The study on the thermal transport properties of matter under high pressure is important but is hard to fulfill in a diamond anvil cell (DAC) because the accurate measurement of the temperature gradient within the sample of DAC is very difficult. In most cases, the sample temperature can be read accurately from the thermocouples that are directly attached to the lateral edges of diamond anvils because both the sample and diamond anvils can be uniformly heated up to a given temperature. But for the thermal transport property studies in DAC, an artificial temperature distribution along the compression axis is a prerequisite. Obviously, the temperature of the top or bottom surface of the sample cannot be substituted by that of diamond anvils although diamond anvils can be considered as a good medium for heat conduction. With temperature field simulation by finite element analysis, it is found that big measurement errors can occur and are fatal to the correct analysis of thermal transport properties of materials. Thus, a method of combining both the four-thermocouple configuration and temperature field analysis is presented for the accurate temperature distribution measurement in DAC, which is based on the single-function relationship between temperature distribution and sample thermal conductivity.

To investigate the effects of the optical field and the Fermi velocity on the transport properties of spin and valley electrons, we impose a normal/ferromagnetic/normal (N/F/N) quantum structure based on the monolayer WSe2. The results indicate that there is a strong switch effect for spin- and valley-related electrons. When left-handed off-resonant circularly polarized light is irradiated in the intermediate ferromagnetic region, 100% polarization for K valley electrons can be achieved in the entire effective energy spectrum of the optical field. Meanwhile, 100% polarization of the K′ valley can also be gained with the right-handed off-resonant circularly polarized light in the junction. Moreover, the perfect polarization of spin-up electrons can be obtained when the ferromagnetic exchange field is applied to the structure. Additionally, the Fermi velocity barrier also changes the energy band of the studied material, which makes the spin and valley transport increase with the increase of the velocity barrier but does not produce spin or valley polarizations. These interesting results clarify that the optical field and the Fermi velocity both make a contribution to the modulation of spin electrons for the two valleys and provide a useful method for the design of novel spintronic and valleytronic devices.

The soil-rock mixture is a cohesive-frictional geomaterial subjected to impacts of composition and structure seriously. When it suffers from gravity or other kinds of loadings, the loss of its bearing capacity always appears a progressive failure. In this study, the ultimate criterion of the frictional material changing from the deformation stage to the failure stage is analyzed first and then the deformation and failure characteristics of the soil-rock mixture with different compositions and structures are discussed by the discrete element method. The results indicate that the deformation and failure of the soil-rock mixture under axial pressure appear a significant phenomenon of detouring around rock blocks. The bond failure zones and the ultimate shear strain increase with the increase of rock block proportion. The distribution of the bond failure zones always has a good uniformity with the inclination of rock block inclinations. The increase of cementation degree between particles expands the distribution of the bond failure zones but minifies the ultimate shear strain.

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Steam reforming (SR) of single model molecules (acetone, butanol, and ethanol) and a specific mixture (butanol/acetone/ethanol = 6/3/1, mass ratio) assumed as a model of biobutanol raw mixture has been researched over mesoporous Ni x /MgO catalysts (x represented nickel mole percent in Ni–Mg) at 673–873 K. The result showed reactant conversion at lower temperatures allowed ranking the three single-molecule compounds as the function of SR activity as follows: ethanol > acetone > butanol. The catalytic performance of mesoporous Ni0.12/MgO catalyst with lower Ni component containing enough active sites outperformed that of mesoporous Ni0.16/MgO catalyst which was more inclined to sinter in all SR tests of single-component compounds except at 673 K. On the contrary, the catalytic behavior of Ni0.16/MgO (richer in nickel) was superior to that of Ni0.12/MgO catalyst in SR of multicomponent compounds. Moreover, in acetone–butanol–ethanol steam reforming (ABESR), SR of ethanol suffered competition from acetone and butanol, suppressing ethanol molecule access to the limited active sites of the catalyst. As a consequence, the conversion of ethanol in SR of multicomponent compounds decreased compared to that in SR of pure ethanol.