检索结果-内蒙古大学图书馆

Adsorption and retention of fracturing fluid and its impact on gas transport in tight sandstone with different clay minerals

引用

Petroleum Science 2025年第1期22卷 370-383页

作者： Yi-Jun Wang Li-Jun You Jian Yang Yi-Li Kang Ming-Jun Chen Jia-Jia Bai Jian Tian State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum University Engineering Technology Research Institute of Southwest Oil & Gas Field Company PetroChina School of Petroleum Engineering Changzhou University State Key Laboratory of Coal Mine Disaster Dynamics and Control Chongqing University

To elucidate the adsorption characteristics and retention mechanisms of fracturing fluids in diverse clay minerals, we conducted on-line nuclear magnetic resonance(NMR) and atomic force microscopy(AFM)experiments. The depth and extent of solid phase damage are determined by the ratio between the size of fine fractions in fracturing fluid residue and the pore-throat size in experiments. Poor physical properties(K < 0.5 m D) result in a more preferential flow pathway effect during flowback, and the stepwise incremental pressure differential proves to be more effective for the discharge of fracturing fluid in submicron pore throats. The permeability is significantly influenced by the differential distribution of retained fracturing fluid, as supported by direct experimental evidence. The presence of good physical properties(K > 0.5 m D) combined with a scattered distribution of retained fracturing fluid is associated with high gas phase recovery permeability, whereas a continuous sheet-like distribution results in low recovery permeability. The expansive surface area and presence of filamentous illite minerals facilitate the multiple winding and adsorption of fracturing fluids, demonstrating strong hydrogen-bonding, multi-layering and multiple adsorption properties. The geological characteristics of the main gas formations exhibit significant variation, and the severity of damage caused by fracturing fluids occurs in diverse sequences. To address this issue, a differentiated strategy for optimizing fracturing fluids has been proposed.

关键词： Clay minerals Formation damage Fracturing fluid retention distribution Adsorption morphology

来源：评论

学校读者我要写书评

暂无评论

Synthesis of novel high-entropy diborides with high-efficiency electromagnetic wave absorption and excellent thermal stability

引用

Journal of Advanced Ceramics 2025年第2期14卷 185-197页

作者： Chencheng Liu Qingyun Chen Peng Sun Xingye Wang Shuyi Zeng Qijie Chen Tong Zhu Yi Zhu Wenlong Zhang Hui Song Yuezhong Wang Kazuhito Nishimura Huasong Liu Nan Jiang College of Physics and Electronic Information Engineering Guilin University of TechnologyGuilin 541004China State Key Laboratory of Advanced Marine Materials Ningbo Institute of Materials Technology and EngineeringChinese Academy of SciencesNingbo 315201China Tianjin Key Laboratory of Optical Thin Films Tianjin Jinhang Technical Physics InstituteTianjin 300308China

Ceramic materials have obvious advantages in thermal stability,but impedance mismatch limits their ability to attenuate electromagnetic(EM)***,a novel series of high-entropy(V_(0.2)Nb_(0.2)Zr_(0.2)Ta_(0.2)X_(0.2))B_(2)(X=Mo,Ti,and Hf)ceramics were successfully synthesized via ultrafast high-temperature sintering(UHS)apparatus based on joule *** results indicated that the effect of high-entropy component on the magnetic loss of the system was relatively small,but the effect on the dielectric loss was *** them,the(V_(0.2)Nb_(0.2)Zr_(0.2)Ta_(0.2)Ti_(0.2))B_(2)(HEB-Ti)sample demonstrated superior absorbing properties due to relatively moderate dielectric loss and optimal EM impedance ***,because of its relatively moderate attenuation constant,it could achieve the maximum penetration of the EM wave and the minimum reflection after absorbing *** a result,the minimum reflection loss(RL_(min))was as low as−40.7 dB,and the effective absorption band covered the entire low-frequency range from 2 to 8 *** excellent absorption performance was mainly due to the synergistic effect of various dielectric attenuation mechanisms,including defect polarization,dipole polarization,and conduction ***,thermogravimetric(TG)analysis showed that the sample exhibited excellent thermal stability and could withstand temperatures up to 550℃in air and 1000℃in an argon gas *** relevant work could provide meaningful references for the design of new high-performance ceramic wave-absorbing materials.

关键词： high-entropy diborides(HEBs) ultrafast high-temperature sintering(UHS) electromagnetic(EM)wave absorption impedance matching

来源：评论

学校读者我要写书评

暂无评论

Enhanced Tube-Based Event-Triggered Stochastic Model Predictive control With Additive Uncertainties

引用

IEEE/CAA Journal of Automatica Sinica 2025年第3期12卷 596-605页

作者： Chenxi Gu Xinli Wang Kang Li Xiaohong Yin Shaoyuan Li Lei Wang the School of Control Science and Engineering Shandong University IEEE the School of Electronic and Electrical Engineering University of Leeds the Qingdao University of Science and Technology the Department of Automation Shanghai Jiao Tong University the Key Laboratory of System Control and Information Processing Ministry of Education of China

This paper proposes an event-triggered stochastic model predictive control for discrete-time linear time-invariant(LTI) systems under additive stochastic disturbances. It first constructs a probabilistic invariant set and a probabilistic reachable set based on the priori knowledge of system *** with enhanced robust tubes, the chance constraints are then formulated into a deterministic form. To alleviate the online computational burden, a novel event-triggered stochastic model predictive control is developed, where the triggering condition is designed based on the past and future optimal trajectory tracking errors in order to achieve a good trade-off between system resource utilization and control performance. Two triggering parameters σ and γ are used to adjust the frequency of solving the optimization problem. The probabilistic feasibility and stability of the system under the event-triggered mechanism are also examined. Finally, numerical studies on the control of a heating, ventilation, and air conditioning(HVAC) system confirm the efficacy of the proposed control.

关键词： Event-triggered mechanism heating, ventilation, and air conditioning (HVAC) control probabilistic reachable set stochastic model predictive control

来源：评论

学校读者我要写书评

暂无评论

Construction of core-triple shell upconversion nanostructures NaNdF4:Yb,Gd@NaGdF4:Yb@NaGdF4:Yb,Er@NaGdF4 with high FRET efficiency for the biochemical sensor

引用

Ceramics International 2025年第12期51卷 16986-16995页

作者： Liao, Chuan Wang, Jiaxuan Liu, Hanqing Xu, Jing Zhou, Wen Guo, Peng Wang, Tao Zhou, Guangjun Hu, Jifan State Key Laboratory of Crystal Materials Shandong University Jinan250100 China Health Inspection and Testing Institute Shandong Provincial Center for Disease Control and Prevention Jinan250014 China Shandong Provincial Key Laboratory of Marine Monitoring Instrument Equipment Technology National Engineering and Technological Research Center of Marine Monitoring Equipment Qingdao266061 China

Upconversion nanoparticles (UCNPs) are excellent energy donors for Föster resonance energy transfer (FRET) systems. However, the lower FRET efficiency to some extend limits its application. To improve the efficiency of FRET, NaNdF4:Yb,Gd@NaGdF4:Yb@NaGdF4:Yb,Er@NaGdF4 core-triple shell (CTS) UCNPs with sensitizers in the core region and activators doped in the outer shell region were successfully prepared by changing the traditional core-shell structure design sequence. By introducing a certain amount of Gd3+ into the core nanoparticles, the crystal growth process of core nanoparticles was regulated, solving the problem of excessive and uneven size caused by high concentration of sensitizers. The insertion of Yb3+ doped transition layer weakens the negative effect between Nd3+ and activator ions, and enhances the luminescence intensity. In addition, comparing CTS UCNPs with UCNPs prepared in the traditional core-shell structure design sequence proves that CTS UCNPs have higher FRET efficiency. A biochemical sensing system was designed using this novel core-shell structure UCNPs, achieving simultaneous detection of GSH and Cd2+ with detection limits of 4.2 nM and 15.2 nM, respectively. The new core-shell structure UCNPs have broader application prospects in the field of biochemical sensing design. © 2024 Elsevier Ltd and Techna Group S.r.l.

关键词： Shells (structures)

来源：评论

学校读者我要写书评

暂无评论

Research on the protection mechanism of methane explosion in underground space by flexible construction

引用

Defence technology(防务技术) 2025年第4期46卷 169-183页

作者： Xianqi Duan Yulong Duan Zishuang Zhang Jun Long Yaqiao Yang Rui Lang College of Safety Engineering Chongqing University of Science and TechnologyChongqing 401331China Chongqing Key Laboratory for Oil and Gas Production Safety and Risk Control Technology Chongqing 401331China

Urban growth has promoted the use of underground spaces,where explosion accidents can be *** this study,we investigated the effect of placing flexible construction in front of rigid obstacles on methane explosion protection by using an experimental platform and adjusting the blockage rate and spacing of the *** aims to reduce the risk of gas explosions in urban underground *** results of the study show that the flame propagation peak speed and peak overpressure are reduced with the decrease in the blocking rate of the flexible obstacle when the blocking rate of the flexible obstacle is less than or equal to the blocking rate of the rigid obstacle,with the decrease in the spacing,the better the protection effect of the methane *** the blockage rate of the flexible obstacle is greater than the blockage rate of the rigid obstacle and spacing is less than the height of the flexible obstacle,rigid and flexible obstacles are connected as a whole,increasing the strength of the *** study can provide a theoretical basis and scientific guidance for optimizing rigid and flexible object hybrid layouts and methane explosion protection technology in urban underground spaces.

关键词： Explosion protection Flexible construction Urban underground space Methane explosions

来源：评论

学校读者我要写书评

暂无评论

Interlinked water and sediment microplastics in the Laizhou Bay of China

引用

Journal of Oceanology and Limnology 2025年第2期43卷 446-458页

作者： Hong CHEN Fenghua JIANG Jingxi LI Wei CAO Di ZHANG Futao ZHANG Shiliang WANG Chengjun SUN College of Safety and Environmental Engineering Shandong University of Science and TechnologyQingdao 266590China Key Laboratory of Analytical Technology Development and Offshore Eco-Environment Conservation First Institute of OceanographyMinistry of Natural ResourcesQingdao 266061China Qingdao National Laboratory of Marine Science and Technology Laboratory of Marine Drugs and Biological ProductsQingdao 266071China

To explore the relationship of microplastic pollution in different media in marine environment,microplastics in the surface seawater and sediments of Laizhou Bay,Bohai Sea,North China,were *** samples were collected using a pre-concentrator equipped with a 20-μm mesh size sieve,and sediment samples were collected by a box *** shape,color,size,and type of microplastics were obtained by a stereomicroscope and a Fourier transform infrared spectrometer(ATR-μ-FT-IR).Results show that the abundance of microplastics in the surface seawater of Laizhou Bay was 858.3±573.2 items/m~3,and that of microplastics in sediments was 151.0±77.4 items/kg dry weight(d.w.)The microplastics in seawater and sediments were mainly ***,the microplastics in seawater were mainly transparent,and those in sediments were transparent and *** highest proportion of microplastics in seawater was rayon(77.48%),followed by polyethylene terephthalate(PET,13.17%).The highest proportion of microplastics in sediments was rayon(73.66%),followed by PET(8.90%).The size of microplastics in 1000-2000μm accounted for the largest proportion of 28.54%in seawater,while that in 500-1000μm took 27.93%in *** in seawater and sediment showed medium-level *** seawater,microplastic abundance was higher in offshore and nearshore areas of *** sediment,microplastic abundance was higher in offshore and nearshore areas of *** results of the principal component analysis(PCA)indicated that microplastics in sediment exhibited greater stability compared to those in *** microplastics in seawater and sediment show a positive correlation in terms of shape and plastic type,while exhibiting a negative correlation in terms of ***,microplastics in sediments were smaller in size,and those in seawater and sediments had consistent size distribution characteristics in space.

关键词： microplastic Laizhou Bay sediment seawater correlation

来源：评论

学校读者我要写书评

暂无评论

Adsorption Characteristics of Congo Red Dye onto Calcinated Mytilus edulis Shell Powders

引用

Journal of Ocean University of China 2025年第1期24卷 229-237页

作者： WANG Xin GE Xiangyun ZHU Siqi LIU Weixiang XING Ronge LI Pengcheng LI Kecheng Marine Science and Engineering College Qingdao Agricultural UniversityQingdao 266109China Key Laboratory of Experimental Marine Biology Center for Ocean Mega-ScienceInstitute of OceanologyChinese Academy of SciencesQingdao 266071China Laboratory for Marine Drugs and Bioproducts Qingdao Marine Science and Technology CenterQingdao 266237China

Dye wastewater poses a significant threat to aquatic organisms due to its high *** or eliminating the dye waste from the water is necessary for a healthy and sustainable *** study investigated the adsorption properties of Congo red dye on Mytilus edulis shell powders prepared by calcination at 500℃,700℃,and 900℃.The modified shell powder products were analyzed by SEM(scanning eletron microscopy)and FTIR(fourier transform infrared spectroscopy)for the morphology and structural *** effects of different calcination temperatures,reaction times,reaction temperatures,and initial concentration of Congo red on the adsorption properties were *** adsorption kinetics and isothermal adsorption models were also *** results revealed that the shell powder calcinated at 900℃showed the best adsorption capacity on Congo red from aqueous *** adsorption reaction reached equilibrium after 150 min and followed by the pseudo-second-order kinetic *** 25℃,96.2%of the Congo red in the solution could be removed,and the adsorption capacity could reach at least 1015 mg g^(–1).The adsorption isotherm is fit with the Freundlich model,indicating a multiphase adsorption *** results are helpful for cleaning and treating printing and dyeing effluents as well as high-value utilization of shell waste resources.

关键词： adsorption Congo red high-temperature calcination Mytilus edulis shell

来源：评论

学校读者我要写书评

暂无评论

Microstructural evolution and hydraulic response of shale self-propped fracture using X-ray computed tomography and digital volume correlation

引用

International Journal of Mining Science and technology 2025年第3期35卷 345-362页

作者： Ting Huang Cheng Zhai Ting Liu Yong Sun Hexiang Xu Yu Wang Jing Huang State Key Laboratory of Coal Mine Disaster Prevention and Control Ministry of EducationChina University of Mining and TechnologyXuzhou 221116China Key Laboratory of Theory and Technology on Coal and Rock Dynamic Disaster Prevention and Control National Mine Safety AdministrationChina University of Mining and TechnologyXuzhou 221116China School of Safety Engineering China University of Mining and TechnologyXuzhou 221116China School of Low-Carbon Energy and Power Engineering China University of Mining and TechnologyXuzhou 221116China

Methane in-situ explosive fracturing technology produces shale debris particles within fracture channels,enabling a self-propping effect that enhances the fracture network conductivity and long-term *** study employs X-ray computed tomography(CT)and digital volume correlation(DVC)to investigate the microstructural evolution and hydromechanical responses of shale self-propped fracture under varying confining pressures,highlighting the critical role of shale particles in maintaining fracture *** indicate that the fracture aperture in the self-propped sample is significantly larger than in the unpropped sample throughout the loading process,with shale particles tending to crush rather than embedded into the matrix,thus maintaining flow *** confining pressure increases,contact areas between fracture surfaces and particles expand,enhancing the system's stability and compressive *** analyses show flow paths becoming increasingly concentrated and branched under high *** resulted in a significant reduction in connectivity,restricting fracture permeability and amplifying the nonlinear gas flow *** study introduces a permeability-strain recovery zone and a novel sensitivity parameter m,delineating stress sensitivity boundaries for permeability and normal strain,with m-value increasing with stress,revealing four characteristic *** findings offer theoretical support for optimizing fracturing techniques to enhance resource extraction efficiency.

关键词： Digital volume correlation X-ray CT scanning Fracture aperture Deformation characteristics Stress sensitivity Permeability

来源：评论

学校读者我要写书评

暂无评论

Effects of carbon content on the microstructure and tensile properties of a low-density steel

引用

International Journal of Minerals,Metallurgy and Materials 2025年第2期32卷 391-401页

作者： Yongxuan Shang Mingyu Fan Shuyong Jiang Zhongwu Zhang Key Laboratory of Superlight Materials and Surface Technology Ministry of EducationCollege of Materials Science and Chemical EngineeringHarbin Engineering UniversityHarbin 150001China State Key Laboratory of Metal Material for Marine Equipment and Application Iron&Steel Research Institute of Ansteel Group CorporationAnshan 114009China

Carbon can change the phase components of low-density steels and influence the mechanical *** this study,a new method to control the carbon content and avoid the formation ofδ-ferrite by decarburization treatment was *** microstructural changes and mechanical characteristics with carbon content induced by decarburization were systematically ***-Jaoul(C-J)analysis was employed to examine the work hardening characteristics during the tensile *** decarburization by heat treatments,the carbon content within the austenite phase decreased,while Mn and Al were almost unchanged;this made the steel with full austenite transform into the austenite and ferrite dual ***,(Ti,V)C carbides existed in both matrix phase and the mole fraction almost the *** addition,the formation of other carbides *** loss induced a decrease in strength due to the weakening of the carbon solid *** the steel with the single austinite,the deformation mode of austenite was the dislocation planar glide,resulting in the formation of *** the dual-phase steel,the deformation occurred by the dislocation planar glide of austenite first,with the increase in strain,the cross slip of ferrite took place,forming dislocation cells in *** the late stage of deformation,the work hardening of austinite increased rapidly,while that of ferrite increased slightly.

关键词： low-density steels carbon content decarburization strengthening mechanisms work hardening behavior

来源：评论

学校读者我要写书评

暂无评论

On-Policy and Off-Policy Value Iteration Algorithms for Stochastic Zero-Sum Dynamic Games

引用

Journal of Systems Science & Complexity 2025年第1期38卷 421-435页

作者： GUO Liangyuan WANG Bing-Chang ZHANG Ji-Feng School of Control Science and Engineering Shandong UniversityJinan 250063China School of Automation and Electrical Engineering Zhongyuan University of TechnologyZhengzhou 450007China Key Laboratory of Systems and Control Academy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing 100190China

This paper considers the value iteration algorithms of stochastic zero-sum linear quadratic games with unkown ***-policy and off-policy learning algorithms are developed to solve the stochastic zero-sum games,where the system dynamics is not *** analyzing the value function iterations,the convergence of the model-based algorithm is *** equivalence of several types of value iteration algorithms is *** effectiveness of model-free algorithms is demonstrated by a numerical example.

关键词： Approximate dynamic programming on-policy off-policy stochastic zero-sum games valueiteration

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：