Topology theory on rough sets.

For further studying the theories and applications of rough sets (RS), this paper proposes a new theory on RS, which mainly includes topological space, topological properties, homeomorphism, and its properties on RS by some new definitions and theorems given. The relationship between partition and countable open covering is discussed, and some applications based on the topological rough space and its topological properties are introduced. Moreover, some perspectives for future research are given. Throughout this paper, the advancements of the new theory on RS and topological algebra not only represent an important theoretical value but also exhibit significant applications of RS and topology.     

Estimation and Spatial-temporal Distribution Characteristics of PM2.5 Concentration by Remote Sensing in China in 2015

Air pollution characterized by PM2.5 pollutants poses severe challenges to the sustainable development of society and human health. Therefore, it is of great significance to clarify the spatial-temporal distribution and evolution of PM2.5 pollutants in China for regional joint prevention and control of PM2.5 pollutants. Based on the MODIS satellite aerosol products, meteorological basic data and PM2.5 pollutant monitoring site monitoring data, a geographically weighted regression model was established to simulate and estimate PM2.5 pollutant concentration in China in 2015 on the basis of aerosol and meteorological data pre-processing. In addition, the spatial distribution pattern, the seasonal evolution characteristics of PM2.5 pollutant concentration were analyzed. The results showed that: (1) the PM2.5 concentration values in China in 2015 as a whole showed obvious spatial zonal differentiation characteristics. The concentration of pollutants in the north is significantly higher than that in the south, and the areas with high PM2.5 concentrations are mainly concentrated in the Beijing-Tianjin-Hebei region, the Jianghuai plain, the Sichuan basin, and the Takaramalkan desert. The area has a wide spatial distribution and significant continuity; (2) The PM2.5 concentration in the fourth quarter showed obvious seasonal adaptive evolution characteristics. The PM2.5 concentration changed significantly in the season. PM2.5 pollution was the heaviest in the fourth quarter, followed by the first quarter of the third quarter and the lowest in the second quarter. The maximum occurred in the fourth quarter (165 μg/m³). The minimum appeared in the second quarter (4.3 μg/m³). Seasonal changes in PM2.5 concentrations were influenced by meteorological factors and human social activities; and (3) The accuracy of the inversion of PM2.5_{concentration by a multi-factorial, geographically weighted regression model was higher, with relative errors in the four quarters being 10.2%, 7.0%, 9.3%, and 8.6%, respectively.}     

深部堵水压裂在川口油田的应用

文章详细介绍了如何利用深部堵水压裂技术来提高油井的生产能力的方法.以川口油田的实例进行测试,获得了较满意的结果.     

二氟甲基的应用和二氟乙酸酯的合成研究

介绍了二氟甲基的应用,并根据起始原料的不同,对二氟甲基的的重要合成砌块二氟乙酸酯的合成工艺进行优缺点分析和探讨。     

Voltammetric studies of a novel bicopper complex modified glassy carbon electrode for the simultaneous determination of dopamine and ascorbic acid

A novel modified glassy carbon electrode (GCE) with a binuclear copper complex was fabricated using a cyclic voltammetric method in phosphate buffer solution. This modified electrode shows very efficient electrocatalytic activity for anodic oxidation of both dopamine (DA) and ascorbic acid (AA) via substantial decrease in anodic overpotentials for both compounds. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) using this modified electrode show two well-resolved anodic waves for the oxidation of DA and AA in mixed solution, which makes it possible for simultaneous determination of both compounds. Linear analytical curves were obtained in the ranges 2.0–120.0 μM and 5.0–160.0 μM for DA and AA concentrations by using DPV methods, respectively. The detection limits were 1.4 × 10⁻⁶ M of DA and 2.8 × 10⁻⁶ M of AA. This electrode was used for AA and DA determinations in medicine and foodstuff samples with satisfactory results.     

香山站500kV1号壳变A相故障处理及分析

介绍了中山香山站500kV1号壳变A相故障解体处理采取的措施,为以后处理该类事故提供了很好的经验.     

利用导电加热切削抑制积屑瘤和鳞刺的研究

通过导电加热的温度补偿，导电加热切削能有效抑制金属切削表面的积屑瘤和鳞刺。刀－工接触区的温升与加热电流密切相关，存在一个与最佳切削温度相适应的最佳加热电流值范围。     

Rapid chemical synthesis and optical properties of ZnO ellipsoidal nanostructures

ZnO ellipsoidal nanostructures were rapidly synthesized using a chemical synthesis method at 90 °C without the assistance of aging procedure, calcination, sonication, microwave, laser or any organic additives. The effects of pH values and Zn²⁺ concentration on the morphologies of ZnO nanostructures were investigated. The instantaneous underdeveloped ZnO nanostructures were successfully obtained by using the electrophoretic deposition (EPD). Based on the experimental results, growth mechanism of ellipsoidal ZnO nanostructures was proposed. The ellipsoidal nanostructures are self-assembled by the oriented-attachment growth of primary nanoparticles, involving the end-to-end oriented-attachment along the major axis and the side-by-side oriented-attachment along the minor axis. Two half-ellipsoids of the ZnO nanostructures germinate in sequence. The UV–vis absorption and photoluminescence of the ellipsoidal nanostructures was also studied. This work presents a simple and ultra-fast route for large-scale fabrication of ZnO ellipsoidal nanostructures.     

Immobilization of type-I collagen and basic fibroblast growth factor (bFGF) onto poly (HEMA-co-MMA) hydrogel surface and its cytotoxicity study

Type-I collagen and bFGF were immobilized onto the surface of poly (HEMA-co-MMA) hydrogel by grafting and coating methods to improve its cytotoxicity. The multi-layered structure of the biocompatible layer was confirmed by FTIR, AFM and static water contact angles. The layers were stable in body-like environment (pH 7.4). Human skin fibroblast cells (HSFC) were seeded onto Col/bFGF-poly (HEMA-co-MMA), Col-poly (HEMA-co-MMA) and poly (HEMA-co-MMA) films for 1, 3 and 5 day. MTT assay was performed to evaluate the extraction toxicity of the materials. Results showed that the cell attachment, proliferation and differentiation on Col/bFGF-poly (HEMA-co-MMA) film were higher than those of the control group, which indicated the improvement of cell-material interaction. The extraction toxicity of the modified materials was also lower than that of the unmodified group. The protein and bFGF immobilized poly (HEMA-co-MMA) hydrogel might hold great promise to be a biocompatible material.     

浅析土家族民居建筑元素的构成

文章通过对土家族建筑元素的构成分析研究,阐述了土家族建筑具有特色的构造技术与审美取向。