Giant negative magnetoresistance induced by the chiral anomaly in individual Cd3As2 nanowires

Cd3As2 is a newly booming Dirac semimetal with linear dispersion along all three momentum directions and can be viewed as 3D analog of graphene. As breaking of either time reversal symmetry or spatial inversion symmetry, the Dirac semimetal is believed to transform into Weyl semimetal with exotic chiral anomaly effect, while the experimental evidence of the chiral anomaly is still missing in Cd3As2. Here we report the magneto-transport properties of individual Cd3As2 nanowires. Large negative magnetoresistance (MR) with magnitude of -63% at 60 K and -11% at 300 K are observed when the magnetic field is parallel with the electric field direction, giving the evidence of the chiral magnetic effect in Cd3As2 nanowires. In addition, the critical magnetic field BC, where there is an extremum of the negative MR, increases with increasing temperature. As the first observation of chiral anomaly induced negative MR in Cd3As2 nanowires, it may offer valuable insights for low dimensional physics in Dirac semimetals.Comment: 4 figure

Motion Analysis of PLET during the Setting-Down Process

The design analysis of Subsea PLET should consider various cases, including in-place analysis, lifting analysis, setting down analysis and so on. The size and vessel space should be checked in the structural design, and the fishing protection function should also be covered. The accurate setting-down process is the prerequisite for the successful construction of the subsea project. Therefore, it is necessary to simulate the various conditions included in the setting down process. Based on practical YC13-1 project and subsea environment condition, a special type of subsea PLET is designed for the pipe rehabilitation. Theoretical study is performed to discuss the load and Fluent software is used to simulate the problems encountered in the setting-down process. Comparison on the calculation results with ROV condition and without ROV condition, it indicates the effective suppression of the movement of PLET with ROV tractive action. The study can be a good reference and guidance for the design and construction of South China Sea oil and gas field project