It is possible to measure different position along the axle direction of tappet. According to the maximum output of signal, the boundary of white iron structure and mottled iron structure can be deduced, and at the sa...It is possible to measure different position along the axle direction of tappet. According to the maximum output of signal, the boundary of white iron structure and mottled iron structure can be deduced, and at the same time, it is possible to use inductance displacement meter to show the chill depth which is the distance from the boundary to the end.展开更多
The combined effects of Sm^(3+)substitution together with the addition of 3 wt%Bi_(2)O_(3)endow Mg Cd ferrites with excellent magnetic permeability and dielectric permittivity.Various concentrations of Sm^(3+)(x=0,0.0...The combined effects of Sm^(3+)substitution together with the addition of 3 wt%Bi_(2)O_(3)endow Mg Cd ferrites with excellent magnetic permeability and dielectric permittivity.Various concentrations of Sm^(3+)(x=0,0.03,0.06,0.09,0.12and 0.15)were employed to modify the permeability(μ)and permittivity(ε)of the Mg Cd ferrites.X-ray diffraction,scanning electron microscopy(SEM),vibrating sample magnetometry and vector network analysis techniques were used to characterize the samples.The measurement results reveal that the ferrites processed a saturation magnetization of up to 36.8 emu/g and coercivity of up to 29.2 Oe via the conventional solid-state reaction method.The surface morphology SEM confirms that with increasing Sm^(3+)concentration,the grain shape changes from a polygon to a circle.Moreover,the dielectric permittivity can reach a value of 23.The excellent properties obtained in Sm^(3+)-substituted Mg ferrites suggest that they could be promising candidates for modern high-frequency antenna substrates or multilayer devices.展开更多
In this study, the essence and origin of the magnetic constant are discussed and a mechanism that allows real estimations of the magnetic constant based upon the vacuum density description is proposed. By considering ...In this study, the essence and origin of the magnetic constant are discussed and a mechanism that allows real estimations of the magnetic constant based upon the vacuum density description is proposed. By considering the vacuum as a liquid with a measurable density and the electron as a vortex, hydrodynamic laws are applied to measure the diminished momentum of a rotating electron in a vacuum, thus obtaining a value similar to the experimentally derived value of the magnetic constant. A consequence of this description is that the magnetic constant can be expressed as the shear stress per unit time of the vacuum;this means that it is an observable vacuum parameter and not a fundamental constant.展开更多
A microwave absorbing sheet with a high complex permeability and a relatively low complex permittivity is obtained by molding of the densely coated flaky carbonyl iron particles(FCIPs)by styrenebutadiene-styrene block...A microwave absorbing sheet with a high complex permeability and a relatively low complex permittivity is obtained by molding of the densely coated flaky carbonyl iron particles(FCIPs)by styrenebutadiene-styrene block copolymer(SBS)in the assistance of coupling agent modification.Direct molding of the core-shell FCIPs without adding extra binder results in a large permeability due to the high filling ratio(55vol%)of absorbents.Importantly,the permittivity is well suppressed by the dense insulate polymer shell on the FCIPs,avoiding the severe impedance mismatch problem of the high filler content microwave absorbing materials.Investigations show that modifying the surface of FCIPs by proper amount of silane coupling agent is critical for the coating quality of the SBS shell,which is verified by resistivity and corrosion current density measurements,and can be interpreted by improved interfacial compatibility between the modified FCIPs and SBS.The obtained microwave absorbing sheet shows a minimum reflection loss of-38.74 dB at 1.57 GHz and has an effective absorption bandwidth from 1.1 to 2.3 GHz at a relatively small thickness of 2 mm.展开更多
Tb0.3Dy0.7Fe1.90 <110> oriented rods were prepared by zone melting with unidirectional solidification.The magnetomechanical coupling factor(k33) was measured by magnetomechanical resonance under different DC bia...Tb0.3Dy0.7Fe1.90 <110> oriented rods were prepared by zone melting with unidirectional solidification.The magnetomechanical coupling factor(k33) was measured by magnetomechanical resonance under different DC bias fields up to 77.4 mT.An effective method was provided to calculate sonic velocity,elastic modulus and compliance constant through measuring resonate frequency(fr),and calculate dynamic magnetostriction(d33) via measuring magnetic permeability,magnetomechanical coupling factor(k33) and compliance constant.Without pre-stress,resonate frequency(fr),sonic velocity and elastic modulus first decreased and then rose with increasing bias magnetic field.Under 10 MPa pre-stress,resonate frequency(fr),sonic velocity and elastic modulus decreased linearly with increasing bias fields.d33 exhibited the same variation trend before and after heat treatment,but heat treatment weakened the decrease of d33 in low field range.展开更多
磁场触发的催化剂轨道电子自旋排列已成为促进析氧反应的一种有趣而可行的策略.然而,具有强d-d库仑相互作用的高熵合金(HEAs)催化剂中的磁场增强机制尚未得到充分挖掘.在此,我们设计了具有优异软磁性的高熵合金金属片,在微小磁场下表现...磁场触发的催化剂轨道电子自旋排列已成为促进析氧反应的一种有趣而可行的策略.然而,具有强d-d库仑相互作用的高熵合金(HEAs)催化剂中的磁场增强机制尚未得到充分挖掘.在此,我们设计了具有优异软磁性的高熵合金金属片,在微小磁场下表现出显著的磁场增强催化作用,其磁导率可作为评估磁场增强的描述因子.具体地,仅施加50 mT的磁场,(FeCoNi)_(82.5)Cr_(17.5)HEAs的过电位下降就超过了36mV@10 mA cm^(-2).此外,过电位的降低与HEA的磁导率呈线性关系.原位拉曼光谱与理论计算结果表明,施加磁场可显著提高自旋密度,改善催化剂的3d电子与*O自由基的2p轨道之间的自旋相互作用,从而有效降低速率决定步骤(*O→*OOH)的能量障碍,进而促进O-O的形成.展开更多
文摘It is possible to measure different position along the axle direction of tappet. According to the maximum output of signal, the boundary of white iron structure and mottled iron structure can be deduced, and at the same time, it is possible to use inductance displacement meter to show the chill depth which is the distance from the boundary to the end.
基金the National Key Research and Development Program of China(Grant No.2018YFE0115500)the National Natural Science Foundation of China(Grant Nos.51902037 and 62005033)+2 种基金the Open Foundation of State Key Laboratory of Electronic Thin Films and Integrated Devices(Grant No.KFJJ201912)the Science and Technology Project Affiliated to the Education Department of Chongqing Municipality(Grant No.KJQN201900615)the Nature Science Foundation of Chongqing(Grant No.cstc2019jcyjmsxm X0696)。
文摘The combined effects of Sm^(3+)substitution together with the addition of 3 wt%Bi_(2)O_(3)endow Mg Cd ferrites with excellent magnetic permeability and dielectric permittivity.Various concentrations of Sm^(3+)(x=0,0.03,0.06,0.09,0.12and 0.15)were employed to modify the permeability(μ)and permittivity(ε)of the Mg Cd ferrites.X-ray diffraction,scanning electron microscopy(SEM),vibrating sample magnetometry and vector network analysis techniques were used to characterize the samples.The measurement results reveal that the ferrites processed a saturation magnetization of up to 36.8 emu/g and coercivity of up to 29.2 Oe via the conventional solid-state reaction method.The surface morphology SEM confirms that with increasing Sm^(3+)concentration,the grain shape changes from a polygon to a circle.Moreover,the dielectric permittivity can reach a value of 23.The excellent properties obtained in Sm^(3+)-substituted Mg ferrites suggest that they could be promising candidates for modern high-frequency antenna substrates or multilayer devices.
文摘In this study, the essence and origin of the magnetic constant are discussed and a mechanism that allows real estimations of the magnetic constant based upon the vacuum density description is proposed. By considering the vacuum as a liquid with a measurable density and the electron as a vortex, hydrodynamic laws are applied to measure the diminished momentum of a rotating electron in a vacuum, thus obtaining a value similar to the experimentally derived value of the magnetic constant. A consequence of this description is that the magnetic constant can be expressed as the shear stress per unit time of the vacuum;this means that it is an observable vacuum parameter and not a fundamental constant.
基金Funded by the Young Top-notch Talent Cultivation Program of Hubei Provincethe National Natural Science Foundation of China(Nos.52071239,51521001)Fundamental Research Funds for the Central Universities(Nos.WUT:2021IVA116 and WUT:2021CG015)。
文摘A microwave absorbing sheet with a high complex permeability and a relatively low complex permittivity is obtained by molding of the densely coated flaky carbonyl iron particles(FCIPs)by styrenebutadiene-styrene block copolymer(SBS)in the assistance of coupling agent modification.Direct molding of the core-shell FCIPs without adding extra binder results in a large permeability due to the high filling ratio(55vol%)of absorbents.Importantly,the permittivity is well suppressed by the dense insulate polymer shell on the FCIPs,avoiding the severe impedance mismatch problem of the high filler content microwave absorbing materials.Investigations show that modifying the surface of FCIPs by proper amount of silane coupling agent is critical for the coating quality of the SBS shell,which is verified by resistivity and corrosion current density measurements,and can be interpreted by improved interfacial compatibility between the modified FCIPs and SBS.The obtained microwave absorbing sheet shows a minimum reflection loss of-38.74 dB at 1.57 GHz and has an effective absorption bandwidth from 1.1 to 2.3 GHz at a relatively small thickness of 2 mm.
基金supported by the New Century Excellent Talents in University (04-0165) the National Natural Science Foundation of China (60534020)
文摘Tb0.3Dy0.7Fe1.90 <110> oriented rods were prepared by zone melting with unidirectional solidification.The magnetomechanical coupling factor(k33) was measured by magnetomechanical resonance under different DC bias fields up to 77.4 mT.An effective method was provided to calculate sonic velocity,elastic modulus and compliance constant through measuring resonate frequency(fr),and calculate dynamic magnetostriction(d33) via measuring magnetic permeability,magnetomechanical coupling factor(k33) and compliance constant.Without pre-stress,resonate frequency(fr),sonic velocity and elastic modulus first decreased and then rose with increasing bias magnetic field.Under 10 MPa pre-stress,resonate frequency(fr),sonic velocity and elastic modulus decreased linearly with increasing bias fields.d33 exhibited the same variation trend before and after heat treatment,but heat treatment weakened the decrease of d33 in low field range.
基金financially supported by the National Natural Science Foundation of China(52188101,Cheng HM,22275205,Peng J)Shenzhen Basic Research Project(JCYJ20200109144616617,Cheng HM)+5 种基金the Science and Technology Foundation of Shenzhen(JCYJ20220530154404010,Peng J)Guangdong Basic and Applied Basic Research Foundation(2023B1515020102,Peng J2022A1515110408,Chen ZJ)China Postdoctoral Science Foundation(2022M713270,Chen ZJ)the Cross Institute Joint Research Youth Team Project of SIAT(E25427,Peng J)supported by the public computing service platform provided by the Network and Computing Center of Huazhong University of Science and Technology。
文摘磁场触发的催化剂轨道电子自旋排列已成为促进析氧反应的一种有趣而可行的策略.然而,具有强d-d库仑相互作用的高熵合金(HEAs)催化剂中的磁场增强机制尚未得到充分挖掘.在此,我们设计了具有优异软磁性的高熵合金金属片,在微小磁场下表现出显著的磁场增强催化作用,其磁导率可作为评估磁场增强的描述因子.具体地,仅施加50 mT的磁场,(FeCoNi)_(82.5)Cr_(17.5)HEAs的过电位下降就超过了36mV@10 mA cm^(-2).此外,过电位的降低与HEA的磁导率呈线性关系.原位拉曼光谱与理论计算结果表明,施加磁场可显著提高自旋密度,改善催化剂的3d电子与*O自由基的2p轨道之间的自旋相互作用,从而有效降低速率决定步骤(*O→*OOH)的能量障碍,进而促进O-O的形成.
