股骨近端防旋髓内钉治疗高龄股骨转子间骨折

因子模型在刻画因子之间的相互关系以及因子与观测变量之间的关联性具有重要作用.在实际应用中,观测数据往往呈现出时序变异多峰、偏态等特性.本文将经典的潜变量模型延伸到非齐次隐马尔可夫潜变量模型,建立了极大似然统计分析程序.经验结果展示所建立的统计程序是有效的.     

Electronic and mechanical properties of half-metallic half-Heusler compounds CoCrZ(Z=S,Se, and Te)

The electronic structures, magnetic properties, half-metallicity, and mechanical properties of half-Heulser compounds CoCrZ(Z = S, Se, and Te) were investigated using first-principles calculations within generalized gradient approximation based on the density function theory. The half-Heusler compounds show half-metallic properties with a half-metallic gap of 0.15 eV for CoCrS, 0.10 eV for CoCrSe, and 0.31 eV for CoCrTe at equilibrium lattice constant, respectively. The total magnetic moments are 3.00μB per formula unit, which agrees well with the Slater-Pauling rule. The half-metallicity,elastic constants, bulk modulus, shear modulus, Pough's ratio, Frantesvich ratio, Young's modulus, Poisson's ratio, and Debye temperature at equilibrium lattice constant and versus lattice constants are reported for the first time. The results indicate that the half-Heulser compounds CoCrZ(Z = S, Se, and Te) maintain the perfect half-metallic and mechanical stability within the lattice constants range of 5.18-5.43  for CoCrS, 5.09-5.61  for CoCrSe, and 5.17-6.42  for CoCrTe,respectively.     

Quantum phase transition and Coulomb blockade effect in triangular quantum dots with interdot capacitive and tunnel couplings

The quantum phase transition and the electronic transport in a triangular quantum dot system are investigated using the numerical renormalization group method.We concentrate on the interplay between the interdot capacitive coupling V and the interdot tunnel coupling t.For small t,three dots form a local spin doublet.As t increases,due to the competition between V and t,there exist two first-order transitions with phase sequence spin-doublet-magnetic frustration phase-orbital spin singlet.When t is absent,the evolutions of the total charge on the dots and the linear conductance are of the typical Coulomb-blockade features with increasing gate voltage.While for sufficient t,the antiferromagnetic spin correlation between dots is enhanced,and the conductance is strongly suppressed for the bonding state is almost doubly occupied.     

木质素模型化合物的电化学催化研究：转化特性与产物选择性（英文）

酚类衍生物是生物油的关键组分,对其电催化加氢（ECH）性质的深入理解对于高效利用生物油至关重要。基于此种考量,本工作研究了生物油中代表性物质愈创木酚的电催化加氢性能,探讨了其电催化加氢的反应机制、转化率和产品选择性在不同反应条件下（温度：40-80°C,高氯酸浓度：0.2–1.0 mol/L,电流强度：（–10）–(–150) m A）的变化。同时,也探索了愈创木酚中间产物（2-甲氧基环己酮和环己酮）等对其电催化加氢的影响。结果表明,愈创木酚的ECH转化率随温度和电流强度的提高而增加,但高氯酸浓度的增加则对转化率具有相反的影响。同时发现,中间产物的存在增强了愈创木酚的电催化加氢转化率,尤其是2-甲氧基环己酮,其效果更为显著。在此基础上,对其他种酚类衍生物（包括苯酚、邻苯二酚、愈创木酚、丁香酚和香草醛）及其混合物的电催化加氢机制的进一步研究中发现,模型化合物的电催化转化率与苯环上官能团的复杂程度成反比。在其中结构最简单的苯酚具有最高的转化率（89.34%）,而由于结构更复杂,香草醛的转化率最低,仅为46.79%。同时,在多组分混合物的电催化加氢研究中发现,模型化合物的协同和竞争机制将显著...