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Effect of Equal Channel Angular Extrusion on the Microstructures and Properties of Two Extruded Al-Mg-Si Alloys

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Journal of Materials Science & Technology 2005年第5期21卷 623-629页

作者： g.w.lorimer School of Materials The University of ManchesterGrosvenor StreetMl 7HS ManchesterUK

The effect of equal channel angular extrusion （ECAE） on the microstructure of two Al-Mg-Si extrusion alloys was investigated by high resolution electron backscattered diffraction （EBSD） using a field emission gun scanning electron microscope （FEg-SEM） and a transmission electron microscope （TEM）. Two contrasting alloys： a dilute alloy, based on alloy 6061 and a concentrated alloy, based on alloy 6069 were employed for this research. It has been found that prior ECAE to extrusion promotes high angle grain boundaries （HAgBs） in the extrusions, and the increase in HAgBs ratio is due to the large shear deformation involved in the process of ECAE. Tensile testing results show that a further ageing treatment strengthens the alloys after extrusion and the ECAE processed extrusions are more ductile than conventional extrusions.

关键词： Equal channel angular extrusion Electron backscattered diffraction Al-Mg-Si alloys

AN ANALYSIS OF SUBgRID-RESOLVED SCALE INTERACTIONS wITH USE OF RESULTS FROM DIRECT NUMERICAL SIMULATIONS

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Acta Mechanica Sinica 1999年第2期15卷 108-115页

作者： H. gong S. Chen g.w. He Environment Safety and Health Division and Center for Nonlinear Studies Los Alamos National Laboratory Los Alamos NM 87545 USA LNM Institute of Mechanics Chinese Academy of Sciences Beijing 100080 China

Subgrid nonlinear interaction and energy transfer are analyzed using direct numerical simulations of isotropic turbulence. Influences of cutoff wave number at different ranges of scale on the energetics and dynamics have been investigated. It is observed that subgrid-subgrid interaction dominates the turbulent dynamics when cut-off wave number locates in the energy-containing range while resolved-subgrid interaction dominates if it is in the dissipation range. By decomposing the subgrid energy transfer and nonlinear interaction into ‘forward’ and ‘backward’ groups according to the sign of triadic interaction, we find that individually each group has very large contribution, but the net of them is much smaller, implying that tremendous cancellation happens between these two groups.

关键词： subgrid nonlinear interaction energy transfer large eddy simulation (LES) subgrid scale (SgS) direct numerical simulation isotropic turbulence

PARAMAgNETIC MEISSNER EFFECTS IN MELT-TEXTURED Y_(0.99)Nd_(0.01)Ba_2Cu_3O_(7-y)SUPERCONDUCTOR

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Acta Metallurgica Sinica(English Letters) 2002年第3期15卷 295-298页

作者： Y.T. Xing Y.Z. wang g.w. Qiao Institute of Metal Research The Chinese Academy of Sciences Shenyang 110016 China

The paramagnetic Meissner effect (PME) was observed on the field-cooled M-T curves of melt-textured Y0.99Nd0.01Ba2Cu3O7-y in applied magnetic fields from 1kOe to 40kOe. In the magnetic field below 1kOe, the sample undergoes the typical transition from the normal state to the superconducting state when it was cooled down. The applied magnetic fields in which the PME occurs, are very high compared with the fields reported in literatures. we propose that the occurrence of the PME may be due to a phase transition of flux vortices in the superconductors.

关键词： YBCO superconductor paramagnetic Meissner effect (PME)

RESEARCH ON THE FORMATION MECHANISM OF INTERNAL CRACK IN THE CONTINUOUS CASTINg SLAB

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Acta Metallurgica Sinica(English Letters) 2007年第1期20卷 35-39页

作者： g.w. Chang g.C. Jin S.Y. Chen X.D. Yue Department of Materials ＆ Chemical Engineering Liaoning Institute of Technology Jinzhou 121000 China

In view of the periodic bending deformation of solid-liquid interface in the solidification process for continuous casting slab, the variation of temperature gradient and dendritic spacing in the front edge of the solid-liquid interface, and the nucleation and propagation process of crack were studied. It is shown that the bending deformation of the interface results in the temperature field change in the front edge of solid-liquid interface, and the occurrence of temperature gradient along drawing direction results in the growth of secondary dendrites. The initial crack formed during the middle and final stage of solidification may extend to the surface of the casting slab and become an internal crack. The results of the theoretical analysis are basically in agreement with that of the experiment.

关键词： continuous casting dendritic spacing internal crack

RESEARCH OF THE FEEDINg SPEED ADOPTINg CORED-wIRE METHOD TO SPHEROIDIZE DUCTILE IRON MELT

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Acta Metallurgica Sinica(English Letters) 2008年第5期21卷 362-368页

作者： g.w. Chang H.X. wang X.D. Yue H.L. Zhang School of Materials and Chemical Engineering Liaoning University of Technology Jinzhou 121001 China Mechanical and Electronic Engineering Department West Anhui University Liu＇an 237012 China Baotou wen Xin Industry Limited Company Baotou 014000 China Manuscript received 29 August 2007

For settling the question of feeding speed in applying the cored-wire method to spheroidize ductile iron melt, ANSYS software was applied to simulate the heat transfer and mass transfer, and the melt time of the steel strip in the iron melt was determined by linking the heat transfer and mass transfer, and then the feeding speed was calcufated. Conclusions have been drawn that the iron layer was formed on the surface of the cored-wire during the wire-feeding process. The thickness is 0.073 mm when the temperature of the iron melt is 1500℃, the time from formation to remelting of the iron layer is 0.063 s. when the temperature of the iron melt is below 1500℃, the time taken for the steel strip to melt is rapidly shortened. when the temperature of the iron melt is above 1500℃, the variation amplitude of the steel strip melt change with time is gradually diminished. The melt time of the steel strip is rapidly increased with the increase of the steel strip thickness. when the temperature of the iron melt is 1500℃ and the carbon content is 4%, the melt time of a steel strip, which has a thickness of 0.5 mm, is thrice that of a steel strip whose thickness is 0.3 mm. The calculation results of the feeding speed are basically in agreement with the applied feeding speed in the factory.

关键词： Ductile iron Spheroidize Feeding speed Numerical simulation

A novel method for clustering cellular data to improve classification

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Neural Regeneration Research 2025年第9期20卷 2697-2705页

作者： Diek w.wheeler giorgio A.Ascoli Center for Neural Informatics Structures&PlasticityKrasnow Institute for Advanced Study Bioengineering Department Volgenau School of Engineering george Mason University FairfaxVAUSA

Many fields,such as neuroscience,are experiencing the vast prolife ration of cellular data,underscoring the need fo r organizing and interpreting large datasets.A popular approach partitions data into manageable subsets via hierarchical clustering,but objective methods to determine the appropriate classification granularity are *** recently introduced a technique to systematically identify when to stop subdividing clusters based on the fundamental principle that cells must differ more between than within *** we present the corresponding protocol to classify cellular datasets by combining datadriven unsupervised hierarchical clustering.w.th statistical *** general-purpose functions are applicable to any cellular dataset that can be organized as two-dimensional matrices of numerical values,including molecula r,physiological,and anatomical *** demonstrate the protocol using cellular data from the Janelia MouseLight project to chara cterize morphological aspects of neurons.

关键词： cellular data clustering dendrogram data classification Levene's one-tailed statistical test unsupervised hierarchical clustering

genistein:a possible solution for the treatment of Alzheimer’s disease

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Neural Regeneration Research 2025年第10期20卷 2903-2905页

作者： Karolina Pierzynowska Bartosz Karaszewski grzegorz węgrzyn Department of Molecular Biology University of GdanskGdanskPoland gdansk Polandand Department of Adult NeurologyFaculty of MedicineMedical University of GdanskGdanskPoland

Neurodegenerative diseases are defined as disorders resulting from the slow and progressive loss of function and eventual death of neural cells that result from the primary pathology of nervous *** can lead to severe nervous system dysfunction,eventually affecting multiple organs and *** hundred neurodegenerative diseases have been described,and owing to their prevalence,severity.

关键词： organs Alzheimer death

Stepping up after spinal cord injury:negotiating an obstacle during.w.lking

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Neural Regeneration Research 2025年第7期20卷 1919-1929页

作者： Alain Frigon Charly g.Lecomte Department of Pharmacology-Physiology Faculty of Medicine and Health SciencesUniversitéde SherbrookeCentre de recherche du Centre Hospitalier Universitaire de SherbrookeSherbrookeQCCanada

Every day walking consists of frequent voluntary modifications in the gait pattern to negotiate *** spinal cord injury,stepping over an obstacle becomes *** over an obstacle requires sensorimotor transformations in several structures of the brain,including the parietal cortex,premotor cortex,and motor *** information and planning are transformed into motor commands,which are sent from the motor cortex to spinal neuronal circuits to alter limb trajectory,coordinate the limbs,and maintain *** spinal cord injury,bidirectional communication between the brain and spinal cord is disrupted and animals,including humans,fail to voluntarily modify limb trajectory to step over an ***,in this review,we discuss the neuromechanical control of stepping over an obstacle,why it fails after spinal cord injury,and how it recovers to a certain extent.

关键词： biomechanics locomotion neurophysiology obstacle negotiation spinal cord injury

glia-to-neuron reprogramming to the rescue?

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Neural Regeneration Research 2025年第5期20卷 1395-1396页

作者： Jack w.Hickmott Cindi M.Morshead Department of Surgery University of TorontoTorontoONCanada Donnelly Centre for Cellular and Biomolecular Research TorontoONCanada Institute of Biomedical Engineering University of TorontoTorontoONCanada The KITE Research Institute Toronto Rehabilitation InstituteUniversity Health NetworkTorontoONCanada

Over the last two decades,the dogma that cell fate is immutable has been increasingly challenged,with important implications for regenerative *** brea kth rough discovery that induced pluripotent stem cells could be generated from adult mouse fibroblasts is powerful proof that cell fate can be *** exciting extension of the discovery of cell fate impermanence is the direct cellular reprogram ming hypothesis-that terminally differentiated cells can be reprogrammed into other adult cell fates without first passing through a stem cell state.

关键词： programming passing proof