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Mussel-inspired PTW@PDA composites for developing high-energy gun propellants with reduced erosion and enhanced mechanical strength

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Defence Technology（防务技术） 2024年第2期32卷 675-690页

作者： Xijin Wang Zhitao Liu Pengfei Sun Feiyun Chen Bin Xu Xin Liao School of Chemistry and Chemical Engineering Nanjing University of Science and TechnologyNanjing 210094JiangsuChina china North Industries Group corporation limited Beijing 100045China

The severe erosion and inadequate mechanical strength are prominent challenges for high-energy gun *** address it,novel PTW@PDA composites was prepared by polydopamine(PDA)-modifying onto potassium titanate whisker(PTW,K_(2)Ti_(6)O_(13)),and after was incorporated into gun propellant as erosion-reducing and mechanical-reinforcing *** interfacial characterizations results indicated that as-prepared PTW@PDA composites exhibits an enhanced surface compatible with propellant matrix,thereby facilitating their dispersion into propellants more effectively than raw PTW *** to original propellants,PTW@PDA-modified propellants exhibited significant less erosion,with a Ti-Kbased protective coating being detected on the eroded *** 0.5 wt%and 1.0 wt%addition of PTW@PDA significantly improved impact,compressive and tensile strength of *** the inevitably reduction in relative force,PTW@PDA slightly increase propellant burning rate while exerting little adverse impact on propellant dynamic *** strategy can provide a promising alternative to develop high-energy gun propellant with less erosion and more mechanical strength.

关键词： High energy gun propellant Potassium titanate whiskers Polydopamine modification Erosion inhibitors Mechanical reinforcing fillers

Fine-grained grid computing model for Wi-Fi indoor localization in complex environments

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Journal of Electronic Science and Technology 2024年第1期22卷 42-52页

作者： Yan Liang Song Chen Xin Dong Tu Liu School of Computer Engineering Chengdu Technological UniversityChengdu611730China HAN Networks corporation limited Beijing100094China

The fingerprinting-based approach using the wireless local area network(WLAN)is widely used for indoor ***,the construction of the fingerprint database is quite *** when the position of the access point(AP)or wall changes,updating the fingerprint database in real-time is *** appropriate indoor localization approach,which has a low implementation cost,excellent real-time performance,and high localization accuracy and fully considers complex indoor environment factors,is preferred in location-based services(LBSs)*** this paper,we proposed a fine-grained grid computing(FGGC)model to achieve decimeter-level localization *** points(RPs)are generated in the grid by the FGGC ***,the received signal strength(RSS)values at each RP are calculated with the attenuation factors,such as the frequency band,three-dimensional propagation distance,and walls in complex *** a result,the fingerprint database can be established automatically without manual measurement,and the efficiency and cost that the FGGC model takes for the fingerprint database are superior to previous *** proposed indoor localization approach,which estimates the position step by step from the approximate grid location to the fine-grained location,can achieve higher real-time performance and localization accuracy *** mean error of the proposed model is 0.36 m,far lower than that of previous ***,the proposed model is feasible to improve the efficiency and accuracy of Wi-Fi indoor *** also shows high-accuracy performance with a fast running speed even under a large-size *** results indicate that the proposed method can also be suitable for precise marketing,indoor navigation,and emergency rescue.

关键词： Fine-grained grid computing (FGGC) Indoor localization Path loss Random forest Reference points(RPs)

Dynamic Scene Graph Generation of Point Clouds with Structural Representation Learning

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Tsinghua Science and Technology 2024年第1期29卷 232-243页

作者： Chao Qi Jianqin Yin Zhicheng Zhang Jin Tang School of Artificial Intelligence Beijing University of Posts and TelecommunicationsBeijing 100876China Standard and Metrology Research Institute China Academy of Railway Sciences Corporation LimitedBeijing 100081China

Scene graphs of point clouds help to understand object-level relationships in the 3D *** graph generation methods work on 2D structured data,which cannot be used for the 3D unstructured point cloud *** point-cloud-based methods generate the scene graph with an additional graph structure that needs labor-intensive manual *** address these problems,we explore a method to convert the point clouds into structured data and generate graphs without given ***,we cluster points with similar augmented features into groups and establish their relationships,resulting in an initial structural representation of the point ***,we propose a Dynamic Graph Generation Network(DGGN)to judge the semantic labels of targets of different *** dynamically splits and merges point groups,resulting in a scene graph with high *** show that our methods outperform other baseline *** output reliable graphs describing the object-level relationships without additional manual labeled data.

关键词： scene graph generation structural representation point cloud

The reservoir characteristics and their controlling factors of the sublacustrine fan in the Paleogene Dongying Formation, Bohai Sea,china

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Journal of Palaeogeography 2024年第1期13卷 127-148页

作者： Xiao-Jun Pang Guan-Min Wang Meng Zhao Qing-Bin Wang Xue-Fang Zhang School of Geosciences China University of Petroleum(East China)QingdaoShandong 266580China Tianjin Branch of china National Offshore Oil corporation limited Tianjin 300459China

Sublacustrine fan is an important element in continental lacustrine basins and is significant for reservoir exploration. Oil and gas resources have been found in the sublacustrine fan sandstone reservoirs of the Paleogene Dongying Formation in the Bohai Sea. In this study, the characteristics of the sublacustrine fan reservoirs and the controlling factors are studied using information from logging, cores, physical properties,casting thin sections, X-ray diffraction of clay minerals, vitrinite reflectance, rock pyrolysis, manometry data,and 3D seismic data. The sublacustrine fans of the Dongying Formation in the LD10, QHD34, and BZ21 structures show high-quality reservoirs with porosity >15 % and permeability >5 m D. The main controlling factors of the high-quality reservoirs are attributed to the favorable sedimentary facies type and negligible compaction,and cementation, substantial dissolution of K-feldspar, overpressure, and the development of faults and fractures. A high-quality sublacustrine fan reservoir model has been established to explain how these factors affected the physical properties. The favorable targets for oil and gas exploration in the Dongying Formation of Bohai Sea include undercompacted sandy debris flow reservoirs showing the dissolution of K-feldspar, and the reservoirs which are connected to the source rocks by faults. This study provides insights to establish the relationship between sedimentology, diagenesis and reservoir quality. The results of this study are significant for the exploration and development of the sublacustrine fan sandstone reservoirs in the Bohai Sea and analogous sandstone reservoirs elsewhere.

关键词： Sublacustrine fan High-quality reservoir Dissolution Overpressure Fault Bohai Sea

Multi-scale Modeling and Finite Element Analyses of Thermal Conductivity of 3D C/SiC Composites Fabricating by Flexible-Oriented Woven Process

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Chinese Journal of Mechanical Engineering 2024年第3期37卷 275-288页

作者： Zheng Sun Zhongde Shan Hao Huang Dong Wang Wang Wang Jiale Liu Chenchen Tan Chaozhong Chen Nanjing University of Aeronautics and Astronautics Nanjing 210016China School of Mechanical Engineering Beijing Institute of TechnologyBeijing 100081China CRRC Institute corporation limited Beijing 100070China

Thermal conductivity is one of the most significant criterion of three-dimensional carbon fiber-reinforced SiC matrix composites(3D C/SiC).Represent volume element(RVE)models of microscale,void/matrix and mesoscale proposed in this work are used to simulate the thermal conductivity behaviors of the 3D C/SiC *** entirely new process is introduced to weave the preform with three-dimensional orthogonal *** 3D steady-state analysis step is created for assessing the thermal conductivity behaviors of the composites by applying periodic temperature boundary *** RVE models of cuboid,hexagonal and fiber random distribution are respectively developed to comparatively study the influence of fiber package pattern on the thermal conductivities at the ***,the effect of void morphology on the thermal conductivity of the matrix is analyzed by the void/matrix *** prediction results at the mesoscale correspond closely to the experimental *** effect of the porosities and fiber volume fractions on the thermal conductivities is also taken into *** multi-scale models mentioned in this paper can be used to predict the thermal conductivity behaviors of other composites with complex structures.

关键词： 3D C/SiC composites Finite element analyses Multi-scale modeling Thermal conductivity

Analysis of Electricity Consumption Pattern Clustering and Electricity Consumption Behavior

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Energy Engineering 2024年第9期121卷 2639-2653页

作者： Liang Zhu Junyang Liu Chen Hu Yanli Zhi Yupeng Liu Power Supply Service Management Center State Grid Jiangxi Electric Power Corporation LimitedNanchang330077China State Grid Jiangxi Electric Power corporation limited Nanchang330077China College of Electrical and Information Engineering Hunan UniversityChangsha410082China

Studying user electricity consumption behavior is crucial for understanding their power usage ***,the traditional clustering methods fail to identify emerging types of electricity consumption *** address this issue,this paper introduces a statistical analysis of clusters and evaluates the set of indicators for power usage *** fuzzy C-means clustering algorithm is then used to analyze 6 months of electricity consumption data in 2017 from energy storage equipment,agricultural drainage irrigation,port shore power,and electric ***,the proposed method is validated through experiments,where the Davies-Bouldin index and profile coefficient are calculated and *** showed that the optimal number of clusters is *** study demonstrates the potential of using a fuzzy C-means clustering algorithmin identifying emerging types of electricity consumption behavior,which can help power system operators and policymakers to make informed decisions and improve energy efficiency.

关键词： Electricity consumption clustering consumption behavior fuzzy C-means

Morphogenesis and Molecular Phylogeny of a Marine Urostylid Ciliate Apokeronopsis wrighti(Protista, Ciliophora, Hypotrichia)

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Journal of Ocean University of china 2024年第4期23卷 1067-1075页

作者： LIAN Chunyu LI Ping ZHANG Tengteng SHAO Chen Department of Zoology College of Life SciencesShaanxi Normal UniversityXi’an 710119China Powerchina Northwest Engineering corporation limited Xi’an 710065China

Hypotrichs are one of the highly differentiated ciliated lineages which play important roles in ecological, environmental,evolutionary and basic biological studies. In the present study, we investigated the living characteristics, infraciliature, nuclear apparatus, ontogenesis and phylogenetic position of a marine hypotrichous ciliate, Apokeronopsis wrighti Long et al., 2008, which was isolated from coastal waters in Shenzhen, china. The new isolate resembles the type population in terms of morphological characteristics, morphometrics, and SSU rRNA gene sequence that is with a 99.7% similarity. Ontogenesis of A. wrighti is characterized by oral primordium for the proter as well as marginal and dorsal kineties anlagen in both filial products formed de novo, and the cirral row arranged along the paroral and endoral arises from several anterior frontoventral-transverse cirral streaks. Phylogenetic analyses based on SSU and concatenated gene data suggest that five species of Apokeronopsis form a monophyletic clade, and the genus Apokeronopsis is closely related to Thigmokeronopsis and Metaurostylopsis.

关键词： 18S rRNA gene Apokeronopsis ciliated protists multi-gene ontogenesis systematics Urostylida

Blast damage zone strength reduction method for deep cavern excavation and its application

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Frontiers of Structural and Civil Engineering 2024年第2期18卷 236-251页

作者： Tianzhi YAO Zuguo MO Li QIAN Yunpeng GAO Jianhai ZHANG Xianglin XING Enlong LIU Ru ZHANG State Key Laboratory of Hydraulics and Mountain River Engineering College of Water Resources and HydropowerSichuan UniversityChengdu 610065China Power china Chengdu Engineering corporation limited Chengdu 610072China

The drill and blast(D&B)method is widely used to excavate underground spaces,but explosions generally cause damage to the ***,no blast simulation method can provide computational accuracy and *** this paper,a blast equivalent simulation method called the blast damage zone strength reduction(BDZSR)method is *** method first calculates the range of the blast-induced damage zone(BDZ)by formulae,then reduces the strength and deformation parameters of the rock within the BDZ ahead of excavation,and finally calculates the excavation damage zone(EDZ)for the D&B method by numerical *** method combines stress wave attenuation,rock damage criteria and stress path variation to derive the BDZ depth calculation *** formulae consider the initial geo-stress,and the reliability is verified by numerical *** calculation of BDZ depth with these formulae allows the corresponding numerical simulation to avoid the time-consuming dynamic calculation process,thus greatly enhancing the calculation *** method was applied to the excavation in Jinping Class II hydropower station to verify its *** results show that the BDZSR method can be applied to blast simulation of underground caverns and provide a new way to study blast-induced damage.

关键词： attenuation of stress wave deep-buried underground building drill and blast in situ stress

Investigation on Magnetorheological Effect of Novel Self-healing Magnetorheological Elastomers

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china Petroleum Processing & Petrochemical Technology 2024年第2期26卷 88-97页

作者： Wang Deping Wang Jing Wang Xin Noman Tariq Yu Zhen Zheng Wenbo Wei Yintao General Research and Development Institute China FAW Corporation LimitedChangchun 130013 China School of Vehicle and Mobility Tsinghua UniversityBeijing 100084China

Magnetorheological elastomers(MREs)hold significant promise in various fields such as automotive engineering,and civil engineering,where they serve as intelligent *** on the application of an external magnetic field,these materials exhibit varying magnetorheological and viscoelastic properties,including shear stress,yield stress,dynamic moduli,and *** this work,a new type of MRE,termed self-healing MREs(SH-MREs),has been developed by adding a novel self-healing agent into existing *** dynamic modulus and loss factor of SH-MREs with different compositions have been characterized under various conditions of frequency,temperature,and *** results show that as the strain value increases,the loss factor also ***,the loss factor initially increases and then decreases with increasing magnetic field *** higher concentrations of ferromagnetic particles increase the loss factor,they enhance the operational range due to their better responsiveness to magnetic ***-MREs demonstrate improved damping capabilities,attributed to the formation of coordination bonds between ferromagnetic particles and the self-healing *** stable structure increases the viscosity of *** results of the regression model suggest a direct proportionality between sensitivity to the magnetic field and the ferromagnetic particle concentration.

关键词： magnetorheological elastomer magnetorheological effect storage modulus loss factor