可扩展的冲击—接触并行计算研究

冲击—接触计算模型在汽车碰撞、金属成型等的模拟计算中有着广泛的应用，鉴于冲击—接触计算过程复杂和计算量大，本文在分布式可扩展的并行计算平台上，设计并实现了冲击—接触的并行计算。算例证明，计算平台稳定可靠，算法简单实用，且具有较好的并行效率和可扩展性。     

Discontinuous and continuous transitions of collective behaviors in living systems

Living systems are full of astonishing diversity and complexity of life. Despite differences in the length scales and cognitive abilities of these systems, collective motion of large groups of individuals can emerge. It is of great importance to seek for the fundamental principles of collective motion, such as phase transitions and their natures. Via an eigen microstate approach, we have found a discontinuous transition of density and a continuous transition of velocity in the Vicsek models of collective motion, which are identified by the finite-size scaling form of order-parameter. At strong noise, living systems behave like gas. With the decrease of noise, the interactions between the particles of a living system become stronger and make them come closer. The living system experiences then a discontinuous gas-liquid like transition of density. The even stronger interactions at smaller noise make the velocity directions of the particles become ordered and there is a continuous phase transition of collective motion in addition.     

Large Decay Rate Variation of ^7Be in Pd and Au

Platinum and gold have the similar crystal structure but different electronic affinities, as well as different effective electron densities near the implanted ions. Both the differences favour larger decay rate of ^7 Be in Pd than that in Au. We measured the variation of the decay rate of ^7Be implanted in Pd and Au host materials. We have found that the decay rate of ^7 Be in Pd is larger than that in Au by 0.8%.     

谈谈正确理解电子电路中有关约束条件的重要性

全面考虑电路的约束条件，对于正确地分析电子电路是非常重要的。本文通过具体的应用实例，强调正确地、全面地理解约束条件在电子电路分析中的重要性。     

Ionic Liquid Based Electrolyte with Mesoporous Silica SBA-15 as Framework for Quasi-solid-state Dye-sensitized Solar Cells

Quasi-solid-state electrolytes were fabricated with mesoporous silica SBA-15 as a framework material. Ionic conductivity measurements revealed that SBA-15 can enhance the conductivity of the quasi-solid-state electrolyte. The diffusion coefficients of polyiodide ions such as Ⅰ3ˉ and Ⅰ5ˉ which were confirmed by Raman spectroscopic measurement, were about twice larger than that of I-. The optimized photoenergy conversion efficiency of dye-sensitized solar cells （DSSC） with the quasi-solid-state electrolyte was 4.3% under AM 1.5 irradiation at 75 mW·cm^-2 light intensity.     

有机多羧酸为桥连配体的过渡金属配位聚合物化学

以FeCl₃∙6H₂O, Na₄bta (H₄bta = 1,2,4,5-benzentetracarboxilic acid), 1,10-phen (1,10-phenanthroline)和H₂O为原料, 用水热技术合成出了以均苯四甲酸根为桥连配体的新的二维配位聚合物[Fe(μ₄-bta)_0.5(phen)(OH)]_n (1). 化合物1的晶体属于单斜晶系, P2₁/n空间群, a = 1.0129(2), b = 0.9265(2), c = 1.5696(3) nm, β = 91.37(3)°, V = 1.4721(5) nm³, Z = 3. 一致性因子R₁ = 0.0292, wR₂ = 0.0798. 结构测定结果表明, 化合物中, 每个bta配体连接四个Fe^III单元, 构成新的μ₄-配位模式, bta的四个脱质子的羧基, 交替地以单齿和双齿配位方式与Fe^III离子连接, 构成二维无限层状结构.磁性测试结果表明, 该化合物中存在着反铁磁相互作作用. 热失重谱显示出, 它具有较好的热稳定性. 此外, 还测定了化合物的IR及UV-Vis谱.     

不宜对光子碰撞引用“ 碰撞恢复系数”概念

参考文献[ 1]对光子碰撞引用“ 弹性恢复系数” , 本文对此提出质疑, 指出光速是光子的性质而不是碰 撞的运动量, 不宜对光子碰撞引用“ 碰撞恢复系数”的概念     

Dynamical Evolution of Globular Clusters in the Galaxy

Given the initial conditions of spatial density distribution, velocity distribution and mass function, the dynamical evolution of globular clusters in the Milky Way is investigated in details by means of Monte Carlo simulations.Four dynamic mechanisms are considered: stellar evaporation, stellar evolution, tidal shocks due to both the disc and bulge, and dynamical friction. It is found that stellar evaporation dominates the evolution of low-mass clusters and all four are important for massive ones. For both the power-law and lognormM initial clusters mass functions, we can find the best-fitting models which can match the present-day observations with their main features of the mass function almost unchanged after evolution of severM Gyr. This implies that it is not possible to determine the initial mass function only based on the observed mass function today. The dispersion of the modelled mass functions mainly depends on the potential wells of host galaxies with the almost constant peaks,which is consistent with current observations.     

Fe-N-C 类催化剂在碱性燃料电池中的研究进展

随着阴离子交换膜的出现、发展和应用,碱性燃料电池的优势日趋明显,针对碱性燃料电池的研究也更广泛而深刻. 在碱性燃料电池中,除了其固有的对催化剂的高包容性和动力学优越性,阴离子交换膜让阴离子定向迁移,从而实现了很好的水相管理,降低了电池中“水涝”的几率,也提供了更广阔的燃料选择空间. 氧还原反应是碱性燃料电池中的重要部分,且其反应动力学相较于氢氧化反应缓慢. 因此,选择并研制合适的阴极氧还原反应催化剂,是提高碱性燃料电池性能和促进燃料电池规模化使用的关键. Fe-N-C类催化剂因其在碱性条件下接近甚至优于 Pt 基催化剂的性能,被视为最有潜力替代 Pt 的非贵金属催化剂. 本文从近 5 年来 Fe-N-C 类催化剂的合成方法、催化活性位点和氧还原反应机理以及在燃料电池中的应用三方面进行了综述.