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P-and SV-wave dispersion and attenuation in saturated microcracked porous rock with aligned penny-shaped fractures

Petroleum Science 2024年第1期21卷 143-161页

作者： Sheng-qing li Wen-Hao Wang Yuan-Da Su Jun-Xin Guo Xiao-Ming Tang School of Geosciences China University of Petroleum(East China)Qingdao 266580ShandongChina Laoshan National Laboratory Qingdao 266071ShangdongChina Guangdong Provincial Key Laboratory of Geophysical High-resolution Imaging Technology Southern University of Science and TechnologyShenzhen 518055GuangdongChina Department of Earth and Space Sciences Southern University of Science and TechnologyShenzhen 518055GuangdongChina

P-and SV-wave dispersion and attenuation have been extensively investigated in saturated poroelastic media with aligned ***,there are few existing models that incorporate the multiple wave attenuation mechanisms from the microscopic scale to the macroscopic ***,in this work,we developed a unified model to incorporate the wave attenuation mechanisms at different scales,which includes the microscopic squirt flow between the microcracks and pores,the mesoscopic wave-induced fluid flow between fractures and background(FB-WIFF),and the macroscopic Biot's global flow and elastic scattering(ES)from the *** Tang's modified Biot's theory and the mixed-boundary conditions,we derived the exact frequency-dependent solutions of the scattering problem for a single penny-shaped fracture with oblique incident P-and *** then developed theoretical models for a set of aligned fractures and randomly oriented fractures using the Foldy *** results indicated that microcrack squirt flow considerably influences the dispersion and attenuation of P-and SV-wave *** coupling effects of microcrack squirt flow with the FB-WIFF and ES of fractures cause much higher velocity dispersion and attenuation for P waves than for SV *** oriented fractures substantially reduce the attenuation caused by the FB-WIFF and ES,particularly for the ES attenuation of SV *** a comparison with existing models in the limiting cases and previous experimental measurements,we validated our model.

关键词： Aligned fractures P-and SV-wave Dispersion and attenuation Microcracked porous background FB-WIFF Elastic scattering Squirt flow

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The effects of various factors on spontaneous imbibition in tight oil reservoirs

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Petroleum Science 2024年第1期21卷 315-326页

作者： Cheng liu Tian-Ru Wang qing You Yue-Chun Du Guang Zhao Cai-li Dai School of Energy Resources China University of GeosciencesBeijing100083PR China School of Petroleum Engineering China University of PetroleumQingdao266580ShandongPR China

Slickwater fracturing fluids have gained widespread application in the development of tight oil reservoirs. After the fracturing process, the active components present in slickwater can directly induce spontaneous imbibition within the reservoir. Several variables influence the eventual recovery rate within this procedure, including slickwater composition, formation temperature, degree of reservoir fracture development, and the reservoir characteristics. Nonetheless, the underlying mechanisms governing these influences remain relatively understudied. In this investigation, using the Chang-7 block of the Changqing Oilfield as the study site, we employ EM-30 slickwater fracturing fluid to explore the effects of the drag-reducing agent concentration, imbibition temperature, core permeability, and core fracture development on spontaneous imbibition. An elevated drag-reducing agent concentration is observed to diminish the degree of medium and small pore utilization. Furthermore, higher temperatures and an augmented permeability enhance the fluid flow properties, thereby contributing to an increased utilization rate across all pore sizes. Reduced fracture development results in a lower fluid utilization across diverse pore types. This study deepens our understanding of the pivotal factors affecting spontaneous imbibition in tight reservoirs following fracturing. The findings act as theoretical, technical, and scientific foundations for optimizing fracturing strategies in tight oil reservoir transformations.

关键词： Tight oil reservoir Spontaneous imbibition Nuclear magnetic resonance Slickwater fracturing fluid Fluid utilization degree

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Characteristics and influencing factors of CO_(2) emission from inland waters in China

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Science China Earth Sciences 2024年第6期67卷 2034-2055页

作者： Ting ZHOU Xiaofeng WANG Zuolin XIAO Zhaoyin qing Xianxiang li Jilong WANG Ziyi QUE Chongqing Key Laboratory of Carbon Cycling and Carbon Regulation in Mountainous Ecosystems Chongqing 401331China School of Geography and Tourism Chongqing Normal UniversityChongqing 401331China Chongqing Field Observation and Research Station of Earth Surface Ecological Processes in Three Gorges Reservoir Area Chongqing 405400China School of Earth System Science Tianjin UniversityTianjin 300072China

Inland water bodies,being the most active biogeochemical cycle reactors,play a pivotal role in the global carbon cycle and CO_(2) *** study integrates existing observation dataset of CO_(2) flux(fCO_(2))in rivers,lakes and reservoirs in China,to elucidate their spatial-temporal patterns and key influencing factors and to reappraise the significance for regional carbon *** showed that,the fCO_(2) in rivers,lakes and reservoirs in China presented significant variability with large range of-379.3-4947.6,-160.1-785.0 and -74.0-1603.1 mg CO_(2)m-2h^(-1),*** median of the fCO_(2) in rivers was of 228.5 mg CO_(2)m^(-2)h^(-1),observably higher than these in lakes and reservoirs(26.0 and 28.3 mg CO_(2)m^(-2)h^(-1),respectively).The fCO_(2)in rivers and reservoirs exhibited similar decreasing trend from south to north as a result of universal climate restraint,the averaged fCO_(2) in Pearl River and Yangtze River basins showed much higher than that in Northeastern ***,the averaged fCO_(2) in the Mongolia-Xinjiang lake district and the Northeast lake district were higher than other lake districts,followed by the qinghai-Xizang lake district,and the Eastern and Yungui lake district were generally low,contradicting the climatic *** water primary production enhancement resulting from human activities was the main driver of spatial variation in the fCO_(2) in ***,the fCO_(2) in rivers presented seasonal pattern with higher wet season than dry season,while opposite patterns were found in lakes and *** temperature,precipitation and water primary production were main ***,it showed pH was a key factor indicating the variability of the fCO_(2) levels either in rivers,lakes or in *** lakes,the fCO_(2) is closely linked to chlorophyll a(Chl-a)and dissolved oxygen(DO),whereas,the fCO_(2) in rivers is primarily associated with organic carbon(OC)and total nitrogen(TN),highlighting the dive

关键词： Rivers/lakes/reservoirs CO_(2) emission Spatio-temporal variability Influence factors Regional contribution

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Joint training with local soft attention and dual cross-neighbor label smoothing for unsupervised person re-identiﬁcation

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Computational Visual Media 2024年第3期10卷 543-558页

作者： qing Han Longfei li Weidong Min Qi Wang qingpeng Zeng Shimiao Cui Jiongjin Chen School of Mathematics and Computer Sciences Nanchang UniversityNanchang 330031China Institute of Metaverse Nanchang UniversityNanchang 330031China Jiangxi Key Laboratory of Smart City Nanchang 330031China

Existing unsupervised person re-identification approaches fail to fully capture theﬁne-grained features of local regions,which can result in people with similar appearances and different identities being assigned the same label after *** identity-independent information contained in different local regions leads to different levels of local *** address these challenges,joint training with local soft attention and dual cross-neighbor label smoothing(DCLS)is proposed in this ***,the joint training is divided into global and local parts,whereby a soft attention mechanism is proposed for the local branch to accurately capture the subtle differences in local regions,which improves the ability of the re-identiﬁcation model in identifying a person’s local signiﬁcant ***,DCLS is designed to progressively mitigate label noise in different local *** DCLS uses global and local similarity metrics to semantically align the global and local regions of the person and further determines the proximity association between local regions through the cross information of neighboring regions,thereby achieving label smoothing of the global and local regions throughout the training *** extensive experiments,the proposed method outperformed existing methods under unsupervised settings on several standard person re-identiﬁcation datasets.

关键词： person re-identification(Re-ID) unsupervised learning(USL) local soft attention joint training dual cross-neighbor label smoothing(DCLS)

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Layered coordination polymer with two-dimensional covalent bismuth-organic networks:Semiconductor and lithium ion storage

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Nano Research 2024年第3期17卷 2181-2185页

作者： Mu-qing li Yulin Cao Lei Qin Hua Cheng Weimin Yang Zhouguang Lu School of Materials Science and Environmental Engineering Shenzhen Polytechnic UniversityShenzhen 518055China Industrial Training Center Shenzhen Polytechnic UniversityShenzhen 518055China Department of Materials Science and Engineering Southern University of Science and TechnologyShenzhen 518055China Department of Chemistry Southern University of Science and TechnologyShenzhen 518055China

Single crystals of a bismuth-based coordination polymer(CP)with carboxyl-thiol ligands,[Bi(C_(8)H_(2)O_(4)S_(2))(C2H8N)]n(Bi-DSBDC-DMA,DMBDC=2,5-disulfur-1,4-dicarboxylate,DMA=dimethylamine),have been successfully synthesized.X-ray diffraction analysis reveals that Bi-DSBDC-DMA possesses a layered structure,with two-dimensional(2D)Bi-DSBDC networks alternating with layers composed of dimethylamine *** material demonstrates semiconducting properties,featuring an optical bandgap of 2.2 eV and an electrical conductivity of 2×10^(-8) S/***,electrodes based on this material exhibit a capacity of 250 mAh/g after 200 cycles for lithium-ion storage.

关键词： bismuth layer coordination polymer(CP) semiconductor lithium ion storage

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Spatial light modulation for femtosecond laser manufacturing:Current developments and challenges

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Science China(Technological Sciences) 2024年第1期67卷 60-72页

作者： ZANG Xue liU ZiTing XU YiShi WANG Yi WANG qing li ZhenZe WANG Lei State Key Laboratory of Integrated Optoelectronics College of Electronic Science and EngineeringJilin UniversityChangchun 130012China State Key Laboratory of Precision Measurement and Instruments Department of Precision InstrumentTsinghua UniversityBeijing 100084China

Since the invention of lasers,spatial-light-modulated laser processing has become a powerful tool for various *** enables multidimensional and dynamic modulation of the laser beam,which significantly improves the processing efficiency,accuracy,and flexibility,and presents wider prospects over traditional mechanical technologies for machining three-dimensional,hard,brittle,or transparent *** this review,we introduce:(1)The role of spatial light modulation technology in the development of femtosecond laser manufacturing;(2)the structured light generated by spatial light modulation and its generation methods;and(3)representative applications of spatial-light-modulated femtosecond laser manufacturing,including aberration correction,parallel processing,focal field engineering,and polarization ***,we summarize the present challenges in the field and possible future research.

关键词： femtosecond laser manufacturing spatial light modulation structured light aberration correction parallel processing focal field engineering polarization control

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Stress Concentration Effect in Interface Between Conductor and Epoxy Resin in Coaxial Components of Power Equipment

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CSEE Journal of Power and Energy Systems 2024年第1期10卷 412-420页

作者： Chuang Wang Kang Lei qing Sun Hui li Jiawei Zhang Lang Zhao Zongren Peng School of Electrical Engineering Xi’an University of TechnologyXi’an 710054China Xi’an Power Supply Company State Grid Shaanxi Electric Power CompanyXi’an 710032China State Key Laboratory of Electrical Insulation and Power Equipment Xi’an Jiaotong UniversityXi’an 710049China

The spacer used in gas insulated switchgear(GIS)plays a vital role in its safe *** mismatch of mechanical properties between conductor and insulating material in spacers results in stress concentration at the interface between *** a hydrostatic test,mechanical damages are often initiated from the *** this paper,the stress between aluminum conductors and epoxy resin is studied by using a simplified coaxial structure *** measurement system and finite element simulation are used to explore the generation of stress and strain during curing and *** real-time measurement of strain at the interface shows that the residual strain in the entire process is primarily generated during the cooling ***,the temperature and stress/strain distribution at the interface during the cooling stage are further studied,and combined with experiments and *** consistency between the finite element simulation and the experimental measurement results verifies the validity of the simulation method *** results show that the maximum of the first principal stress generated during the cooling stage of the production process is concentrated on the upper and lower edges of the interface which is critical to the impact of the production quality of the spacer.

关键词： Epoxy resin GIS interface stress/strain distribution

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Development and validation of a prognostic immunoinflammatory index for patients with gastric cancer

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World Journal of Gastroenterology 2024年第24期30卷 3059-3075页

作者： Zhi-Chang Ba Xi-qing Zhu Zhi-Guo li Yuan-Zhou li Department of Radiology Harbin Medical University Cancer HospitalHarbin 150081Heilongjiang ProvinceChina Department of Gastrointestinal Surgery Harbin Medical University Cancer HospitalHarbin 150081Heilongjiang ProvinceChina

BACKGROUND Studies have demonstrated the influence of immunity and inflammation on the development of *** single biomarkers of immunity and inflam-mation have been shown to be clinically predictive,the use of biomarkers integrating both to predict prognosis in patients with gastric cancer remains to be *** To investigate the prognostic and clinical significance of inflammatory biomarkers and lymphocytes in patients undergoing surgical treatment for gastric *** Univariate COX regression analysis was performed to identify potential prognostic factors for patients with gastric cancer undergoing surgical *** absolute shrinkage and selection operator-COX(LASSO-COX)regression analysis was performed to integrate these factors and formulate a new prognostic immunoinflammatory index(PII).The correlation between PII and clinical charac-teristics was statistically *** incorporating the PII score were devised and validated based on the time-dependent area under the curve and decision curve *** Patients exhibiting elevated neutrophil-to-lymphocyte ratio,platelet-to-lymphocyte ratio,and systemic immune inflammatory index displayed inferior progression-free survival(PFS)and overall survival(OS).Conversely,low levels of CD3(+),CD3(+)CD8(+),CD4(+)CD8(+),and CD3(+)CD16(+)CD56(+)T lymphocytes were associated with improved PFS and OS,while high CD19(+)T lymphocyte levels were linked to worse PFS and *** PII score demonstrated associations with tumor characteristics(primary tumor site and tumor size),establishing itself as an independent prognostic factor for both PFS and ***-dependent area under the curve and decision curve analysis affirmed the effectiveness of the PII-based nomogram as a robust prognostic predictive *** PII may be a reliable predictor of prognosis in patients with gastric cancer undergoing surgical treatment,and it offers insights into cancer-related immune-inflammatory re

关键词： Gastric cancer Immunity Inflammation Prognosis Nomogram

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Microstructure design of advanced magnesium-air battery anodes

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Journal of Magnesium and Alloys 2024年第2期12卷 443-464页

作者： Xu Huang qingwei Dai qing Xiang Na Yang Gaopeng Zhang Ao Shen Wanming li School of Metallurgy and Materials Engineering Chongqing University of Science and TechnologyChongqing 401331China School of Materials and Architectural Engineering Guizhou Normal UniversityGuiyang 550025China School of Material and Metallurgy University of Science and Technology LiaoningAnshan 114051China

Metal-air battery is an environmental friendly energy storage system with unique open ***(Mg)and its alloys have been extensively attempted as anodes for air batteries due to high theoretical energy density,low cost,and ***,the study on Mg-air battery(MAB)is still at the laboratory level currently,mainly owing to the low anodic efficiency caused by the poor corrosion *** order to reduce corrosion losses and achieve optimal utilization efficiency of Mg anode,the design strategies are reviewed from microstructure ***,the corrosion behaviors have been discussed,especially the negative difference effect derived by hydrogen *** attention is given to the effect of anode micro-structures on the MAB,which includes grain size,grain orientation,second phases,crystal structure,twins,and *** further improvement,the discharge performance,long period stacking ordered phase and its enhancing effect are ***,given the current debates over Mg dendrites,the potential risk,the impact on discharge,and the elimination strategies are *** control and single crystal would be promising ways for MAB anode.

关键词： Magnesium Air battery Anode Microstructure Anodic efficiency

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Analyses on an electronic voltage transformer's failure by its resonance with very fast transient overvoltage and suppression

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High Voltage 2024年第1期9卷 150-162页

作者： Ruoyu Han Houda Zhu qing Chen Hongbin li Yue Tong linshan Han Yang Jiao School of Electrical and Electronic Engineering Huazhong University of Science and TechnologyWuhanChina China Electric Power Research Institute WuhanChina School of Artificial Intelligence and Automation Huazhong University of Science and TechnologyWuhanChina

As voltage measuring devices are widely used in the high voltage power system with a primary-secondary-fusion structure,electronic voltage transformers are directly connected to the primary conductor and would face much more serious electromagnetic environments than general secondary *** a result,they would still experience failures even when general protection measures are adopted to suppress overvoltages'*** address this issue,an innovative method is proposed after analyses are conducted on the resonance between a transformer and an *** this method,an air-cored coil is installed in a transformer to artificially shift its natural frequency and to dodge the high-frequency dominant component of a transient overvoltage,avoiding the aforementioned resonance and suppressing the secondary *** addition,simulations and laboratory tests are conducted to prove this method's validity.

关键词： transient resonance mentioned

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