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1.
Rhenium is a superconductor with a relatively weak tendency to oxidize, which is advantageous in superconducting quantum circuit and qubit applications. In this work, Re/A1-A1Ox/Re Josephson tunnel junctions were fabricated using a selective film-etching process similar to that developed in Nb trilayer technology. The Re films had a superconducting transition temperature of 4.8 K and a transition width of 0.2 K. The junctions were found to be highly reproducible using the fabrication process and their characteristics had good quality with a low leakage current and showed a superconducting gap of 0.55 meV.  相似文献   
2.
The neutron total cross-sections of thulium (^169Tm) were measured in the neutron energy region from 0.01 eV to 100 eV by using the time-of-flight method at the Pohang Neutron Facility, which consists of an electron linac, a water-cooled tantalum target with a water moderator, and a 12 m time of flight path, Two thulium plates with different thicknesses were used for the neutron transmission measurement. The background level was determined by using a notch-filter of Co, In, and Cd sheets. The present measurement was compared with the previous ones, and a new set of resonance parameters of ^169Tm isotope was obtained from the transmission rate by using the SAMMY code, with a comparison with the recommended parameters by Mughabghab.  相似文献   
3.
Nb/Al-AlOx/Nb tunnel junctions with controllable critical current density Jc are fabricated using the standard selective Nb etching process.Tunnel barriers are formed in different oxygen exposure conditions (oxygen pressure P and oxidation time t),giving rise to Jc ranging from 100 A/cm2 to above 2000 A/cm2.Jc shows a familiar linear dependence on P × t in logarithmic scales.We calculate the energy levels of the phaseand flux-type qubits using the achievable junction parameters and show that the fabricated Nb/Al-AlOx/Nb tunnel junctions can be used conveniently for quantum computation applications in the future.  相似文献   
4.
利用球型光学模型、耦合道理论、核内级联、激子模型、蒸发模型、带宽度涨落修正的Hauser-Feshbach模型,Bohr-Wheeler裂变理论,对入射能量从阈能到200 MeV的p+238U各种反应进行了计算,计算结果和实验符合较好.  相似文献   
5.
We have constructed a scanning low-Tc superconducting quantum interference device (SQUID) microscope, in which the SQUID is mounted on the lower end of a copper rod and cooled to liquid helium temperature. There is a 65μm thick sapphire window under the SQUID. The sample at room temperature underneath the window can be scanned to produce magnetic images. The microscope has a spatial resolution of 100-150μm and a magnetic field sensitivity of 3-60pT/\sqrt{Hz} in a magnetically unshielded environment. We have used this scanning SQUID microscope to measure various room temperature samples.  相似文献   
6.
Considering the properties of slow change and quasi-periodicity of magnetocardiography (MCG) signal, we use an integrated technique of adaptive and low-pass filtering in dealing with two-channel MCG data measured by high Tc SQUIDs. The adaptive filter in the time domain is based on a noise feedback normalized least-mean-square (NLMS) algorithm, and the low-pass filter with a cutoff at 100Hz in the frequeucy domain characterized by Caussian functions is combined with a notch at the power line frequency. In this way, both relevant and irrelevant noises in original MCG data are largely eliminated. The method may also be useful for other slowly varying quasi-periodical signals.  相似文献   
7.
Nb/Al-AlOx/Nb tunnel junctions are often used in the studies of macroscopic quantum phenomena and superconducting qubit applications of the Josephson devices. In this work, we describe a convenient and reliable process using electron beam lithography for the fabrication of high-quality, submicron-sized Nb/Al-AlOx/Nb Josephson junctions. The technique follows the well-known selective Nb etching process and produces high-quality junctions with Vm=100 mV at 2.3 K for the typical critical current density of 2.2 kA/cm^2, which can be adjusted by controlling the oxygen pressure and oxidation time during the formation of the tunnelling barrier. We present the results of the temperature dependence of the sub-gap current and in-plane magnetic-field dependence of the critical current, and compare them with the theoretical predictions.  相似文献   
8.
The neutron total cross-sections of thulium(169Tm) were measured in the neutron energy region from 0.01 eV to 100 eV by using the time-of-flight method at the Pohang Neutron Facility,which consists of an electron linac,a water-cooled tantalum target with a water moderator,and a 12 m time of flight path.Two thulium plates with different thicknesses were used for the neutron transmission measurement.The background level was determined by using a notch-filter of Co,In,and Cd sheets.The present measurement was ...  相似文献   
9.
成功制备了用于无损检测的YBCO垫圈型DC SQUID,利用该器件建立了一套扫描SQUID显微镜无损检测装置,采用多极激励场的结构,引入高阶梯度,提高敏感元件-高温SQUID的平衡度,以及减小激励场的空间尺度来提高探测元件无损检测的灵敏度,利用该装置对圆孔缺陷的铝材料样品施加电磁激励并进行了二维磁场扫描成像,获得了较好的实验结果.  相似文献   
10.
科学数据共享的重要性已经引起了我国政府的重视,介绍了中国核数据中心在核数据共享项目进行的研究工作.该研究工作主要包括建立核数据数据库和共享平台的建设两方面的内容.The importance of scientific data sharing has been attracted attention of our government. The research of nuclear data sharing in China Nuclear Data Center are introduced. The work includes research of nucler database and development of online service system.  相似文献   
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