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Petroleum Science 2020年第3期17卷 615-627页

作者： Hong-Bing Li Jia-Jia Zhang Sheng-Juan Cai hao-jie pan Research Institute of Petroleum Exploration and Development Petrochina Company LimitedBeijing 100083China School of Geosciences China University of Petroleum(East China)Qingdao 266580China

Carbonate reservoirs exhibit strong heterogeneity in the distribution of pore types that can be quantitatively characterized by applying Xu–Payne multi-porosity ***,there are some prerequisites to this model the porosity and saturation need to be *** general,these application conditions are difficult to satisfy for seismic *** order to overcome this problem,we present a two-step method to estimate the porosity and saturation and pore type of carbonate reservoirs from seismic *** step one,the pore space of the carbonate reservoir is equivalent to a single-porosity system with an effective pore aspect ratio;then,a 3D rock-physics template(RPT)is established through the Gassmann’s equations and effective medium models;and then,the effective aspect ratio of pore,porosity and fluid saturation are simultaneously estimated from the seismic data based on 3D *** step two,the pore space of the carbonate reservoir is equivalent to a triple-porosity *** with the inverted porosity and saturation in the first step,the porosities of three pore types can be inverted from the seismic elastic *** application results indicate that our method can obtain accurate physical properties consistent with logging data and ensure the reliability of characterization of pore type.

关键词： Carbonate reservoirs Pore type Physical properties Rock-physics modeling Rock-physics inversion

Preparation of vanadium-based electrode materials and their research progress in solid-state flexible supercapacitors

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Rare Metals 2024年第2期43卷 431-454页

作者： Rui-jie Zhu Jiang Liu Chao Hua hao-Yu pan Yi-Jun Cao Meng Li Zhongyuan Critical Metals Laboratory Zhengzhou UniversityZhengzhou450001China School of Chemical Engineering Zhengzhou UniversityZhengzhou450001China

Solid-state flexible supercapacitors(SCs)have many advantages of high specific capacitance,excellent flexibility,fast charging and discharging,high power density,environmental friendliness,high safety,light weight,ductility,and long cycle *** are the ideal choice for the development of flexible energy storage technology in the future,and provide a good prospect for energy storage *** present,solid-state flexible SCs are widely used for portable electronic equipment and wearable energy storage equipment,the research of them has become the focus of a growing number of *** material is the key part of SCs and always determines the electrochemical performance of *** has been a hotspot and focus of ***-based compounds are considered to be a promising electrode material for SCs because of variable valence,open structure,high theoretical capacity,and low ***,this study first gives an overview of solid-state flexible SCs,then reviews the current research status of vanadium-based electrode materials in solid-state flexible SCs,and proposes some strategies to solve some problems of vanadium-based electrode materials.

关键词： Vanadium-based materials Flexible energy storage Specific capacitance Supercapacitors(SCs)

Intelligent Diagnosis Method for Typical Co-frequency Vibration Faults of Rotating Machinery Based on SAE and Ensembled ResNet-SVM

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Chinese Journal of Mechanical Engineering 2024年第4期37卷 215-230页

作者： Xiancheng Zhang Xin pan hao Zeng haofu Zhou Beijing Key Laboratoryof Health Monitoring and Self-recovery for High-end Mechanical Equipment Beijing University of Chemical TechnologyBeijing 100029China Engineering Research Center of Chemical Safety(Ministry of Education) Beijing University of Chemical TechnologyBeijing 100029China Engineering Management Department of China Three Gorges New Energy(Group)Co. Ltd.Beijing 101199China

Intelligent fault diagnosis is an important method in rotating machinery fault diagnosis and equipment health *** deal with co-frequency vibration faults,a type of typical fault in rotating machinery,this paper proposes a fault diagnosis method based on the stacked autoencoder(SAE)and ensembled ***,the time-and frequency-domain features of several co-frequency vibration faults are summarized based on the mechanism analysis and calculated using actual vibration *** realize and validate the high-precision diagnosis method of rotating equipment with co-frequency faults proposed in this study,the following three criteria are required:First,to improve the effectiveness and robustness of the ensembled model and the sliding window using data augmentation,adding noise,autoencoder(AE)and SAE methods are analyzed in terms of principle and practical ***,ResNet is used as the feature extractor for the ensembled ResNet-SVM *** extraction is carried out twice,and the extracted co-frequency fault features are more ***,the data augmentation method and ensemble ResNet-SVM are combined for fault diagnosis and compared with other *** experimental results show that the accuracy of the proposed method can exceed 99.9%.

关键词： Co-frequency vribation Data argumentation Ensembeled ResNet-SVM High precision fault diagnosis

Diophantine equations and Fermat's last theorem for multivariate(skew-)polynomials

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Applied Mathematics(A Journal of Chinese Universities) 2024年第1期39卷 159-173页

作者： pan jie JIA Yu-ming LI Fang School of Mathematical Sciences Zhejiang UniversityHangzhou 310058China Henan Experimental High School Zhengzhou 450003China

Fermat’s Last Theorem is a famous theorem in number theory which is diﬃcult to ***,it is known that the version of polynomials with one variable of Fermat’s Last Theorem over C can be proved very *** aim of this paper is to study the similar problems about Fermat’s Last Theorem for multivariate(skew)-polynomials with any characteristic.

关键词： Fermat's last theorem polynomial ring skew polynomial ring

Micro-mechanism Study on the Different Antioxidants Protective Effect of Vegetable Oil by ReaxFF Molecular Dynamics

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CSEE Journal of Power and Energy Systems 2024年第3期10卷 1269-1279页

作者： haoxi Cong Xuefeng Hu hao pan Qingmin Li State Key Laboratory of Alternate Electrical Power System With Renewable Energy Sources North China Electric Power UniversityBeijing 102206China

The aging problem of vegetable oil has severely restricted the popularization and application of vegetable oil *** antioxidants is the most recommended *** present,there is insufficient research on the micromechanism application of the protective effect of antioxidants on vegetable *** this paper,multiple vegetable oil models with different types and concentrations of antioxidants are *** the molecular dynamics simulation based on ReaxFF is carried out at different temperatures and oxygen *** show that the protective mechanism of antioxidants is to release H and combine this with free radicals generated by the decomposition of unsaturated fatty acids(UFA)in the *** addition,the protective effects of four antioxidants show different *** stronger ones are tert-butyl hydroquinone(TBHQ)and butylated hydroxytoluene(BHT),while the weaker ones are butylated hydroxyanisole(BHA)and propyl gallate(PG).TBHQ has a better protective effect at lower concentrations,but the decomposition of UFA is promoted at higher *** the temperature rises,the decomposition of UFA is *** the addition of oxygen,smaller molecular compounds are easily oxidized,and the decomposition of UFA is *** above research could reveal the microscopic mechanism of antioxidant protection on vegetable oil,providing theoretical references for further exploration of effective vegetable oil aging protection technology.

关键词： Antioxidant molecular dynamics transformer vegetable oil

Scenario Modeling-Aided AP Placement Optimization Method for Indoor Localization and Network Access

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China Communications 2024年第3期21卷 37-50页

作者： pan hao Chen Yu Qi Xiaogang Liu Meili School of Mathematics and Statistics Xidian UniversityXi’an 710126China Science and Technology on Near-Surface Detection Laboratory Wuxi 214035China School of Software Nanchang Hangkong UniversityNanchang 330063China

Owing to the ubiquity of wireless networks and the popularity of WiFi infrastructures,received signal strength(RSS)-based indoor localization systems have received much *** placement of access points(APs)significantly influences localization accuracy and network ***,the indoor scenario and network access are not fully considered in previous AP placement optimization *** study proposes a practical scenario modelingaided AP placement optimization method for improving localization accuracy and network *** order to reduce the gap between simulation-based and field measurement-based AP placement optimization methods,we introduce an indoor scenario modeling and Gaussian process-based RSS prediction *** that,the localization and network access metrics are implemented in the multiple objective particle swarm optimization(MOPSO)solution,Pareto front criterion and virtual repulsion force are applied to determine the optimal AP ***,field experiments demonstrate the effectiveness of the proposed indoor scenario modeling method and RSS prediction model.A thorough comparison confirms the localization and network access improvement attributed to the proposed anchor placement method.

关键词： indoor localization MOPSO network access RSS prediction

Coalbursts in China: Theory, practice and management

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第1期16卷 1-25页

作者： Yishan pan Yimin Song hao Luo Yonghui Xiao Institute of Disaster Rock Mechanics Liaoning UniversityShenyang110036China School of Civil Engineering North China University of TechnologyBeijing100144China College of Computer Science Liaoning UniversityShenyang110036China School of Physics Liaoning UniversityShenyang110036China

Coalburst is one of the most serious disasters that threaten the safe production of coal mines, and this disaster is particularly serious in China. This paper presents an overview of coalbursts in China since 1980s. From the "stress and energy" and "regional and local" perspectives, the achievements in the theory, practice and management of coalbursts in China are systematically summarized. A theoretical system of coalbursts has been formed to reveal the deformational behavior of coalbursts and explain the mechanism of coalbursts. The occurrence conditions of coalbursts are put forward and the critical stress is obtained. The stress index method for risk evaluation of coalbursts before mining is proposed, and the deformation localization prediction method of coalbursts is put forward. The relationship between energy release and absorption in the process of coalbursts is found, and the prevention and control methods of coalbursts, including the regional method, the local method and support, are presented. The safety evaluation index of coalburst prevention and control is put forward. The integrated prevention and control method for coal and gas outbursts is proposed. The prevention and control technology and equipment of coalbursts have also been developed. Amongst them, the distribution law of the critical stress in China coalburst mines is discovered. The technology and equipment for monitoring, prevention and control of coalbursts, as well as for integrated prevention and control of combined coalbursts and other disasters, have been developed. The energy-absorbing and coalburst-preventing support technology for roadways is invented, and key engineering parameters of coalburst prevention and control are pointed out. In China, coalburst prevention and control laws and standards have been developed. Technical standards for coalbursts are formulated, statute and regulations for coal mines are established, and regulatory documents are promoted.

关键词： Coalbursts Rockbursts Dynamic disaster Energy-absorbing support Monitoring and early warning

A UWB/IMU-Assisted Fingerprinting Localization Framework with Low Human Efforts

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China Communications 2024年第6期21卷 40-52页

With the rapid development of smart phone,the location-based services(LBS)have received great attention in the past *** to the widespread use of WiFi and Bluetooth devices,Received Signal Strength Indication(RSSI)fingerprintbased localization method has obtained much development in both academia and *** this work,we introduce an efficient way to reduce the labor-intensive site survey process,which uses an UWB/IMU-assisted fingerprint construction(UAFC)and localization framework based on the principle of Automatic radio map generation scheme(ARMGS)is proposed to replace the traditional manual *** be specific,UWB devices are employed to estimate the coordinates when the collector is moved in a reference point(RP).An anchor self-localization method is investigated to further reduce manual measurement work in a wide and complex environment,which is also a grueling,time-consuming process that is lead to artificial ***,the measurements of IMU are incorporated into the UWB localization algorithm and improve the label accuracy in *** addition,the weighted k-nearest neighbor(WKNN)algorithm is applied to online localization ***,filed experiments are carried out and the results confirm the effectiveness of the proposed approach.

关键词： indoor localization machine learning ultra wideband WiFi fingerprint

Toughening additive manufactured Zr-based bulk metallic glass composites by martensite phase transformation

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Journal of Materials Science & Technology 2024年第3期170卷 95-102页

作者： Pengcheng Zhang Cheng Zhang jie pan Di Ouyang Lin Liu State Key Laboratory of Materials Processing and Die&Mould Technology School of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan 430074China

Additive manufacturing technology based on laser powder bed fusion(LPBF)offers a novel approach for fabricating bulk metallic glass(BMG)products without restriction in size and ***,the BMGs prepared by LPBF usually suffered from less plasticity and poorer fracture toughness as compared to their cast counterparts due to partial crystallization in heat-affected zones(HAZs).Since crystallization in HAZs is hard to avoid completely in LPBF BMGs,it is desirable to design a suitable alloy system,in which only ductile crystalline phase,instead of brittle intermetallics,is formed in *** unique structure could effectively increase the toughness/plasticity of the LPBF *** achieve this goal,a quaternary BMG system with a composition of Zr_(47.5)Cu_(45.5)Al_(5)Co_(2)is adopted and subjected to *** is found that nearly a single phase of B_(2)-ZrCu is precipitated in HAZs,while a fully amorphous phase is formed in molten pools(MPs).This B_(2)phase reinforced BMG composite exhibits excellent mechanical properties with enhanced plasticity and ***,it is easy to modulate the mechanical properties by altering the amount of the B_(2)phase via adjusting the laser energy ***,the best combination of strength,plasticity,and notch toughness is obtained in the BMG composite containing 27.4%B_(2)phase and 72.6%amorphous phase,which exhibits yield strength(σ_(s))of 1423 MPa,plastic strain(ε_(p))of 4.65%,and notch toughness(K_(q))of 53.9 MPa m 1/***,a notable strain-hardening is also *** improvement of plasticity/toughness and appearance of strain-hardening behavior are mainly due to the martensite phase transformation from the B_(2)phase to the Cm phase during plastic deformation(i.e.,the phase transformation-induced plasticity effect).The current work provides a guide for making advanced BMGs and BMG composites by additive manufacturing.

关键词： Laser powder bed fusion Bulk metallic glass composites Phase transformation-induced plasticity Deformation mechanism

Noteworthy phenomena in pediatric inherited cardiomyopathy

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World Journal of Pediatrics 2024年第6期20卷 635-637页

作者： Jin-Hang Jiang jie Tian Bo pan Department of Pediatric Cardiology National Clinical Key Cardiovascular SpecialtyNational Clinical Research Center for Child Health and DisordersMinistry of Education Key Laboratory of Child Development and DisordersChildren's Hospital of Chongqing Medical University136 Zhongshan Er RoadYuzhong DistirctChongqing 400014China Key Laboratory of Children's Important Organ Development and Diseases Chongqing Municipal Health CommissionChongqingChina

Pediatric cardiomyopathy has an early onset and poor ***,it was referred to as idiopathic cardiomyopathy due to unknown ***,recent advances in molecular genetics and molecular biology have demonstrated that most pediatric cardiomyopathy cases are related to genetic factors,mainly involving single gene and single nucleotide mutations[1,2].Although the pathogenicity of some gene mutations in patients has not been fully elucidated,genetic factors are still considered the main cause of pediatric cardiomyopathy.

关键词： cardiomyopathy pediatric etiology