The grain refinement mechanism and texture evolution of electromagnetically formed polycrystalline Cu sheets were investigated using the electron back-scattered diffraction(EBSD) technique. It is found that the averag...The grain refinement mechanism and texture evolution of electromagnetically formed polycrystalline Cu sheets were investigated using the electron back-scattered diffraction(EBSD) technique. It is found that the average grain size decreases from 35.88 μm to 8.77 μm. The grain refinement was mainly attributed to dynamic recrystallization(DRX) at the grain boundary regions of bulged Cu samples where the inhomogeneous dislocation density and the large lattice misorientation were observed. The DRX mechanisms at the grain boundaries were discussed with respect to the strain-induced grain boundary migration nucleation. Moreover, the orientation distribution function(ODF) of the sample with the strain of 50% demonstrated a strong {110}<211> texture and a relatively weak {001}<100> texture. The texture evolution was discussed using the plastic work values of the grains with various orientations, which were calculated according to the Taylor model and the virtual work principle. The experimental results show that the expended plastic work of the grains with {110} orientation is 9.69 MPa, which is distinctly higher than those of the grains with the {001} and {111} orientations. This indicates that the formation of the {110} orientated texture would be preferred with increasing strain in good agreement with the experimental result.展开更多
proach change of CGRP with time in periodontal ligaments of rats in magnetic field, maxillae of 28 Wistar rats of 6 7 weeks were placed in magnetic fields of permanent magnets Nd 2 Fe 4 B. Changes of CGRP w...proach change of CGRP with time in periodontal ligaments of rats in magnetic field, maxillae of 28 Wistar rats of 6 7 weeks were placed in magnetic fields of permanent magnets Nd 2 Fe 4 B. Changes of CGRP with t ime in maxillary periodontal ligaments of the rats were studied by immunohistochemistry. The result showed that: magnetic field had dynamic effect and some promotional effect on recove?E F F E C T O F M A G N E T I C F I E L D O N C A L C I T O N I N G E N E- R E L A T E D P E P T I D E I N P E R I O D O N T A L L I G A M E N T S O F R A T S X. Chang , K. Qin and Y. L. Lu Orthodontic Department of Stomatology College , China Medical University , Shenyang 110001 , China Manuscript received 24 June 1999 In order to approach change of C G R P with tim e in periodontal liga m ents of rats in m agneticfield , m axillae of 28 Wistar rats of 6 7 weeks w ere placed in m agnetic fields of per m anentm agnets Nd 2 Fe4 B. Changes of C G R P with tim e in m axillary periodontal liga ments of therats were stu died by i m m unohistoche mistry . The result sho wed that : m agnetic field had dy na m ic effect an d so m e pro motional effect on recovering and reconstruction of the periodontaltissues in it . This provided a better theoretical evidence for clinical use of per m anent m agnets .展开更多
Background Traumatic optic neuropathy （TON） is one of the reasons for permanent vision loss.Currently,the clinical practices may not be sufficient for direct assessments and comprehensively determining the location ...Background Traumatic optic neuropathy （TON） is one of the reasons for permanent vision loss.Currently,the clinical practices may not be sufficient for direct assessments and comprehensively determining the location and extent of the patients with optic nerve injury in traumatic optic neuropathy.Magnetic resonance imaging （MRI） provides a non-invasive option.However,rare reports have found whether the differentdegree of injury of the optic nerve can be detected by manganese-enhanced MRI （MEMRI）.This study aimed to explore the efficacy of MEMRI in the visual pathway for different severity of opitic nerve injury in rats.Methods The different injuries of mild,moderate,and heavy damages were created by modified reverse tweezer and were evaluated by counting retinal ganglion cells （RGCs） and VEP ananlysis.Sprague-Dawley （SD） rats were intravitreally injected with 2 I of 25 mmol/L MnCl2,which has been confirmed as a safe injection concentration.The contrast-to-noise ratio （CNR） of MEMRI for optic nerve enhancement at different injury levels was measured.Results The location of the significantly decreased signal point on optic nerve （ON） was corresponding to the location we made.However,similar findings are not obvious,or even have not been observed in 28 days in each group and also in 14 days at F100 group,indicating that MEMRI could be directly intuitive positioned in the early stage on the optic nerve injury.Conclusions The possibility of using MEMRI in optic nerve injury in a safe injection concentration of 25 mmol/L is confirmed.Therefore,it is possible to detect the severity of the optic nerve by MEMRI examination.展开更多
The formula of input impedance of dipole antenna in Gigahertz Transverse ElectroM agnetic(GTEM) cell based on the dyadic Green's function is first obtained in this paper. The validation of the formula is verified ...The formula of input impedance of dipole antenna in Gigahertz Transverse ElectroM agnetic(GTEM) cell based on the dyadic Green's function is first obtained in this paper. The validation of the formula is verified by the results of theoretical derivation and simulation with well agreements. In comparison with the formula of input impedance in free space, the relationship between the change of input impedance with the length of antenna and the position of antenna in GTEM cell is obtained. In addition, some meaningful conclusions are presented, which not only can be referred by the further research of ElectroM agnetic Interference(EMI) measurements in GTEM cell, but also provide the theoretical basis for testing compensation and error analysis.展开更多
基金Funded by the National Fundamental Research Program of China(No.2011CB012806)
文摘The grain refinement mechanism and texture evolution of electromagnetically formed polycrystalline Cu sheets were investigated using the electron back-scattered diffraction(EBSD) technique. It is found that the average grain size decreases from 35.88 μm to 8.77 μm. The grain refinement was mainly attributed to dynamic recrystallization(DRX) at the grain boundary regions of bulged Cu samples where the inhomogeneous dislocation density and the large lattice misorientation were observed. The DRX mechanisms at the grain boundaries were discussed with respect to the strain-induced grain boundary migration nucleation. Moreover, the orientation distribution function(ODF) of the sample with the strain of 50% demonstrated a strong {110}<211> texture and a relatively weak {001}<100> texture. The texture evolution was discussed using the plastic work values of the grains with various orientations, which were calculated according to the Taylor model and the virtual work principle. The experimental results show that the expended plastic work of the grains with {110} orientation is 9.69 MPa, which is distinctly higher than those of the grains with the {001} and {111} orientations. This indicates that the formation of the {110} orientated texture would be preferred with increasing strain in good agreement with the experimental result.
文摘proach change of CGRP with time in periodontal ligaments of rats in magnetic field, maxillae of 28 Wistar rats of 6 7 weeks were placed in magnetic fields of permanent magnets Nd 2 Fe 4 B. Changes of CGRP with t ime in maxillary periodontal ligaments of the rats were studied by immunohistochemistry. The result showed that: magnetic field had dynamic effect and some promotional effect on recove?E F F E C T O F M A G N E T I C F I E L D O N C A L C I T O N I N G E N E- R E L A T E D P E P T I D E I N P E R I O D O N T A L L I G A M E N T S O F R A T S X. Chang , K. Qin and Y. L. Lu Orthodontic Department of Stomatology College , China Medical University , Shenyang 110001 , China Manuscript received 24 June 1999 In order to approach change of C G R P with tim e in periodontal liga m ents of rats in m agneticfield , m axillae of 28 Wistar rats of 6 7 weeks w ere placed in m agnetic fields of per m anentm agnets Nd 2 Fe4 B. Changes of C G R P with tim e in m axillary periodontal liga ments of therats were stu died by i m m unohistoche mistry . The result sho wed that : m agnetic field had dy na m ic effect an d so m e pro motional effect on recovering and reconstruction of the periodontaltissues in it . This provided a better theoretical evidence for clinical use of per m anent m agnets .
文摘Background Traumatic optic neuropathy （TON） is one of the reasons for permanent vision loss.Currently,the clinical practices may not be sufficient for direct assessments and comprehensively determining the location and extent of the patients with optic nerve injury in traumatic optic neuropathy.Magnetic resonance imaging （MRI） provides a non-invasive option.However,rare reports have found whether the differentdegree of injury of the optic nerve can be detected by manganese-enhanced MRI （MEMRI）.This study aimed to explore the efficacy of MEMRI in the visual pathway for different severity of opitic nerve injury in rats.Methods The different injuries of mild,moderate,and heavy damages were created by modified reverse tweezer and were evaluated by counting retinal ganglion cells （RGCs） and VEP ananlysis.Sprague-Dawley （SD） rats were intravitreally injected with 2 I of 25 mmol/L MnCl2,which has been confirmed as a safe injection concentration.The contrast-to-noise ratio （CNR） of MEMRI for optic nerve enhancement at different injury levels was measured.Results The location of the significantly decreased signal point on optic nerve （ON） was corresponding to the location we made.However,similar findings are not obvious,or even have not been observed in 28 days in each group and also in 14 days at F100 group,indicating that MEMRI could be directly intuitive positioned in the early stage on the optic nerve injury.Conclusions The possibility of using MEMRI in optic nerve injury in a safe injection concentration of 25 mmol/L is confirmed.Therefore,it is possible to detect the severity of the optic nerve by MEMRI examination.
基金Supported by Chinese Academy of Sciences(No.Y140110213)
文摘The formula of input impedance of dipole antenna in Gigahertz Transverse ElectroM agnetic(GTEM) cell based on the dyadic Green's function is first obtained in this paper. The validation of the formula is verified by the results of theoretical derivation and simulation with well agreements. In comparison with the formula of input impedance in free space, the relationship between the change of input impedance with the length of antenna and the position of antenna in GTEM cell is obtained. In addition, some meaningful conclusions are presented, which not only can be referred by the further research of ElectroM agnetic Interference(EMI) measurements in GTEM cell, but also provide the theoretical basis for testing compensation and error analysis.
