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991.
The compound In0.95CNi3 has been synthesized and the basic properties have been investigated. It has the typical antiperovskite structure (space group Pm3m, lattice parameter 3.7836 Å). The electronic specific coefficient γ and Debye temperature ΘD are found to be 14.1 mJ/mol K2 and 372 K, respectively. It behaves as a ferromagnetic metal below the Curie temperature (577 K). The emergence of ferromagnetism is suggested to originate from the deviation of the Ni/In atomic ratio from the ideal stoichiometry. The possible mechanisms have been discussed in detail in terms of this deviation. 相似文献
992.
Electronic and atomic structures of different terminations of the (0 0 1) non-polar orientation of BaZrO3 surfaces have been studied using first-principles calculations. We found that surface energies at both possible surface terminations, BaO and ZrO2, were very close. The (0 0 1)-BaO and (0 0 1)-ZrO2 terminated surfaces have bandgap values smaller than that of a bulk BaZrO3 crystal. In addition, the relative surface stability has been analyzed as a function of chemical environment. 相似文献
993.
We propose the parameters of the Stillinger-Weber potential for hexagonal boron nitride (BN) structures. For the reliability of these parameters, the structural property of BN fullerenes is investigated. The stability of BN fullerenes increases with increasing the number of atoms, due to the reduction of the curvature effect of BN fullerenes. The structures of the relative stable fullerenes are B16N16, B18N18, B22N22, B25N25, and B28N28. 相似文献
994.
We measure the content of random uncorrelated noise in heart rate variability using a general method of noise level estimation using a coarse-grained entropy. We show that usually, except for atrial fibrillation, the level of such noise is within 5-15% of the variance of the data and that the variability due to the linearly correlated processes is dominant in all cases analyzed but atrial fibrillation. The nonlinear deterministic content of heart rate variability remains significant and may not be ignored. 相似文献
995.
996.
We study experimentally the interaction of a dark spot with a nonlinear photonic lattice with fully incoherent white light emitted from an incandescent bulb in the self-defocussing photovoltaic media when the dark spot is aimed at different positions of lattices with different lattice spacing. In this case a host of novel phenomena is demonstrated, including dark spot induced lattice dislocation-deformation, the annihilation of the dark spot and so on. Results demonstrate that the interaction between incoherent dark spot and photonic lattice is always attraction and the large-spacing photonic lattice is analogous to the continuous medium. 相似文献
997.
998.
应用英国Edinburgh FLS920P型稳态和时间分辨荧光光谱仪,对日落黄与诱惑红溶液进行荧光光谱的实验测量,得到日落黄荧光峰在420 nm,诱惑红荧光峰在432 nm。进一步,应用Gaussian 09W软件构建日落黄分子与诱惑红分子的基态和激发态的几何构型,基于密度泛函理论和含时密度泛函理论,完成对两种分子基态和激发态的优化和计算。优化过程中,采用MPWK泛函和6-31g(d)基组;计算过程中,采用B3LYP泛函和6-311g(d,p)基组。考虑到溶剂效应对计算结果的影响,因此在计算过程中引入了极化连续介质模型,最后计算得到日落黄的荧光峰在435 nm,与实验所得有3.57%的相对误差;计算得到诱惑红荧光峰在443 nm,与实验所得有2.55%的相对误差,两种分子荧光峰的相对误差都在允许范围之内,说明计算合理。在分析光谱特性时,发现两种分子荧光峰的产生与分子内电荷转移有关。 相似文献
999.
本文基于分子温度与压强的关系,计算在不同压强下基态和最低三态硝基甲烷的分子温度,对应计算其沿着CN键裂解反应的热化学和动力学参数.发现基态的硝基甲烷沿着CN键的分解反应是吸热反应,不具自发性,反应转换温度为1550.2 K,平衡常数在80-1202 K温度范围内很低.最低三态的硝基甲烷沿着CN键的裂解是放热反应,反应的Gibbs自由能在80-2558.5 K范围内为负,有好的自发性,且反应较为彻底.298.15-2558.5 K温度范围内反应活化能随着温度的升高而改变,使反应速率随着温度的升高而急剧增大.对应硝基甲烷爆压15 GPa,其分子温度为4617.6 K,该温度下三态分子分解反应的反应速率为1.088×10~8cm~3·mol~(-1)·s~(-1).推算硝基甲烷沿着CN键分解反应混合物的终态温度,当混合物为硝基、甲基和基态的硝基甲烷分子时,反应的终温为1611.37 K,等效能为1676.47 cm~(-1).当混合物为硝基、甲基、基态和最低三态的硝基甲烷分子时,反应的终温为1184.79 K,等效能为1232.65 cm~(-1).两种情况下终态等效能都足以维持硝基甲烷分子沿C-N键裂解反应的发生.这个能量也足以导致混合物中的NO_2分解为NO和O,这与实验检测的结论相一致. 相似文献
1000.
The present work concerns the study of solvent effects on the geometrical structures, as well as one- and two-photon absorption (TPA) processes, for two series of alkyne and alkene π-bridging molecules, within the framework of the polarization continuum model. Particular emphasis was put on the characterization of solvent effects on the molecular geometrical structures and geometric distortion, which were measured by the bond-length-alternation parameter. The π centres in the compounds are seen to play a decisive role in increasing the TPA cross section and nonlinear optical properties. All studied molecules have relatively strong TPA characteristics, while the alkyne π-bridging ones yield larger TPA cross sections. 相似文献