Spark平台上利用网络加权Voronoi图的分散迭代社区聚类并行化研究

针对当下数据大规模增长对计算能力需求的急剧增长,传统独立运行的机器在大规模网络社区中执行社区检测操作时无法提供所需的数据处理能力的问题,提出一种网络加权Voronoi图的并行分散迭代社区聚类法(NWVD-PDICCM).利用基于网络加权Voronoi图的分散迭代社区聚类方法(NWVD-DICCM)提取大型网络的有效社区...     

耦合效应下的煤矿顶板事故风险因素评价研究

在考虑人为因素、设备因素、环境因素和管理因素间的交互耦合效应的基础上,通过 N-K模型量化煤矿顶板事故风险因素的耦合效应,建立加权直觉模糊集决策矩阵,并结合TOPSIS模型构建煤矿顶板事故风险因素的评价模型。对我国2008—2018年发生的185起典型煤矿顶板事故进行实例分析,总结出主观的人为因素或管理因素是煤矿顶板事故风险中更活跃的因素,与客观的设备因素或环境因素耦合易引发煤矿顶板事故,且人为因素比管理因素的影响更为关键。     

The effect of annealing on the properties of Ga2O3 anodic films

The effect of annealing and oxygen plasma on the electrical characteristics of gallium oxide films has been investigated. Ga₂O₃ films with thicknesses of 200–300 nm were formed by the anodic oxidation of n-GaAs wafers with the donor concentration N _d = (1–2) × 10¹⁶ cm⁻³. It is shown that, after annealing at 900°C for 30 min, the gallium arsenide films contain only the β Ga₂O₃ phase. The effect of the duration of oxygen plasma treatment prior to annealing on the nucleation of β-phase crystallites with different orientations has been studied. It has been established that the electrical conductivity of the Ga₂O₃ films can be managed by annealing and variation in the duration of oxygen plasma treatment. It is shown that the response of the V/Ni-GaAs-Ga₂O₃-V/Ni structure to a mixture exhaled by a person depends on the value and sign of the potential on the control electrode.     

同位素释放器与氧活化仪器组合测井的应用

文章介绍了同位素五参数测井和氧活化测井的测井原理，分析了它们各自的优势与不足，采用同位素释放器和氧活化仪器组合的方式，使一次下井可以同时完成同位素、氧活化两种工艺方法，为提高吸水剖面测井质量提供了新的手段。     

Comparison of a new algorithm with the supervised classifications

In this study, a new classification algorithm in which only the selected pixels have been attempted to be classified (selected pixels classification: SPC) has been introduced and compared with the well known supervised classification methods such as maximum likelihood, minimum distance, nearest neighbour and condensed nearest neighbour. To examine the algorithm, Landsat Thematic Mapper (TM) data have been used to classify the crop cover in the selected region. It is clearly demonstrated that the SPC method has the higher accuracy with comparable CPU times.     

GSM话音质量综合优化方法研究

中国移动综合考虑网络RxQual、MOS评分提出基于用户主观感受和网络客观质量的话音质量评估标准,本文基于此标准对影响GSM网络话音质量的因素进行分析,创新性的给出各种影响因素排序,针对不同影响因素提出优化措施,最后结合某移动公司GSM网络话音质量优化效果验证综合优化方法的可行性。     

Antioxidative activities and the chemical constituents of two Chinese teas,Camellia kucha and C. ptilophylla

Two kinds of green tea were prepared with the young shoots of Camellia kucha and C. ptilophylla, and antioxidative activities of the chemical constituents were determined. Levels of alkaloids, catechins, total polyphenols, flavonoids and amino acids were determined by high‐performance liquid chromatography and UV‐Vis spectrophotometer. Antioxidative activity was evaluated by applying 2,2‐diphenyl‐1‐picrylhydrazyl radical assay and ferric reducing antioxidant power assay. Our results showed that theobromine was the only alkaloid in C. ptilophylla, while there was theacrine in C. kucha, which was coexisting with the caffeine. We confirmed the high content of (?)‐gallocatechin gallate in C. ptilophylla was not the epimerisation of (?)‐epigallocatechin gallate during the heating procedure. These wild teas had higher content of tea polyphenols, water extracts, amion acids and stronger antioxidative activity compared with the longjing tea. They could be used for the development of noncaffeine beverages and new types of tea.     

丁草胺和苄嘧磺隆对2种沉水植物的生物毒性

[目的]旨在为评估农田除草剂对非靶标水生植物的生态风险提供依据。[方法]评价了丁草胺和苄嘧磺隆对沉水植物黑藻和竹叶眼子菜的生物毒性。[结果]丁草胺和苄嘧磺隆分别从1、0.05 mg a.i./L的质量浓度开始显著降低黑藻和竹叶眼子菜的叶绿素含量。丁草胺对黑藻和竹叶眼子菜鲜质量的12dED50值分别为1.16、3.91mga.i./L,而苄嘧磺隆的分别为0.003 3、0.087 mg a.i./L。[结论]丁草胺和苄嘧磺隆均为易危害非靶标水生植物的除草剂,且苄嘧磺隆的危害潜力更大。     

Influence of Composition on Self-toughening and Oxidation Properties of Y-α-Sialons

Y-α-sialon ceramics with different compositions were hot-press sintered. Varying the m or n value in theα-Sialon general formula, both the α-sialon grain morphology and phase assemblages present diversification, therefore, affecting the toughness and hardness. Meanwhile, varying the compositional parameters also influenced the composition and structure of the intergranular glass phase, as well as its oxidation behavior at 1100-1200 ℃. The oxidation of the intergranular phase Mt in the Y-α-sialon ceramics was significantly enhanced with further rising the oxidation temperature to 1300 ℃.