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Production induced fracture closure of deep shale gas well under thermo-hydro-mechanical conditions

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Petroleum Science 2024年第3期21卷 1796-1813页

作者： Shi-Ming Wei Yang Xia Yan Jin Xu-Yang Guo Jing-Yu Zi Kai-Xuan Qiu Si-Yuan Chen College of Science China University of Petroleum(Beijing)Beijing102249China CNOOC research Institute Ltd Beijing100028China The University of Hong Kong Hong Kong999077China

Deep shale gas reservoirs have geological characteristics of high temperature,high pressure,high stress,and inferior ability to pass through *** multi-stage fractured horizontal well is the key to exploiting the deep shale gas ***,during the production process,the effectiveness of the hydraulic fracture network decreases with the closure of fractures,which accelerates the decline of shale gas *** this paper,we addressed the problems of unclear fracture closure mechanisms and low accuracy of shale gas production prediction during deep shale gas *** we established the fluid—solid—heat coupled model coupling the deformation and fluid flow among the fracture surface,proppant and the shale *** the fluid—solid—heat coupled model was applied to the fracture network,it was well solved by our numerical method named discontinuous discrete fracture *** with the conventional discrete fracture method,the discontinuous discrete fracture method can describe the three-dimensional morphology of the fracture while considering the effect of the change of fracture surface permeation coefficient on the coupled fracture—matrix flow and describing the displacement discontinuity across the *** simulations revealed that the degree of fracture closure increases as the production time proceeds,and the degree of closure of the secondary fractures is higher than that of the primary *** creep and proppant embedment both increase the degree of fracture *** reduction in fracture surface permeability due to proppant embedment reduces the rate of fluid transfer between matrix and fracture,which has often been overlooked in the ***,it significantly impacts shale gas production,with calculations showing a 24.7%cumulative three-year yield *** study is helpful to understand the mechanism of hydraulic fracture ***,it provides the theoretical guidance for maintaining the long

关键词： Shalegas Fracture closure Fluid-solid-heat coupling Discontinuous discrete fracture

LociScan,a tool for screening genetic marker combinations for plant variety discrimination

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The Crop Journal 2024年第2期12卷 583-593页

作者： Yang Yang Hongli Tian Hongmei Yi Zi Shi Lu Wang Yaming Fan Fengge Wang Jiuran Zhao beijing Key Laboratory of Maize DNA Fingerprinting and Molecular Breeding Maize Research InstituteBeijing Academy of Agriculture and Forestry SciencesBeijing 100097China

To reduce the cost and increase the efficiency of plant genetic marker fingerprinting for variety discrimination,it is desirable to identify the optimal marker *** describe a marker combination screening model based on the genetic algorithm(GA)and implemented in a software tool,Loci ***-based variety discrimination power provided the largest optimization space among multiple fitness *** GA parameters,an increase in population size and generation number enlarged optimization depth but also calculation *** algorithm afforded the same optimization depth as GA but vastly increased calculation *** comparison with two other software tools,Loci Scan accommodated missing data,reduced calculation time,and offered more fitness *** large datasets,the sample size of training data exerted the strongest influence on calculation time,whereas the marker size of training data showed no effect,and target marker number had limited effect on analysis speed.

关键词： Plant variety discrimination Genetic marker combination Variety discrimination power Genetic algorithm

Climatic impacts induced by winter wheat irrigation over North China simulated by the nonhydrostatic RegCM4.7

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Advances in Climate Change research 2024年第2期15卷 197-210页

作者： Jia WU Zhen-Yu HAN Xue-Jie GAO Zheng-Jia LIU National Climate centre China Meteorological AdministrationBeijing 100081China Key Laboratory for Climate Studies China Meteorological AdministrationBeijing 100081China Climate Change research Center Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science and TechnologyNanjing 210044China Institute of Geographic Sciences and Natural Resources research Chinese Academy of SciencesBeijing 100101China

Quantification of the impact of winter wheat irrigation on the climate and the occurrence of extreme climatic events over North China is crucial for regional adaptation *** related studies mainly focused on the impact on surface processes;however,few focused on the effects of extreme events using high-resolution nonhydrostatic regional climate ***,the 9-km-resolution nonhydrostatic RegCM4.7 was coupled with a crop irrigation scheme and an updated winter wheat irrigation dataset to better simulate irrigation *** experiments were conducted with and without winter wheat irrigation to isolate the effects of *** showed that irrigation simulation reduces the model biases in temperature,precipitation,latent heat flux,soil moisture,sensitive heat flux,and top-layer soil ***,it also reduces the bias and increases the correlation with observations obtained in irrigated areas,especially in summer,indicating better representation of irrigation *** wheat irrigation tends to cause substantial cooling of the local surface maximum,minimum,and mean air temperatures(by-1.68,-0.34,and-0.79℃,respectively)over irrigated areas of North China,with the largest changes observed in relation to maximum ***,precipitation is found to increase during spring and summer,which is strongly related to water vapor transport in the lower levels of the *** analyses indicated that the number of annual mean hot days decrease(-13.9 d),whereas the number of both comfort days(+10.2 d)and rainy days(days with total precipitation greater than 1 mm:+6.6 d)increase over irrigated areas,demonstrating beneficial feedback to human perception and ***,although the heat wave risk increases(number of annual mean heat wave days:+5.8 d),the impact is limited to small areas within irrigated ***,no notable change was found in terms of heavy rainfall events and precipitation intensity

关键词： Nonhydrostatic regional climate model Irrigation effect Extreme events North China

Efficient construction of calcium fluoride nanoaggregates for enhanced water vapor adsorption

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Particuology 2024年第6期89卷 191-197页

作者： Dan-Lei Yang Jing Cao Rong-Kun Liu Jie-Xin Wang School of Life Sciences and Chemical Engineering Jiangsu Second Normal UniversityNanjing210013China State Key Laboratory of Organic-Inorganic Composites Beijing University of Chemical TechnologyBeijing 100029China research Center of the Ministry of Education for High Gravity Engineering and Technology Beijing University of Chemical TechnologyBeijing100029China Petrochemical research Institute PetroChinaBeijing102206China

Calcium fluoride(CaF_(2))is an ideal adsorbent for the dehydration of gaseous hydrogen fluoride(HF)containing water *** this work,a novel CaF_(2)absorbent,spherical CaF_(2)nanoaggregates(NAs)with a closely packed structure,was proposed and efficiently fabricated by spray drying *** the building blocks of CaF_(2)NAs,the CaF_(2)nanoparticles(NPs)were prepared by the addition of excess calcium ions(Ca^(2+))or fluorine ions(F−)in the *** results indicated that the CaF_(2)NPs synthesized by excess Ca^(2+)and the corresponding NAs exhibited much better water vapor adsorption properties than their counterparts by excess F−,owing to higher zeta *** importantly,whether excess Ca^(2+)or F^(−),CaF_(2)NAs had further enhanced water vapor adsorption capacity compared to primary CaF_(2)NPs,possibly owing to their unique nano-micro secondary structures and higher surface *** work has great potential in the development of high-performance absorbents for separating moisture from corrosive gas HF.

关键词： CaF_(2)nanoaggregates Water vapor adsorption Spray drying

Observation and verification of surface electrical explosion driven by radial-distributed pulsed current in laboratory lightning strike test

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High Voltage 2024年第1期9卷 137-149页

作者： Ruoyu Han Yuchen Cao Yakun Liu Xi Chen Ting Li Chen Li Pengfei Li State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijingChina School of Mechatronical Engineering Beijing Institute of TechnologyBeijingChina Department of Electrical Engineering Shanghai Jiaotong UniversityShanghaiChina beijing Institute of Astronautical System Engineering BeijingChina Aerospace research Institute of Materials and Processing Technology BeijingChina

The laboratory lightning test is essential for assessing the effectiveness of lightning strike protection(LSP).Particularly,direct lightning strike damage can be performed with pulsed current injection into the *** paper focuses on the dynamic process of arc plasma and shock wave behaviour in the vicinity of the‘strike’point.A rod-plate discharge load is built for testing aluminium and coated plate under 40-kA-level pulsed *** visualisation of the luminous discharge plasma and its flow field via high-speed photography(from different angles)is meticulously designed and implemented,synchronised with electro-physical *** results indicate some new mechanisms for lightning strike damage,apart from the impulse heat loading from the thermal *** transient current injection through the arc root concentrates on a thin skin layer(skin-depth effect),with the radial-attenuated current density,driving asynchronously electrical explosions on the plate *** inhomogeneous Joule heating of the plate leads to outwardly propagating phase transition and shock wave along the conductive *** addition,the electro-thermal instability is observed and regarded as the seed of irregular erosion *** information reveals two different plasma states of main discharge arc channel and adjacent surface electrical *** correspondence of the physical mechanism of electrical explosion and optical radiation is *** images for different regions depict erosion characteristics and summarise influencing factors,further confirming the mechanism *** research clarifies the role of skin-depth effect in transaction arc erosion for electrode,complements the electrical explosion theory with unevenly distributed current and helps optimise strategies of LSP.

关键词： electrical lightning radial

A semi-analytical multi-harmonic balance method on full-3D contact model for dynamic analysis of dry friction systems

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Chinese Journal of Aeronautics 2024年第2期37卷 309-329页

作者： He SUN Dayi ZHANG Yaguang WU Qingyang SHEN Dianyin HU research Institute of Aero-Engine Beihang UniversityBeijing 100191China School of Energy and Power Engineering Beihang UniversityBeijing 100191China beijing Key Laboratory of Aero-Engine Structure and Strength Beijing 100191China Sino-French Engineering School Beihang UniversityBeijing 100191China AECC Sichuan Gas Turbine research Establishment Chengdu 610500China

Dry friction damping structures are widely-used in aero-engines to mitigate *** nonlinear nature of friction and the two-dimensional in-plane motion on the contact interface bring challenges to accurately and efficiently predict the forced response of frictionally damped *** state-of-the-art Multi-Harmonic Balance Method(MHBM)on quasi-3D contact model in engineering cannot precisely capture the kinematics on the friction interface although the efficiency is *** full-3D contact model can describe the constitutive relationship of the interface in a more accurate manner;however,the efficiency and convergence are not guaranteed for large-scale *** this paper,a semi-analytical MHBM on full-3D contact model is *** original Trajectory Tracking Method(TTM)for evaluating the contact force is reformulated to make the calculation more concise and the derivation of the Analytical Jacobian Matrix(AJM)*** on the chain rule of derivation,the AJM which is the core to upgrade the performance is *** a shrouded blade finite element model,the accuracy and efficiency of the proposed method are compared with both the MHBM on full-3D contact model with numerical Jacobian matrix and the MHBM on quasi-3D contact model with *** results show that the AJM improves significantly the efficiency of the MHBM on full-3D contact *** time cost of the proposed method is in the same order of magnitude as that of the MHBM on quasi-3D contact *** also confirm that the full-3D contact model is necessary for the dynamic analyses of shrouded *** one uses the quasi-3D model,the estimation relative error of damping can even reach 31.8%in some *** addition,the AJM also brings benefits for stability *** is highly recommended that engineers use the MHBM on full-3D contact model for the dynamic analysis and design of shrouded blades.

关键词： Dry friction damping Multi-harmonic balance method Trajectory tracking method Jacobian matrix Shrouded blade

Numerical analysis on the factors affecting post-peak characteristics of coal under uniaxial compression

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International Journal of Coal Science & Technology 2024年第1期11卷 42-60页

作者： Zhiguo Lu Wenjun Ju Fuqiang Gao Taotao Du CCTEG Coal Mining research Institute BeijingChina State Key Laboratory of Coal Intelligent Mining and Strata Control(China Coal research Institute) BeijingChina

The post-peak characteristics of coal serve as a direct reflection of its failure process and are essential parameters for evaluating brittleness and bursting *** the significant factors that influence post-peak characteristics can offer valuable insights for the prevention of coal *** this study,the Synthetic Rock Mass method is employed to establish a numerical model,and the factors affecting coal post-peak characteristics are analyzed from four perspectives:coal matrix mechanical parameters,structural weak surface properties,height-to-width ratio,and loading *** research identifies four significant influencing factors:deformation modulus,density of discrete fracture networks,height-to-width ratio,and loading *** response and sensitivity of post-peak characteristics to single-factor and multi-factor interactions are *** result suggested that feasible prevention and control measures for coal bursts can be formulated through four approaches:weakening the mechanical properties of coal pillars,increasing the number of structural weak surfaces in coal pillars,reducing the width of coal pillars,and optimizing mining and excavation *** efficacy of measures aimed at weakening the mechanical properties of coal is successfully demonstrated through a case study on coal burst prevention using large-diameter borehole drilling.

关键词： Post-peak behavior Synthetic rock mass Coal bursts Coal burst prevention

Tirofiban combined with Aspirin in the Treatment of Acute Penetrating Artery Territory Infarction (STRATEGY): protocol for a multicentre, randomised controlled trial

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Stroke & Vascular Neurology 2024年第1期9卷 75-81,I0047-I0052页

作者： Xiaoling Liao Shuo Feng Yicong Wang Yuesong Pan Weiqi Chen Hui Qu Xingquan Zhao Liping Liu Yongjun Wang Yilong Wang Department of Neurology Beijing Tiantan HospitalCapital Medical UniversityBeijingChina China National Clinical research Center for Neurological Diseases Beijing TiantanHospitalCapital Medical UniversityBeijingChina Chinese Institute for Brain research BeijingChina National Center for Neurological Diseases BeijingChina Advanced Innovation Center for Human Brain Protection Capital Medical UniversityBeijingChina beijing Laboratory of Oral Health Capital Medical UniversityBeijingChina

Background Perforating artery territorial infarction(PAI)caused by branch atheromatous disease(BAD)is prone to recurrence and early progression without an effective and well-documented antiplatelet treatment ***,an adjunctive antiplatelet agent,has shown great potential to treat acute ischaemic ***,whether the combination of tirofiban and aspirin can improve the prognosis of PAI remains *** To explore an effective and safe antiplatelet regimen for reducing the risk of recurrence and early neurological deterioration(END)in PAI caused by BAD by comparing the tirofiban and aspirin combination with placebo and aspirin *** Tirofiban combined with Aspirin in the Treatment of Acute Penetrating Artery Territory Infarction(STRATEGY)trial is an ongoing multicentre,randomised,placebo-controlled trial in *** patients shall be randomly assigned to receive standard aspirin with tirofiban or placebo on the first day and standard aspirin from days 2 to *** primary endpoint is a new stroke or END within 90 *** primary safety endpoint is severe or moderate bleeding within 90 *** The STRATEGY trial will assess whether tirofiban combined with aspirin is effective and safe in preventing recurrence and END in patients with *** registration number NCT05310968.

关键词： Aspirin regimen centre

Influences of Graupel Microphysics on CMA-GFS Simulation of Summer Regional Precipitation

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Journal of Meteorological research 2024年第1期38卷 27-38页

作者： Zhe LI Qijun LIU Zhanshan MA CMA Earth System Modeling and Prediction centre China Meteorological Administration(CMA)Beijing 100081

The horizontal resolution of global numerical weather prediction models is continuously developing. However, due to the imperfect precipitation simulation/forecast of these models, the demand for considering riming particles in cloud microphysical schemes in these models is increasing. This study employed the latest versions of global atmospheric reanalysis data (ERA5), the satellite retrieval data of the Global Precipitation Observation Program (GPM),and station precipitation observations to explore the impacts of adding graupel to the cloud microphysical scheme in the China Meteorological Administration-Global Forecast System (CMA-GFS) on summer regional precipitation simulations in four Chinese climate zones. The results verify that the new graupel scheme can enable CMA-GFS to decently predict global graupel distribution, especially in tropical and midlatitude regions. The addition of graupel in the cloud microphysics increases the precipitation simulation in North China, while that in Southwest China is weakened and dispersed. Moreover, graupel scheme increases the precipitation simulations of almost all *** increase in light rain is obvious, and the absolute value of heavy rain is strengthened. This may be because graupel quickly melts into rain after falling out of the zero-temperature layer due to its large mass and fast falling speed, increasing surface precipitation. In summary, the addition of graupel in the cloud microphysical scheme can improve CMA-GFS’s underestimation of strong precipitation.

关键词： graupel cloud microphysical scheme precipitation China Meteorological Administration-Global Forecast System(CMA-GFS) climate zone