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We study the dynamics of quantum discord between two qubits coupled collectively to a thermal reservoir. For comparison, we also consider the dynamics of quantum entanglement. It is shown that we can obtain a stable quantum discord induced by the thermal environment when the discord of the initial state is zero. The thermal environment can also induce a stable amplification of the initially prepared quantum discord for certain Xtype states. It is very valuable that the quantum discord is more resistant against the thermal environment than quantum entanglement. And, we have demonstrated that the sudden death of discord in a Markovian regime is impossible even at high temperature. It provides us a feasible way to create and protect quantum correlation in the case of a high-temperature thermal environment for various physical system such as trapped ions, quantum dots or Josephson junctions.

Inner flow field numerical simulation model of conical nozzle was established. The relationship between conical nozzle structural parameters and its performance were obtained with simulation research. Simulation results show that the maximum outlet velocity of conical nozzle and the fluctuation range of radial velocity at outlet are determined by its convergence angle α and slenderness ratio Cp. With the increasing of α, the maximum outlet velocity of nozzle is increased at first and then reduced. When α is small, the fluctuation range of radial velocity at outlet is minute. When α is big, the fluctuation range of radial velocity at outlet is dramatic. With the increasing of Cp, the maximum outlet velocity of nozzle is increased at first and then reduced. When Cp is small, the fluctuation range of radial velocity at outlet is obvious. When Cp is big, the fluctuation range of radial velocity at outlet is minute. The optimal structural parameters of the nozzle are α = 40°, Cp =30°. Experiments of conical nozzle performance with different α were carried out. Experimental results show that ejection range of water jet is maximal when α = 40°.

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Seafloor polymetallic sulfide specimens were developed according to engineering rock test method standard (GB/T 50266-2013). Seafloor polymetallic sulfide wet density and dry density were tested. Uniaxial compressive strength and triaxial compression strength of seafloor polymetallic sulfide were tested using rock mechanics test system MTS 815. Elasticity modulus and Poisson's ratio of seafloor polymetallic sulfide were calculated based on specimens stress-strain curves. Cohesion and internal friction angle were calculated based on specimens triaxial test Mohr stress circle. Test results show that seafloor polymetallic sulfide dry density average value is 2.6 g/cm3, wet density average value is 2.94 g/cm3. Uniaxial compressive strength and triaxial compression strength of seafloor polymetallic sulfide are unstable. Average value of the uniaxial compressive strength is 10.243MPa. Average value of triaxial compression strength test peak load is 47.166KN. Cohesion is 2.447MPa and internal friction angle is 38.04o.