检索结果-南通市图书馆

Rare-earth-niobate high-entropy ceramic foams with enhanced thermal insulation performance

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Materials Science & technology 2022年第21期116卷 94-102页

作者： R.W.yang y.P.Liang J.Xu X.y.Meng J.t.Zhu S.y.cao M.y.Wei R.X.Zhang J.L.yang F.Gao State Key Laboratory of Solidification Processing MIIT Key Laboratory of Radiation Detection Materials and DevicesSchool of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi’an710072China NPU-QMUL Joint Research Institute of Advanced Materials and Structure Northwestern Polytechnical UniversityXi’an710072China State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and EngineeringTsinghua UniversityBeijing100084China State Key Laboratory of Materials Processing and Die&Mould technology School of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan430074China

the introduction of porous structures into high-entropy ceramics is expected to further improve its thermal insulation performance.In this work,a series of novel rare-earth-niobate high-entropy ceramic foams((Dy_(0.2)Ho_(0.2)y_(0.2)Er_(0.2)yb_(0.2))_(3)NbO_(7))with hierarchical pore structures were prepared by a particle-stabilized foaming method.Atomic-scale analysis reveals that high entropy causes atom displacement and lattice distortion.the high-entropy ceramic foams exhibit high porosity(90.13%-96.13%)and ultralow thermal conductivity(0.0343-0.0592 W/(m·K))at room temperature.High-entropy ceramic foam prepared by a 20 wt%slurry sintered at 1500℃has the porosity of 96.12%and extremely low thermal conductivity of 0.0343 W/(m·K).the existence of walls and secondary pores contributes to reduced thermal conductivity.there is a temperature difference of over 800℃between frontside and backside of the sample under fire resistance test.the research indicates that these as-prepared high-entropy ceramic foams are expected to be promising thermal insulation materials.

关键词： Rare-earth niobate High-entropy ceramic foams Particle-stabilized foaming Atomic-scale analysis thermal conductivity

Biogenesis,action and biological functions of an Arabidopsis 5' t RF,5' ts R-Ala

在线全文

学校读者我要写书评

暂无评论

Science China(Life Sciences) 2022年第5期65卷 1050-1052页

作者： Chunyan Liu Bo cao Xiaofeng cao State Key Laboratory of Plant Genomics and National Center for Plant Gene Research(Beijing) Institute of Genetics and Developmental BiologyChinese Academy of SciencesBeijing 100101China State Key Laboratory of Microbial Metabolism School of Life Sciences&BiotechnologyShanghai Jiao Tong UniversityShanghai 200030China Center for Excellence in Molecular Plant Sciences Chinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China

transfer RNAs(tRNAs) are one class of most conserved and abundant RNA species with 76–90 nucleotides(nt) in length.they constitute approximately 4%–15% of total cellular RNAs and are well known for translating the c... 详细信息

关键词： action translating toll

Early Paleozoic granitic magmatism related to the processes from subduction to collision in South Altyn, NW China

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2015年第8期58卷 1513-1522页

作者： LIU Liang KANG Lei cao yuting yANG WenQiang State Key Laboratory of Continental Dynamics Department of Geology Northwest University Shandong Provincial Key Laboratory of Depositional Mineralization & Sedimentary Minerals College of Earth Science & EngineeringShandong University of Science and Technology

Four episodes of granitic rocks at 517, 501–496, 462–451, and 426–385 Ma occurred in the South Altyn subduction-collision complex. the first episode of granite emplacement predates the formation of the ophiolite type mafic rock(?500 Ma), and the three subsequent episodes can be temporally correlated to high-pressure(HP) to ultrahigh-pressure(UHP) metamorphism at ca. 500 Ma, retrograde granulite-facies metamorphism at ca. 450 Ma, and amphibolite-facies metamorphism at ca. 420 Ma, respectively. A comprehensive study of these granitic rocks, along with the regional geological background, mafic-ultramafic rocks, and HP-UHP metamorphism, indicates that the four episodes of granitic magmatism are sequentially derived from the partial melting of the earlier subducted oceanic crust at 517 Ma, the thickened continental crust due to continental subduction at ca. 500 Ma, the mid-upper crust in response to slab breakoff at ca. 450 Ma, and the tectonic transition from contraction to extension at ca. 420 Ma. the formation age of 517 Ma for oceanic adakite provides a direct constraint on the time of the oceanic subduction in South Altyn. In addition, there is a ca. 10 Myr interval between the oceanic subduction to the continental deep subduction, suggesting that the Early Paleozoic tectonic evolution might have been a successive process in South Altyn. the four episodes of formation of granitic rocks, mafic-ultramafic rocks, and HP-UHP metamorphic rocks have fully recorded the tectonic evolution, beginning with the oceanic subduction, followed by continental subduction, and later exhumation during the Early Paleozoic in South Altyn.

关键词：花岗质岩石大陆俯冲碰撞络合物早古生代岩浆活动阿尔金镁铁质-超镁铁质岩超高压变质作用

同方期刊数据库

Blood vessels in fat tissues and vasculature-derived signals in controlling lipid metabolism and metabolic disease

在线全文

学校读者我要写书评

暂无评论

Chinese Medical Journal 2022年第22期135卷 2647-2652页

作者： yihai cao Department of Microbiology Tumor and Cell BiologyKarolinska Institute17165 StockholmSweden Hong Kong Centre for Cerebro-Cardiovascular Health Engineering Hong KongChina

Metabolic disorders,including endocrine disorders,obesity,diabetes,cerebrocardiovascular disease,and even cancer,are the most common and lethal diseases with the leading all-cause mortality around the globe.[1]For example,according to the World Health Organization,type 2 diabetes mellitus(t2DM)as a chronic disease owing to insulin resistance became the ninth leading cause of death with 1.5 million deaths in 2019.[2]Currently,there are approximately 422 million people worldwide suffering from diabetes,with the majority living in low-and middle-income countries.[3]High t2DM prevalence has been associated with obesity and lifestyle factors such as lack of physical exercise,although genetic factors are linked to a subpopulation of t2DM patients.

关键词： Blood metabolism obesity

富含CXCL13+CD8+t细胞胃癌患者具有不良临床预后和免疫逃逸

在线全文

学校读者我要写书评

暂无评论

中华医学杂志 2022年第12期102卷 888-888页

作者：夏楠(编译) 高毓(编译) 周福祥(编译) Jin K cao y Gu y 武汉大学中南医院不详

胃癌作为一种异质性疾病,具有不同的分子表型和免疫环境,使得患者的临床预后和治疗效果难以预测。近年来,多项研究证明免疫检查点抑制剂(ICIs)用于治疗实体肿瘤非常有效,但胃癌患者免疫治疗的总应答率不到15%。多种因素可能影响免疫治... 详细信息

胃癌作为一种异质性疾病,具有不同的分子表型和免疫环境,使得患者的临床预后和治疗效果难以预测。近年来,多项研究证明免疫检查点抑制剂(ICIs)用于治疗实体肿瘤非常有效,但胃癌患者免疫治疗的总应答率不到15%。多种因素可能影响免疫治疗的反应性,其中CD8+细胞毒性t细胞对肿瘤抗原的反应会发生大量的功能和表型改变从而启动免疫反应,而PD-1等抑制性受体可以抑制这一过程,故ICIs可通过阻断这些抑制性受体使CD8+t细胞介导的免疫恢复活力。趋化因子配体13(CXCL13)作为一种不良的生存预测因子,已在多种恶性肿瘤中得到研究。CXCL13在滤泡辅助t细胞(tFH)中的分泌和生理作用已被较好地描述,但CD8+肿瘤浸润淋巴细胞(tILs)相关的CXCL13的临床意义尚不清楚。

关键词：抑制性受体细胞毒性t细胞胃癌患者异质性疾病实体肿瘤免疫治疗应答率免疫逃逸

thermal stability and deformation mechanisms in Ni-Co-Fe-Cr-Al-ti-Nb-type nanoparticle-strengthened high-entropy alloys

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & technology 2023年第36期167卷 171-183页

作者： J.X.Hou J.y.Zhang J.X.Zhang J.H.Luan y.X.Wang B.X.cao y.L.Zhao Z.B.Jiao X.J.Liu W.W.Song P.K.Liaw t.yang Department of Materials Science and Engineering Hong Kong Institute for Advanced StudyCity University of Hong KongHong KongChina School of Materials Science and Engineering Harbin Institute of Technology(Shenzhen)Shenzhen 518055China Department of Mechanical Engineering The Hong Kong Polytechnic UniversityHong KongChina Steel Institute RWTH Aachen UniversityAachen 52072Germany Institute of Materials Engineering University of KasselKassel 334125Germany Department of Materials Science and Engineering The University of TennesseeKnoxvilleTN 37996-2200USA City University of Hong Kong China

the precipitate morphologies,coarsening kinetics,elemental partitioning behaviors,grain structures,and tensile properties were explored in detail for L1_(2)-strengthened Ni_(39.9)Co_(20)Fe_(15)Cr_(15)Al_(6)ti_(4-x)Nb_(x)B_(0.1)(x=0 at.%,2 at.%,and 4 at.%)high-entropy alloys(HEAs).By substituting ti with Nb,the spheroidal-to-cuboidal precipitate morphological transition,increase in the coarsening kinetics,and phase decomposition upon aging at 800°C occurred.the excessive addition of Nb brings about the grain boundary precipitation of an Nb-rich phase along with the phase decomposition from the L1_(2)to lamellar-structured D019 phase upon the long-term aging duration.By partially substituting ti with Nb,the chemically complex and thermally stable L12 phase with a composition of(Ni_(58.8)Co_(9.8)Fe_(2.7))(Al_(12.7)ti_(5.8)Nb_(7.5)Cr_(2.3))ensures the stable phase structure and clean grain boundaries,which guarantees the superb high-temperature mechanical properties(791±7 MPa for yielding and 1013±11 MPa for failure)at 700℃.Stacking faults(SFs)were observed to prevail during the plastic deformation,offering a high work-hardening capability at 700°C.An anomalous rise in the yield strength at 800℃was found,which could be ascribed to the multi-layered super-partial dislocations with a cross-slip configuration within the L1_(2)particles.

关键词： High-entropy alloys Coarsening kinetics Coherent precipitation strengthening Mechanical properties

Groundwater Recharge and Mixing in Arid and Semiarid Regions:Heihe River Basin,Northwest China

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 2016年第3期90卷 971-987页

作者： cao Guoliang ZHENG Chunmiao Craig t.SIMMONS Institute of Water Sciences Peking UniversityBeijing 100871China School of the Environment&National Centre for Groundwater Research and training Adelaide SA 5001Australia School of Environmental Science and Engineering South University of Science and Technology of ChinaShenzhen 518055China Department of Geological Sciences University ofAlabamaTuscaloosaAlabama 35487USA

A sound understanding of groundwater recharged from various sources occurring at different time scales is crucial for water management in arid and semi-arid river basins. Groundwater recharge sources and their geochemical evolution are investigated for the Heihe River Basin （HRB） in northwest China on the basis of a comprehensive compilation of geochemical and isotopic data. Geochemical mass- balance modeling indicates that mountain-block recharge accounts for a small fraction （generally less than 5%） of the shallow and deep groundwater sustaining the oasis, whereas infiltration of rivers and irrigation water contribute most of the groundwater recharge. Dedolomitization is the primary process responsible for the changes in groundwater chemical and carbon isotope compositions from the piedmont to the groundwater discharge zone, where the dedolomitization is very likely enhanced by modern agricultural activities affecting the shallow groundwater quality. Analysis of radioactive isotopes suggests that these primary recharge sources occur at two different time scales. Radiocarbon-derived groundwater age profiles indicate a recharge rate of approximately 12 mm/year, which probably occurred during 2000-7000 years B.P., corresponding to the mid-Holocene humid period. the recharge of young groundwater on the tritium-dated time scale is much higher, about 360 mm/year in the oasis region. Infiltration from irrigation canals and irrigation return flow are the primary contributors to the increased young groundwater recharge. this study suggests that groundwater chemistry in the HRB has been influenced by the complex interaction between natural and human-induced geochemical processes and that anthropogenic effects have played a more significant role in terms of both groundwater quantity and quality.

关键词： Heihe River Basin groundwater recharge groundwater mixing isotope hydrology

Vibration-induced nanoscale friction modulation on piezoelectric materials

在线全文

学校读者我要写书评

暂无评论

Friction 2022年第10期10卷 1650-1659页

作者： Jiawei cao Qunyang LI Applied Mechanics Laboratory Department of Engineering MechanicsTsinghua UniversityBeijing 100084China State Key Laboratory of tribology Tsinghua UniversityBeijing 100084China

Mechanical vibration,as an alternative of application of solid/liquid lubricants,has been an effective means to modulate friction at the macroscale.Recently,atomic force microscopy(AFM)experiments and model simulations also suggest a similar vibration-induced friction reduction effect for nanoscale contact interfaces,although an additional external vibration source is typically needed to excite the system.Here,by introducing a piezoelectric thin film along the contact interface,we demonstrate that friction measured by a conductive AFM probe can be significantly reduced(more than 70%)when an alternating current(AC)voltage is applied.Such real-time friction modulation is achieved owing to the localized nanoscale vibration originating from the intrinsic inverse piezoelectric effect,and is applicable for various material combinations.Assisted by analysis with the Prandtl–tomlinson(P–t)friction model,our experimental results suggest that there exists an approximately linear correlation between the vibrational amplitude and the relative factor for perturbation of sliding energy corrugation.this work offers a viable strategy for realizing active friction modulation for small-scale interfaces without the need of additional vibration source or global excitation that may adversely impact device functionalities.

关键词： vibration friction modulation piezoelectric materials contact resonance Prandtl-tomlinson(P-t)model

Detecting large-scale underwater cracks based on remote operated vehicle and graph convolutional neural network

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Structural and Civil Engineering 2022年第11期16卷 1378-1396页

作者： Wenxuan cao Junjie LI Faculty of Infrastructure Engineering Dalian University of TechnologyDalian 116024China College of Water Conservancy and Hydropower Engineering Hohai UniversityNanjing 210098China

It is of great significance to quickly detect underwater cracks as they can seriously threaten the safety of underwater structures.Research to date has mainly focused on the detection of above-water-level cracks and hasn’t considered the large scale cracks.In this paper,a large-scale underwater crack examination method is proposed based on image stitching and segmentation.In addition,a purpose of this paper is to design a new convolution method to segment underwater images.An improved As-Projective-As-Possible(APAP)algorithm was designed to extract and stitch keyframes from videos.the graph convolutional neural network(GCN)was used to segment the stitched image.the GCN’s m-IOU is 24.02%higher than Fully convolutional networks(FCN),proving that GCN has great potential of application in image segmentation and underwater image processing.the result shows that the improved APAP algorithm and GCN can adapt to complex underwater environments and perform well in different study areas.

关键词： underwater cracks remote operated vehicle image stitching image segmentation graph convolutional neural network