Neutron diffraction aund inelastic scatterilug were curried out on YBa_(2)Cu_(3)O_(7-y)(r=0.5,1.0、1.25).It was coufirmed that the substitutiou of Sr for Ba in YBa_(2)Cu_(3)O_(7-y) inrcases the oxyge1n vacancies int t...Neutron diffraction aund inelastic scatterilug were curried out on YBa_(2)Cu_(3)O_(7-y)(r=0.5,1.0、1.25).It was coufirmed that the substitutiou of Sr for Ba in YBa_(2)Cu_(3)O_(7-y) inrcases the oxyge1n vacancies int the CuO chain.Moreuver.the sntbstittiou strengtlenx the coupling betw1ell the Ba O plane aldl the Cu O rhain,Moreoer. the crystiul stnlbility.Tlusse the ppossill.rnuscs of Te depression for Sr xilrtittril YBa_(2)Cu_(3)O_(7-y).展开更多
Neutron diffraction study on the structure of Bi_(2)Sr_(1.855)Ca_(1.145)Cu_(2)O_(8) was carried out.Data refinements show that the average subcell structure for Bi_(2)Sr_(1.855)Ca_(1.145)Cu_(2)O_(8) is in the best fit...Neutron diffraction study on the structure of Bi_(2)Sr_(1.855)Ca_(1.145)Cu_(2)O_(8) was carried out.Data refinements show that the average subcell structure for Bi_(2)Sr_(1.855)Ca_(1.145)Cu_(2)O_(8) is in the best fit of the space group Fmmm and the structure is described by alternate stacking of SrO-CuO_(2)-Ca-CuO_(2)-SrO slab and a double BiO layers.An oxygen layer sandwiched by the bismuth layers was conRrmed.展开更多
High performance high-temperature superconducting (HTS) filters have been designed and constructed for satellite application. The filters are actually a superconducting integration of an 8-pole band-pass filter with a...High performance high-temperature superconducting (HTS) filters have been designed and constructed for satellite application. The filters are actually a superconducting integration of an 8-pole band-pass filter with an adjustable band-stop filter onto a single piece of LaAlO3 substrate (with dimension of 0.5×45×20 mm3). Typical results of the filters, i.e., Filters A (made by YBCO) & B (made by TBCCO) will be reported. The measured responses of Filter A showed excellent specifications, e.g., an insertion loss less than 0.1 dB, a return loss better than -22.5 dB in pass-band, band-edge steepness greater than 12 dB/MHz and out-of-band rejection at a certain band deeper than -110 dB. To satisfy the requirement of rocket launch and space operation, three filters of the above design have undergone mechanical environmental simulation tests for space qualification. Detailed analysis of the response curves of Filter B measured before and after the tests showed that no noticeable change in the per-formance can be found. All the filters passed the rigorous ground simulation tests, which is the first time in China for HTS devices and provided a solid foundation for satellite applications of high-temperature superconductors in the near future.展开更多
A high Q HTS cavity resonator with resonating frequency f0=5.624 GHz was fabricated using high quality HTS film and high purity sapphire. The unloaded quality factor of the HTS resonator was as high as QU=1.09×10...A high Q HTS cavity resonator with resonating frequency f0=5.624 GHz was fabricated using high quality HTS film and high purity sapphire. The unloaded quality factor of the HTS resonator was as high as QU=1.09×106 at the nitrogen temperature, 77 K. A HTS local oscillator combining the high Q cavity resonator with a C-band low noise GaAs HEMT amplifier was then designed and constructed. The phase noise of the oscillator, measured by a HP 3048A noise measurement system, is -134 dBc/Hz at 10 kHz offset when the temperature is 77 K. This result is close to the best level reported by other groups in the world.展开更多
基金Supported by the National Natural Science Foundation of China。
文摘Neutron diffraction aund inelastic scatterilug were curried out on YBa_(2)Cu_(3)O_(7-y)(r=0.5,1.0、1.25).It was coufirmed that the substitutiou of Sr for Ba in YBa_(2)Cu_(3)O_(7-y) inrcases the oxyge1n vacancies int the CuO chain.Moreuver.the sntbstittiou strengtlenx the coupling betw1ell the Ba O plane aldl the Cu O rhain,Moreoer. the crystiul stnlbility.Tlusse the ppossill.rnuscs of Te depression for Sr xilrtittril YBa_(2)Cu_(3)O_(7-y).
基金Supported by the National Natural Science Foundation of Chinathe National Center for Research and Development on Superconductivity.
文摘Neutron diffraction study on the structure of Bi_(2)Sr_(1.855)Ca_(1.145)Cu_(2)O_(8) was carried out.Data refinements show that the average subcell structure for Bi_(2)Sr_(1.855)Ca_(1.145)Cu_(2)O_(8) is in the best fit of the space group Fmmm and the structure is described by alternate stacking of SrO-CuO_(2)-Ca-CuO_(2)-SrO slab and a double BiO layers.An oxygen layer sandwiched by the bismuth layers was conRrmed.
基金the Chinese Academy of Sciences (KJCX2-SW-W01)Beijing Mu-nicipal Science & Technology Commission (H010410050111)+1 种基金the Ministry of Sci-ence and Technology of China (2002AA306181)the National Natural Science Foundation of China (Grant No.10474127)
文摘High performance high-temperature superconducting (HTS) filters have been designed and constructed for satellite application. The filters are actually a superconducting integration of an 8-pole band-pass filter with an adjustable band-stop filter onto a single piece of LaAlO3 substrate (with dimension of 0.5×45×20 mm3). Typical results of the filters, i.e., Filters A (made by YBCO) & B (made by TBCCO) will be reported. The measured responses of Filter A showed excellent specifications, e.g., an insertion loss less than 0.1 dB, a return loss better than -22.5 dB in pass-band, band-edge steepness greater than 12 dB/MHz and out-of-band rejection at a certain band deeper than -110 dB. To satisfy the requirement of rocket launch and space operation, three filters of the above design have undergone mechanical environmental simulation tests for space qualification. Detailed analysis of the response curves of Filter B measured before and after the tests showed that no noticeable change in the per-formance can be found. All the filters passed the rigorous ground simulation tests, which is the first time in China for HTS devices and provided a solid foundation for satellite applications of high-temperature superconductors in the near future.
文摘A high Q HTS cavity resonator with resonating frequency f0=5.624 GHz was fabricated using high quality HTS film and high purity sapphire. The unloaded quality factor of the HTS resonator was as high as QU=1.09×106 at the nitrogen temperature, 77 K. A HTS local oscillator combining the high Q cavity resonator with a C-band low noise GaAs HEMT amplifier was then designed and constructed. The phase noise of the oscillator, measured by a HP 3048A noise measurement system, is -134 dBc/Hz at 10 kHz offset when the temperature is 77 K. This result is close to the best level reported by other groups in the world.
