检索结果-南通市图书馆

npj Computational Materials 2022年第1期8卷 1930-1942页

作者： Tianju Xue Zhengtao Gan Shuheng liao jian Cao Department of Mechanical Engineering Northwestern UniversityEvanston60208ILUSA

The phase-field(PF)method is a physics-based computational approach for simulating interfacial *** has been used to model powder melting,rapid solidification,and grain structure evolution in metal additive manufacturing(AM).However,traditional direct numerical simulation(DNS)of the PF method is computationally expensive due to sufficiently small mesh ***,a physics-embedded graph network(PEGN)is proposed to leverage an elegant graph representation of the grain structure and embed the classic PF theory into the graph *** reformulating the classic PF problem as an unsupervised machine learning task on a graph network,PEGN efficiently solves temperature field,liquid/solid phase fraction,and grain orientation variables to minimize a physics-based loss/energy *** approach is at least 50 times faster than DNS in both CPU and GPU implementation while still capturing key physical ***,PEGN allows to simulate large-scale multi-layer and multi-track AM build effectively.

关键词： network additive phase

Two New Bisabolane Sesquiterpenes from Ligularia Thyrsoidea

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 1999年第1期15卷 69-71页

作者： liao jian-chun YANG Li JIA Zhong-jian Department of Chemistry National Laboratory of Applied ChemistryLanzhou UniversityLanzhou730000

ＩｎＣｈｉｎａ，ｍｏｒｅｔｈａｎ２０Ｌｉｇｕｌａｒｉａｓｐｅｃｉｅｓ（Ｃｏｍｐｏｓｉｔａｅ）ｈａｖｅｂｅｅｎｕｓｅｄｆｏｒｆｏｌｋｍｅｄｉｃｉｎｅｓｗｉｔｈａｎｔｉｂｉｏｔｉｃ，ａｎｔｉｐｈｌｏｇｉｓｔｉｃａｎｄａｎ... 详细信息

ＩｎＣｈｉｎａ，ｍｏｒｅｔｈａｎ２０Ｌｉｇｕｌａｒｉａｓｐｅｃｉｅｓ（Ｃｏｍｐｏｓｉｔａｅ）ｈａｖｅｂｅｅｎｕｓｅｄｆｏｒｆｏｌｋｍｅｄｉｃｉｎｅｓｗｉｔｈａｎｔｉｂｉｏｔｉｃ，ａｎｔｉｐｈｌｏｇｉｓｔｉｃａｎｄａｎｔｉｔｕｍｏｒａｃｔｉｖｉｔｉｅｓ...

关键词： Ligularia thyrsoidea Bisabolane Sesquiterpene 2D NMR

High-temperature oxidation behaviour of minor Hf-dopedβ-NiAI single crystals in dry and humid atmospheres

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2023年第8期42卷 2767-2773页

作者： Kai Yan jian He Hong-bo Guo School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100191China State Key Laboratory of Virtual Reality Technology and Systems Beihang UniversityBeijing 100191China School of Energy and Power Engineering Beihang UniversityBeijing 100191China School of Materials Science and Engineering Beihang UniversityBeijing 100191China

Oxidation behaviour of undopedβ-NiAl andβ-NiAl-0.05Hf single crystals were investigated at 1100℃in 20 vol%O_(2)+Ar and 15 vol%H2O+Ar,*** contrary to the well-known beneficial effect of Hf additions on the oxidation behaviour of polycrystallineβ-NiAl,severe-scale spallation is observed forβ-NiAl-0.05Hf single-crystal alloy,especially in dry *** is proposed that the presence of the grain boundaries in the polycrystalline substrate enables proper content of Hf segregating at the grain boundaries of the oxide scale and at the scale-substrate interface,which promotes the conditions required for reactive element *** the reactive element effect of Hf does not work,its strong affinity with oxygen will accelerate the process of high-temperature ***,the absence of the grain boundaries as fast diffusion paths partially compromises the adverse influence of water vapour on cyclic oxidation resistance ofβ-NiAl single crystal,resulting in considerable suppression of the oxidation rate and less loss of protection compared with that in dry *** addition,interfacial cavities are observed in dry and humid atmospheres,which may eventually result in the spallation of the oxide scale.

关键词： Oxidation Reactive element Water vapour β-NiAl Grain boundary

Effect of Si Content on Dynamic Recrystallization of Al-Si-Mg Alloys During Hot Extrusion

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2014年第12期30卷 1271-1277页

作者： Yuna Wu Hengcheng liao jian Yang Kexin Zhou jiangsu Key Laboratory of Advanced Metallic Materials School of Materials Science and Engineering Southeast University

By using electron backscatter diffraction（EBSD） and transmission electron microscopy（TEM）, the effect of Si content on microstructure characteristics of three as-extruded Ale SieM g alloys was investigated. Results showed that the density of coarse Si particles played a critical role in dynamic recrystallization. Dynamic recrystallization rarely occurred in S1 alloy with less Si content; however, it happened in the Si-rich zones in S2 alloy with a medium Si content. And a mature recrystallization was observed in S3 alloy with high Si content. Although deformation was carried out at high temperature, particle-stimulated dynamic recrystallization occurred in Si-rich zones.

关键词： Al-Si-Mg alloys Electron backscatter diffraction(EBSD) Transmission electron microscopy(TEM) Dynamic recrystallization Hot extrusion

Appraising the potential of calcium sulfoaluminate cement-based grouts in simulated permafrost environments

在线全文

学校读者我要写书评

暂无评论

Frontiers of Structural and Civil Engineering 2023年第5期17卷 722-731页

作者： jian ZHAO Guangping HUANG Lin liao Wei Victor LIU Department of Civil and Environmental Engineering University of AlbertaEdmonton T6G 1H9Canada College of Mining Engineering Taiyuan University of TechnologyTaiyuan 030024China

The aim of this study is to appraise the potential of calcium sulfoaluminate(CSA)cement-based grouts in simulated permafrost *** hydration and performance of CSA cement-based grouts cured in cold environments(10,0,and−10℃)are investigated using a combination of tests,including temperature recording,X-ray diffraction(XRD)tests,thermogravimetric analysis(TGA),and unconfined compressive strength(UCS)*** recorded temperature shows a rapid increase in temperature at the early stage in all the ***,results of the TGA and XRD tests show the generation of a significant quantity of hydration products,which indicates the rapid hydration of CSA cement-based grouts at the early stage at low ***,the CSA cement-based grouts exhibit remarkably high early *** UCS values of the samples cured for 2 h at−10,0,and 10℃ are 6.5,12.0,and 12.3 MPa,*** UCS of the grouts cured at−10,0,and 10℃ increases continuously with age and ultimately reached 14.9,19.0,and 30.6 MPa at 28 d,*** findings show that the strength of grouts fabricated using CSA cement can develop rapidly in cold environments,thus rendering them promising for permafrost applications.

关键词： permafrost low temperatures calcium sulfoaluminate cement-based grouts hydration reaction compressive strength

A novel cobalt-free oxide dispersion strengthened medium-entropy alloy with outstanding mechanical properties and irradiation resistance

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21期152卷 190-200页

作者： Ao Fu Bin Liu bo Liu Yuankui Cao jian Wang Tao liao Jia Li Qihong Fang Peter K.Liaw Yong Liu State Key Laboratory of Powder Metallurgy Central South UniversityChangsha 410083China Key Laboratory of Radiation Physics and Technology of Ministry of Education Institute of Nuclear Science and TechnologySichuan UniversityChengdu 610064China State Key Lab of Advanced Design and Manufacturing for Vehicle body Hunan UniversityChangsha 410082China Department of Materials Science and Engineering The University of TennesseeKnoxvilleTN 37996USA

A novel cobalt-free oxide dispersion strengthened(ODS)equiatomic FeCrNi medium entropy alloy(MEA)was successfully fabricated through mechanical alloying and hot extrusion(HE).The ODS FeCrNi MEA is composed of a single face-centered cubic(FCC)matrix,in which highly dispersed oxide nanoparticles,including Y_(2)Ti_(2)O_(7),Y_(2)TiO_(5) and Y_(2)O_(3),are uniformly *** with the FeCrNi MEA,the ODS FeCrNi MEA exhibits the improved yield strength(1120 MPa)and ultimate tensile strength(1274 MPa)with adequate ductility retention(12.1%).Theoretical analysis of the strengthening mechanism indicates that the high strength is mainly attributed to the grain-boundary strengthening caused by fine grains and the precipitation strengthening resulted from the oxide ***,the matrix that easily activates mechanical twinning during the deformation process is the main reason to ensure moderate *** addition,the introduction of high-density oxide nanoparticles can disperse the defect distri-bution and suppress the defect growth and irradiation-induced segregation,leading to the excellent irra-diation *** findings provide innovative guidance for the development of high-performance structural materials for future nuclear energy applications with balanced strength and ductility.

关键词： Medium-entropy alloys Irradiation Oxide nanoparticles Strength Deformation mechanism

Hypersurfaces with Isotropic Para-Blaschke Tensor

维普期刊数据库评论

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 Mathematica Sinica,English Series 2014年第7期30卷 1195-1209页

作者： jian bo FANG Kun ZHANG Department of Mathematics and Statistics Chuxiong Normal University

Let Mn be an n-dimensional submanifold without umbilical points in the （n ＋ 1）-dimen- sional unit sphere Sn＋l. Four basic invariants of Mn under the Moebius transformation group of Sn＋1 are a 1-form Ф called moebius form, a symmetric （0, 2） tensor A called Blaschke tensor, a symmetric （0, 2） tensor B called Moebius second fundamental form and a positive definite （0, 2） tensor g called Moebius metric. A symmetric （0,2） tensor D = A ＋ μB called para-Blaschke tensor, where μ is constant, is also an Moebius invariant. We call the para-Blaschke tensor is isotropic if there exists a function ,λ such that D = λg. One of the basic questions in Moebius geometry is to classify the hypersurfaces with isotropic para-Blaschke tensor. When λ is not constant, all hypersurfaces with isotropic para-Blaschke tensor are explicitly expressed in this paper.

关键词： Moebius geometry para-Blaschke tensor isotropic

3D-QSAR Studies on the Imidazopyrimidine Derivatives

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Structural Chemistry 2020年第11期39卷 1985-1989页

作者： TONG jian-bo CAO Xu Shaanxi Key Laboratory of Chemical Additives for Industry Shaanxi University of Science and TechnologyXi'an 710021China

Comparative molecular field analysis(CoMFA) and comparative molecular similarity indices analysis(CoMSIA) for imidazopyrimidine derivatives were performed to get the molecular active conformation selection, molecular alignment, as well as the establishment of corresponding 3 D-QSAR model. The model established by this method has good ability to predict such compounds. For CoMFA model, the cross-validated q2 and non-cross-validated r2 values are 0.665 and 0.872, respectively. The best q2 value for CoMSIA model is 0.632 and r2 value is 0.923. Using this information and the three-dimensional equipotential map for molecular design can theoretically obtain some new antibacterial drugs with higher activity. There are two newly designed molecules with activity values of 7.921 and 7.872, which are higher than that of the template molecule No. 12 with an activity value of 7.850, and the QSAR research results can provide a theoretical reference for the synthesis of new drugs.

关键词： 3D-QSAR comparative molecular force field analysis molecular design

Characterization of the fracture compressibility and its permeability for shale under the effects of proppant embedment and compaction:A preliminary study

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2022年第3期19卷 1125-1138页

作者： jian-Hua Li bo-bo Li Qiao-Yun Cheng Zheng Gao Guangdong Provincial Key Laboratory of Deep Earth Sciences and Geothermal Energy Exploitation and Utilization Institute of Deep Earth Sciences and Green EnergyCollege of Civil and Transportation EngineeringShenzhen UniversityShenzhen518060GuangdongChina Shenzhen Key Laboratory of Deep Underground Engineering Sciences and Green Energy Shenzhen UniversityShenzhen518060GuangdongChina College of Mining Guizhou UniversityGuiyang550025GuizhouChina Guizhou Key Laboratory of Comprehensive Utilization of Non-metallic Mineral Resources Guiyang550025GuizhouChina National&Local Joint Laboratory of Engineering for Effective Utilization of Regional Mineral Resources from Karst Areas Guizhou UniversityGuiyang550025GuizhouChina

Hydraulic fracturing technology plays a key role in improving the recovery rate of shale *** improvement of permeability in relation to hydraulic fracturing depends on changes brought about by the proppant on the fracture structure in *** it is of great significance to describe the microscopic changes during this process by means of an accurate theoretical *** this study,based on the heterogeneity of shale fracture and the compaction and embedment of a proppant,we proposed a permeability model to examine the combined effects of a proppant and stress to describe the change mechanism in ***,changes in fracture width and porosity were considered,and a calculation model of fracture compressibility under proppant compaction and embedment was *** difference from previous studies is that the compressibility and permeability of supported fractures can be further quantified and analyzed by this ***,its rationality was verified by publicly released test *** results show that,the compressive effect of stress and the embedding of proppant both have a negative impact on shale permeability.

关键词： Shale Fracture compressibility Permeability Hydraulic fracturing Proppant embedment

A Novel 3D Gait Model for Subject Identification Robust against Carrying and Dressing Variations

在线全文

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2024年第7期80卷 235-261页

作者： jian Luo bo Xu Tardi Tjahjadi jian Yi College of Information Science and Engineering Hunan Normal UniversityChangsha410000China School of Engineering University of WarwickCoventryCV47ALUK

Subject identification via the subject’s gait is challenging due to variations in the subject’s carrying and dressing conditions in real-life *** paper proposes a novel targeted 3-dimensional(3D)gait model(3DGait)represented by a set of interpretable 3DGait descriptors based on a 3D parametric body *** 3DGait descriptors are utilised as invariant gait features in the 3DGait recognition method to address object carrying and *** 3DGait recognitionmethod involves 2-dimensional(2D)to 3DGaitdata learningbasedon3Dvirtual samples,a semantic gait parameter estimation Long Short Time Memory(LSTM)network(3D-SGPE-LSTM),a feature fusion deep model based on a multi-set canonical correlation analysis,and SoftMax recognition ***,a sensory experiment based on 3D body shape and pose deformation with 3D virtual dressing is used to fit 3DGait onto the given 2D gait images.3Dinterpretable semantic parameters control the 3D morphing and dressing *** degree measurement determines the semantic descriptors of 2D gait images of subjects with various shapes,poses and ***,using the 2D gait images as input and the subjects’corresponding 3D semantic descriptors as output,an end-to-end 3D-SGPE-LSTM is constructed and ***,body shape,pose and external gait factors(3D-eFactors)are estimated using the 3D-SGPE-LSTM model to create a set of interpretable gait descriptors to represent the 3DGait Model,i.e.,3D intrinsic semantic shape descriptor(3DShape);3D skeleton-based gait pose descriptor(3D-Pose)and 3D dressing with other ***,the 3D-Shape and 3D-Pose descriptors are coupled to a unified pattern space by learning prior knowledge from the *** research on CASIA B,CMU Mobo,TUM GAID and GPJATK databases shows that 3DGait is robust against object carrying and dressing variations,especially under multi-cross variations.

关键词： Gait recognition human identification three-dimensional gait canonical correlation analysis