We have developed a simple sintering system to prepare the yttria-stabilized-zirconia(YSZ)bicrystals.Grain-boundary junctions made from the epitaxial YBa_(2)Cu_(3)O_(7-δ) films on the bicrystal substrates demonstrate...We have developed a simple sintering system to prepare the yttria-stabilized-zirconia(YSZ)bicrystals.Grain-boundary junctions made from the epitaxial YBa_(2)Cu_(3)O_(7-δ) films on the bicrystal substrates demonstrated Josephson behavior.Using new square washer design,single-level magnetometer of dc superconducting quantum interference.device(SQUID)has been fabricated.Owing to the flux focusing effect of the large washer,the magnetic field sensitivity of the devices has been enhanced.The magnetic field resolution of the magnetometer is IpT/Hz^(1/2) at 10Hz,and increases to 3pT/Hz^(1/2) at 1Hz at 77K.展开更多
The semiconductor-superconductor con tact system of Ge/Y-Ba-Cu-O(YBCO)/SrTiO_(3) has been successfully fabricated by two steps of deposition.The YBCO film in the contact of Ge/YBCO did not lose its superconductivity a...The semiconductor-superconductor con tact system of Ge/Y-Ba-Cu-O(YBCO)/SrTiO_(3) has been successfully fabricated by two steps of deposition.The YBCO film in the contact of Ge/YBCO did not lose its superconductivity and its T_(c)(on set)did not degrade as well.The top layer of Ge was polycrystalline with preferred orientation corresponding to the epitaxial structure of the underlayer of YBCO.展开更多
The structural,magnetic and superconducting properties of the Tl_(2)Ba_(2)(Ca_(1-x)Mg_(x))_(2)Cu_(3)O_(y)system with x=0,0.05,0.1,0.15,0.2,0.3,0.4,0.5 were studied.Replacement of calcium by magnesium depresses Tc from...The structural,magnetic and superconducting properties of the Tl_(2)Ba_(2)(Ca_(1-x)Mg_(x))_(2)Cu_(3)O_(y)system with x=0,0.05,0.1,0.15,0.2,0.3,0.4,0.5 were studied.Replacement of calcium by magnesium depresses Tc from 116.3K(x=0)to 93.3K(x=0.5).The critical current also decreases with increasing x.展开更多
It is proposed that the high T_(c) superconductivlty in Ba-La-Cu-O system comes from the phonon cloud mediated Fröhlich polaron pair.The T_(c) should be lower than the transition temperature of small polaron into...It is proposed that the high T_(c) superconductivlty in Ba-La-Cu-O system comes from the phonon cloud mediated Fröhlich polaron pair.The T_(c) should be lower than the transition temperature of small polaron into large polaron.Estimated value of T_(c) is also given based on the mechanism proposed by the authors.展开更多
As the carriers of electromagnetic information about the cardiac system,both magnetocardiography(MCG) and electrocardiography(ECG) are non-stationary signals(NSS).The essential and crucial features of NSS are the loca...As the carriers of electromagnetic information about the cardiac system,both magnetocardiography(MCG) and electrocardiography(ECG) are non-stationary signals(NSS).The essential and crucial features of NSS are the local time-frequency characteristics(LTFCH).Under the constraint of the uncertainty principle in the time-frequency domain(TFD),the LTFCH of those non-stationary signals can be determined by evolutionary spectrum analysis(ESA).In this paper,by analyzing the QRS complexes of both MCG and ECG data from healthy volunteers,we have derived some characteristic parameters(CHPs) in the TFD,such as the quality factor(Q) and center frequency(fz).According to the experiment results,we believe that there are threshold ranges of Q and fz values in the dynamic behavior of the cardiac system for healthy projects.If the CHPs are in the proper ranges,the cardiac system is in a normal condition and homeostasis can be self-correcting.In contrast,if the values of the CHPs are less than the proper ranges,the homeostasis of the cardiac system is lost and some cardiac diseases may result.The assumption of the threshold ranges is verified by sample data from different cardiac diseases,and the results support the assumption.The CHPs are not only a kind of new reference criterion for ECG in clinical diagnosis,but also afford a technological route for the application of MCGs in cardiology.展开更多
基金Supported by the National Research and Development Center for SuperconductivityFEUYT of State Educational Commission of China.
文摘We have developed a simple sintering system to prepare the yttria-stabilized-zirconia(YSZ)bicrystals.Grain-boundary junctions made from the epitaxial YBa_(2)Cu_(3)O_(7-δ) films on the bicrystal substrates demonstrated Josephson behavior.Using new square washer design,single-level magnetometer of dc superconducting quantum interference.device(SQUID)has been fabricated.Owing to the flux focusing effect of the large washer,the magnetic field sensitivity of the devices has been enhanced.The magnetic field resolution of the magnetometer is IpT/Hz^(1/2) at 10Hz,and increases to 3pT/Hz^(1/2) at 1Hz at 77K.
基金Supported by the National Center for Research&Development on SuperconductivityBeijing Zhongguancun Associated Center of Analysis and Measurement.
文摘The semiconductor-superconductor con tact system of Ge/Y-Ba-Cu-O(YBCO)/SrTiO_(3) has been successfully fabricated by two steps of deposition.The YBCO film in the contact of Ge/YBCO did not lose its superconductivity and its T_(c)(on set)did not degrade as well.The top layer of Ge was polycrystalline with preferred orientation corresponding to the epitaxial structure of the underlayer of YBCO.
文摘The structural,magnetic and superconducting properties of the Tl_(2)Ba_(2)(Ca_(1-x)Mg_(x))_(2)Cu_(3)O_(y)system with x=0,0.05,0.1,0.15,0.2,0.3,0.4,0.5 were studied.Replacement of calcium by magnesium depresses Tc from 116.3K(x=0)to 93.3K(x=0.5).The critical current also decreases with increasing x.
基金supported by the Science Fund of the Chinese Academy of Sciences。
文摘It is proposed that the high T_(c) superconductivlty in Ba-La-Cu-O system comes from the phonon cloud mediated Fröhlich polaron pair.The T_(c) should be lower than the transition temperature of small polaron into large polaron.Estimated value of T_(c) is also given based on the mechanism proposed by the authors.
基金supported by the National Natural Science Foundation of China (607710003)
文摘As the carriers of electromagnetic information about the cardiac system,both magnetocardiography(MCG) and electrocardiography(ECG) are non-stationary signals(NSS).The essential and crucial features of NSS are the local time-frequency characteristics(LTFCH).Under the constraint of the uncertainty principle in the time-frequency domain(TFD),the LTFCH of those non-stationary signals can be determined by evolutionary spectrum analysis(ESA).In this paper,by analyzing the QRS complexes of both MCG and ECG data from healthy volunteers,we have derived some characteristic parameters(CHPs) in the TFD,such as the quality factor(Q) and center frequency(fz).According to the experiment results,we believe that there are threshold ranges of Q and fz values in the dynamic behavior of the cardiac system for healthy projects.If the CHPs are in the proper ranges,the cardiac system is in a normal condition and homeostasis can be self-correcting.In contrast,if the values of the CHPs are less than the proper ranges,the homeostasis of the cardiac system is lost and some cardiac diseases may result.The assumption of the threshold ranges is verified by sample data from different cardiac diseases,and the results support the assumption.The CHPs are not only a kind of new reference criterion for ECG in clinical diagnosis,but also afford a technological route for the application of MCGs in cardiology.
