最近HERA发现 l q共振态可能是e+ d共振,该事例非标准模型(SM)所预期,与亚夸克层次有关.用价-海亚夸克混合模型和Preon模型给出的"编外"粒子研究 l q共振态的物理机制,结果发现:产生 l q共振的物理基础是由于"编外"...最近HERA发现 l q共振态可能是e+ d共振,该事例非标准模型(SM)所预期,与亚夸克层次有关.用价-海亚夸克混合模型和Preon模型给出的"编外"粒子研究 l q共振态的物理机制,结果发现:产生 l q共振的物理基础是由于"编外"玻色子中存在具有B+23物质性质的"反轻子型夸克",在反轻子和夸克之间传递相互作用的是具有ε物质性质的"编外"玻色子,在ε物质的相互交换下 e d共振与 νe u共振可以相互转变,并与早前的中微子统一模型、新名古屋模型相符.展开更多
High-pressure behaviour of orthorhombic MgSiO3 perovskite crystal is simulated by using the density functional theory and plane-wave pseudopotentials approach up to 120 GPa pressure at zero temperature. The lattice co...High-pressure behaviour of orthorhombic MgSiO3 perovskite crystal is simulated by using the density functional theory and plane-wave pseudopotentials approach up to 120 GPa pressure at zero temperature. The lattice constants and mass density of the MgSiO3 crystal as functions of pressure are computed, and the corresponding bulk modulus and bulk velocity are evaluated. Our theoretical results agree well with the high-pressure experimental data. A thermodynamic method is introduced to correct the temperature effect on the O-K first-principles results of bulk wave velocity, bulk modulus and mass density in lower mantle PIT range. Taking into account the temperature corrections, the corrected mass density, bulk modulus and bulk wave velocity of MgSiO3-perovskite are estimated from the first-principles results to be 2%, 4%, and 1% lower than the preliminary reference Earth model （PREM） profile, respectively, supporting the possibility of a pure perovskite lower mantle model.展开更多
We experimentally investigated some of the mechanical properties of ReB2 under high temperature/pressure(TIP)conditions.High-T experiments(up to 600℃at 1 atm)were carried out in a high-T oven attached to a convention...We experimentally investigated some of the mechanical properties of ReB2 under high temperature/pressure(TIP)conditions.High-T experiments(up to 600℃at 1 atm)were carried out in a high-T oven attached to a conventional x-ray diffractometer whereas high-P experiments(up to about 42 GPa at 25℃)were conducted in a diamond-anvil cell using synchrotron x-ray radiation.High-T data suggest a highly isotropic thermal expansivity whereas high-P data suggest a highly anisotropic compressibility for ReB2.展开更多
Elastic properties of three high pressure polymorphs of CaCO_3 are investigated based on first principles calculations.The calculations are conducted at 0 GPa–40 GPa for aragonite, 40 GPa–65 GPa for post-aragonite, ...Elastic properties of three high pressure polymorphs of CaCO_3 are investigated based on first principles calculations.The calculations are conducted at 0 GPa–40 GPa for aragonite, 40 GPa–65 GPa for post-aragonite, and 65 GPa–150 GPa for the P2_1/c-h-CaCO_3 structure, respectively. By fitting the third-order Birch–Murnaghan equation of state（EOS）, the values of bulk modulus K_0 and pressure derivative K~＇_0 are 66.09 GPa and 4.64 for aragonite, 81.93 GPa and 4.49 for post-aragonite, and 56.55 GPa and 5.40 for P2_1/c-h-CaCO_3, respectively, which are in good agreement with previous experimental and theoretical data. Elastic constants, wave velocities, and wave velocity anisotropies of the three highpressure CaCO_3 phases are obtained. Post-aragonite exhibits 25.90%–32.10% V_P anisotropy and 74.34%–104.30% V_S splitting anisotropy, and P2_1/c-h-CaCO_3 shows 22.30%–25.40% V_Panisotropy and 42.81%–48.00% V_S splitting anisotropy in the calculated pressure range. Compared with major minerals of the lower mantle, CaCO_3 high pressure polymorphs have low isotropic wave velocity and high wave velocity anisotropies. These results are important for understanding the deep carbon cycle and seismic wave velocity structure in the lower mantle.展开更多
文摘最近HERA发现 l q共振态可能是e+ d共振,该事例非标准模型(SM)所预期,与亚夸克层次有关.用价-海亚夸克混合模型和Preon模型给出的"编外"粒子研究 l q共振态的物理机制,结果发现:产生 l q共振的物理基础是由于"编外"玻色子中存在具有B+23物质性质的"反轻子型夸克",在反轻子和夸克之间传递相互作用的是具有ε物质性质的"编外"玻色子,在ε物质的相互交换下 e d共振与 νe u共振可以相互转变,并与早前的中微子统一模型、新名古屋模型相符.
基金Supported by the National Natural Science Foundation of China under Grant Nos 40474033 and 10376024, and the Specialized Research Fund for the Doctoral Program of Higher Education of China under Grant No 20050613017.
文摘High-pressure behaviour of orthorhombic MgSiO3 perovskite crystal is simulated by using the density functional theory and plane-wave pseudopotentials approach up to 120 GPa pressure at zero temperature. The lattice constants and mass density of the MgSiO3 crystal as functions of pressure are computed, and the corresponding bulk modulus and bulk velocity are evaluated. Our theoretical results agree well with the high-pressure experimental data. A thermodynamic method is introduced to correct the temperature effect on the O-K first-principles results of bulk wave velocity, bulk modulus and mass density in lower mantle PIT range. Taking into account the temperature corrections, the corrected mass density, bulk modulus and bulk wave velocity of MgSiO3-perovskite are estimated from the first-principles results to be 2%, 4%, and 1% lower than the preliminary reference Earth model （PREM） profile, respectively, supporting the possibility of a pure perovskite lower mantle model.
基金Supported by the National Natural Science Foundation of China under Grant No 40872033the Fundamental Research Funds for the Central Universities.
文摘We experimentally investigated some of the mechanical properties of ReB2 under high temperature/pressure(TIP)conditions.High-T experiments(up to 600℃at 1 atm)were carried out in a high-T oven attached to a conventional x-ray diffractometer whereas high-P experiments(up to about 42 GPa at 25℃)were conducted in a diamond-anvil cell using synchrotron x-ray radiation.High-T data suggest a highly isotropic thermal expansivity whereas high-P data suggest a highly anisotropic compressibility for ReB2.
基金supported by the National Natural Science Foundation of China(Grant Nos.41174071,41373060,41374096,and 41403099)the Seismic Fund of Institute of Earthquake Science,China Earthquake Administration(CEA)(Grant Nos.2012IES0408,2014IES0407,and 2016IES0101)
文摘Elastic properties of three high pressure polymorphs of CaCO_3 are investigated based on first principles calculations.The calculations are conducted at 0 GPa–40 GPa for aragonite, 40 GPa–65 GPa for post-aragonite, and 65 GPa–150 GPa for the P2_1/c-h-CaCO_3 structure, respectively. By fitting the third-order Birch–Murnaghan equation of state（EOS）, the values of bulk modulus K_0 and pressure derivative K~＇_0 are 66.09 GPa and 4.64 for aragonite, 81.93 GPa and 4.49 for post-aragonite, and 56.55 GPa and 5.40 for P2_1/c-h-CaCO_3, respectively, which are in good agreement with previous experimental and theoretical data. Elastic constants, wave velocities, and wave velocity anisotropies of the three highpressure CaCO_3 phases are obtained. Post-aragonite exhibits 25.90%–32.10% V_P anisotropy and 74.34%–104.30% V_S splitting anisotropy, and P2_1/c-h-CaCO_3 shows 22.30%–25.40% V_Panisotropy and 42.81%–48.00% V_S splitting anisotropy in the calculated pressure range. Compared with major minerals of the lower mantle, CaCO_3 high pressure polymorphs have low isotropic wave velocity and high wave velocity anisotropies. These results are important for understanding the deep carbon cycle and seismic wave velocity structure in the lower mantle.
