Kirchhoff index of composite graphs

Let G₁+G₂, G₁°G₂ and G₁{G₂} be the join, corona and cluster of graphs G₁ and G₂, respectively. In this paper, Kirchhoff index formulae of these composite graphs are given.     

Study of the parameters in electrical discharge machining through response surface methodology approach

Whereas the efficiency of traditional cutting processes is limited by the mechanical properties of the processed material and the complexity of the workpiece geometry, electrical discharge machining (EDM) being a thermal erosion process, is subject to no such constraints. The lack of correlations between the cutting rate, the surface finish and the physical material parameters of this process made it difficult to use. This paper highlights the development of a comprehensive mathematical model for correlating the interactive and higher order influences of various electrical discharge machining parameters through response surface methodology (RSM), utilizing relevant experimental data as obtained through experimentation. The adequacy of the above the proposed models have been tested through the analysis of variance (ANOVA). Optimal combination of these parameters was obtained for achieving controlled EDM of the workpieces.     

低温等离子体放电的数值模型

综述了迄今为止各种分析低温等离子体放电物理过程的数值模型,以帮助我们从数值模型出发理解许多至今仍无法解释的现象,同时也为低温等离子体在等离子体处理技术、气体激光等工业应用以及在微电子、材料制备、环保、航空航天、军事等领域的应用提供了研究方法.     

Quantitative analysis of morphine and noscapine using corona discharge ion mobility spectrometry with ammonia reagent gas

Morphine and noscapine were determined using corona discharge ion mobility spectrometry. The detection limits were 5.6 × 10⁻¹¹ and 6.7 × 10⁻¹¹ g for morphine and noscapine, respectively. The linear dynamic ranges of the calibration plots for the compounds were about three orders of magnitude. The method has also been successfully applied for simultaneous determination of the compounds using the standard addition method.     

ZrO2陶瓷表面Cu-Ti复合渗镀研究

应用加弧辉光复合渗镀技术和自制Cu-Ti二元金属复合靶,对ZrO2陶瓷表面进行Cu-Ti复合渗镀。采用X射线能量色散谱分析(EDS)、扫描电子显微镜(SEM)面扫描、X射线衍射(XRD)、声发射划痕等试验方法对渗镀层的元素组成、成分分布、相组成、界面结合强度进行分析测试。结果表明渗镀层中存在Cu、Ti及Fe元素,各组分分布较为均匀,没有明显的成分偏聚现象;渗镀层由Cu2Ti、Cu2Ti4O、Ti8O15组成;渗镀层与陶瓷基体结合良好,在100 N最大载荷下未出现剥离和崩落现象。     

Differentiation of 18O‐ and 16O‐rich layers in anodic alumina films by glow discharge time‐of‐flight mass spectroscopy

The performance of glow discharge time‐of‐flight mass spectrometry in isotopic differentiation is revealed using the distribution of oxygen isotopes ¹⁶O and ¹⁸O in barrier‐type anodic alumina films as a focus. Anodic alumina films comprising ¹⁸O‐rich layers of controlled thickness were formed by the appropriate combination of anodising of superpure aluminium in electrolytes enriched with ¹⁸O isotopes and of natural abundance of ¹⁸O isotopes. Analysis of the elemental depth profiles of selected ionic species, i.e. ¹⁶O¹⁸O, allowed determination of the locations of the ¹⁸O‐rich layers and the ¹⁸O/¹⁶O interface. Copyright © 2010 John Wiley & Sons, Ltd.     

Development of ambient sampling chemi/chemical ion source with dielectric barrier discharge

The development of a new configuration of chemical ionization (CI)‐based ion source is presented. The ambient air containing the gaseous sample is sniffed into an enclosed ionization chamber which is of sub‐ambient pressure, and is subsequently mixed with metastable species in front of the ion inlet of the mass spectrometer. Metastable helium atoms (He*) are used in this study as the primary ionizing agents and are generated from a dielectric barrier discharge (DBD) source. The DBD is powered by an AC high‐voltage supply and the configuration of the electrodes is in such a way that the generated plasma is confined within the discharge tube and is not extended into the ionization chamber. The construction of the ion source is simple, and volatile compounds released from the bulky sample can also be analyzed directly by approaching the sample to the sampling nozzle. When combined with heated nitrogen or other desorption methods, its application can also be extended to non‐volatile compounds, and the consumption for helium can be kept minimum solely for maintaining the stable discharge and gas phase ionization. Applications to non‐proximate sample analysis, direct determination of active ingredients in drug tablets and the detection of trace explosive such as hexamethylene triperoxide diamine are demonstrated. Copyright © 2010 John Wiley & Sons, Ltd.     

不同尺寸微腔介质阻挡放电的对比研究

为进一步降低放电起始电压,产生数量较多、分布较均匀的低温等离子体,设计并制作了一种印刷电路板上的新型微电极——微腔结构电极,在高频正弦交流电压下,对尺寸l为0.3 mm、0.5 mm和1.0 mm微腔结构电极进行实验,根据得到的Lissajous图形进行分析。实验研究表明:外加电压相同条件下,微腔阵列的表面积与接地电极的面积之比D为0.69时,微腔与接地电极间的等效电容C_q、放电气隙电压U_g、半个周期内放电通道传输的电荷量Q_g、平均放电功率P均达到最大;但微腔电介质表面功率密度ρ却在D为0.36时达到最大;且高压电极与接地电极间的等效电容C_d变化很小,基本接近于静态介电常数对应的数值。     

海量数据环境下大型ISP网络流量卸载方法研究

海量数据环境下大型ISP网络流量爆炸性增长造成网络阻塞。当前网络流量卸载方法通过预测确定待卸载网络流量,卸载准确率较低,服务质量差。为此,提出一种新的海量数据环境下大型ISP网络流量卸载方法,通过最大熵法,依据采集流量中的语义信息对流量类型进行识别。依据海量数据环境下大型ISP网络流量源节点的位置关系,通过图论法确定最佳传输路线,实现对大型ISP网络流量的卸载。依据中继节点数量与总卸载时间最少原则,通过Dijkstra方法对海量数据环境下大型ISP网络流量最佳卸载路线进行求解。实验结果表明,采用所提方法对大型ISP网络流量进行卸载,不仅流量类型识别精度高,而且卸载率高,服务质量高。