Tunneling conductance in normal metal/insulator/triplet superconductor junctions is studied theoretically as a function of the bias voltage at zero temperature and finite temperature. The results show there are zero-b...Tunneling conductance in normal metal/insulator/triplet superconductor junctions is studied theoretically as a function of the bias voltage at zero temperature and finite temperature. The results show there are zero-bias conductance peak, zero-bias conductance dip and double-minimum structures in the spectra for p-wave superconductor junctions. The existence of such structures in the conductance spectrum can be taken as evidence that the pairing symmetry of Sr2RuO4 is p-wave symmetry.展开更多
In the article, the Josephson system ＂Superconductor-Fluctuation Superconductor-Superconductor＂, consisting of a combination of superconductors with a fluctuation superconductor was considered. The possibility of tr...In the article, the Josephson system ＂Superconductor-Fluctuation Superconductor-Superconductor＂, consisting of a combination of superconductors with a fluctuation superconductor was considered. The possibility of transformation of the superconducting （Cooper） pairs in psevdocorrelated （fluctuation） of a pair of electrons is shown, and vice versa, the fluctuation pairs in the Cooper pairs in such a Josephson system. The characteristic features of the Andreev reflection of the weakly bound electron, which is part of the fluctuation pairs in the interface ＂fluctuation superconductor-superconductor＂ with a probability of forming a pair of ＂Electron-Hole＂ and the generation of psevdocorrelated pair discussed. The probability of formation of two correlated superconducting electron pairs, forming original cluster with a charge 4e, in the interface ＂Fluctuation Superconductor-Superconductor＂ as a result of transmutation of the reflected hole into an electron or subjection Andreev reflection of both electrons of fluctuation pairs is viewed. The above processes may be useful for better understanding the fluctuation effects in superconducting materials which appear at temperatures above the critical value.展开更多
A repulsive vortex\|vortex interaction model was used to numerically study the melting transition of the two\|dimensional vortex system with Monte Carlo method. Then a δ\|function\|like peak in the specific heat was ...A repulsive vortex\|vortex interaction model was used to numerically study the melting transition of the two\|dimensional vortex system with Monte Carlo method. Then a δ\|function\|like peak in the specific heat was observed and the internal energy showed a sharp drop at the melting temperature, which indicated that there exists a first\|order melting transition at finite temperatures. The Lindemann criterion was also investigated and valid, but different from previous simulation results.展开更多
The purpose of ship deperming is to reduce its permanent magnetism to avoid the threat of magnetic sea-mines which appeared first in battlefields in World War II and stored by many navies and unanimous groups since th...The purpose of ship deperming is to reduce its permanent magnetism to avoid the threat of magnetic sea-mines which appeared first in battlefields in World War II and stored by many navies and unanimous groups since then. Magnetic fields for deperming are mostly generated by electric current through conductor cable and the intensity of such fields decreases with the distance from the cable. In order to impose sufficient field to the ship, the deperming cable is tightly wrapped around the hull of the ship. A cable with superconducting material as the conductor is expected to pass high electric current because of its zero-electric resistivity and has potential to make deperming coil system more separated from the ship hull. In the previous study, we designed superconducting coil system set flat on the seabed for ship deperming by calculating magnetic field generated by the coil based on the characteristic of HTS （high temperature superconducting） tape seen in published papers. This time we have kept our design to utilize HTS tape conductors that are existing and readily available in the open market. In addition, the limitations of the manufacturing potential and capacity of the HTS tape conductor industry have been taken into account for the design. Then we designed the refrigerating system which is to keep the superconducting property of the cable materials.展开更多
This paper shows that the Josephson coupling energy and the zero-point energy have indelible rules on the superfluid density and the superconductivity in the high-T<SUB>c</SUB> cuprates. This paper also sh...This paper shows that the Josephson coupling energy and the zero-point energy have indelible rules on the superfluid density and the superconductivity in the high-T<SUB>c</SUB> cuprates. This paper also shows that the values of T<SUB>c</SUB> at underdoped and overdoped regions are determined by the damage conditions of the phase coherence in the classical and the quantum XY-models, respectively.展开更多
In order to carry on ECRH experiments and research on HL-2A tokamak, two sets of 4 mm gyrotrons were imported from GYCOM. Each of them has a superconducting magnet system to offer a required magnetic field configurati...In order to carry on ECRH experiments and research on HL-2A tokamak, two sets of 4 mm gyrotrons were imported from GYCOM. Each of them has a superconducting magnet system to offer a required magnetic field configuration. In gyrotron, a strong magnetic field is necessary for electron beam to satisfy the electron cyclotron resonance condition and to excite one the eigemodes in the cavity. Its functions are： （I） to make electrons gyrate, （ 2 ） to offer enough adiabatic compression value to make electrons acquire strong transverse energy. During the period of adjustment, magnetic field distribution was measured. Meanwhile, operating current of superconducting magnet and operating frequency of gyrotron were determined.展开更多
Objective To study the value of ultrasound elastography in evaluation of ethanol-induced lesions of liver. Methods Alcohol with a dose of 2 ml was injected into a fresh porcine liver under ultrasound guidance to creat...Objective To study the value of ultrasound elastography in evaluation of ethanol-induced lesions of liver. Methods Alcohol with a dose of 2 ml was injected into a fresh porcine liver under ultrasound guidance to create stiff necrosis. Then freehand elastography of the lesion from the identical scan plane was obtained with SONOLINE Antares system using VF10-5 probe at about every 30 seconds till 6 minutes later. The original high quality radiofrequency data were acquired through an ultrasound research interface which was provided by the ultrasound system. Then, corresponding elastograms were produced offline using cross-correlation technique and compared with gross pathology findings. Results Gray-scale sonogram showed a hyperechoic area with acoustic shadow below appeared immediately after alcohol injection. The hyperechoic area tended to be diffuse and its boundary to be illegible with time. On the contrary, the ethanol-induced lesion in elastogram appeared as a low swain hard region surrounded by high strain soft hepatic tissues, with clear but irregular boundaries. Sequential elastograms with the sketched lesion boundaries showed that the lesion area increased in the first 3 minutes after ethanol injection, and then reached a plateau which corresponding to gross specimen. Conclusion Ultrasound elastography is capable of detecting and evaluating the diffusion of ethanol-induced hepatic lesion, and more sensitive and accurate than routine sonography.展开更多
文摘Tunneling conductance in normal metal/insulator/triplet superconductor junctions is studied theoretically as a function of the bias voltage at zero temperature and finite temperature. The results show there are zero-bias conductance peak, zero-bias conductance dip and double-minimum structures in the spectra for p-wave superconductor junctions. The existence of such structures in the conductance spectrum can be taken as evidence that the pairing symmetry of Sr2RuO4 is p-wave symmetry.
文摘In the article, the Josephson system ＂Superconductor-Fluctuation Superconductor-Superconductor＂, consisting of a combination of superconductors with a fluctuation superconductor was considered. The possibility of transformation of the superconducting （Cooper） pairs in psevdocorrelated （fluctuation） of a pair of electrons is shown, and vice versa, the fluctuation pairs in the Cooper pairs in such a Josephson system. The characteristic features of the Andreev reflection of the weakly bound electron, which is part of the fluctuation pairs in the interface ＂fluctuation superconductor-superconductor＂ with a probability of forming a pair of ＂Electron-Hole＂ and the generation of psevdocorrelated pair discussed. The probability of formation of two correlated superconducting electron pairs, forming original cluster with a charge 4e, in the interface ＂Fluctuation Superconductor-Superconductor＂ as a result of transmutation of the reflected hole into an electron or subjection Andreev reflection of both electrons of fluctuation pairs is viewed. The above processes may be useful for better understanding the fluctuation effects in superconducting materials which appear at temperatures above the critical value.
文摘A repulsive vortex\|vortex interaction model was used to numerically study the melting transition of the two\|dimensional vortex system with Monte Carlo method. Then a δ\|function\|like peak in the specific heat was observed and the internal energy showed a sharp drop at the melting temperature, which indicated that there exists a first\|order melting transition at finite temperatures. The Lindemann criterion was also investigated and valid, but different from previous simulation results.
文摘The purpose of ship deperming is to reduce its permanent magnetism to avoid the threat of magnetic sea-mines which appeared first in battlefields in World War II and stored by many navies and unanimous groups since then. Magnetic fields for deperming are mostly generated by electric current through conductor cable and the intensity of such fields decreases with the distance from the cable. In order to impose sufficient field to the ship, the deperming cable is tightly wrapped around the hull of the ship. A cable with superconducting material as the conductor is expected to pass high electric current because of its zero-electric resistivity and has potential to make deperming coil system more separated from the ship hull. In the previous study, we designed superconducting coil system set flat on the seabed for ship deperming by calculating magnetic field generated by the coil based on the characteristic of HTS （high temperature superconducting） tape seen in published papers. This time we have kept our design to utilize HTS tape conductors that are existing and readily available in the open market. In addition, the limitations of the manufacturing potential and capacity of the HTS tape conductor industry have been taken into account for the design. Then we designed the refrigerating system which is to keep the superconducting property of the cable materials.
文摘This paper shows that the Josephson coupling energy and the zero-point energy have indelible rules on the superfluid density and the superconductivity in the high-T<SUB>c</SUB> cuprates. This paper also shows that the values of T<SUB>c</SUB> at underdoped and overdoped regions are determined by the damage conditions of the phase coherence in the classical and the quantum XY-models, respectively.
文摘In order to carry on ECRH experiments and research on HL-2A tokamak, two sets of 4 mm gyrotrons were imported from GYCOM. Each of them has a superconducting magnet system to offer a required magnetic field configuration. In gyrotron, a strong magnetic field is necessary for electron beam to satisfy the electron cyclotron resonance condition and to excite one the eigemodes in the cavity. Its functions are： （I） to make electrons gyrate, （ 2 ） to offer enough adiabatic compression value to make electrons acquire strong transverse energy. During the period of adjustment, magnetic field distribution was measured. Meanwhile, operating current of superconducting magnet and operating frequency of gyrotron were determined.
基金Supported by National Natural Science Foundation of China (30470466)
文摘Objective To study the value of ultrasound elastography in evaluation of ethanol-induced lesions of liver. Methods Alcohol with a dose of 2 ml was injected into a fresh porcine liver under ultrasound guidance to create stiff necrosis. Then freehand elastography of the lesion from the identical scan plane was obtained with SONOLINE Antares system using VF10-5 probe at about every 30 seconds till 6 minutes later. The original high quality radiofrequency data were acquired through an ultrasound research interface which was provided by the ultrasound system. Then, corresponding elastograms were produced offline using cross-correlation technique and compared with gross pathology findings. Results Gray-scale sonogram showed a hyperechoic area with acoustic shadow below appeared immediately after alcohol injection. The hyperechoic area tended to be diffuse and its boundary to be illegible with time. On the contrary, the ethanol-induced lesion in elastogram appeared as a low swain hard region surrounded by high strain soft hepatic tissues, with clear but irregular boundaries. Sequential elastograms with the sketched lesion boundaries showed that the lesion area increased in the first 3 minutes after ethanol injection, and then reached a plateau which corresponding to gross specimen. Conclusion Ultrasound elastography is capable of detecting and evaluating the diffusion of ethanol-induced hepatic lesion, and more sensitive and accurate than routine sonography.
