9 results about "Phonon scattering" patented technology

The application discloses a method for calculating lattice thermal conductivity of rare earth oxide based on first principle. The method comprises the following steps: establishing a crystal structure model of the rare earth oxide, and constructing a supercell model after structure optimization; calculating second-order interatomic force constants by using a first principle method to obtain a phonon dispersion relation, and calculating third-order interatomic force constants to obtain a phonon scattering rate; solving the lattice thermal conductivity by using a Wigner transport equation, wherein the lattice thermal conductivity comprises a particle contribution described by a diagonal item of a phonon spectral function and a wave contribution described by a non-diagonal item, and the two are added to obtain a thermal conductivity contribution of each phonon mode; and integrating and summing all phonon modes in a Brillouin zone to output a frequency, temperature and direction dependence of the total lattice thermal conductivity. The application can accurately predict the lattice thermal conductivity and anisotropy of the rare earth oxide in a wide temperature range without an empirical parameter.

The application relates to the technical field of thermoelectric materials, in particular to a MnTe alloying-regulated AgSbTe2-based thermoelectric material and preparation and application thereof. Through the MnTe alloying strategy, local composition fluctuation and lattice distortion are induced in the AgSbTe2 matrix, sub-micron scale Ag2Te second phases and Mn-Te enrichment regions are formed, intrinsic Ag / Sb cation disorder is combined, a multi-scale phonon scattering network is constructed, the propagation of phonons with different frequencies is effectively inhibited, the lattice thermal conductivity is significantly reduced, meanwhile, through carrier concentration optimization and Fermi level regulation, the Seebeck coefficient is effectively improved while the reasonable electrical conductivity is maintained, the power factor of the material is obviously improved, and therefore, the thermoelectric performance of the MnTe solid solution sample is significantly improved.

The present application relates to the technical field of probabilistic bit device, and particularly relates to a single-molecule probabilistic bit device based on external circuit coupling, a preparation method and application, the single-molecule probabilistic bit device comprises a single-molecule junction formed by a graphene electrode pair and a probabilistic bit functional group, and a plurality of rigid benzene rings in a triphenylmethyl skeleton in the single-molecule junction realize high delocalization of unpaired electrons through a conjugated structure, effectively weakening the coupling effect between spin and molecular vibration, conformational fluctuation, inhibiting the rapid decoherence process caused by phonon scattering from the molecular structure level, so that the spin state can still maintain a limited coherence lifetime at room temperature, and the basic requirement of the device on the spin state holding time can be met.The device has randomness, controllability and scalability at the circuit level, and provides a hardware basis for constructing a brain-like probabilistic computing network.The preparation method provided by the present application is simple in process and is conducive to large-scale production.

This invention relates to the field of silicone technology, specifically to a silicone composite thermally conductive material and its preparation process. The preparation process of a silicone composite thermally conductive material includes: pretreatment of graphene filler, preparation of modified graphene filler, preparation and modification of heterogeneous filler, and preparation of the silicone composite thermally conductive material. This invention utilizes modified graphene and the construction of a boron nitride-silica heterogeneous filler to form a multi-level thermally conductive network. Combined with electric field-induced ordered arrangement of fillers and pretreatment of graphene with chemically reduced gel and directional ice template, multiple methods are used synergistically to reduce interfacial thermal resistance and phonon scattering, constructing continuous thermally conductive channels. Simultaneously, it improves the structural uniformity, thermal conductivity stability, and mechanical properties of the composite material, effectively solving problems such as filler agglomeration and migration, and significantly improving the thermal conductivity of the silicone composite material.

This invention discloses a method, device, and medium for predicting the remaining lifetime of power semiconductor modules, relating to the field of semiconductor lifetime prediction technology. The method includes: collecting material lattice parameters and thermodynamic operating condition data to generate a transport dataset using molecular dynamics simulation; generating a reciprocal space group velocity tensor field based on the transport dataset; generating a thermodynamic entropy change index based on the reciprocal space group velocity tensor field; performing time-series cumulative analysis based on the thermodynamic entropy change index to output a phonon entropy change feature sequence; extracting a statistical feature subset and a dynamic gradient subset from the phonon entropy change feature sequence; constructing a spiking neural network and inputting the phonon entropy change feature sequence to generate an operation function; and calling the transport equation and initializing it based on the statistical feature subset to generate an initial transport equation. This invention achieves accurate modeling of phonon scattering nonlinear effects by dynamically reconstructing the collision terms of the transport equation using a spiking neural network, overcoming the problem of thermal transport model mismatch under varying operating conditions.

The application discloses an active region structure of a non-polar plane GaN-based terahertz quantum cascade laser, characterized in that the active region has multiple periods of three-well structure, wherein the potential well layer is GaN and the potential barrier layer is AlGaN; and a corresponding non-polar plane GaN-based terahertz quantum cascade laser. An active region structure of a two-well structure and a laser are also disclosed. The application discloses two active region structures of a three-well resonant phonon and a two-well phonon scattering injection terahertz quantum cascade laser based on a non-polar plane GaN, when the doping is 6*10 10 cm ‑2 , the peak gain of the two structures at 10K is 90.1 and 91.3 cm ‑1 , respectively, at 300K, the peak gain of 41.8 and 44.2 cm ‑ 1 is obtained at 8.2 and 7.7 terahertz, which is higher than the calculated double-metal waveguide loss. The overall results show that at room temperature, a GaN-based terahertz quantum cascade laser is possible at about 8 terahertz.

This invention proposes a gallium nitride-based semiconductor laser with a graded thermal conductivity waveguide layer. By fitting the In ion intensity distribution or In atom concentration distribution, the transverse phonon velocity distribution, and the thermal conductivity distribution of the graded thermal conductivity upper and lower waveguide layers using SIMS testing, all of these curves satisfy the Stirling function or the LineMod function. The gradient of the transverse TA phonon velocity homogenizes phonon scattering in the lower waveguide layer, reduces thermally induced lattice distortion, avoids optical field mode distortion, and improves the optical field confinement factor. The gradient of the transverse phonon velocity homogenizes the temperature distribution in the upper waveguide layer, changing the thermal stress from concentrated to distributed, reducing phonon transport loss caused by interface scattering. It avoids the "bottleneck effect" of heat flow at the interface between the active region and the lower waveguide layer, further reducing the temperature coefficient of the threshold, accelerating heat flow to the substrate, and preventing thermal runaway caused by increased driving current after exceeding the threshold.

The embodiment of the application provides a solid waste-based high-temperature heat storage composite material based on gradient interface engineering and nanowire reinforcement and a preparation method thereof, which comprises a porous framework, a phase change core material and a gradient reinforcement layer; the porous framework is a composite of one or both of alumina microspheres and silica microspheres, and the inside of the porous framework is a network structure that penetrates each other; the phase change core material is coated on the surface of the porous framework; and the gradient reinforcement layer comprises a vertical array of boron nitride nanosheets on the outer layer and silicon carbide nanowires on the inner layer. The application aims to utilize coal gangue solid waste, solve the problems of high-temperature phonon scattering and interface separation through in-situ synthesis of SiC nanowires and BN gradient interface structure, break through the dispersion and high-temperature stability bottleneck of the traditional filler adding method, and thus realize the high performance and environmental protection and economy of the solid waste-based high-temperature heat storage material.

This invention provides a modified illite, its preparation method, and its application, belonging to the field of functional materials technology. The preparation method of the modified illite of this invention includes the following steps: (1) first, pulverizing the illite, and then adjusting the water content of the illite to below 5%; (2) microwave activation of the illite at a power of 600-800W for 10-30 minutes to obtain the modified illite. This invention uses illite as raw material and modifies it through a microwave activation process, introducing oxygen vacancies and lattice distortion into the illite crystal structure, enhancing its phonon scattering, improving its infrared radiation efficiency, and preparing a high-performance infrared radiation functional powder.