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A mathematical model for predicting the productivity of fractured horizontal wells of tight sandstone gas:A case study in the Sulige gas field 被引量:1
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作者 Qiangui Zhang Yuxuan Yan +4 位作者 Weitao Li Yufei Chen xiangyu fan Pengfei Zhao Yuxin Geng 《Natural Gas Industry B》 2024年第2期170-184,共15页
The Sulige tight sandstone gas reservoir is marked by low permeability,intricate pore structures,and notable lateral heterogeneity,making it difficult to predict the productivity of fractured horizontal wells in the r... The Sulige tight sandstone gas reservoir is marked by low permeability,intricate pore structures,and notable lateral heterogeneity,making it difficult to predict the productivity of fractured horizontal wells in the reservoir.In this study,a productivity prediction model for fractured horizontal wells is developed based on the characteristics of the Sulige gas reservoir,including its high start-up pressure gradient,strong stress sensitivity,obvious non-Darcy flow,and typical slippage and diffusion effects.This new model fully accounts for each hydraulic fracture in the horizontal wells based on the superposition principle and Green's function.This model facilitates efficient productivity calculations and enables rapid quantitative analysis of the influencing factors specific to horizontal wells with hydraulic fractures,fully integrating the specific characteristics of the Sulige gas field.The accuracy of this model is tested against field data from Wells LX1 and LX2 in the Sulige field,indicating good agreement between the predicted values and field data.Well LX2 is used as a case study to analyze the influences of geological and engineering factors on well productivity.The following conclusions are drawn:1)Well productivity is notably influenced by the start-up pressure gradient and stress sensitivity,with a minor impact from non-Darcy effects.2)Productivity linearly decreases with increased hydraulic fracture spacing.3)Productivity increases,and the increment rate gradually decreases,with increases in the length and conductivity of the hydraulic fractures.This model provides valuable guidance on predicting productivity in tight sandstone gas reservoirs,such as that of the Sulige gas field. 展开更多
关键词 Productivity prediction Tight sandstone gas reservoir Fractured horizontal well productivity Start-up pressure gradient Stress sensitivity Sulige gas field
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Wigner-Hough transform based on slice's entropy and its application to multi-LFM signal detection 被引量:6
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作者 Hongwei Wang xiangyu fan +1 位作者 You Chen Yuanzhi Yang 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2017年第4期634-642,共9页
To enhance the capacity of the radar-reconnaissance interception receiver recognizing linear frequency modulated (LFM) at a low signal-noise ratio, this paper presents WignerHough transform (WHT) of the LFM signal and... To enhance the capacity of the radar-reconnaissance interception receiver recognizing linear frequency modulated (LFM) at a low signal-noise ratio, this paper presents WignerHough transform (WHT) of the LFM signal and its corresponding characteristics, derives the probability density functions of the LFM signal and Gaussian white noise within WHT based on entropy (WHTE), dimension under different assumptions and puts forward a WHT algorithm based on entropy of slice to improve the capacity of detecting the LFM signal. Entropy of the WHT domain slice is adopted to assess the information size of polar radius or angle slice, which is converted into the weight factor to weight every slice. Double-deck weight is used to weaken the influences of noise and disturbance terms and WHTE treatment and signal detection procedure are also summarized. The rationality of the algorithm is demonstrated through theoretical analysis and formula derivation, the efficiency of the algorithm is verified by simulation comparison between WHT, fractional Fourier transform and periodic WHT, and it is highlighted that the WHTE algorithm has better detection accuracy and range of application against strong noise background. 展开更多
关键词 low signal-to-noise ratio linear frequency modulated signal probability density function Wigner-Hough transform (WHT) signal detection entropy of slice
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利用剩余活性污泥合成聚羟基脂肪酸酯的研究进展 被引量:7
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作者 孟栋 李枘枘 +4 位作者 刘玉玲 樊祥宇 黄兆松 古鹏飞 李强 《生物工程学报》 CAS CSCD 北大核心 2019年第11期2165-2176,共12页
利用单一微生物发酵是现阶段获得聚羟基脂肪酸酯(PHA)的主要方式,但过高的生产成本限制了其大规模应用。近年来利用活性污泥菌群混合培养合成PHA被广泛研究。将剩余污泥处理与PHA合成相结合,不仅可以省去纯培养所必需的灭菌环节,同时可... 利用单一微生物发酵是现阶段获得聚羟基脂肪酸酯(PHA)的主要方式,但过高的生产成本限制了其大规模应用。近年来利用活性污泥菌群混合培养合成PHA被广泛研究。将剩余污泥处理与PHA合成相结合,不仅可以省去纯培养所必需的灭菌环节,同时可以实现剩余污泥的资源化利用。剩余污泥的水解酸化、菌群富集驯化及PHA合成受环境因素影响,深入的生物合成机制研究有助于混合培养合成PHA的推广应用。文中主要介绍利用剩余污泥合成PHA的可行性、影响剩余污泥水解酸化的因素、污泥菌群富集驯化合成PHA及其机制等方面的研究进展。 展开更多
关键词 聚羟基脂肪酸酯 活性污泥 挥发性脂肪酸 微生物混合培养
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A failure criterion for shale considering the anisotropy and hydration based on the shear slide failure model 被引量:3
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作者 Qiangui Zhang Bowei Yao +7 位作者 xiangyu fan Yong Li Nicholas fantuzzi Tianshou Ma Yufei Chen Feitao Zeng Xing Li Lizhi Wang 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2023年第4期447-462,共16页
A failure criterion fully considering the anisotropy and hydration of shale is essential for shale formation stability evaluation.Thus,a novel failure criterion for hydration shale is developed by using Jaeger’s shea... A failure criterion fully considering the anisotropy and hydration of shale is essential for shale formation stability evaluation.Thus,a novel failure criterion for hydration shale is developed by using Jaeger’s shear failure criterion to describe the anisotropy and using the shear strength reduction caused by clay minerals hydration to evaluate the hydration.This failure criterion is defined with four parameters in Jaeger’s shear failure criterion(S_(1),S_(2),a andφ),three hydration parameters(k,ω_(sh)andσ_(s))and two material size parameters(d and l0).The physical meanings and determining procedures of these parameters are described.The accuracy and applicability of this failure criterion are examined using the published experimental data,showing a cohesive agreement between the predicted values and the testing results,R^(2)=0.916 and AAREP(average absolute relative error percentage)of 9.260%.The error(|D_(p)|)is then discussed considering the effects ofβ(angle between bedding plane versus axial loading),moisture content and confining pressure,presenting that|Dp|increases whenβis closer to 30°,and|D_(p)|decreases with decreasing moisture content and with increasing confining pressure.Moreover,|D_(p)|is demonstrated as being sensitive to S1and being steady with decrease in the data set whenβis 0°,30°,45°and 90°. 展开更多
关键词 SHALE Failure criterion Mechanical strength Shear slide failure ANISOTROPY HYDRATION
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Intent Inference Based Trajectory Prediction and Smooth for UAS in Low-Altitude Airspace with Geofence 被引量:3
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作者 Qixi Fu Xiaolong Liang +1 位作者 Jiaqiang Zhang xiangyu fan 《Computers, Materials & Continua》 SCIE EI 2020年第4期417-444,共28页
In order to meet the higher accuracy requirement of trajectory prediction for Unmanned Aircraft System(UAS)in Unmanned Aircraft System Traffic Management(UTM),an Intent Based Trajectory Prediction and Smooth Based on ... In order to meet the higher accuracy requirement of trajectory prediction for Unmanned Aircraft System(UAS)in Unmanned Aircraft System Traffic Management(UTM),an Intent Based Trajectory Prediction and Smooth Based on Constrained State-dependent-transition Hybrid Estimation(CSDTHE-IBTPS)algorithm is proposed.Firstly,an intent inference method of UAS is constructed based on the information of ADS-B and geofence system.Moreover,a geofence layering algorithm is proposed.Secondly,the Flight Mode Change Points(FMCP)are used to define the relevant mode transition parameters and design the guard conditions,so as to generate the mode transition probability matrix and establish the continuous state-dependent-transition model.After that,the constrained Kalman filter(CKF)is applied to improve State-dependent-transition Hybrid Estimation(SDTHE)algorithm by applying equality constraint to the velocity of UAS in the straight phase and turning phase,respectively,and thus the constrained state-dependent-transition hybrid estimation(CSDTHE)algorithm is constructed.Finally,the results of intent inference and hybrid estimation are used to make trajectory prediction.Furthermore,each flight segment of trajectory is smoothed respectively by Rauch-Tung-Striebel(RTS)backward smooth method using the proposed CSDTHE-RTS algorithm,so as to obtain more accurate trajectory prediction results.The simulation shows that the proposed algorithm can reduce the errors of trajectory prediction and the time delay of intent inference. 展开更多
关键词 Trajectory prediction unmanned aircraft system geofence intent inference hybrid estimation Rauch-Tung-Striebel(RTS)backward smooth
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Progresses of mycobacteriophage-based Mycobacterium tuberculosis detection
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作者 ZICHEN LIU SIYAO GUO +3 位作者 MENGZHI JI KAILI SUN ZHONGfanG LI xiangyu fan 《BIOCELL》 SCIE 2020年第4期683-694,共12页
Tuberculosis(TB)remains a major cause of morbidity and mortality worldwide,particularly in developing countries.A rapid and efficient method for TB diagnosis is indispensable to check the trend of tuberculosis expansi... Tuberculosis(TB)remains a major cause of morbidity and mortality worldwide,particularly in developing countries.A rapid and efficient method for TB diagnosis is indispensable to check the trend of tuberculosis expansion.The emergence of drug-resistant bacteria has increased the challenge of rapid drug resistance tests.Due to its high specificity and sensitivity,bacteriophage-based diagnosis is intensively pursued.In this review,we mainly described mycobacteriophage-based diagnosis in TB detection,especially two prevalent approaches:fluorescent reporter phage and phage amplified biologically assay(PhaB).The rationale of reporter phage is that phage carrying fluorescent genes can infect host bacteria specifically.Phage amplified biological assay based on the principle that phages can infect the live Mycobacterium tuberculosis in the specimen under suitable conditions and produce plaques.Other phage-based diagnostic methods,such as a combination of the amplified biologically assay and nucleic acid amplification or lateral flow assays,are also actively explored.This review will help us improve the understanding of mycobacteriophages in TB detection and better promote the development of the rapid diagnosis of M.tuberculosis. 展开更多
关键词 MYCOBACTERIOPHAGE TUBERCULOSIS DIAGNOSIS REPORTER PHAGE PHAGE amplified biologically ASSAY
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TGFβ signaling-induced miRNA participates in autophagic regulation by targeting PRAS40 in mesenchymal subtype of glioblastoma
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作者 Yingbin Xie Luyue Chen +8 位作者 Junhu Zhou Qixue Wang Chao Yang Can Xu xiangyu fan Yanli Tan Yanan Wang Chunsheng Kang Chuan fang 《Cancer Biology & Medicine》 SCIE CAS CSCD 2020年第3期664-675,共12页
Objective:Mesenchymal subtype of glioblastoma(mesGBM)is a refractory disease condition characterized by therapeutic failure and tumor recurrence.Hyperactive transforming growth factor-β(TGF-β)signaling could be a si... Objective:Mesenchymal subtype of glioblastoma(mesGBM)is a refractory disease condition characterized by therapeutic failure and tumor recurrence.Hyperactive transforming growth factor-β(TGF-β)signaling could be a signature event in mesGBM,which leads to dysregulation of downstream targets and contribute to malignant transformation.In this study we aimed to investigate the hyperactive TGFβsignaling-mediated pathogenesis and possible downstream targets for the development of novel therapeutic interventions for mesGBM.Methods:GBM-BioDP is an online resource for accessing and displaying interactive views of the TCGA GBM data set.Transcriptomic sequencing followed by bioinformatic analysis was performed to identify dysregulated microRNAs.Target prediction by MR-microT and dual luciferase reporter assay were utilized to confirm the predicted target of novel_miR56.CCK-8 assays was used to assesse cell viability.The miRNA manipulation was proceeded by cell transfection and lentivirus delivery.A plasmid expressing GFP-LC3 was introduced to visualize the formation of autophagosomes.Orthotopic GBM model was constructed forin vivo study.Results:TGFβ1 and TGFβreceptor type II(TβRII)were exclusively upregulated in mesGBM(P<0.01).Dysregulated miRNAs were identified after LY2109761(a TβRI/II inhibitor)treatment in a mesGBM-derived cell line,and novel_miR56 was selected as a promising candidate for further functional verification.Novel_miR56 was found to potentially bind to PRAS40 via seed region complementarity in the 3'untranslated region,and we also confirmed that PRAS40 is a direct target of novel_miR56 in glioma cells.In vitro,over expression of novel_miR56 in tumor cells significantly promoted proliferation and inhibited autophagy(P<0.05).The expression levels of P62/SQSTM was significantly increased accompanied by the decrease of BECN1 and LC3B-II/I,which indicated that autophagic activity was reduced after novel_miR56 treatment.In addition,over expression of novel_miR56 also promoted tumor growth and inhibited autophagyin vivo,which is associated with worse prognosis(P<0.05).Conclusions:In summary,we provide novel insight into TGFβsignaling-mediated pathogenesis in mesGBM and TGFβsignaling-induced novel_miR56 may be a novel target for mesGBM management. 展开更多
关键词 Autophagy GLIOBLASTOMA microRNA PRAS40 TGFβsignaling
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Prophages domesticated by bacteria promote the adaptability of bacterial cells
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作者 ZICHEN LIU YUNFENG DENG +2 位作者 MENGZHI JI WENQING SUN xiangyu fan 《BIOCELL》 SCIE 2020年第2期157-166,共10页
Prophages are temperate phages integrated into the host bacterial genome.They play an important role in the adaptation and the pathogenicity of bacteria,especially pathogenic bacteria.In this review,we described the d... Prophages are temperate phages integrated into the host bacterial genome.They play an important role in the adaptation and the pathogenicity of bacteria,especially pathogenic bacteria.In this review,we described the distribution of prophages in different hosts and different environments,and focused on the significance of prophages.At the singlecell level,prophages can help the host adapt to harsh external environments by directly carrying virulence genes,encoding regulatory factors and activating lysogeny.At the population level,prophages can influence the overall evolutionary direction and ecological function of the host bacterial community.This review will help us understand the important role of prophages as unique organisms in individual bacteria and microbial populations. 展开更多
关键词 TEMPERATE PHAGE Adaptation Evolution Ecological function
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How does the e-commerce policy affect urban land resource carrying capacity?
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作者 xiangyu fan Xinhai Lu +1 位作者 Bing Kuang Nan Ke 《Chinese Journal of Population,Resources and Environment》 2025年第4期579-589,共11页
National e-commerce demonstration city(NEDC)pilots play a crucial role in transforming urban e-commerce and significantly affect urban land resource carrying capacity(LRCC).Using panel data from prefecture-level citie... National e-commerce demonstration city(NEDC)pilots play a crucial role in transforming urban e-commerce and significantly affect urban land resource carrying capacity(LRCC).Using panel data from prefecture-level cities in China spanning 2006 to 2020,this study treats the NEDC pilot program as a quasi-natural experiment.A theoretical mechanism analysis was conducted to explore the implications of the NEDC pilot program on urban LRCC,and the propensity score matching double-difference method was used to estimate its effects.The findings show that the NEDC pilot program significantly inhibits the enhancement of urban LRCC,a conclusion that remains robust after multiple validity tests.Moreover,as the level of green development in urban land increases,the impact of the NEDC pilot program on urban LRCC shifts from positive to negative.This negative effect is especially pronounced in regions with lower levels of urban informatization,as well as in central and western areas and large cities.Furthermore,the mechanism analysis indicates that the NEDC pilot program exerts a significant negative influence on urban LRCC through three main channels:technological innovation,industrial structure,and economic correlation. 展开更多
关键词 E-commerce Urban land resource carrying capacity Propensity score matching Double difference Policy assessment
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Bacteriophages in water pollution control:Advantages and limitations 被引量:9
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作者 Mengzhi Ji Zichen Liu +3 位作者 Kaili Sun Zhongfang Li xiangyu fan Qiang Li 《Frontiers of Environmental Science & Engineering》 SCIE EI CSCD 2021年第5期29-43,共15页
Wastewater is a breeding ground for many pathogens,which may pose a threat to human health through various water transmission pathways.Therefore,a simple and effective method is urgently required to monitor and treat ... Wastewater is a breeding ground for many pathogens,which may pose a threat to human health through various water transmission pathways.Therefore,a simple and effective method is urgently required to monitor and treat wastewater.As bacterial viruses,bacteriophages(phages)are the most widely distributed and abundant organisms in the biosphere.Owing to their capacity to specifically infect bacterial hosts,they have recently been used as novel tools in water pollution control.The purpose of this review is to summarize and evaluate the roles of phages in monitoring pathogens,tracking pollution sources,treating pathogenic bacteria,infecting bloom-forming cyanobacteria,and controlling bulking sludge and biofilm pollution in wastewater treatment systems.We also discuss the limitations of phage usage in water pollution control,including phage-mediated horizontal gene transfer,the evolution of bacterial resistance,and phage concentration decrease.This review provides an integrated outlook on the use of phages in water pollution control. 展开更多
关键词 PHAGE Water pollution monitoring Harmful bacteria biocontrol Horizontal gene transfer Bacterial resistance
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A review of the shale wellbore stability mechanism based on mechanicalechemical coupling theories 被引量:5
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作者 Qiangui Zhang Wenyu Jia +2 位作者 xiangyu fan Yongchang Liang Yang Yang 《Petroleum》 2015年第2期91-96,共6页
Wellbore instability in hard brittle shale is a critical topic related to the effective exploitation of shale gas resources.This review first introduces the physicalechemical coupling theories applied in shale wellbor... Wellbore instability in hard brittle shale is a critical topic related to the effective exploitation of shale gas resources.This review first introduces the physicalechemical coupling theories applied in shale wellbore stability research,including total water absorption method,equivalent pore pressure method,elasticity incremental method of total water potential and non-equilibrium thermodynamic method.Second,the influences of water activity,membrane efficiency,clay content and drilling fluid on shale wellbore instability are summarized.Results demonstrate that shale and drilling fluid interactions can be the critical factors affecting shale wellbore stability.The effects of thermodynamics and electrochemistry may also be considered in the future,especially the microscopic reaction of shale and drilling fluid interactions.An example of this reaction is the chemical reaction between shale components and drilling fluid. 展开更多
关键词 Petroleum engineering SHALE Wellbore stability Mechanicalechemical coupling Instability mechanism
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