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开发了氮空心阴极放电PIC/MC二维自洽模型。研究了N2传统空心阴极向微空心阴极放电转变过程中电势和电场的变化。结果表明，不同尺寸的空心阴极放电的电势及电场分布规律几乎类似，但空心阴极孔径减小且气压增加时，电场近似线性增加；典型微空心阴极电场比传统空心阴极放电电场约大3个量级；微空心阴极放电产生的电子，氮分子离子和氮原子离子的密度比传统空心阴极放电约大3个量级，且微空心阴极放电中，N2+密度比N+密度大8倍以上。     

水泥生料品质激光在线检测设备研制

水泥质量的优劣直接影响到建筑工程的安全,使用品质合格的水泥材料是保证工程结构质量的必要前提,因此快速检测水泥生料成份对于及时指导调整原料配比和保障水泥产品品质具有重要意义。传统的生料检测需要经过取样、制样、化验等环节,检测结果严重滞后于生产。我们通过产学研协同攻关,研制了一套基于激光诱导击穿光谱(laser-induced breakdown spectroscopy,LIBS)技术的水泥生料品质在线检测设备,该设备由LIBS光学检测系统和气动取送样系统两部分组成,实现了对水泥生产线上水泥生料品质的实时连续测量,避免了传统的取制样环节,从而大大缩短了化验时间,所测水泥生料成分的实时数据能够及时指导调整水泥原料的配比,保证水泥质量的合格。我们利用该LIBS水泥品质在线检测设备对水泥生产线上生料中的主成分Al_2O_3,CaO,Fe_2O_3,MgO和SiO2进行了定量分析,利用全谱归一化和支持向量机(support vector machine,SVM)对水泥生料建立定标模型,对水泥生料中Al_2O_3,CaO,Fe_2O_3,MgO和SiO_2测量的最大误差分别是0.34%,0.35%,0.07%,0.14%和0.55%。现场实验结果表明,本水泥生料品质激光在线检测设备的测量结果与传统化验法的结果相吻合,测量精度与X射线荧光光谱法(XRF)相接近,从而证实了LIBS可以作为水泥在线检测的一种有前景的方法。     

Electronic dynamic behavior in inductively coupled plasmas with radio-frequency bias

The inflexion point of electron density and effective electron temperature curves versus radio-frequency （RF） bias voltage is observed in the H mode of inductively coupled plasmas （ICPs）. The electron energy probability function （EEPF） evolves first from a Maxwellian to a Druyvesteyn-like distribution, and then to a Maxwellian distribution again as the RF bias voltage increases. This can be explained by the interaction of two distinct bias-induced mechanisms, that is： bias- induced electron heating and bias-induced ion acceleration loss and the decrease of the effective discharge volume due to the sheath expansion. Furthermore, the trend of electron density is verified by a fluid model combined with a sheath module.     

Changes of the electron dynamics in hydrogen inductively coupled plasma

Changes of the electron dynamics in hydrogen （H2） radio-frequency （RF） inductively coupled plasmas are investigated using a hairpin probe and an intensified charged coupled device （ICCD）. The electron density, plasma emission intensity, and input current （voltage） are measured during the E to H mode transitions at different pressures. It is found that the electron density, plasma emission intensity, and input current jump up discontinuously, and the input voltage jumps down at the E to H mode transition points. And the threshold power of the E to H mode transition decreases with the increase of the pressure. Moreover, space and phase resolved optical emission spectroscopic measurements reveal that, in the E mode, the RF dynamics is characterized by one dominant excitation per RF cycle, while in the H mode, there are two excitation maxima within one cycle.     

Spatial variation behaviors of argon inductively coupled plasma during discharge mode transition

A Langmuir probe and an ICCD are employed to study the discharge mode transition in Ar inductively coupled plasma. Electron density and plasma emission intensity are measured during the E (capacitive discharge) to H (inductive discharge) mode transitions at different pressures. It is found that plasma exists with a low electron density and a weak emission intensity in the E mode, while it has a high electron density and a strong emission intensity in the H mode. Meanwhile, the plasma emission intensity spatial (2D image) profile is symmetrical in the H mode, but the 2D image is an asymmetric profile in the E mode. Moreover, the electron density and emission intensity jump up discontinuously at high pressure, but increase almost continuously at the E to H mode transition under low pressure.     

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采用粒子模拟与蒙特卡罗模型相结合(PIC/MCC)的方法，建立了氮分子气体辉光放电自洽的混合模型，其中带电粒子在电场中的运动及其产生的自洽场由PIC方法的静电模型描述，粒子间的碰撞过程由MC方法描述。模拟了放电过程及带电粒子(e、N2+、N+)在整个放电空间的行为及与之对应的自洽电场和电势的分布，通过计算带电粒子在负辉区的几率分布函数，讨论了带电粒子(e、N2+、N+)在负辉区的行为和分布特征。计算的分子离子密度与实验结果一致。     

Review of methodological and experimental LIBS techniques for coal analysis and their application in power plants in China

Laser-induced breakdown spectroscopy (LIBS) is an emerging analytical spectroscopy technique. This review presents the main recent developments in China regarding the implementation of LIBS for coal analysis. The paper mainly focuses on the progress of the past few years in the fundamentals, data pretreatment, calibration model, and experimental issues of LIBS and its application to coal analysis. Many important domestic studies focusing on coal quality analysis have been conducted. For example, a proposed novel hybrid quantification model can provide more reproducible quantitative analytical results; the model obtained the average absolute errors (AREs) of 0.42%, 0.05%, 0.07%, and 0.17% for carbon, hydrogen, volatiles, and ash, respectively, and a heat value of 0.07 MJ/kg. Atomic/ionic emission lines and molecular bands, such as CN and C₂, have been employed to generate more accurate analysis results, achieving an ARE of 0.26% and a 0.16% limit of detection (LOD) for the prediction of unburned carbon in fly ashes. Both laboratory and on-line LIBS apparatuses have been developed for field application in coal-fired power plants. We consider that both the accuracy and the repeatability of the elemental and proximate analysis of coal have increased significantly and further efforts will be devoted to realizing large-scale commercialization of coal quality analyzer in China.