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Numerical and theoretical analysis on soil arching effect of prefabricated piles as deep foundation pit supports

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Underground Space 2024年第3期16卷 314-330页

作者： Qianwei xu Jinli Xie Linhai Lu Yongji Wang Chaojun Wu qiang Meng Key Laboratory of Road and Traffic Engineering Ministry of EducationTongji UniversityShanghai 201804China Jinan Rail Transit Group Co. LtdJinan 250101China Guangxi Nanning Airport Comprehensive Transportation Hub Construction Co. Ltd.Nanning 530048China

This study presents a detailed investigation into the soil arching effects within deep foundation pits(DFPs),focusing on their mechanical behavior and implications for structural *** rigorous 3D finite element modeling and parameter sensitivity analyses,the research explores the formation,geometric characteristics,and spatial distribution of soil arching *** investigation encompasses the influence of key parameters such as elastic modulus,cohesion,and internal friction angle on the soil arching *** findings reveal that soil arching within DFPs exhibits distinct spatial characteristics,with the prominent arch axis shifting as excavation depth *** soil arching is observed when the pile spacing approximates three times the pile diameter,enhancing soil retention and minimizing deformation *** analyses highlight the significant impact of soil parameters on soil arching behavior,underscoring the critical role of cohesive forces and internal friction angles in shaping arching *** elucidating the interplay between soil parameters and soil arching effects,the research provides insights for optimizing pile spacing and structural stability.

关键词： Soil arching effect Numerical analysis Foundation pit support Pile spacing

PVDF-assisted pyrolysis strategy for corrugated plate oxygen electrocatalysis nanoreactor:Simultaneously realizing efficient active sites and rapid mass transfer

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Journal of Energy Chemistry 2024年第10期97卷 612-621,I0013页

作者： Chenxi xu Liang Chen Haihui Zhou Shifeng Qin Zhaohui hou Yangyang Chen Jiale Sun Junwei xu Zhongyuan Huang Cllege of Chemistry and Chemical Engineering Hunan UniversityChangsha 410082HunanChina Key Laboratory of Hunan Province for Advanced Carbon-based Functional Materials School of Chemistry and Chemical EngineeringHunan Institute of Science and TechnologyYueyang 414006HunanChina College of Materials Science and Technology Central South University of Forestry and TechnologyChangsha 410004HunanChina

Though Zn-air batteries(ZABs)are one of the most promising system for energy storage and conversion,challenge still persists in its commercial application due to the sluggish kinetics of oxygen reduction/evolution reaction(ORR/OER).Hereby,a polyvinylidene fluoride(PVDF)-assisted pyrolysis strategy is proposed to develop a novel corrugated plate-like bifunctional electrocatalyst using two-dimensional zeolitic imidazolate frameworks(2D ZIF-67)as the *** employed PVDF plays an important role in inheriting the original 2D structure of ZIF-67 and modulating the composition of the final *** a result,a corrugated plate-like electrocatalyst,high-density Co nanoparticles decorated 2D Co,N,and F tri-doped carbon nanosheets,can be *** acquired electrocatalyst enables efficient active sites and rapid mass transfer simultaneously,thus showing appreciable electrocatalytic performance for rechargeable Zn-air ***,our proposed strategy offers a new perspective to the design of advanced oxygen electrocatalysts.

关键词： Active sites Mass transfer Corrugated plate Oxygen electrocatalyst Zn-air batteries

Evolution of MnO–SiO2–Al_(2)O_(3)–MgO inclusions during heat treatment at 1100℃

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Journal of Iron and Steel Research International 2024年第5期31卷 1221-1231页

作者： xu-bo Lei Jian-li Li qiang Zeng Hang-yu Zhu Yue Yu The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan430081HubeiChina Hubei Provincial Key Laboratory for New Processes of Ironmaking and Steelmaking Wuhan University of Science and TechnologyWuhan430081HubeiChina Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education Wuhan University of Science and TechnologyWuhan430081HubeiChina

To investigate the evolutionary behavior of the MnO–SiO_(2)–Al_(2)O_(3)–MgO inclusions during heat treatment,water quenched samples were isothermally held at 1100°C for 120 min in Ar and air atmosphere,and the obtaining samples were analyzed by X-ray diffraction,scanning electron microscopy and energy dispersive *** showed that 3MnO·Al_(2)O_(3)·3SiO_(2)and MnO·SiO_(2)were detected in the 5 wt.%MgO system after isothermal holding in Ar atmosphere,while MgO·Al_(2)O_(3),MnO·SiO_(2)and Mn7O8·SiO4 were detected in air *** evolutionary behavior of the 10,15 and 20 wt.%MgO systems after isothermal holding in different atmosphere were *** affected the solid phase transformation of the low MgO content *** calculation results of FactSage 8.1 showed that MgO·Al_(2)O_(3)was formed in the 5 wt.%MgO system with air *** solid phase transformation was accompanied by grain coarsening during the isothermal holding *** differences in the solid phase transformation in different atmosphere of the 5 wt.%MgO system indicated that it was a gas-phase transport grain coarsening *** enrichment of Al element in the liquid phase region at the grain edges,the homogeneous distribution of Mg element and the disappearance of the liquid phase within the crystal revealed that other MgO content systems were liquid–solid transport grain coarsening mechanism.

关键词： Evolution Glassy phase Inclusion Heat treatment MgO·Al_(2)O_(3)

Impurity formation mechanism of silicon carbide crystals smelted by Acheson process

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Journal of Iron and Steel Research International 2024年第6期31卷 1367-1375页

作者： Dong Feng Hong-qiang Ru xu-dong Luo Jie-gang You Ling Zhang School of Materials and Metallurgy University of Science and Technology LiaoningAnshan 114051LiaoningChina Key Laboratory for Anisotropy and Texture of Materials(Ministry of Education) Institute of Advanced CeramicsSchool of Materials Science and EngineeringNortheastern UniversityShenyang 110819LiaoningChina Liaoning Institute of Science and Technology Benxi 117004LiaoningChina

In order to further promote the application of SiC refractories in modern steel metallurgy,the occurrence forms and formation mechanism of impurities in SiC crystals smelted by Acheson process were *** techniques of inductively coupled plasma-atomic emission spectrometry,X-ray diffraction,and scanning electron microscopy were combined to examine the types and occurrence forms of impurities in smelted SiC *** results showed that the main impurities in the SiC are free Si,free C,oxides(CaO·Al_(2)O_(3)·2SiO_(2),3Al_(2)O_(3)·2SiO_(2),CaO·SiO_(2) and SiO_(2))and alloy phases(Fe_(x)Si_(y),Fe_(x)Si_(y)Ti_(z) and Fe_(x)Al_(y)Si_(z)).The formation process of impurities during the smelting of SiC can be described as follows:At high temperature,the SiO_(2) and Fe,Ti related oxide impurities present in the raw materials are reduced to Si,Fe,and Ti metal *** the reduction process,the free Si,Fe_(x)Si_(y) and Fe_(x)Si_(y)Ti_(z) are precipitated from the melt during *** Si primarily exists in aggregated form within the SiC crystal,while the alloy phase is predominantly found at the interface between SiC and free Si,with Fe_(x)Si_(y)Ti_(z) embedded within *** the end of the cooling process,other impurity oxides such as Al_(2)O_(3),CaO,and some unreduced SiO_(2) solidify to form calcium-aluminum-silicate glass phases,predominantly located between SiC *** remaining C from the reaction is mainly dispersed as free C within the SiC crystal and at the interface between SiC and free Si.

关键词： Impurity element Formation mechanism Smelted SiC crystal SiC refractory Occurrence form

First Record of Cyclocarya from the Early Oligocene Qaidam Basin,North Tibet:Implications for the Paleogeography and Paleoecology

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Journal of Earth Science 2024年第1期35卷 201-211页

作者： Yafei hou Bowen Song Xiangchuan Li Fang Han xu Zhang Kexin Zhang Institute of Geological Survey China University of GeosciencesWuhan 430074China Faculty of Materials Science and Chemistry China University of GeosciencesWuhan 430074China State Key Laboratory of Biogeology and Environmental Geology China University of GeosciencesWuhan 430074China College of Earth Sciences and Resources&Key Laboratory of Western Mineral Resources and Geological Engineering of the Ministry of Education Chang'an UniversityXi'an 710054China State Key Laboratory of Palaeobiology and Stratigraphy Nanjing Institute of Geology and PalaeontologyChinese Academy of SciencesNanjing 210008China School of Earth Sciences East China University of TechnologyNanchang 330013China

As the largest intermontane basin in the northeastern Tibetan Plateau(TP),the Qaidam Basin provides unique insight into paleoclimatic change and its relationship with global change and uplift on the *** this study,based on morphological comparison,fossil fruit of Cyclocarya from the Early Oligocene Shangganchaigou Formation in the Qaidam Basin is assigned as Cyclocarya *** discovery of Cyclocarya *** demonstrates the occurrence of Cyclocarya in the Oligocene sediment in Qaidam *** is the first record of Cyclocarya fossil of Early Oligocene Age in China and indicates that Cyclocarya has existed on the northeastern TP since at least the Early *** living analogues of the current fossil now lives in sub-tropical China,where the East Asian Monsoon is *** the new fossils and previously reported fossil remains of plants and fishes,it can be inferred that the Early Oligocene Qaidam Basin was primarily influenced by westerly circulation and had a relatively warm and humid climate,which was in sharp contrast to the present-day climate in Qaidam Basin.

关键词： biostratigraphy climate change winged-fruit fossil Qaidam Basin Early Oligocene paleoclimate paleogeography

Competitive oxidation behavior of Ni-based superalloy GH4738 at extreme temperature

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International Journal of Minerals,Metallurgy and Materials 2024年第1期31卷 138-145页

作者： Hui xu Shufeng Yang Enhui Wang Yunsong Liu Chunyu Guo Xinmei hou Yanling Zhang State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China Institute for carbon neutrality University of Science and Technology BeijingBeijing 100083China

A high thrust-to-weight ratio poses challenges to the high-temperature performance of Ni-based superalloys. The oxidation behavior of GH4738 at extreme temperatures has been investigated by isothermal and non-isothermal experiments. As a result of the competitive diffusion of alloying elements, the oxide scale included an outermost porous oxide layer (OOL), an inner relatively dense oxide layer (IOL), and an internal oxide zone (IOZ), depending on the temperature and time. A high temperature led to the formation of large voids at the IOL/IOZ interface. At 1200℃, the continuity of the Cr-rich oxide layer in the IOL was destroyed, and thus, spallation occurred. Extension of oxidation time contributed to the size of Al-rich oxide particles with the increase in the IOZ. Based on this finding,the oxidation kinetics of GH4738 was discussed, and the corresponding oxidation behavior at 900-1100℃ was predicted.

关键词： Ni-based superalloy GH4738 extreme temperature competitive oxidation oxidation mechanism oxidation kinetics

Microfluidic-based isolation of circulating tumor cells with high-efficiency and high-purity

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Chinese Chemical Letters 2024年第8期35卷 101-111页

作者： Feng Wu xuemin Kong Yixuan Liu Shuli Wang Zhong Chen xu hou Fujian Engineering Research Center for Solid-State Lighting Department of Electronic ScienceSchool of Electronic Science and EngineeringXiamen UniversityXiamen 361005China College of Physics and New Energy Xuzhou University of TechnologyXuzhou 221018China State Key Laboratory of Physical Chemistry of Solid Surfaces College of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005China College of Physical Science and Technology Xiamen UniversityXiamen 361005China Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province(IKKEM) Xiamen 361102China

The isolation of circulating tumor cells(CTCs)from complex biological samples is of paramount signifi-cance for advancing cancer diagnosis,prognosis,and ***,the low concentration of CTCs and nonspecific adhesion of white blood cells(WBCs)present challenges that hinder the efficiency and purity of captured ***-based strategies utilize precise fluid control at the micron level to incorporate specific micro/nanostructures or recognition molecules,enabling effective CTCs ***,by employing surface modification designs that exhibit exceptional anti-adhesion properties against WBCs,the purity of isolated CTCs can be further *** review offers an in-depth explo-ration of recent advancements,challenges,and opportunities associated with microfluidic-based CTCs iso-lation from biological ***,we will comprehensively introduce the microfluidic-based strate-gies for achieving high-efficiency CTCs isolation,which includes the morphological design of microchan-nels for physical force-based CTCs isolation and the specific modification of microchannel surfaces for affinity-based CTCs ***,a review of recent research advances in microfluidic-based high-purity CTCs isolation is presented,focusing on strategies that decrease the nonspecific adhesion of WBCs through surface micro-/nanostructure construction or chemical and biological ***,we will summarize the article by providing the prospective opportunities and challenges for the future development of microfluidic-based CTCs isolation.

关键词： Microfluidics Isolation Circulating tumor cells High-efficiency High-purity

A homing rescue gene drive with multiplexed gRNAs reaches high frequency in cage populations but generates functional resistance

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Journal of Genetics and Genomics 2024年第8期51卷 836-843页

作者： Shibo hou Jingheng Chen Ruobing Feng xuejiao xu Nan Liang Jackson Champer Center for Bioinformatics Center for Life SciencesSchool of Life SciencesPeking UniversityBeijing 100871China

CRISPR homing gene drives have considerable potential for managing populations of medically and agriculturally significant *** operate by Cas9 cleavage followed by homology-directed repair,copying the drive allele to the wild-type chromosome and thus increasing in frequency and spreading throughout a ***,resistance alleles formed by end-joining repair pose a significant *** address this,we create a homing drive targeting the essential hairy gene in Drosophila *** resistance alleles are recessive lethal,while drive carriers have a recoded“rescue”version of *** drive inheritance rate is moderate,and multigenerational cage studies show drive spread to 96%–97%of the ***,the drive does not reach 100%due to the formation of functional resistance alleles despite using four *** alleles have a large deletion but likely utilize an alternate start ***,revised designs targeting more essential regions of a gene may be necessary to avoid such functional *** of the rescue element’s native 3'UTR with a homolog from another species increases drive inheritance by 13%–24%.This was possibly because of reduced homology between the rescue element and surrounding genomic DNA,which could also be an important design consideration for rescue gene drives.

关键词： Genedrive Homing drive Rescueelement Population modification Multiplexed gRNAs Resistance alleles Cage study

Divergent defluorocarboxylation of α-CF_(3) alkenes with formate via photocatalyzed selective mono-or triple C-F bond cleavage

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Science China Chemistry 2024年第1期67卷 368-373页

作者： Xing-Yu Wang Pei xu Wen-Wen Liu Hao-qiang Jiang Song-Lei Zhu Dong Guo xu Zhu Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy School of PharmacyXuzhou Medical UniversityXuzhou 22100China

Unprecedented divergent synthesis of gem-difluorovinylacetic acid and glutaric acid derivatives fromα-CF_(3)alkenes with formate as the carbonyl source was *** reaction can undergo selective mono-or triple C-F bond cleavage by simply switching the photocatalyst and hydrogen atom transfer(HAT)catalyst under visible-light-induced conditions at room *** acts as both the C1 source and the reductant through the generation of CO_(2)^(·-)species,which underwent Giese radical addition to electron-deficient alkenes to trigger the consecutive C-F bond cleavage and carboxylation process.

关键词： C-F bond activation defluorocarboxylation carbon dioxide radical anion visible light