eco.ogical balance of boreal and temperate *** mainly grows in high-altitude *** present,there are limited studies on the response of *** to different light qualities,so it is necessary to investigate the photosynthetic physiological changes of *** in different light *** our study,*** was grown for 8 months under light filtered by three different co.ored *** three treatments were blue film,green film,and white plastic *** effects of blue(B),green(G),and white(W)light on photosynthetic pigment co.tent,absolute growth,photosynthetic parameters,soluble sugar co.tent,and chlorophyll fluorescence parameters were studied,*** to the Wtreatment,the chlorophyll a and b,carotenoids,total chlorophyll co.tent(a+b),absolute growth of seedling height,net photosynthetic rate(PN),water use efficiency(WUE),total soluble sugars,sucrose,and nonphotochemical quenching(NPQ)of *** were significantly increased under B ***,chlorophyll a and b,carotenoids,total chlorophyll(a+b),transpiration rate(Tr),intercellular co.(2) co.centration(Ci),stomatal co.ductance(gs),absolute growth of seedling height and leaf length,reducing sugar,total soluble sugar co.tent,and NPQ were significantly increased under G *** results showed that the absolute growth and chlorophyll co.tent of *** were increased under B light,while the sugar and photosynthetic parameters were increased under G *** studies may look into how B light impacts absolute growth and promotional mechanisms,as well as how G light affects the accumulation of sugar levels.

关键词： Blue light green light white light photosynthetic pigment soluble sugar

Paleo-uplift forced regional sedimentary evolution: A case study of the Late Triassic in the southeastern Sichuan Basin, South China

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PETROLEUM 2024年第3期10卷 462-473页

作者： He, Fangyu Cheng, Qingsong Zhang, Dongtao Ji, Yubing Wang, Ziying Lu, Tenghui PetroChina Zhejiang Oilfield co Hangzhou 310023 Peoples R China southwest Petr Univ Sch Geosci & Technol Chengdu 610500 Peoples R China southwest Petr Univ Sichuan Nat Gas Geol Key Lab Chengdu 610500 Peoples R China

The sedimentary environment of the Upper Triassic in the southeastern Sichuan Basin is obviously co.trolled by Luzhou paleo-uplift (LPU). However, the influence of paleo-uplift on the sedimentary patterns of the initial stages of this period in the southeastern Sichuan Basin has not yet been clear, which has plagued oil and gas exploration and development. This study shows that there is a marine sedimentary sequence, which is co.sidered to be the first member of Xujiahe Formation (T3X1) in the southeastern Sichuan Basin. The development of LPU resulted in the sedimentary differences between the eastern and western Sichuan Basin reco.ding T3X1 and co.trolled the regional sedimentary pattern. The western part is dominated by marine sediments, but the eastern paleo-uplift area is dominated by co.tinental sedimentation in the early stage of T3X1, and it begins to transform into a marine sedimentary environment co.sistent with the whole basin in the late stage of the period reco.ded by the Xujiahe Formation. The evidences are as follows: (1) time series: based on the cyclostratigraphy analysis of Xindianzi section and Well D2, in the southeastern Sichuan Basin, the period of sedimentation of the Xujiahe Formation is about 5.9 Ma, which is basically co.sistent with the Qilixia section, eastern Sichuan basin, where the Xujiahe Formation is widely co.sidered to be relatively co.plete; (2) distribution and evolution of palaeobiology: based on analysis of abundance evolution of major spore-pollen, many land plant fossils are preserved in the lower part of T3X1, indicates the sedimentary environment of co.tinental facies. In the upper part of T3X1, the fossil of terrestrial plants decreased, while the fossil of marine and tidal environment appeared, this means that it was affected by the sea water in the late stages of T3X1; (3) geochemistry: calculate the salinity of water from element indicates that the uplift area is co.tinental sedimentary environment in the early stage of

关键词： Luzhou paleo-uplift Late Triassic Cyclostratigraphy Palynology Sedimentary environment POLARITY TIME-SCALE XUJIAHE FORMATION NEWARK SUPERGROUP NORTH-AMERICA PALEOCLIMATE XUANHAN REco.D APTS

SpikingMiniLM: energy-efficient spiking transformer for natural language understanding

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Science China(Information Sciences) 2024年第10期67卷 115-128页

作者： Jiayu ZHANG Jiangrong SHEN Zeke WANG Qinghai GUO Rui YAN Gang PAN Huajin TANG co.lege of computer Science and Technology Zhejiang University The State Key Lab of Brain-Machine Intelligence Zhejiang University co.laborative Innovation Center of Artificial Intelligence Zhejiang University Advanced co.puting and Storage Laboratory Huawei Technologies Co. Ltd. co.lege of computer Science and Technology Zhejiang University of Technology MOE Frontier Science Center for Brain Science and Brain-Machine Integration Zhejiang University

In the era of large-scale pretrained models, artificial neural networks（ANNs） have excelled in natural language understanding（NLU） tasks. However, their success often necessitates substantial co.putational resources and energy co.sumption. To address this, we explore the potential of spiking neural networks（SNNs） in NLU——a promising avenue with demonstrated advantages, including reduced power co.sumption and improved efficiency due to their event-driven characteristics. We propose the SpikingMiniLM,a novel spiking Transformer model tailored for natural language understanding. We first introduce a multi-step enco.ing method to co.vert text embeddings into spike trains. Subsequently, we redesign the attention mechanism and residual co.nections to make our model operate on the pure spike-based paradigm without any normalization technique. To facilitate stable and fast co.vergence, we propose a general parameter initialization method grounded in the stable firing rate principle. Furthermore, we apply an ANN-to-SNN knowledge distillation to overco.e the challenges of pretraining SNNs. Our approach achieves a macro-average sco.e of 75.5 on the dev sets of the GLUE benchmark, retaining 98% of the performance exhibited by the teacher model MiniLMv2. Our smaller model also achieves similar performance to BERTMINIwith fewer parameters and much lower energy co.sumption, undersco.ing its co.petitiveness and resource efficiency in NLU tasks.

关键词： spiking neural networks natural language understanding spiking Transformer spike-based attention multi-step enco.ing ANN-to-SNN distillation

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Capillary Property of Entangled Porous Metallic Wire materials and Its Application in Fluid Buffers:Theoretical Analysis and Experimental Study

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Defence Technology（防务技术） 2024年第1期31卷 400-416页

作者： Yu Tang Yiwan Wu Hu Cheng Rong Liu Engineering Research Center for Metal Rubber School of Mechanical Engineering and AutomationFuzhou UniversityFuzhou 350156China AECC Guizhou Liyang Aviation Power co. LTDGuiyang 550014China co.lege of computer and Information Sciences Fujian Agriculture and Forestry UniversityFuzhou 350156China

Strong impact does serious harm to the military industries so it is necessary to choose reasonable cushioning material and design effective buffers to prevent the impact of *** on the capillary property entangled porous metallic wire materials(EPMWM),this paper designed a co.posite buffer which uses EPMWM and visco.s fluid as cushioning materials under the low-speed impact of the reco.l force device of weapon equipment(such as artillery,mortar,etc.).co.bined with the capillary model,porosity,hydraulic diameter,maximum pore diameter and pore distribution were used to characterize the pore structure characteristics of *** calculation model of the damping force of the co.posite buffer was *** low-speed impact test of the co.posite buffer was *** parameters of the buffer under low-speed impact were identified acco.ding to the model,and the nonlinear model of damping force was *** test results show that the co.posite buffer with EPMWM and visco.s fluid can absorb the impact energy from the reco.l movement effectively,and provide a new method for the buffer design of weapon equipment(such as artillery,mortar,etc.).

关键词： Entangled porous metallic wire materials Capillary property Visco.sfluid Low-speed impact Damping force

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Optical multipath self-interference cancellation for a wideband in-band full-duplex system using a silico. photonic modulator chip

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Chinese Optics Letters 2024年第7期22卷 126-131页

作者： Xiao Yu Jia Ye Lianshan Yan Tao Zhou Yue Zhu Peng Li Xihua Zou Wei Pan Center for Information Photonics and co.munications School of Information Science and TechnologySouthwest Jiaotong UniversityChengdu 611756China Key Laboratory of Electronic Information co.trol Southwest China Research Institute of Electronic EquipmentChengdu 610029China Microwave Photonics Research Laboratory School of Electrical Engineering and Computer ScienceUniversity of OttawaOttawaONK1N6N5Canada

We propose and experimentally demonstrate a photonic method for wideband multipath self-interference cancellation using a silico. photonic modulator *** chip generates phase-inverted reference signals by leveraging the opposite phase between optical *** managing amplitude and phase imbalances between self-interference and reference signals,the approach rectifies discrepancies through co.sistent chip manufacturing and packaging *** photonic multi-dimensional multiplexing,including wavelength and polarization,enables the acquisition of multiple reference *** results show multipath cancellation depths of 25.53 dB and 23.81 dB for bandwidths of 500 MHz and 1 GHz,achieved by superimposing 2-path reference signals.

关键词： microwave photonics multipath self-interference silico. photonics

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A Fluorinated,Ion-co.ducting and Adaptive Supramolecular Polymer Protective Layer for Stabilizing Lithium Metal Anodes

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CCS Chemistry 2024年第5期6卷 1157-1164页

作者： Tao Chen Bo Qin Yunco.g Liu Zhekai Jin Haiping Wu Chao Wang Xi Zhang Institute of Smart City and Intelligent Transportation Southwest Jiaotong UniversityChengdu 610032 Key Lab of Organic Optoelectronics and Molecular Engineering Department of ChemistryTsinghua UniversityBeijing 100084 Department of Battery Technology BYD Shanghai Co.Ltd.Shanghai 201611

Perfluoropolyether(PFPE)is a promising material for protective co.tings on Li metal anodes due to its chemical inertness and minimal swelling in ***,a co.ventional PFPE co.ting with poor ionic co.ductivity and mechanical stability is still not satisfactory for long-term cycling of Li ***,we design and synthesize an adaptive and high-co.ductivity supramolecular polymer(PFPE-EG-I).This polymer is co.structed from PFPE chains,ethylene glyco.(EG)segments,and hydrogen-bonding moieties derived from isophoronediisocyanate,serving as a multifaceted artificial solid electrolyte interphase(SEI).The inco.porated EG segments enhance the Li+co.ductivity of the SEI,and the hydrogen-bonding units introduce a dynamic self-adaptive behavior to the polymer matrix.A solution-processed PFPE-EG-I co.ting is demonstrated to promote uniform Li deposition and mitigate side reactions between Li and the ***,this leads to enhanced co.lombic efficiency and prolonged cycle longevity in lithium metal batteries(LMBs).The innovative design of this multifunctional artificial SEI offers a promising avenue for the realization of dendrite-free Li anodes,paving the way for the advancement of high-performance LMBs.

关键词： supramolecular polymers batteries lithium anodes artificial solid electrolyte interphase perfluoropolyether