Formation and atomic structures of boron nitride nanohorns

Boron nitride (BN) nanohorns were synthesized by an arc-melting method, and atomic structure models for BN nanohorns with tetragonal BN rings were proposed from high-resolution electron microscopy. Stability and electronic structures of the BN nanohorns were investigated by molecular orbital/mechanics calculations. The calculation showed that multiwalled BN nanohorns would be stabilized by stacking of BN nanohorns. The energy gap of BN nanohorn was calculated to be 0.8 eV, which is lower compared to those of BN clusters and nanotubes.     

利用磁控溅射与液氮冷凝相结合产生金属及其化合物团簇

利用磁控溅射与液氮冷凝相结合的团簇产生设备成功地制备了多种金属及金属化合物等团簇，团簇尺寸大小为２－３０ｎｍ，其微结构为晶体结构。     

矽肺病人发元素谱的Q型逐次信息群分

用Ｑ型逐次信息群分对白银矿区４２名矽肺患者和４１名正常人头发样的元素谱Ｃｒ、Ｚｎ、Ｍｇ、Ａｌ、Ｃｄ进行无监督模式识别，获得分类清晰的谱系图，８３个样本的判别正确率达９８．８％。     

Linux机群文件系统的研究与实现

机群是当前高性能计算领域的主流体系结构，随着Linux操作系统的成熟和pc机性能的提高，用Linux和pc节点构造的机群系统越来越多地应用于高性能计算领域。I／O子系统和机群文件系统的性能对整个机群系统的性能有重要的影响，本文在曙光3000cosmos机群文件系统的基础上，针对曙光3000LLinux机群系统设计实现了基于Linux的机群文件系统cosmos－L，对cosmos－L进行了性能测试，并与PVFS文件系统进行了比较。     

An approach based on two-dimensional graph theory for structural cluster detection and its histopathological application

An approach based on graph theory is described for detecting clusters of cells in tissue specimens (two-dimensional space). With a set of discrete basic elements (cell nuclei) having several measurable features (area, surface, main and minor axis of best-fitting ellipses) a graph is defined as having attributes associated with edges. Different minimum spanning trees (MSTs) can be constructed using different weight functions on the attributes (attributed MST). Analysis of the MST and of an attributed MST by use of a decomposition function allows detection of image areas with similar local properties. These clusters, which are then clusters of the tree, describe, for example, partial growth in different directions in a case of a human fibrosarcoma assuming that tumour cell nuclei are homogeneous with respect to their configuration and size. The model allows the separation of clusters of tumour cells growing in different directions and the approximation of the different growth angles. This decomposition also allows us to create new (higher) orders of structure (cluster tree).     

Activated diffusion in relaxed porous clusters

We study diffusion through disordered porous structures, where the size of the diffusing particle is of the order of the pore diameter, and focus on the effect of particle-wall interactions. Such ‘configurational diffusion’ is important in catalysis, separation, and membrane technology, yet it is still poorly understood. We consider three types of cluster cluster aggregation (CCA) structures using simulations carried out on a cubic lattice. Namely, (1) next-neighbor (classic) CCA, where each site may have up to six nearest neighbors; (2) CCA where each site may have up to 26 nearest neighbor in its first coordination shell; and (3) a relaxed CCA solid formed by a process of energy minimization. We find that at low interaction strengths, diffusivity through the various types of CCA structure of similar porosity is independent of the mode of preparation and can be well predicted. However, at high interaction strengths which inhibit the diffusivity considerably, clusters characterized by lower surface-to-volume ratio display lower diffusivities. We suggest a simple model that accounts for the dependence of the diffusivity on the interaction parameter.     

Formation of single-phase BaO nanoclusters

Combined analysis employing in-situ X-ray photoelectron spectroscopy, Auger electron spectroscopy, and ex-situ X-ray diffraction has demonstrated the feasibility to deposit single-phase barium oxide overlayers by a direct sublimation of BaO material from an effusion cell. Furthermore, in situ scanning tunneling microscopy has confirmed that the BaO grows as nanoclusters with dimensions down to ~ 2 nm.     

基于混合矩特征提取的飞机图像识别

提出了一种新的基于图像区域纹理混合矩特征的飞机识别算法.该算法基于一阶直方图的颜色矩特征和基于灰度共生矩阵提取区域图像相关性、角二阶矩、对比度、相关性、倒数差分矩特征,实现有效降维,并采用聚类分析方法对飞机图像进行识别,实验结果显示基于该特征提取的识别方法识别正确率达95%以上,通过对比试验说明,该算法有较好的识别性能.     

NSC技术在宝钢铁钢快速分析计算机系统中的应用

作为一种构建高可靠、永不间断系统的关键技术,NonStop在关键应用领域得到广泛运用。宝钢检化验快速分析计算机在工业标准服务器上应用NSC技术,构建出了一套满足实时应用的高可靠性、高性价比的过程控制计算机系统。     

Effect of the cascade energy on defect production in uranium dioxide

The primary damage induced by a displacement cascade in a pure uranium dioxide matrix was investigated using classical molecular dynamics simulations. Cascades were initiated by accelerating a uranium primary knock-on atom (PKA) to a kinetic energy ranging from 1 keV to 80 keV inside a perfect UO₂ lattice at low temperature (300 K and 700 K). There is little effect of temperature in the temperature range studied. Following the cascade event, the damage level, defined as the total number of defects irrespective of whether they form clusters or not, is proportional to the initial kinetic energy of the PKA, in agreement with the literature relating to other materials. The linear dependence of damage upon initial PKA energy results from the formation of subcascades at high energy and constitutes a simple law which can be applied to any material and used in order to extrapolate molecular dynamics results to high energy PKAs. The nature of irradiation induced defects has also been studied as a function of the cascade energy.