Magnetic calorimeter for registration of small energy release

A scheme of magnetic calorimeter for registration of rare events characterized by small energy release (cosmic rays, WIMPs, solitary X-ray quanta) is proposed. The calorimeter is brought to operation by adiabatic demagnetization, and its magnetic response is measured by a quantum interferometer (SQUID, A. Barone and G. Paterno, Physics and applications of Josephson Effect). Special consideration is given to the specific features of calorimeter operation in the ferromagnetic transition region. The trigger registration of ultrasmall energy release by a ferromagnetic system in the metastable state is described.     

部分相干涡旋光束在大气湍流中的远场传输特性

运用广义惠更斯-菲涅耳原理,详细研究了部分相干涡旋光束在湍流介质中的远场传输规律.研究表明,部分相干涡旋光束的光谱相干度及光强分布与光束的拓扑电荷数、空间相对相干长度及湍流介质的折射率结构常数等因素有关.在湍流介质中,光谱相干度存在相位奇点,并且随着空间相对相干长度的增大,相干涡旋逐渐演化为强度涡旋,而湍流介质的强弱对部分相干涡旋光束的影响则相反,随着湍流介质的折射率常数的增大,强度涡旋逐渐演化为相干涡旋.     

7T大口径NbTi超导磁体降温通电实验

介绍了用于超导导体测试用超导磁体降温通电实验,降温采用500W@4.5K制冷机系统。300—10K直接采用冷He气循环冷却超导磁体,温度低于10K直接输入LHe。该磁体在4.2K温度下可通1000A的电流,其中心磁场为7T,储能为3M J。     

Growth and properties of air-processed GdBa2Cu3O7−δ superconductors with fined Gd2BaCuO5 and Gd2Ba4CuFeOy additions

We have succeeded in synthesizing a powder form of Gd₂Ba₄CuFeO_y (Gd2411) in air. GdBa₂Cu₃O_7−δ (Gd123)/Gd₂BaCuO₅ (Gd211) precursor powders added with different amounts of Gd₂Ba₄CuFeO_y (x = 0, 0.002, 0.004, 0.02) in molar ratio to Gd123 have been fabricated successfully into the form of large, single grains by the top seeded melt growth (TSMG) process. The relation between the additions amounts of Gd2411/Gd211 and critical current density (J_C) was analyzed. We found Gd2411 particles stably exist in the Gd123 matrix without degradation of superconducting properties owing to the existence of the Fe magnetic ion. The trapped field was observed to increase significantly compared with the bulk without Gd2411 additions.     

Mechanisms of the pancake vortex and vortex line movement in the high Tc superconductors Bi2Sr2CaCu2O8+δand La1.93Sr0.07CuO4+δ

In the strict sense, it is not very clear why with magnetic field increasing, the normal-superconductive (NS) transition becomes broad for Bi2Sr2CaCu2O8+δ(Bi2212) while the NS transitions are almost parallel for La1.93Sr0.07CuO4+δ(La214). In this paper, R-T relations are measured by the six-probe method. We propose a moving mechanism of the pancake vortex and vortex line for Bi2212. The theoretical curves fit the experiment data well.     

管内电缆导体稳定性理论与实验研究

管内电缆导体 ,又称 CICC,是目前大型低温超导磁体的首选导体。随着超导技术的发展 ,CICC在大型超导核聚变实验装置及超导储能磁体中的应用具有不可比拟的优越性。为降低导体成本而提出了在 CICC中采用的超导股线配以纯铜股线的设计方案 ,开展含纯铜股线 CICC稳定性机理及实验的研究 ,并开发 CICC优化设计软件 ,对 CICC在高科技中的应用意义重大。     

The effect of Dirac phase on acoustic vortex in media with screw dislocation

We study acoustic vortex in media with screw dislocation using the Katanaev–Volovich theory of defects. It is shown that the screw dislocation affects the beam?s orbital angular momentum and changes the acoustic vortex strength. This change is a manifestation of topological Dirac phase and is robust against fluctuations in the system.