Analysis of complexity indices for classification problems: Cancer gene expression data

Currently, cancer diagnosis at a molecular level has been made possible through the analysis of gene expression data. More specifically, one usually uses machine learning (ML) techniques to build, from cancer gene expression data, automatic diagnosis models (classifiers). Cancer gene expression data often present some characteristics that can have a negative impact in the generalization ability of the classifiers generated. Some of these properties are data sparsity and an unbalanced class distribution. We investigate the results of a set of indices able to extract the intrinsic complexity information from the data. Such measures can be used to analyze, among other things, which particular characteristics of cancer gene expression data mostly impact the prediction ability of support vector machine classifiers. In this context, we also show that, by applying a proper feature selection procedure to the data, one can reduce the influence of those characteristics in the error rates of the classifiers induced.     

New Insights into the Decisional Use of Process Capability Indices via Hypothesis Testing

Process capability indices C_p, C_pk, and C_pm are still nowadays widely used in industry—thanks to their easy formulation and implementation. This paper aims to give new mathematical insights in order to support their use in decision‐making via hypothesis testing. The minimum sample size usually needed in the applications to achieve fixed significance level and power is reported in light of the new mathematical aspects for C_pk and C_pm, which avoid misleading conclusions and the use of extensive numerical experiments. In addition, power curves for C_pk and C_pm, which have not previously appeared in the literature before, are also presented. Lastly, easy‐to‐follow diagrams for hypothesis testing with C_pk and C_pm and two critical scenarios for C_pm are included in the paper to facilitate the applicative use and the comprehension of the novel inferential aspects. Copyright © 2014 John Wiley & Sons, Ltd.     

辉钼矿工艺矿物学特征与选矿指标关系研究

在选矿试验研究的基础上,结合对蚀变岩、花岗岩及石英脉等类型辉钼矿的工艺矿物学特征考察,分析了矿石类型、嵌布特征和矿粒粒度等与其选矿指标的关系。研究表明,辉钼矿的选矿指标与其矿粒粒度关系密切,随着辉钼矿矿粒面积累计含量的增加,其选矿指标提高明显。本研究的开展,将为全面开展典型矿产资源工艺矿物学特征调查,运用现代测试分析技术(如MLA等),快速分析矿物嵌布粒度、分布状态等矿石特征,研究总结其与选矿工艺指标关系,建立矿产资源节约与综合利用评价指标体系,实现矿产资源合理开发利用评价,为促进矿产资源节约与综合利用管理奠定基础。     

Urbanization Effect on Floristic and Landscape Patterns of Green Spaces

The study explored the effects of intensive urbanization on urban plant diversity and landscape pattern. An inventory of plant species in managed green spaces in the nine urban districts of Guangzhou (south China) with varied development history was conducted. The relationships among species richness, diversity and urban development were analysed by community ecology attributes, cluster analysis, growth-form differentiation and district fidelity indices, and statistical tests. The 1055 vascular species were dominated by a small number of common evergreen species, accompanied by many rare species. By species richness, tree was the dominant growth form, followed by herb and shrub. Species richness and diversity were slightly below urban-fringe secondary forests. Old and young districts offered disparate conditions for species enrichment to establish urban landscape patterns with divergent floristic and growth-form assemblages. Urban species profile and vegetation landscapes were mainly influenced by planning and management of the urban landscape and changing landscape fashion.     

Effect of CO2 Exposure on the Chemical Stability and Mechanical Properties of BaZrO3‐Ceramics

The reactivity of BaZrO₃ with CO₂ has been addressed as one of the major challenges with BaZrO₃‐based electrolytes in protonic ceramic fuel cells. Here, we present a study of the effect of CO₂ exposure on BaZrO₃‐materials at elevated temperatures. Dense BaZr_1?xY_xO_3?x/2 (x = 0, 0.05, 0.1, 0.2) and BaCe_0.2Zr_0.7Y_0.1O_2.95 ceramics were prepared by sintering of powder prepared by spray pyrolysis. The Vickers indentation method was used to determine the hardness and estimate the fracture toughness of pristine materials as well as the corresponding materials exposed to CO₂. Formation of BaCO₃ on the surface of exposed ceramics was confirmed by X‐ray diffraction and electron microcopy. The reaction resulted in formation of Ba‐deficient perovskite at the exposed surface. The reaction with CO₂ was most pronounced at 650°C compared to the other temperatures applied in the study. The reactivity was also shown to depend on the Y‐content and the grain size and was most pronounced for BaZr_0.9Y_0.1O_2.95. The reaction with CO₂ was observed to have a profound effect on the fracture toughness of the ceramics, demonstrating a depression of the mechanical stability of the materials. The results are discussed with respect to the chemical and mechanical stability of BaZrO₃ materials, with particular emphasis on the composition and grain size.     

Processing of ZrO2 scaffolds coated by glass–ceramic derived from 45S5 bioglass

Three dimensional, highly porous, ZrO₂ scaffolds coated by glass–ceramic derived from 45S5 bioglass were fabricated. The surface reactivity of 45S5 in aqueous solution was investigated as a function of the immersion time. The influence of the solid loading on the rheological behavior of 45S5 aqueous slips with ammonium polyacrylate (NH₄PA) was studied; besides the effect of poly(vinyl)alcohol (PVA) on the relative viscosity was determined. The structure and microstructure of uncoated and coated ZrO₂ scaffolds were characterized. The high ionic exchange capability of 45S5 was demonstrated by the pH rise, the significant weight loss and the amorphous calcium phosphate nucleation, upon its immersion in aqueous solution. The addition of PVA did not affect the dispersion properties of the 45S5 powder, which were basically controlled by its negative surface charge. 30 wt% 45S5 slips with 4 wt% PVA exhibited a yield stress and an adequate viscosity in the low shear rate range, to produce a bioglass coating into the ZrO₂ scaffold. The glass-ceramic coating was distributed along the strut surfaces, forming a thin film without altering the porosity and the strut thickness of the original ZrO₂ scaffold structure.     

不同煤配比对胶质层指数的影响研究

为提高焦炭质量,降低生产成本,采用陕北地区常见的气煤、肥煤、东风煤进行单独炼焦,分析3种煤单独炼焦时生成的焦炭质量。在此基础上将3种煤按不同比例配煤炼焦,分析不同配比下焦炭质量的变化,研究最佳配煤方案。结果表明：气煤单独炼焦所得焦炭质量差,但配入气煤可增加产气率和焦饼收缩度;肥煤是优质炼焦煤,但单独炼焦所得焦炭气孔率高,需配煤以改善焦炭质量;东风煤无法单独炼焦,但少量配入可增加焦炭强度,减少优质炼焦煤用量。气煤、肥煤、东风煤质量比为1∶6∶3时,焦炭质量最好,孔隙小,无缝隙和绽边,色泽为银灰色,无海绵体,部分熔合;配煤胶质层最大厚度Y=20.4 mm,最终收缩度X=7.2 mm。     

低灰熔点无烟煤煤焦与CO_2催化气化特性研究

利用碱金属碳酸盐作催化剂,对低灰熔点无烟煤煤焦与CO2的催化气化反应活性进行研究.结果表明,反应活性主要受温度、催化剂种类及担载量的影响,催化活性顺序为:K2CO3Na2CO3Li2CO3,煤焦的反应活性随着催化剂担载量的增加而提高;在反应过程中,催化剂与煤焦中的物质会发生一定程度的反应,生成不溶性盐;煤焦的比表面积会随着催化剂担载量的增大而减小,但催化活性反而增强,其主要受到催化剂提供的反应活性中心的影响.     

中国纺织业国际竞争力评价指标体系研究(Ⅰ)

面对中国加入WTO和经济全球化的国际背景,研究中国纺织产业国际竞争力具有突出的重要意义。因此,本文基于产业国际竞争力的基本理论,对我国纺织产业国际竞争力的研究意义、现状、定义、构建原则、影响因素及评价指标体系作了详细的论述与分析,以期为今后的进一步研究打下良好的基础。     

铂催化硅氢加成反应研究进展

硅氢加成反应是合成有机硅材料最重要的途径之一,铂催化剂作为其应用最广的催化剂,具有重要的意义。本文首先介绍了硅氢加成反应机理的研究现状;分析了聚合物长链段铂配合物、含多个铂原子铂簇化合物及N-杂环卡宾铂配合物均相铂催化剂的研究进展,致力于改善均相催化剂催化选择性差、催化活性难以控制等缺点;分别阐述了不同铂催化剂载体如无机二氧化硅、炭载体、金属氧化物、有机高分子、固载液等作为铂催化剂载体的优点,负载铂催化剂具有可回收、产物选择性好的优点,有效解决了工业上铂损失的问题;最后对铂催化硅氢加成反应的发展趋势进行了展望分析,铂负载能力的提高、铂负载催化剂的分离、硅氢加成反应的原理、催化范围的扩大等均是今后研究的重要方向。