迷向周期和方法在β-簮结构折褶模拟中的应用

采用新近提出的迷向周期和方法(IPS),结合自导Lang evin动态模拟,模拟研究9余肽折褶成β簮结构的情况,表明了该结构与NMR观察到的基本一致,而Ewald模拟由于是强烈的镜像相互作用会产生构型偏差,获得致密构型的几率增大,表明IPS方法更适合于周期边界条件的模拟.     

Elaboration of AlSi10Mg casting alloys using directional solidification processing

The effects of pulling velocity on the solidification behavior and microstructural parameters of AlSi10Mg alloys prepared in a Bridgman-type directional solidification furnace were investigated. The microstructure, particularly the secondary dendritic arm spacing (SDAS), and the Brinell hardness (BH) of the solidified AlSi10Mg alloys were characterized for samples with cylindrical shapes and different conicities (θ=0°, 5°, and 10°). Microstructural studies revealed an increased density of α-Al phase dendrites and a decreased interdendritic distance with increasing pulling velocity. The dendrites were found to be preferentially oriented along the pulling direction for low pulling velocities. For larger pulling velocities, the dendrites grew first in the cooling direction but then broke as others nucleated and coarsened. The HB values of the solidified samples increased as the pulling velocity increased. In regard to sample conicity, smaller dendrites were observed for an apex angle of θ=5°, resulting in the largest HB value. This result was interpreted in terms of the favorable orientation of the dendrite along the pulling direction.     

Coupling agent based simulation with dynamic networks analysis to study the emergence of mutual knowledge as a percolation phenomenon

The emergence of mutual knowledge is a major cognitive mechanism for the robustness of complex socio-technical systems. It has been extensively studied from an ethnomethodological point of view and empirically reproduced by multi-agent simulations. Whilst such simulations have been used to design real work settings the underlying theoretical grounding for the process is vague. The aim of this paper is to investigate whether the emergence of mutual knowledge (MK) in a group of colocated individuals can be explained as a percolation phenomenon. The followed methodology consists in coupling agent-based simulation with dynamic networks analysis to study information propagation phenomena: After using an agent-based simulation the authors generated and then analyzed its traces as networks where agents met and exchanged knowledge. Deep analysis of the resulting networks clearly shows that the emergence of MK is comparable to a percolation process. The authors specifically focus on how changes at the microscopic level in the proposed agent based simulator affect percolation and robustness. These results therefore provide theoretical basis for the analysis of social organizations.     

重力由地球表面直至太空与宇宙——重力与广义相对论引论

本书初版于2003年，重印于2004年。据作者自称：“这是一本重力学面临革命新形势的读物。从地球地面开始通往宇宙的旅行中，开始倚靠牛顿大师及其继任人员对重力的认识，然后又由爱因斯坦及近代物理学家对万有引力知识的开拓和发展。就这样，我们已掌握很多的物理规律，最终目的，就是深入认识宇宙是如何工作的。”     

Genome-wide atlas of gene expression in the adult mouse brain

Molecular approaches to understanding the functional circuitry of the nervous system promise new insights into the relationship between genes, brain and behaviour. The cellular diversity of the brain necessitates a cellular resolution approach towards understanding the functional genomics of the nervous system. We describe here an anatomically comprehensive digital atlas containing the expression patterns of approximately 20,000 genes in the adult mouse brain. Data were generated using automated high-throughput procedures for in situ hybridization and data acquisition, and are publicly accessible online. Newly developed image-based informatics tools allow global genome-scale structural analysis and cross-correlation, as well as identification of regionally enriched genes. Unbiased fine-resolution analysis has identified highly specific cellular markers as well as extensive evidence of cellular heterogeneity not evident in classical neuroanatomical atlases. This highly standardized atlas provides an open, primary data resource for a wide variety of further studies concerning brain organization and function.