The magnetic anisotropy of Fe 25 Ni 75 nanocrystallites in the range of 10～20 nm was measured by the law of approach to saturation. The samples were prepared by mechanical alloying process, and the average ...The magnetic anisotropy of Fe 25 Ni 75 nanocrystallites in the range of 10～20 nm was measured by the law of approach to saturation. The samples were prepared by mechanical alloying process, and the average crystal size was determined by X ray diffraction. The effective magnetic anisotropy of these fine particles is found in an order of 10 6 erg/cm 3 that is much greater than that of normal crystal size of particles. The dependence of magnetic anisotropy on the particle size was studied. It has been demonstrated that the strain anisotropy occupies the most of the total magnetic anisotropy, and the internal strain is a critical factor for their magnetic properties.展开更多
Fe 100- x Ni x alloys of ultrafine particle with the average grain size of about 10 nm were synthesized by mechanically alloying process. The samples were investigated by X ray diffraction and measure...Fe 100- x Ni x alloys of ultrafine particle with the average grain size of about 10 nm were synthesized by mechanically alloying process. The samples were investigated by X ray diffraction and measurements of the saturation magnetization and coercivity force. Both b.c.c and f.c.c phase exist within a wide range for Fe 100- x Ni x , while x ≤45. The effective magnetic anisotropy K e was measured by applying the law of approach to saturation. The value of K e decreases with an increase of Ni content. It is noticed that the strain anisotropy makes a large contribution to the magnetic anisotropy. The estimation of grain size leads to the determination of the single domain critical size and domain wall energy. The exchange stiffness and exchange integral deduced from the relationship between the effective magnetic anisotropy and domain wall energy are in agreement with that calculated by other methods.展开更多
Objective:To explore the detection and clinical significance of immune function, inflammatory factors and ESR levels in children with Mycoplasma pneumoniae infection.Methods: A total of 122 children with Mycoplasma pn...Objective:To explore the detection and clinical significance of immune function, inflammatory factors and ESR levels in children with Mycoplasma pneumoniae infection.Methods: A total of 122 children with Mycoplasma pneumoniae from September 2015 to February 2017 were selected as the observation group, while 120 healthy children were selected as the control group. The differences of immunoglobulin, T lymphocyte subsets, inflammatory factors and erythrocyte sedimentation rate (ESR) were compared in the two groups, and the correlation between ESR and inflammatory factors was analyzed.Results: There was a significant difference in peripheral blood T lymphocyte level between the two groups;CD3+, CD4+ and CD4+/CD8+ in the observation group were significantly lower than those in the control group, while CD8+ was significantly higher in the observation group than in the control group. The IgA of the observation group was significantly lower than that of the control group, and there was no significant difference between IgG and the control group, and IgM was significantly higher than that of the control group. The two groups of hypersensitive C reactive protein (hs-CRP), tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ) and ESR expression level were significant differences;the hs-CRP, TNF-α, IFN-γ and ESR in the observation group were significantly higher than those in the control group;the ESR of the children with mycoplasma pneumonia was positively correlated with the level of hs-CRP, TNF-α and IFN-γ, which was statistically significant.Conclusions:The cell immunity, humoral immune function of children with Mycoplasma pneumoniae infection are relatively low, and the inflammatory reaction is more severe, and the inflammatory factors of the body are positively related to the level of ESR expression.展开更多
Magnetoelastic couplings in giant magnetostrictive materials(GMMs)attract significant interests due to their extensive applications in the fields of spintronics and energy harvesting devices.Understanding the role of ...Magnetoelastic couplings in giant magnetostrictive materials(GMMs)attract significant interests due to their extensive applications in the fields of spintronics and energy harvesting devices.Understanding the role of the selection of materials and the response to external fields is essential for attaining desired functionality of a GMM.Herein,machine learning(ML)models are conducted to predict saturation magnetostrictions(λ_(s))in RFe_(2)-type(R=rare earth)GMMs with different compositions.According to ML-predicted composition–λsrelations,it is discovered that the values ofλshigher than1100×10^(-6)are almost situated in the composition space surrounded by 0.26≤x≤0.60 and 1.90≤y≤2.00 for the ternary compounds of Tb_(x)Dy_(1-x)Fe_(y).Assisted by ML predictions,the compositions are further narrowed down to the space surrounded by 0.26≤x≤0.32 and 1.92≤y≤1.97 for the excellent piezomagnetic(PM)performance in the Tb_(x)Dy_(1-x)Fe_(y)based PM device through our developed high-throughput(HTP)micromagnetic simulation(MMS)algorithm.Accordingly,high sensitivities up to10.22-13.61 m T·MPa^(-1)are observed in the optimized range within which the available experimental data fall well.This work not only provides valuable insights toward understanding the mechanism of magnetoelastic couplings,but also paves the way for designing and optimizing highperformance magnetostrictive materials and PM sensing devices.展开更多
Rare earth giant magnetostrictive materials(GMMs)Tb_(1-x)Dy_(x)Fe_(2±δ)(Tb-Dy-Fe)have been successfully employed in many microelectromechanical devices due to their excellent magnetostrictive properties at room ...Rare earth giant magnetostrictive materials(GMMs)Tb_(1-x)Dy_(x)Fe_(2±δ)(Tb-Dy-Fe)have been successfully employed in many microelectromechanical devices due to their excellent magnetostrictive properties at room temperature.However,Tb-Dy-Fe still shows a relatively large coercivity with high hysteresis,which inevitably limits its application range.Herein,micromagnetic simulations are performed to investigate the size effect of precipitated phase(α-Fe)on coercivity in Tb-Dy-Fe.Simulation results demonstrate that the coercivity is reduced from 31.46 to 12.48 mT with increasing the size ofα-Fe from 4 to 50 nm in Tb-Dy-Fe since the precipitated phase ofα-Fe can act as a magnetization reversal nucleus.This decreasing trend of coercivity can be well fitted with an inverse square relationship,which agrees well with the nucleation theory.Our study highlights that the coercivity of Tb-Dy-Fe can be tailored by tuning the size ofα-Fe precipitation.展开更多
The barocaloric effect(BCE)is a promising alternative to traditional vapor compressing refrigeration because of its environmentally friendly impact and high energy efficiency.However,the driving hydrostatic pressure f...The barocaloric effect(BCE)is a promising alternative to traditional vapor compressing refrigeration because of its environmentally friendly impact and high energy efficiency.However,the driving hydrostatic pressure for most BCE materials is relatively high,which is not conducive to practical application.In this paper,we report that the large barocaloric entropy change of MnAs_(0.94)Sb_(0.06)alloy can be induced by low hydrostatic pressures.Its phase transition temperature is strongly sensitive to the applied pressure,resulting in a large barocaloric coefficient of 134 K·GPa^(-1)on cooling and 126 K·GPa^(-1)on heating.The maximum barocaloric entropy change and adiabatic temperaturechange resulted from hydrostatic pressure of 40 MPa reach up to 26.3 J·kg^(-1)·K^(-1)and 14.4 K,respectively,showing an excellent barocaloric performance.The results demonstrate that the MnAs_(0.94)Sb_(0.06)alloy is a promising alternative for BCE refrigeration.展开更多
文摘The magnetic anisotropy of Fe 25 Ni 75 nanocrystallites in the range of 10～20 nm was measured by the law of approach to saturation. The samples were prepared by mechanical alloying process, and the average crystal size was determined by X ray diffraction. The effective magnetic anisotropy of these fine particles is found in an order of 10 6 erg/cm 3 that is much greater than that of normal crystal size of particles. The dependence of magnetic anisotropy on the particle size was studied. It has been demonstrated that the strain anisotropy occupies the most of the total magnetic anisotropy, and the internal strain is a critical factor for their magnetic properties.
文摘Fe 100- x Ni x alloys of ultrafine particle with the average grain size of about 10 nm were synthesized by mechanically alloying process. The samples were investigated by X ray diffraction and measurements of the saturation magnetization and coercivity force. Both b.c.c and f.c.c phase exist within a wide range for Fe 100- x Ni x , while x ≤45. The effective magnetic anisotropy K e was measured by applying the law of approach to saturation. The value of K e decreases with an increase of Ni content. It is noticed that the strain anisotropy makes a large contribution to the magnetic anisotropy. The estimation of grain size leads to the determination of the single domain critical size and domain wall energy. The exchange stiffness and exchange integral deduced from the relationship between the effective magnetic anisotropy and domain wall energy are in agreement with that calculated by other methods.
文摘Objective:To explore the detection and clinical significance of immune function, inflammatory factors and ESR levels in children with Mycoplasma pneumoniae infection.Methods: A total of 122 children with Mycoplasma pneumoniae from September 2015 to February 2017 were selected as the observation group, while 120 healthy children were selected as the control group. The differences of immunoglobulin, T lymphocyte subsets, inflammatory factors and erythrocyte sedimentation rate (ESR) were compared in the two groups, and the correlation between ESR and inflammatory factors was analyzed.Results: There was a significant difference in peripheral blood T lymphocyte level between the two groups;CD3+, CD4+ and CD4+/CD8+ in the observation group were significantly lower than those in the control group, while CD8+ was significantly higher in the observation group than in the control group. The IgA of the observation group was significantly lower than that of the control group, and there was no significant difference between IgG and the control group, and IgM was significantly higher than that of the control group. The two groups of hypersensitive C reactive protein (hs-CRP), tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ) and ESR expression level were significant differences;the hs-CRP, TNF-α, IFN-γ and ESR in the observation group were significantly higher than those in the control group;the ESR of the children with mycoplasma pneumonia was positively correlated with the level of hs-CRP, TNF-α and IFN-γ, which was statistically significant.Conclusions:The cell immunity, humoral immune function of children with Mycoplasma pneumoniae infection are relatively low, and the inflammatory reaction is more severe, and the inflammatory factors of the body are positively related to the level of ESR expression.
基金financially supported by the National Key R&D Program of China(No.2021YFB3501401)the National Natural Science Foundation of China(Nos.52001103,U22A20117)Zhejiang Provincial Natural Science Foundation of China(No.LQ21E010001)。
文摘Magnetoelastic couplings in giant magnetostrictive materials(GMMs)attract significant interests due to their extensive applications in the fields of spintronics and energy harvesting devices.Understanding the role of the selection of materials and the response to external fields is essential for attaining desired functionality of a GMM.Herein,machine learning(ML)models are conducted to predict saturation magnetostrictions(λ_(s))in RFe_(2)-type(R=rare earth)GMMs with different compositions.According to ML-predicted composition–λsrelations,it is discovered that the values ofλshigher than1100×10^(-6)are almost situated in the composition space surrounded by 0.26≤x≤0.60 and 1.90≤y≤2.00 for the ternary compounds of Tb_(x)Dy_(1-x)Fe_(y).Assisted by ML predictions,the compositions are further narrowed down to the space surrounded by 0.26≤x≤0.32 and 1.92≤y≤1.97 for the excellent piezomagnetic(PM)performance in the Tb_(x)Dy_(1-x)Fe_(y)based PM device through our developed high-throughput(HTP)micromagnetic simulation(MMS)algorithm.Accordingly,high sensitivities up to10.22-13.61 m T·MPa^(-1)are observed in the optimized range within which the available experimental data fall well.This work not only provides valuable insights toward understanding the mechanism of magnetoelastic couplings,but also paves the way for designing and optimizing highperformance magnetostrictive materials and PM sensing devices.
基金financially supported by the National Key R&D Program of China(No.2021YFB3501401)the National Natural Science Foundation of China(No.52001103)+1 种基金Zhejiang Provincial Natural Science Foundation of China(No.LQ21E010001)the Ten Thousand Talents Plan of Zhejiang Province of China(No.2019R52014)。
文摘Rare earth giant magnetostrictive materials(GMMs)Tb_(1-x)Dy_(x)Fe_(2±δ)(Tb-Dy-Fe)have been successfully employed in many microelectromechanical devices due to their excellent magnetostrictive properties at room temperature.However,Tb-Dy-Fe still shows a relatively large coercivity with high hysteresis,which inevitably limits its application range.Herein,micromagnetic simulations are performed to investigate the size effect of precipitated phase(α-Fe)on coercivity in Tb-Dy-Fe.Simulation results demonstrate that the coercivity is reduced from 31.46 to 12.48 mT with increasing the size ofα-Fe from 4 to 50 nm in Tb-Dy-Fe since the precipitated phase ofα-Fe can act as a magnetization reversal nucleus.This decreasing trend of coercivity can be well fitted with an inverse square relationship,which agrees well with the nucleation theory.Our study highlights that the coercivity of Tb-Dy-Fe can be tailored by tuning the size ofα-Fe precipitation.
基金financially supported by the National Natural Science Foundation of China (No.U22A20117)the National Natural Science Foundation of China (No.52271175)。
文摘The barocaloric effect(BCE)is a promising alternative to traditional vapor compressing refrigeration because of its environmentally friendly impact and high energy efficiency.However,the driving hydrostatic pressure for most BCE materials is relatively high,which is not conducive to practical application.In this paper,we report that the large barocaloric entropy change of MnAs_(0.94)Sb_(0.06)alloy can be induced by low hydrostatic pressures.Its phase transition temperature is strongly sensitive to the applied pressure,resulting in a large barocaloric coefficient of 134 K·GPa^(-1)on cooling and 126 K·GPa^(-1)on heating.The maximum barocaloric entropy change and adiabatic temperaturechange resulted from hydrostatic pressure of 40 MPa reach up to 26.3 J·kg^(-1)·K^(-1)and 14.4 K,respectively,showing an excellent barocaloric performance.The results demonstrate that the MnAs_(0.94)Sb_(0.06)alloy is a promising alternative for BCE refrigeration.
