Abstract

The luminescence spectra of coal fractions with dimensions d ≤ 63 μm were studied directly during the action of neodymium laser pulses (τ_i = 120 μs). Depending on the radiation energy density H, the luminescence spectra have a different character. The glow at minimum values of the laser pulse energy density \(H_{{{\text{cr}}}}^{{(1)}}\) is associated with the ignition of fine coal particulates (~1 μm) present in the fractions, and with the ignition of reactive microprotrusions on the surface of larger coal particles. The luminescence spectra at this stage are of a non-thermal nature and are associated with the radiation of volatile molecules in the gas phase and their oxidation products. With an increase in the laser pulse energy density H, a thermal glow of the surface of larger coal particles is observed, which is described by the Planck formula at T = 3100 K. When H = \(H_{{{\text{cr}}}}^{{(2)}}\) is reached, the surface of the coal particles ignites during the action of the laser pulse. Contributions to the spectra are the glow of the surface of coal particles, emitted carbon particles, and the glow associated with the emission of excited molecules H₂, H₂O, and CO₂. With an increase in H > \(H_{{{\text{cr}}}}^{{(2)}}\), the processes leading to the glow of coal particles during a laser pulse are similar to those described above for \(H_{{{\text{cr}}}}^{{(2)}}\), but the glow intensity increases.

中文翻译：

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自由生成模式下激光脉冲作用下硬煤颗粒表面的辉光光谱特性

摘要

煤的级分，其尺寸的发光光谱ð ≤63μm的进行了钕激光脉冲的作用期间直接研究（τ_我= 120微秒）。取决于辐射能量密度H，发光光谱具有不同的特性。激光脉冲能量密度的最小值\（H _ {{{\ text {cr}}}} ^ {{{（1）}} \）与点燃馏分中存在的细煤颗粒（〜1μm）有关，并与点燃较大煤颗粒表面上的反应性微突起有关。该阶段的发光光谱是非热性质的，并且与气相中的挥发性分子及其氧化产物的辐射有关。随着激光脉冲能量密度H的增加，观察到较大煤颗粒表面的热辉光，这由普朗克公式在T = 3100 K处描述。当H = \（H _ {{{\ text {cr }}}} ^ {{{（2）}} \）当达到激光束的作用时，煤颗粒的表面会点燃。对光谱的贡献是煤颗粒，发射的碳颗粒的表面的辉光以及与激发分子H ₂，H ₂ O和CO ₂的发射相关的辉光。随着H > \（H _ {{{text {cr}}} ^ {{（2）}} \）的增加，在激光脉冲期间导致煤颗粒发光的过程与上述过程相似。为\（H _ {{{\ text {cr}}}} ^ {{（（2）}} \），但是发光强度会增加。