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水力压裂多裂缝扩展诱发光纤应变演化试验研究

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石油机械 2024年第8期52卷 101-107页

作者：王溯陈勉吕嘉昕中国石油大学(北京)油气资源与探测国家重点实验室中国石油大学(北京)石油工程教育部重点实验室

为解决光纤监测水力压裂过程中裂缝扩展形态认识不清的难题,提出了一种基于光纤应变监测的水力压裂物理模拟试验方法。将基于光频域反射(OFDR)技术的分布式光纤解调器与大型真三轴压裂物理模拟试验相结合,开展了人造试样及页岩试样水力... 详细信息

为解决光纤监测水力压裂过程中裂缝扩展形态认识不清的难题,提出了一种基于光纤应变监测的水力压裂物理模拟试验方法。将基于光频域反射(OFDR)技术的分布式光纤解调器与大型真三轴压裂物理模拟试验相结合,开展了人造试样及页岩试样水力压裂光纤实时监测物理模拟试验。试验结果表明,基于OFDR的分布式光纤传感技术可以高空间分辨率、高精度监测应变的演化,光纤的应变数据可以清晰地反映裂缝的产生、扩展和闭合。根据试验结果提出了一种基于光纤应变感测的水力压裂裂缝形态判别准则,该准则可以根据光纤应变演化信息判断部分裂缝类别。研究结论可高效地指导分布式光纤数据解释工作,可为光纤压裂监测的现场规模应用提供参考。

关键词：水力压裂裂缝识别分布式光纤监测页岩储层层理缝高角度天然裂缝光纤应变

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基于多源异构数据的胶东经济圈旅游资源供需匹配时空特征

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地球信息科学学报 2024年第2期26卷 393-407页

作者：刘佳纪晓萌陆嘉欣张桐艳中国海洋大学管理学院青岛266100 教育部人文社会科学重点研究基地中国海洋大学海洋发展研究院青岛266100

有效识别旅游资源供需空间匹配特征是提升旅游资源利用效率、优化旅游资源空间布局、推进旅游高质量发展的关键所在。随着空间信息技术的迭代更新,多源数据为旅游资源供需空间匹配及其交互关系拓展了新的研究视角,其中POI和数字足迹的... 详细信息

有效识别旅游资源供需空间匹配特征是提升旅游资源利用效率、优化旅游资源空间布局、推进旅游高质量发展的关键所在。随着空间信息技术的迭代更新,多源数据为旅游资源供需空间匹配及其交互关系拓展了新的研究视角,其中POI和数字足迹的挖掘为旅游资源供需匹配的研究提供了有力的数据支持。本研究选取山东省胶东经济圈为研究区域,基于高德地图、同程网和马蜂窝网络游记平台等多源数据渠道,获取2016—2021年胶东经济圈旅游资源的POI数据和旅游流的“O-D”数据,在此基础上运用核密度估计和复杂网络分析分别识别二者的空间结构特征,并进一步结合空间匹配测算模型探索胶东经济圈旅游资源供需匹配的时空演化规律。研究表明:(1)胶东经济圈旅游资源供给呈“康乐游憩类、公共休闲类、观赏科普类、宗教祭祀类”梯度递减的数量结构特征,以及“整体聚集、局部分散”的空间分布特征;(2)旅游流在时间上节假日效应和季相性特征明显,在空间上“陆海”差异显著,其中疫情发生前表现出由海岸向陆域扩散的态势,后疫情常态化下旅游流渐有复苏迹象;在类型结构上,康乐游憩类和公共休闲类成为旅游需求的主导类型;(3)旅游资源供需匹配关系的空间结构可划分为供需平衡、供给主导和需求主导3大类型,其中供需平衡类以“低-低”匹配为主导,供给主导类主要分布于陆域,空间分布形态较为零散,需求主导类主要沿海岸线呈环状分布,分布范围由海岸逐渐向陆域扩散。本研究基于多源异构数据拓展了旅游资源供需匹配的应用边界,为促进胶东经济圈及其他沿海地区旅游资源供需匹配提供理论基础和方法支撑。

关键词：多源异构数据旅游资源旅游流复杂网络供需匹配沿海城市胶东经济圈

Noise attenuation of frequency-modulated multi-rotor using sound field reproduction

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Chinese Journal of Aeronautics 2023年第11期36卷 185-203页

作者： Xice XU Yang lu Mengxue SHAO jiaxin lu National Key Laboratory of Rotorcraft Aeromechanics Nanjing University of Aeronautics and AstronauticsNanjing 210016China

Multi-rotor aircraft has great potential in urban traffic and military use and its noise problem has attracted more attention ***-rotor aircrafts are typically controlled by changing the rotation speeds of the *** reduce the noise of multiple frequency-modulated rotors,a global noise attenuation method is proposed in this ***,the fast prediction method is used to estimate the global noise of the multirotor with different configurations ***,the sound field reproduction method is used to obtain the control signal of the loudspeaker array to achieve global noise ***,the influence of array arrangement on noise reduction is analyzed in the acoustic modal domain,which reveals that different optimization models are needed to minimize the noise power or/and the noise pressure in some directions when the scale of the array is ***,to improve the real-time performance of the system,the online calculation of the optimal control signal is transformed into the offline design of the optimal filter,which satisfies the target frequency-domain ***,the experimental results of the noise of a model quadrotor in the anechoic chamber were consistent with the predicted *** simulation results of noise attenuation for the quadrotor show that the method proposed reduced the global noise power by about 13 ***,the noise region radiated from the quadrotor to the ground with the boundary of 40 dB was reduced to 8.4%of that before control.

关键词： Acoustic modal analysis Frequency-modulated multirotor Noise attenuation Optimal filter design Sound reproduction

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中国旅游产业链发展格局演变及空间效应研究

地理与地理信息科学 2024年第3期40卷 122-134页

作者：刘佳安珂珂赵青华陆嘉欣中国海洋大学管理学院山东青岛266100 中国海洋大学海洋发展研究院山东青岛266100

产业链现代化是建设现代化产业体系及助推中国式现代化进程的重要抓手,全面揭示旅游产业链发展现状及其影响因素对于提升旅游产业链现代化水平具有实际意义。该文以2001-2019年中国30个省域为研究对象,构建涵盖旅游供需链、企业链、空... 详细信息

产业链现代化是建设现代化产业体系及助推中国式现代化进程的重要抓手,全面揭示旅游产业链发展现状及其影响因素对于提升旅游产业链现代化水平具有实际意义。该文以2001-2019年中国30个省域为研究对象,构建涵盖旅游供需链、企业链、空间链、价值链的旅游产业链发展水平评价指标体系,利用核密度估计、Dagum基尼系数及其分解、探索性空间数据分析等方法对中国旅游产业链发展的时序演变规律、空间差异特征及空间关联格局进行分析,并运用空间杜宾模型探讨影响中国旅游产业链发展的主要因素及其空间效应。研究发现:(1)中国旅游产业链发展水平呈平稳提升态势,表现出由东部地区向中部、东北及西部地区递减的分布态势。(2)中国旅游产业链发展的总体区域差异呈波动缩小趋势,区域间差异是其主要来源,且东部与西部地区旅游产业链发展的区域间差异最大;东部地区旅游产业链发展的区域内差异最大,西部、东北地区次之,中部地区最小。(3)中国旅游产业链发展具有空间相关性和空间集聚特征,供给、需求、创新、政策等层面因素是影响中国旅游产业链发展的主要因素。其中,旅游资源禀赋、旅游人力资本、互联网、产业融合发展与对外开放水平有利于推进本地区旅游产业链发展,旅游需求总量、旅游需求结构与对外开放水平能通过正向空间溢出效应带动邻近地区旅游产业链发展。

关键词：旅游产业链时空格局格局演变影响因素空间效应

Statistical Characteristics of Suction Pressure Signals for a Centrifugal Pumpunder Cavitating Conditions

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Journal of Thermal Science 2017年第1期26卷 47-53页

作者： LI Xiaojun YU Benxu JI Yucheng lu jiaxin YUAN Shouqi Key Laboratory of Fluid Transmission Technology of Zhejiang Province Zhejiang Sci-Tech University Hangzhou310018 China Jiangsu Feixiang Pump Manufacturing Co. LTD Taizhou 214537 China National Research Center of Pumps Jiangsu University Zhenjiang 212013 China

Centrifugal pumps are often used in operating conditions where they can be susceptible to premature failure. The cavitation phenomenon is a common fault in centrifugal pumps and is associated with undesired effects. Among the numerous cavitation detection methods, the measurement of suction pressure fluctuation is one of the most used methods to detect or diagnose the degree of cavitation in a centrifugal pump. In this paper, a closed loop was established to investigate the pump cavitation phenomenon, the statistical parameters for PDF (Probability Density Function), Variance and RMS (Root Mean Square) were used to analyze the relationship between the cavitation performance and the suction pressure signals during the development of cavitation. It is found that the statistical parameters used in this research are able to capture critical cavitation condition and cavitation breakdown condition, whereas difficult for the detection of incipient cavitation in the pump. At part-load conditions, the pressure fluctuations at the impeller inlet show more complexity than the best efficiency point (BEP). Amplitude of PDF values of suction pressure increased steeply when the flow rate dropped to 40 m3/h (the design flow rate was 60 m3/h). One possible reason is that the flow structure in the impeller channel promotes an increase of the cavitation intensity when the flow rate is reduced to a certain degree. This shows that it is necessary to find the relationship between the cavitation instabilities and flow instabilities when centrifugal pumps operate under part-load flow rates. © 2017, Science Press, Institute of Engineering Thermophysics, CAS and Springer-Verlag Berlin Heidelberg.

关键词： Centrifugal pumps Electric load flow Flow rate Impellers Probability density function

金沙江白鹤滩水库巧家淹没区维管植物资源及区系分析

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西南大学学报（自然科学版） 2024年第1期46卷 96-111页

作者：张小萍傅睿张钊罗娴韩少丽卢佳欣叶晓敏曾波三峡库区生态环境教育部重点实验室/重庆市三峡库区植物生态与资源重点实验室/西南大学生命科学学院重庆400715 中国电建集团华东勘测设计研究院有限公司杭州311122

白鹤滩水电站是我国在金沙江修建的世界上在建规模最大的水电站,电站竣工形成水库后,库区内金沙江原有河岸带及河岸带以上至825 m高程区域成为被水库蓄水淹没的淹没区,且在该淹没区内会形成落差达60 m的库岸水位消落区.为掌握白鹤滩水... 详细信息

白鹤滩水电站是我国在金沙江修建的世界上在建规模最大的水电站,电站竣工形成水库后,库区内金沙江原有河岸带及河岸带以上至825 m高程区域成为被水库蓄水淹没的淹没区,且在该淹没区内会形成落差达60 m的库岸水位消落区.为掌握白鹤滩水库淹没区内的本底维管植物资源,也为白鹤滩水库成库后形成消落区的生态演变、生态保护和治理修复工作中适宜植物的筛选提供基础数据,在2020年白鹤滩水库还未建成蓄水前对库区巧家段淹没区的本底维管植物资源进行了实地调查,并就其区系成分特征进行了分析.研究表明:①白鹤滩水库建成前金沙江巧家段淹没区本底维管植物有50科160属207种,其中河岸带有18科52属59种,河岸带以上至825 m高程区域有49科154属199种,二者共有17科46属51种;无论是在整个淹没区,还是在河岸带或河岸带以上至825 m高程区域均表现为禾本科(Gramineae)物种数量最多,菊科(Compositae)物种数量次之.②无论是在河岸带还是在河岸带以上至825 m高程区域中,草本植物均为本底维管植物中占绝对优势的生长型;一年生植物和地上芽植物均为本底维管植物中的优势生活型.③金沙江巧家段淹没区本底维管植物区系成分具有明显的热带分布性质,属于热带分布类型的有28科118属,分别占淹没区总科数和总属数的56.0%和73.75%.其中,河岸带本底维管植物有50%的科和67.31%的属为热带区系类型;河岸带以上至825 m高程区域本底维管植物有55.1%的科和72.73%的属为热带区系类型.该研究对掌握白鹤滩水库巧家段淹没区本底维管植物组成和特征,预测白鹤滩水库消落区未来植物物种组成、植被演变、消落区生态保护和治理修复工作中适宜植物的选择具有特别意义.

关键词：金沙江白鹤滩水库淹没区维管植物组成区系特征

Evaluation method for electromagnetic interference complexity of high voltage switch based on feature extraction and GCC-GRU network

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High Voltage 2024年第3期9卷 749-761页

作者： Wenchao lu Jiandong Duan Lin Cheng Jiangping lu jiaxin Tao Jianning Yin School of Electrical Engineering Xi'an University of TechnologyXi'anChina Power Research Institute of State Grid Shaanxi Electric Power Co. LtdXi'anChina

When some new-type sensors are subjected electromagnetic interference(EMI),the traditional standard can no longer serve as the guidance for their EMI ***,it is necessary to evaluate the complexity of the new sensing equipment's suffering from electromagnetic interference.A hybrid method of feature extraction and complexity evaluation of Electromagnetic Interference signals based on generalised correntropy criterion(GCC)is ***,a variational mode decomposition al-gorithm for adaptive extraction of decomposed signals is constructed using GCC,and Generalised S-transform is used for processing and ***,according to the time-frequency space model,a new quantitative evaluation criterion interference factor is proposed,which overcomes the shortcomings of the traditional qualitative classification and the inability to solve the cross classification of ***,the Gated Recurrent Unit is introduced,and the GCC-GRU evaluation model with GCC as the loss function is *** authors conduct EMI tests and measured signal eval-uation with Medium Voltage and High Voltage switches,and the results show that the method proposed is correct and effective.

关键词： complexity criterion network

Electro-spraying/spinning: A novel battery manufacturing technology

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Green Energy & Environment 2024年第1期9卷 81-88页

作者： Zhuan Hu jiaxin Hao Dongyang Shen Caitian Gao Zhaomeng Liu Jianguo Zhao Bingan lu School of Physics and Electronics Hunan UniversityChangsha410082China State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body Hunan Provincial Key Laboratory of Multi-electron Based Energy Storage DevicesHunan UniversityChangsha410082China School of Physics and Electronic Information Luoyang Normal UniversityLuoyang471934China Section of Environmental Protection Key Laboratory of Eco-Industry School of MetallurgyNortheastern UniversityShenyangLiaoning110819China

Lithium-ion battery(LIB) industry seems to have met its bottle neck in cutting down producing costs even though much efforts have been put into building a complete industrial chain. Actually, manufacturing methods can greatly affect the cost of battery production. Up to now, lithium ion battery producers still adopt manufacturing methods with cumbersome sub-components preparing processes and costly assembling procedures, which will undoubtedly elevate the producing cost. Herein, we propose a novel approach to directly assemble battery components(cathode, anode and separator) in an integrated way using electro-spraying and electro-spinning technologies. More importantly, this novel battery manufacturing method can produce LIBs in large scale, and the products show excellent mechanical strength, flexibility, thermal stability and electrolyte wettability. Additionally, the performance of the as-prepaed Li Fe PO_(4)||graphite full cell produced by this new method is comparable or even better than that produced by conventional manufacturing approach. In brief, this work provides a new promising technology to prepare LIBs with low cost and better performance.

关键词： Electro-spraying Electro-spinning Integrated electrode Lithium-ion battery

Impact of climate change and human activities on the spatiotemporal dynamics of surface water area in Gansu Province, China

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Journal of Arid Land 2024年第6期16卷 798-815页

作者： lu Haitian ZHAO Ruifeng ZHAO Liu LIU jiaxin LYU Binyang YANG Xinyue College of Geography and Environmental Science Northwest Normal UniversityLanzhou 730070China Key Laboratory of Resource Environment and Sustainable Development of Oasis Gansu ProvinceLanzhou 730070China School of Geography Planning and Spatial SciencesUniversity of TasmaniaHobart TAS 7005Australia School of Chinese Language and Literature Xi'an International Studies UniversityXi'an 710128China Department of Mechanics and Aerospace Engineering Southern University of Science and TechnologyShenzhen 518055China School of Design and Built Environment Curtin UniversityPerth 6102Australia

Understanding the dynamics of surface water area and their drivers is crucial for human survival and ecosystem stability in inland arid and semi-arid *** study took Gansu Province,China,a typical area with complex terrain and variable climate,as the research *** on Google Earth Engine,we used Landsat data and the Open-surface Water Detection Method with Enhanced Impurity Control method to monitor the spatiotemporal dynamics of surface water area in Gansu Province from 1985 to 2022,and quantitatively analyzed the main causes of regional differences in surface water *** findings revealed that surface water area in Gansu Province expanded by 406.88 km2 from 1985 to *** surface water area exhibited significant fluctuations,while permanent surface water area showed a steady ***,terrestrial water storage exhibited a trend of first decreasing and then increasing,correlated with the dynamics of surface water *** change and human activities jointly affected surface hydrological processes,with the impact of climate change being slightly higher than that of human ***,climate change affected the'source'of surface water to a greater extent,while human activities tended to affect the'destination'of surface *** of surface water resources faced by inland arid and semi-arid areas like Gansu Province are ***,we summarized the surface hydrology patterns typical in inland arid and semi-arid areas and tailored surface water'supply-demand'balance *** study not only sheds light on the dynamics of surface water area in Gansu Province,but also offers valuable insights for ecological protection and surface water resource management in inland arid and semi-arid areas facing water scarcity.

关键词： surface water area terrestrial water storage Open-surface Water Detection Method with Enhanced Impurity Control method Google Earth Engine climate change human activities inland arid and semi-arid areas