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Effect of gas saturation on P-wave velocity in tight sandstone

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Applied Geophysics 2024年第3期21卷 487-495,617页

作者： Pan Bao-Zhi Zhou Wei-Yi guo Yu-hang Fang Chun-Hui Zhang Li-Hua College of Geo-exploration Science and Technology Jilin UniversityChangchun 130026China

By measuring the variation of the P-and S-wave velocities of tight sandstone samples under water saturation,it was confirmed that with the decrease in water saturation,the P-wave velocity first decreased and then *** variation in velocity was influenced by the sandstone’s *** commonly used Gassmann equation based on fluid substitution theory was *** the calculated results with the measured data,it was found that the Gassmann equation agreed well with the measured data at high water saturation,but it could not explain the bending phenomenon of P-wave velocity at low *** indicated that these equations could not accurately describe the relationship between fluid content and rock acoustic *** reasons for this phenomenon were discussed through Taylor’s *** coefficients of the fitting formula were calculated and verified by fitting the measured acoustic velocity changes of the *** relationship between P-wave velocity and saturation was discussed,which provides experimental support for calculating saturation using seismic and acoustic logging data.

关键词： Tight sandstone Saturation model Reservoir parameters Acoustic wave measurement

可见光促进惰性碳-氢键对羰基的加成反应进展

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有机化学 2024年第1期44卷 54-69页

作者：童红恩郭宏宇周荣太原理工大学化学学院太原030024

仲醇和叔醇是重要的有机化合物,其结构普遍存在于具有生物活性的天然产物和药物分子中,且可以作为上游原料制备多种高附加值化学品.在众多合成方法中,醛酮的亲核加成反应是合成此类化合物最有效的方法之一,但通常需要使用预官能化底物,... 详细信息

仲醇和叔醇是重要的有机化合物,其结构普遍存在于具有生物活性的天然产物和药物分子中,且可以作为上游原料制备多种高附加值化学品.在众多合成方法中,醛酮的亲核加成反应是合成此类化合物最有效的方法之一,但通常需要使用预官能化底物,不仅效率较低,且原子经济性不高.可见光催化的兴起,为惰性碳-氢键的活化提供了一种温和高效的方法,促进了惰性碳-氢键直接对醛酮加成反应的发展,推动仲醇和叔醇的合成进入新的阶段.根据反应机理的不同,分别对经由还原性自由基-极性交叉、自由基-自由基交叉偶联和自由基加成机制的三类可见光诱导的惰性碳-氢键对羰基的加成反应进行了综述,并对该领域的局限性和未来发展方向做出了简要分析.

关键词：仲醇叔醇可见光催化还原性自由基-极性交叉自由基-自由基交叉偶联自由基加成

河北太行山五个自然景观的昆虫物种多样性比较与区系分析

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环境昆虫学报 2024年第2期46卷 438-448,I0004-I0008页

作者：荆彤彤任国栋河北大学生命科学学院河北省动物系统学与应用重点实验室河北保定071002

本文基于多年对河北太行山区自北向南5个自然景观(小五台山、五岳寨、不老青山、老爷山、太行山南段)的昆虫物种考察和资料总结,获得昆虫5 945种,隶属4纲32目353科3 046属,对其种类组成和多样性组成进行了横向分析比较,得到如下初步结果... 详细信息

本文基于多年对河北太行山区自北向南5个自然景观(小五台山、五岳寨、不老青山、老爷山、太行山南段)的昆虫物种考察和资料总结,获得昆虫5 945种,隶属4纲32目353科3 046属,对其种类组成和多样性组成进行了横向分析比较,得到如下初步结果:鳞翅目和鞘翅目是构成河北太行山区昆虫物种多样性的最主要类群,两者的物种总数高达3 834种,占昆虫总种数的64.49%;属级构成中日界(3 046属,100%)>古北界(2 511属,82.40%)>东洋界(1 830属,60.07%),凸显该地区的中日界性质(100%),同时与古北界有密切的联系,与东洋界也有较强的关联;在中国动物地理区中,华北区(3 046属,100%)>华中区(2 556属,83.91%)>蒙新区(2 404属,78.92%),华北区成分最为显著(100%),与华中区与蒙新区的联系较为紧密,其次为西南区、东北区、青藏区,而与华南区的联系最弱。对比分析了5个自然景观的鞘翅目物种多样性G-F指数,以小五台山的最高,不老青山最低,整体呈现由北向南随维度不断降低,其物种多样性不断增加的趋势;五岳寨国家森林公园与不老青山森林景区相似性较高(0.53),为中度相似,老爷山与太行山南段、不老青山与老爷山、五岳寨与老爷山为轻度相似;而小五台与五岳寨、小五台山与不老青山、小五台山与老爷山、小五台山与太行山南段为极不相似的关系,讨论了多个相关问题。

关键词：河北太行山昆虫物种多样性区系组成 G-F指数 Jaccard相似性系数

Variations of phyllosphere microorganisms in asymptomatic and tobacco brown spot leaves before and after spraying 12% difenoconazole + fluxapyroxad SC

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农药学学报 2024年第5期26卷 932-948页

作者： LI tong WANG Hancheng YE guo WANG Qing NGANGUEM NZALLE Yranney Brice WANG Feng CAI Liuti FENG Ruichao Zhang Songbai College of Agriculture Yangtze UniversityJingzhou 434025Hubei ProvinceChina Guizhou Academy of Tobacco Science Guiyang 550081China College of Life Science Yangtze UniversityJingzhou 434025Hubei ProvinceChina Guizhou Medical University Guiyang 550025China

12%difenoconazole+fluxapyroxad SC(commercial name:Jiangong)was first released by BASF in China in *** has been registered to control many diseases,including pear scab,apple Alternaria leaf spot,tomato early blight,cucumber powdery mildew,*** study evaluated the bioactivity of Jiangong against Alternaria alternata and explored variations of phyllosphere microorganisms in both asymptomatic and tobacco brown spot leaves at different persistence periods(0,5,10,and 15 days post-fungicide application)using high-throughput sequencing *** results indicated that Jiangong effectively inhibited mycelial growth(average EC_(50) value of 0.51μg/mL),conidia germination(average EC_(50) value of 3.47μg/mL),and the carbon metabolism of *** asymptomatic and symptomatic leaves presented complex microbial *** fungal diversity was noted in asymptomatic leaves,while higher bacterial diversity was found in symptomatic *** application,the diversity and abundance of microbial community structures in both types of leaves changed over *** microbiome communities showed greater sensitivity than bacterial groups,with the microbiome communities of asymptomatic leaves being more affected than those of symptomatic *** community diversity decreased for both symptomatic and asymptomatic leaves after 5 days of application,while the diversity of fungal community in symptomatic leaves showed an upward trend after 10 days of ***,bacterial community diversity increased in both symptomatic and asymptomatic leaves after 5 days of application but then declined in asymptomatic leaves after 15 *** abundance of the dominant function group of phyllosphere bacteria(metabolism,genetic information processing,environmental information processing)was not affected by the application of ***,the abundance of the dominant function group of phyllosphere fungi(animal pathogen-endophyte-wood saprotroph,endophyte-pla

关键词： tobacco brown spot difenoconazole fluxapyroxad microorganism communities diversity high-throughput sequencing

WavEnhancer: Unifying Wavelet and Transformer for Image Enhancement

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Journal of Computer Science & Technology 2024年第2期39卷 336-345页

作者：李梓诺陈绪行郭淑娜王书强潘治文 Department of Computer and Information Science University of MacaoMacao 999078China Research Center for Biomedical Information Technology Shenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhen 518055China

Image enhancement is a widely used technique in digital image processing that aims to improve image aesthetics and visual quality. However, traditional methods of enhancement based on pixel-level or global-level modifications have limited effectiveness. Recently, as learning-based techniques gain popularity, various studies are now focusing on utilizing networks for image enhancement. However, these techniques often fail to optimize image frequency domains. This study addresses this gap by introducing a transformer-based model for improving images in the wavelet domain. The proposed model refines various frequency bands of an image and prioritizes local details and high-level features. Consequently, the proposed technique produces superior enhancement results. The proposed model’s performance was assessed through comprehensive benchmark evaluations, and the results suggest it outperforms the state-of-the-art techniques.

关键词： transformer wavelet transform image enhancement

Generation and regulation of electromagnetic pulses generated by femtosecond lasers interacting with multitargets

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Nuclear Science and Techniques 2024年第1期35卷 96-107页

作者： Ya-Dong Xia De-Feng Kong Qiang-You He Zhen guo Dong-Jun Zhang tong Yang Hao Cheng Yu-Ze Li Yang Yan Xiao Liang Ping Zhu Xing-Long Xie Jian-Qiang Zhu Ting-Shuai Li Chen Lin Wen-Jun Ma Xue-Qing Yan State Key Laboratory of Nuclear Physics and Technology and Key Laboratory of HEDP of the Ministry of EducationCAPTPeking UniversityBeijing 100871China Beijing Laser Acceleration Innovation Center Beijing 101407China Institute of Guangdong Laser Plasma Technology Guangzhou 510540China National Laboratory on High Power Laser and Physics Shanghai Institute of Optics and FineChinese Academy of SciencesShanghai 201800China School of Materials and Energy University of Electronic Science and Technology of ChinaChengdu 611731China

Ultrashort and powerful laser interactions with a target generate intense wideband electromagnetic pulses(EMPs).In this study,we report EMPs generated by the interactions between petawatt(30 fs,1.4×10^(20) W/cm^(2))femtosecond(fs)lasers with metal flat,plastic flat,and plastic nanowire-array(NWA)*** analyses are conducted on the EMPs in terms of their spatial distribution,time and frequency domains,radiation energy,and *** results indicate that EMPs from metal targets exhibit larger amplitudes at varying angles than those generated by other types of targets and are enhanced significantly for NWA *** a plastic target holder and increasing the laser focal spot can significantly decrease the radiation energy of the ***,the composite shielding materials indicate an effective shielding effect against *** simulation results show that the NWA targets exert a collimating effect on thermal electrons,which directly affects the distribution of *** study provides guidance for regulating EMPs by controlling the laser focal spot,target parameters,and target rod material and is beneficial for electromagnetic-shielding design.

关键词： Electromagnetic pulses Laser plasma interaction Electromagnetic shielding Electron distribution

Optical microfiber or nanofiber:a miniature fiber-optic platform for nanophotonics

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Photonics Insights 2024年第1期3卷 27-74页

作者： Jianbin Zhang Hubiao Fang Pan Wang Wei Fang Lei Zhang Xin guo Limin tong Interdisciplinary Center for Quantum Information New Cornerstone Science LaboratoryState Key Laboratory of Extreme Photonics and InstrumentationCollege of Optical Science and EngineeringZhejiang UniversityHangzhouChina Jiaxing Key Laboratory of Photonic Sensing&Intelligent Imaging Intelligent Optics&Photonics Research CenterJiaxing Research Institute Zhejiang UniversityJiaxingChina Collaborative Innovation Center of Extreme Optics Shanxi UniversityTaiyuanChina

An optical micro/nanofiber(MNF)is a quasi-one-dimensional free-standing optical waveguide with a diameter close to or less than the vacuum wavelength of *** the tiny geometry with highrefractive-index contrast between the core and the surrounding,the MNF exhibits favorable optical properties such as tight optical confinement,strong evanescent field,and large-diameter-dependent waveguide ***,as a quasi-one-dimensional structure with extraordinarily high geometric and structural uniformity,the MNF also has low optical loss and high mechanical strength,making it favorable for manipulating light on the micro/nanoscale with high *** the past two decades,optical MNFs,typically being operated in single mode,have been emerging as a miniaturized fiber-optic platform for both scientific research and technological *** this paper,we aim to provide a comprehensive overview of the representative advances in optical MNFs in recent *** from the basic structures and fabrication techniques of the optical MNFs,we highlight linear and nonlinear optical and mechanical properties of the ***,we introduce typical applications of optical MNFs from nearfield optics,passive optical components,optical sensors,and optomechanics to fiber lasers and atom ***,we give a brief summary of the current status of MNF optics and technology,and provide an outlook into future challenges and opportunities.

关键词： micro/nanofibers fabrication optical properties mechanical properties optical applications

A novel refined dynamic model of high-speed maglev train-bridge coupled system for random vibration and running safety assessment

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Journal of Central South University 2024年第7期31卷 2532-2544页

作者： MAO Jian-feng LI Dao-hang YU Zhi-wu CAI Wen-feng guo Wei Zhang Guang-wen School of Civil Engineering Central South UniversityChangsha 410075China National Engineering Research Center of High-speed Railway Construction Technology Changsha 410075China China Railway Group Limited Beijing 100039China China Railway Eryuan Engineering Group Co. Ltd.Chengdu 610031China

Running safety assessment and tracking irregularity parametric sensitivity analysis of high-speed maglev train-bridge system are of great concern,especially need perfect refinement models in which all properties can be well characterized based on various stochastic excitations.A three-dimensional refined spatial random vibration analysis model of high-speed maglev train-bridge coupled system is established in this paper,in which multi-source uncertainty excitation can be considered simultaneously,and the probability density evolution method(PDEM)is adopted to reveal the system-specific uncertainty dynamic *** motion equation of the maglev vehicle model is composed of multi-rigid bodies with a total 210-degrees of freedom for each vehicle,and a refined electromagnetic force-air gap model is used to account for the interaction and coupling effect between the moving train and track beam bridges,which are directly established by using finite element *** model is proven to be applicable by comparing with Monte Carlo *** applying the proposed stochastic framework to the high maglev line,the random dynamic responses of maglev vehicles running on the bridges are studied for running safety and stability ***,the effects of track irregularity wavelength range under different amplitude and running speeds on the coupled system are *** results show that the augmentation of train speed will move backward the sensitive wavelength interval,and track irregularity amplitude influences the response remarkably in the sensitive interval.

关键词： maglev train-bridge interaction electromagnetic force-air gap model stochastic dynamic analysis running safety assessment probability density evolution method

“提质增效”还是“了无相干”——全要素能源效率提升能否改善制造业出口质量

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山西财经大学学报 2024年第7期46卷 76-86页

作者：赵瑞彤郭沛山西大学经济与管理学院山西太原030006

在环境和能源约束日渐严苛的背景下,同时面临着保增长、保出口等多重压力,而提高全要素能源效率是破解压力的重要着力点,提升全要素能源效率能够通过改变要素投入进而提高产品出口质量。以全要素能源效率的测度为基础,重点讨论新形势下... 详细信息

在环境和能源约束日渐严苛的背景下,同时面临着保增长、保出口等多重压力,而提高全要素能源效率是破解压力的重要着力点,提升全要素能源效率能够通过改变要素投入进而提高产品出口质量。以全要素能源效率的测度为基础,重点讨论新形势下其对制造业出口质量的影响。研究表明:制造业行业全要素能源效率对出口质量的影响显著为正,技术创新、能源结构优化和能源强度降低是主要影响路径;全要素能源效率对重工业行业的影响更大;进一步研究显示,轻工业行业主要通过技术创新和能源强度机制发挥作用,重工业行业则可通过技术创新、能源结构和能源强度三个渠道发挥作用。

关键词：全要素能源效率制造业出口质量能源强度能源结构技术创新