Innovation and Development

Breakthrough in Research of QCD Phase Diagram of Nuclear Materials

Recently, Prof. Xu Jun at the Nuclear Physics Laboratory of the Shanghai Institute of Applied Physics, CAS in collaboration with Prof. Che-Ming Ko at the Texas A&M University quantitatively explained the elliptic flow splitting between particles and their antiparticles observed in the Beam-Energy Scan program by the STAR Collaboration at the Relativistic Heavy-Ion Collider (RHIC) in the Brookhaven Laboratory, and acquired the information of the QCD phase diagram and the critical point of hadron-quark phase transition based on a multiphase transport model, where mean-field potentials of particles were introduced. The research result has been already formally published by Physical Review Letters (Phys. Rev. Lett. 112, 012301 (2014)). To explain the elliptic flow splitting between particles and their antiparticles, Prof. Xu and his collaborators used the Nambu-Jona-Lasinio model to describe the partonic phase in the multiphase transport model, while the mean-field potentials of particles were introduced to partonic and hadronic phases. The study demonstrates that the quark vector interaction is the key to quantitatively explain the elliptic flow splitting between particles and their antiparticles, while the former affects the QCD phase structure and the site of the critical point of phase transition.

New Depth Record: Deep-Sea Manipulator Excellent Performance

Recently, two types of 7000 m hydraulic manipulators developed by Shenyang Institute of Automation, CAS, went through pressure tests at the 702 Institute of CSIC and the SIA. The first type is a 7-function master-slave servo hydraulic manipulator; the second type is a 6-function switched mode hydraulic manipulator. All parts of the manipulators were placed in a high pressure chamber that emulates pressure at a deep sea environment up to 7000 meter depth. The test verified important performance factors including sealing and activity of the two manipulators by activating each joint of the manipulators and observing their movements under high pressure. In the first round of test, most joints acted well, but one rotary actuator joint displayed slow movement and stalled occasionally under 30 MPa water pressure,. This observation triggered further structural improvement. A follow-up test is tehn carried out at SIA, and the test results show that the joint rotated normally in water pressure from 0MPa to 71.5 MPa, which is equivalent to pressure at 7000m seawater depth. These tests showed that the manipulators passed the 7000 meter depth pressure test. The tests also verified other special tools and general components serving as accessories of the manipulators such as cutters, cable retrievers, and hydraulic compensators developed in the same project.