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Precipitation of multi-type nano-quasicrystals in a Mg-zn-Y alloy

Journal of Magnesium and Alloys 2024年第3期12卷 997-1008页

作者： W.z.Wang X.z.zhou L.f.zhang H.Q.Ye z.Q.yang Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of ScienceShenyang 110016China Ji Hua Laboratory Foshan 528251China foshan University Foshan 528231China

Mg-6zn-1Y(at.%)ribbons with strengthening precipitates of multi-type nanoquasicrystals were prepared by melt-spinning followed by aging *** evolution of the rapidly solidified ribbons during isothermal aging was comprehensively studied using various electron microscopy *** new kinds of decagonal quasicrystals were formed in aged ribbons,in addition to precipitation of nanometer icosahedral ***-resolution observations reveal that both decagonal quasicrystals can be modeled by quasiperiodic tiling with decagonal clusters of 2.5 nm in diameter,but overlap of neighboring clusters in both decagonal quasicrystals is different from the Gummelt model observed in other quasicrystals.A shell composed of complex Laves Mg-zn domains was formed surrounding each decagonal quasicrystal precipitate upon prolonged *** addition,all kinds of nanoprecipitates exhibit excellent structure and size stability at 573 *** findings may have implications for not only fundamental studies about quasicrystals,but also microstructural manipulation of high-performance Mg alloys.

关键词： Quasicrystal Mg alloys Rapid solidification Scanning-transmission electron microscopy.

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Microstructure evolution and shape memory behaviors of Ni_(47)Ti_(44)Nb_(9)alloy subjected to multistep thermomechanical loading with different prestrain levels

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Journal of Materials Science & Technology 2024年第4期171卷 80-93页

作者： Y.H.zhang H.Li z.W.yang X.Liu Q.f.Gu State Key Laboratory of Solidification Processing School of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi’an 710072China Shaanxi Key Laboratory of High-Performance Precision forming Technology and Equipment Northwestern Polytechnical UniversityXi’an 710072China

Ni_(47)Ti_(44)Nb_(9)shape memory alloy(SMA)is a promising material in the aerospace field due to its wide transformation *** application of shape memory effect depends on multistep thermomechan-ical loading,viz.,low-temperature deformation and subsequent heating to ***-temperature deformation prestrain plays a pivotal role in shape memory properties tailoring of SMA ***,microstructure evolution and deformation mechanisms of Ni_(47)Ti_(44)Nb_(9)SMA subjected to vari-ous prestrain levels are still *** this end,microstructure evolution and shape memory behaviors of Ni_(47)Ti_(44)Nb_(9)alloy subjected to multistep thermomechanical loading with prestrain levels of 8%-16%at-28℃(M_(s)+30℃)were *** results demonstrate that the stress-strain curve of the specimen exhibits four distinct stages at a maximal prestrain of 16%.Whereas stageⅡand stageⅢend at prestrains of∼8%and∼12%,*** stageⅡ,the stress-induced martensitic transformation is accompanied by the dislocation slip of the NiTi matrix andβ-Nb *** stageⅢ,in addition to the higher density of dislocations and further growth of stress-induced martensite variants(SIMVs),(001)compound twins are introduced as a result of the(001)deformation twinning in stress-induced ***{20-1}martensite twins are gradually introduced in stageⅣ.Correspondingly,after subsequent unloading and heating,a higher density of{114}austenite twins form in the specimen with a larger prestrain of 16%.With increasing prestrain from 8%to 16%,the recoverable strainε_(re)^(T)upon heating increases first and then ***ε_(re)^(T)obtains a maximum of 7.03%at 10%prestrain and de-creases to 6.17%at 16%*** increase ofε_(re)^(T)can be attributed to the formation of new SIMVs,the further growth of existing SIMVs,and the recoverable(001)compound *** the decrease ofε_(re)^(T)is mainly associated with the irrecoverable strain by{20−1}martensite *** effe

关键词： Ni_(47)Ti_(44)Nb_(9)shape memory alloy Wide transformation hysteresis Thermomechanical loading Microstructure evolution Shape memory behaviors Stress-induced martensitic transformation Deformation twinning

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Scientific discovery of a unique cloud-shaped rock pillar in an ancient quarry in zhejiang Province

Scientific discovery of a unique cloud-shaped rock pillar in...

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中国科学院地质与地球物理研究所2015年度（第15届）...

作者： L.Deng L.H.Li z.f.yang Key Laboratory of Shale Gas and Geoengineering Institute of Geology and GeophysicsChinese Academy of Sciences

In this paper,one unique cloud-shaped nock pillar is discovered in an ancient quarry in zhejiang Province,Textual research indicates that this ancient quarry was initially exploited La Liang Dynasty(502-557 BC}.Geological conditions of the ancient quarry arc elaborated in this *** investigation results indicate that this rock pillar was left during *** reconstruction through the data acquired by 3D laser scanning presents that ii has a complex ***-Dimensional finite difference stimulation using Mohr-Coulomb parameters acquired from back analysis has been conducted to analyze its stress distribution and *** results suggest a maximum stress of1,7 MPa in this pillar,the stress reduces from bottom to top,and from one side to the opposite side of the pillar,and finally the stress exhibits a similar *** displacement in B side reduces from bottom to top,then increases reversely.

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Triggers of rockfall on a slope related to large ancient underground caves cultural heritage(China)

Triggers of rockfall on a slope related to large ancient und...

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中国科学院地质与地球物理研究所2015年度（第15届）...

作者： X.L.Wang L.Q.zhang z.f.yang Key Laboratory of Shale Gas and Geoengineering Institute of Geology and GeophysicsChinese Academy of Sciences

The large underground ancient caves of feifeng Mountain(30,000 m2 China),located at zhejiang Province,eastern of China,were formed by excavating the tuffaceous rocks for building stones in the ancient *** study area lies at the contact between Upper Jurassic and Upper Cretaceous sedimentary *** considering the southern slope of the feifeng Mountain where the ancient caves are located,we observe the presence of a soft muddy-siltstone layer separating different tuffaceous *** thickness of the soft layer is about 15 in,and it plays an important role in the stability of the *** main faults control the structural setting of feifeng Mountain:a thrust-compressional fault,with dip of 70°to 80°and dip direction of 300°;a NW fault,with dip of 75°to 85°and dip direction of 210°;and a EW fault nearest to feifeng *** tectonic structures including tectonic faults and tectonic joints have the similar geometric characteristics at the local and regional ***,the location of rockfall has a strong relationship with the geometric characteristics of tectonic joints at the local *** triggers of the rockfall in the study area include the tectonic structures,special stratum(stuff and thick soft layer),and finally the excavation in ancient time was defined.

关键词： ancient underground caves cultural heritage tectonic structures rockfall

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A Study on Visualized field Distribution of Intensive Microwave field

A Study on Visualized Field Distribution of Intensive Microw...

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2006 7th International Symposium on Antennas, Propagation and EM Theory

作者： G.L.Sun W.X.Li z.f.yang W.J.Liu Department of electronic Information Science and Technology Nankai University

The measurement of the distribution of intensive microwave field based on a new method which is put up by designing a testing container and 'Multi-channeled,Synchronous,Temperature sampling and processing system' in this *** the method,it is possible to describe the distribution of microwave field and achieve the visualization of the distribution of microwave power by use of *** is proved by experiments that this method is feasible and reliable.

关键词： field distribution multi-channeled synchronous temperature sampling MATLAB

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Investigation on the gutters in caverns Nos.1-5 of Longyou Caverns

Investigation on the gutters in caverns Nos.1-5 of Longyou C...

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中国科学院地质与地球物理研究所2015年度（第15届）...

作者： Y.f.Tan L.H.Li W.T.He z.f.yang Y.fu Key Laboratory of Shale Gas and Geoengineering Institute of Geology and GeophysicsChinese Academy of Science Longyou Grottoes Research Institute

Work on groundwater hydraulics is one of the most complicated issues in underground *** an ancient engineering,Longyou rock caverns are famous for the scale,the building technique and the impressive drainage *** to the field study,52 gutters and 6 water traps exist in caverns ***,only one drainage ditch was found in cavern No.2 due to later exploitation in *** paper mainly presents the intention,layout and types of the gutters,whereby the scientific,historical and aesthetic values are acknowledged based on the above *** knowledge achieved from this research could be useful for the design of the modern drainage system in cavern Nos.1-5.

关键词： water proof gutter underground engineering Longyou Caverns

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Roof cracks investigation and cracking mechanism analysis of Niuchang ancient cave in Longyou,Southeast China

Roof cracks investigation and cracking mechanism analysis of...

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中国科学院地质与地球物理研究所2015年度（第15届）...

作者： z.H.Han A.Braun.L.Q.zhang J.zhou z.f.yang G.Chen Y.fu J.zheng Institute of Geology and Geophysics Chinese Academy of Sciences

By means of Three-Dimensional(3D)terrestrial laser scanning and vertical projection,the distribution of roof cracks in Niuchang cave No,1 was investigated and a high-precision 3D geometrical model was established to conduct a fLAC 3D numerical analysis of the roof stress *** simulation results and their theoretical analysis showed that the layering of roof rock mass can increase the tensile stress concentration in the roof and may also affect the quantity and distribution of *** concentration zones of tensile stress on the roof are in accordance with the actual crack *** it is assumed that tensile stress of above 0.35 MPa can activate the *** work can not only provide some knowledge for the roof cracking mechanism and development trend of other ancient caves especially open to the public,but also help to improve the understanding of in-situ rock strength and long-term stability of ancient cases.

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Engineering geological conditions of large ancient quarrying caverns in Shepan Island,zhejiang Province,China

Engineering geological conditions of large ancient quarrying...

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中国科学院地质与地球物理研究所2015年度（第15届）...

作者： L.H.LI X.L.Deng z.f.yang W.D.Sun S.B.Chen P.f.Liu Key Laboratory of Shale Gas and Geoengineering Institute of Geology and GeophysicsChinese Academy of Science China University of Mining and Technology

Shepan Island large ancient underground quarry is located in zhejiang Province,eastern *** a period of 800 years,the island has been experiencing large-scale quarrying activities since the Southern Song Dynasty(AD 1127-1279).Nowadays,many large ancient underground cavern groups have been *** ancient cultural relics,these caverns enjoy a high tourism reputation and other *** present,most of these caverns still maintain their ***,different levels of deformation and failure also occurred in some *** quarrying method,structures of the caverns,structure and quality of the surrounding rock mass were analyzed by using field investigations and laboratory *** on above research results,it is concluded that unique quarrying methods and cavern structures account for the long-term stability of these *** most important factor is the good quality of the rock mass,which implies that a good engineering geological condition is the fundamental reason for the long-term stability of Shepan Island ancient quarry caverns.

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Three-dimensional geological modeling of Longyou grotto No.3 with terrestrial laser scanning

Three-dimensional geological modeling of Longyou grotto No.3...

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中国科学院地质与地球物理研究所2015年度（第15届）...

作者： J.zhou A.Braun L.Q.zhang X.L.Wang R.H.Xiao z.f.yang z.H.Han Key Laboratory of Shale Gas and Geoengineering Institute of Geology and GeophysicsChinese Academy of Sciences University of Chinese Academy of Sciences

Terrestrial laser scanning is a Three-Dimensional(3D)measuring technology that rapidly developed in recent *** this measuring technology users can generate a 3D point cloud,derive the size and geometry of objects rapidly and accurately and build a high resolution 3D surface *** technology is/widely used in many fields,such as geotechnical engineering,surveying and mapping and preservation of cultural *** Longyou grottoes,a group of ancient underground caverns,are a famous sightseeing place in *** a realistic geological model for stability assessment is important in order to develop and protect Longyou grottoes in terms of preserving the cultural relics and safety of the visiting *** cloud data for Longyou grottoes No.1 to 5 have been acquired by a Leica ScanStation 2 and each of the point cloud datasets were joined together with the help of targets organized before *** point cloud data was transformed to another coordinate system to be merged with contour line data of the local *** to a geological survey and the point cloud data,several points in the same bedding planes were extracted in the entrance of cavern No.3,which were used to reconstruct the bedding planes by least square regression method.A detailed model of cavern No.3 was built and a numerical analysis to calculate the tensile stress in the roof was carried *** a comparison was made about whether or not taking the bedding planes into the models of the tensile stress in the *** numerical results show that weak mudstone interlayers have a significant influence on the stress state in the roof of cavern *** decreasing strength of the interlayers,the trend of tensile stress areas enlarging is consistent with the expansion cracks.

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Weathering rates of chisel imprints on politic siltstone inside five Longyou caverns

Weathering rates of chisel imprints on politic siltstone ins...

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中国科学院地质与地球物理研究所2015年度（第15届）...

作者： L.H.LI Y.f.Tan X.L.Deng W.T.He z.f.yang Y.fu E.C.Liu Key Laboratory of Shale Gas and Geoengineering Institute of Geology and GeophysicsChinese Academy of Science

Literature review indicates that the studies on rock weathering and stone decay have been focused on either granite,or limestone,or *** paper presents a case study on the weathering rate of politic *** politic siltstone is the surrounding rock of underground *** caverns had been filled with water for 2000 years and the water in the caverns was pumped out in *** then,the weathering of the surrounding rock has been becoming *** disintegration is the main weathering *** chisel imprints on the inner surface of the surrounding rock were measured by using the mixture of plasticene and some additives in 2004 and2008,*** maximum height difference and fluctuation ratio are adopted as the quantitative indexes to describe the shapes of the chisel *** to the measured results,the weathering rate of the chisel imprints of the pelitic siltstone is *** weathering rate of the surrounding rock is about 0.35 to 1.06 mm/*** measures should be carried out as soon as possible.

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