共查询到19条相似文献,搜索用时 140 毫秒
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介绍了利用Nd:YAG激光的三倍频激发自发振动喇曼散射技术对燃烧场的诊断及相关的实验原理,测量了不同配比条件下的CH4-air预混火焰内的主要组分(N2,O2,H2O,CH4)及其相对浓度;并分别用分子浓度测温法和斯托克斯谱与反斯托克斯谱强度比法测量了火焰的温度;还对该技术测温、测浓度的不确定度进行了分析。将该技术应用到对复杂的固体燃剂燃烧场的诊断,取得了燃烧场中几种主要燃烧组分(N2,H2CO,CH4,H2O)的喇曼光谱,以及这些组分在燃烧过程中的变化信息。 相似文献
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本文利用高分辨的里德堡态氘原子标识-交叉分子束装置,研究了碰撞能为4.5∽6.5 kcal/mol范围内Cl(2P)[Cl(2P3/2)和Cl*(2P1/2)]与D2的反应. 虽然自旋轨道激发态反应Cl*(2P1/2)+D2在波恩-奥本海默(B-O)近似下本应是禁阻的,但实验中观测到了该反应的贡献. 通过测量靠近后向的碰撞能相关的微分散射截面连线,发现低碰撞能下的产物主要来自于B-O近似禁阻的反应Cl*+D2. 随着碰撞能的提高,自旋轨道基态反应Cl+D2的反应性增加明显要比自旋轨道激发态反应Cl*+D2更快,并且在高碰撞能下成为产物的主要来源. 实验结果表明:在低碰撞能下,Cl*中自旋轨道激发态的额外能量,可以帮助B-O近似禁阻的反应Cl*+D2越过势垒;然而当碰撞能接近和高于反应势垒时,B-O近似允许的反应Cl+D2占主导地位. Cl/Cl*+D2反应中B-O近似有效性的特征与其同位素反应Cl/Cl*+H2是一致的. 相似文献
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利用微波放电Cl2/He等离子体作为Cl源,对反应NCl(a1Δ) + I(2P3/2)→NCl(X3Σ) + I(2P1/2)进行了实验研究,得到了较大的I(2P1/2)自发辐射荧光信号,检测到NCl(a1Δ,b1Σ)自发辐射荧光光谱在存在少量I(2P1/2)下发生的显著变化,其中NCl(a1Δ)自发辐射荧光信号降低,同时由于I(2P1/2)的作用,NCl(b1Σ)自发辐射荧光信号大幅度增加。在考察各反应气体流量对I(2P1/2)自发辐射荧光信号的影响时发现,在本次实验条件下,各种气体的最佳流量:He为1~4mmol/s, I2为0.01~0.03mmol/s, Cl2为1.0mmol/s左右,而HN3流量略大于Cl2流量时信号升高幅度开始变缓,约为Cl2流量的两倍时信号不再有显著的变化。 相似文献
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本文根据密度泛函理论(density functional theory , DFT), 采用MS分子动力学仿真软件对羟基修饰的单壁碳纳米管(SWNT-OH) 吸附SF6局部放电分解的四种主要组分SOF2, SO2F2, SO2和CF4进行了详细的理论计算, 通过分析气体分子和SWNT-OH的前线轨道, 吸附过程中吸附能、电荷转移量和电子态密度的情况, 以及吸附前后SWNT-OH能隙的变化, 评判了SWNT-OH对气体分子的敏感性和选择性, 给出了SWNT-OH是否可以制备气体传感器检测SF6局部放电分解组分的理论依据. 相似文献
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根据分子的共同特征,将彼此紧密关联的分子,区别为三种基本类型,利用对称性分析方法,探求出这三类分子的内旋转势函数的一般公式。应用这些公式到具体分子时,能够非常简捷地写出它们的势函数表达式。利用第一类势函数分析具体问题时,算得的68个分子势垒数值,除少数外,所有计算结果与实验结果的差异均在实验误差范围之内。同时并发现当甲基上的C-H键换成C=C键时,作用能量大为减小;对于具有几个旋转轴的分子,隔开两个以上键间的作用能完全可以忽略。应用第二类势函数,具体联系了五类15个很重要的相关分子,即:CH2Cl-CH2Cl,CHCl2-CHCl2和CHCl2-CH2Cl;CH2F-CH2F,CHF2-CHF2和CHF2-CH2F;CCl2F-CCl2F,CClF2-CClF2和CClF2-CCl2F;CH2(CH3)-CH2(CH3),CH(CH3)2-CH(CH3)2和CH(CH3)2-CH2(CH3)以及C(CH3)2Cl-C(CH3)2Cl,C(CH3)Cl2-C(CH3)Cl2和C(CH3)Cl2-C(CH3)2Cl。理论上得到的结果和实验数据比较有满意的符合,对尚无实验涉及的某些分子的结与性构能,也在理论上作了一些预测。根据第三类势函数,探计了CClFH-CClFH与C(CH3)ClH-C(CH3)ClH两个分子的内旋转;从理论上推测了消式与活性式的内旋转异构体的数目及其构型。 相似文献
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用密度泛函方法和相对论有效原子实势,分别对PdCO2,PdCO和PdH的基态几何构型进行优化, 得到PdCO2分子基态为Cs构型, Pd与CO2分子在同一平面, 键长PdC为0.203 0 nm, CO为0.118 3 nm, CO′为0.121 0 nm, 键角∠OCO′为154.215°,电子状态为1A′; PdCO分子基态电子状态为1+, 键长PdC为0.183 4 nm, CO为0.114 0 nm, 键角∠PdCO为180°; PdH分子基态为2∑, 键长PdH为0.152 6 nm。根据电子-振动近似理论计算了不同温度下金属Pd 与CO2,CO及H2分子反应的生成热力学函数, 导出了反应平衡压力随温度的变化关系。分析认为杂质CO2气体引起Pd合金膜中毒可能是由于CO2分子吸附在Pd膜表面,形成Pd的CO2化合物后,再自发分解为PdO和CO,而使Pd表面出现O和CO中毒所致。 相似文献
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介绍了一种新的产生单重态氧(O2(1△g)的气固化学反应体系,即在固定床式反应器中采用固体过氧化钠粉末与氯气(Na2O2/Cl2)进行反应的气固化学反应体系。实验分别通过用对近红外敏感的光谱仪和锗探头监测了反应产生的(O2(1△g)的发射光谱和1 270 nm的光信号,同时通过数据采集系统监测了反应池固体反应层和测试池中气体的温度的变化曲线。实验测得了(O2(1△g)在1 270 nm附近的特征发射光谱,此光谱表明该体系是一个很好的产生(O2(1△g)的体系,同时,实验现象表明该反应是强放热反应。 相似文献
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本文采用基质隔离红外光谱分别对15.0 K温度下的HC(N2)CN/O2/N2和HCCNCO/O2/N2混合物(1/50/1000)的激光光解过程开展了实验研究. 结果表明:两者在紫外激光光照下均可产生Criegee中间体NCC(H)OO的顺、反两种构象异构体. 对NCC(H)OO的红外光谱解析得到了氧同位素(18O)标记实验和BP86/6-311++G(3df,3pd)理论计算结果的支持. 实验发现NCC(H)OO在紫外光照下可进一步与氧气分子发生二次反应,生成氰基甲醛和臭氧,而未得到被理论所预测的能量较低的双环氧乙烷异构体cyclic-NCC(O2)H. 相似文献
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对利用微波放电直接解离Cl2生成Cl,Cl与HN3反应生成Ncl(a^1Δ)和NCl(b^1∑)的过程进行了实验研究,得到了较强的Ncl(a^1Δ)和NCl(b^1∑)自发辐射光谱,考察了Cl2流量和He/Cl2配比对NCl(a^1Δ)和NCl(b^1∑)生成的影响,发现对于一定的He流量,Cl2流量对NCl(a^1Δ)和NCl(b^1∑)生成的影响存在一最佳范围,而最佳He/Cl2配比不是一定值,而是随He流量升高而变大,在实验所考察的He流量范围(5-40L/min)内,最佳He/Cl2配比在30:1-100:1之间。 相似文献
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对利用微波放电直接解离Cl2生成Cl, Cl与HN3反应生成NCl(a1Δ )和NCl(b1∑)的过程进行了实验研究。得到了较强的NCl(a1Δ 和NCl(b1∑)自发辐射光谱,考察了Cl2流量和He/Cl2配比对NCl(a1Δ 和NCl(b1∑)生成的影响。发现对于一定的He流量,Cl2流量对NCl(a1Δ 和NCl(b1∑)生成的影响存在一最佳范围,而最佳He/Cl2配比不是一定值,而是随He流量升高而变大,在实验所考察的He流量范围(5~40 L/min)内,最佳He/Cl
2配比在30∶1~100∶1之间。 相似文献
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利用微波放电C12/He等离子体作为Cl源,对反应NCl(a^1△) I(^2P3/2)→NCl(X^3∑) I(^2P3/2)进行了实验研究,得到了较大的I(^2P3/2)自发辐射荧光信号,检测到NCl(a^1△,b^1∑)自发辐射荧光光谱在存在少量I(^2P3/2)下发生的显著变化,其中NCl(a^1△)自发辐射荧光信号降低,同时由于I(^2P3/2)的作用,NCl(b^1∑)自发辐射荧光信号大幅度增加。在考察各反应气体流量对I(^2P3/2)自发辐射荧光信号的影响时发现,在本次实验条件下,各种气体的最佳流量:He为1—4mmol/s,I2为0.01—0.03mmol/s,Cl2为1.0mmol/s左右,而HN3流量略大于Cl2流量时信号升高幅度开始变缓,约为Cl2流量的两倍时信号不再有显著的变化。 相似文献
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Experimental study on the system of Cl/Cl_2/He/HN_3/I_2 总被引:2,自引:0,他引:2
Using a microwave generator, chlorine diluted by helium was dissociated to chlorine atoms that subsequently reacted with hydrogen azide to produce the excited states of NCl(a1△). Meanwhile, molecular iodine with carrier gas of helium reacted with atomic chlorine to produce atomic iodine which then was pumped to excited state of I(2P1/2) by an energy transfer reaction from NCl(a1△). In this paper, the changes of NCl(a1△) and NCl(b1∑) emission intensity is presented when I2/He is introduced into the stream of Cl/Cl2/He/HN3/NCl(a1△)/NCl(b1∑). The dependences of atomic iodine I(2P1/2) on flow rates of gases were also investigated. The optimum parameters for I(2P1/2) production are given. 相似文献
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Wei Li Bowen Mei Yuyang Li Sven Eckart Hartmut Krause Siyuan Ma Yan Zhang 《Proceedings of the Combustion Institute》2021,38(2):2135-2142
Laminar flame propagation was investigated for pentanone isomers/air mixtures (3-pentanone, 2-pentanone and 3-methyl-2-butanone) in a high-pressure constant-volume cylindrical combustion vessel at 393–423 K, 1–10 atm and equivalence ratios of 0.6–1.5, and in a heat flux burner at 393 K, 1 atm and equivalence ratios of 0.6–1.5. Two kinds of methods generally show good agreement, both of which indicate that the laminar burning velocity increases in the order of 3-methyl-2-butanone, 2-pentanone and 3-pentanone. A kinetic model of pentanone isomers was developed and validated against experimental data in this work and in literature. Modeling analysis was performed to provide insight into the flame chemistry of the three pentanone isomers. H-abstraction reactions are concluded to dominate fuel consumption, and further decomposition of fuel radicals eventually produces fuel-specific small radicals. The differences in radical pools are concluded to be responsible for the observed fuel isomeric effects on laminar burning velocity. Among the three pentanone isomers, 3-pentanone tends to produce ethyl and does not prefer to produce methyl and allyl in flames, thus it has the highest reactivity and fastest laminar flame propagation. On the contrary, 3-methyl-2-butanone tends to produce allyl and methyl instead of ethyl, and consequently has the lowest reactivity and slowest laminar flame propagation. 相似文献
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Electron spin resonance (ESR) studies of ClO3 and ClO2 radicals in X-irradiated potassium perchlorate, KClO4, single crystals are carried out to investigate the radiation decomposition pathways. The orientation of the maximum principal component of the35Cl hyperfine tensor is determined by ESR and identified with that of the bond ruptured on irradiation. It is found that the weaker Cl-O(2)×2 bonds related by the mirror symmetry survive radiation damage, while the stronger Cl-O(3) and Cl-O(l) bonds get ruptured to form the ClO3 and ClO2 radicals, thus providing evidence for the important role played by the lattice symmetry during radiative decomposition. 相似文献
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The detection of C2 radicals in a premixed acetylene-oxygen flame by using polarization spectroscopy is reported. The signal was recorded in the Swan system,d
3
II
g–a
3
II
u (0, 0), using a pulsed dye laser. The spectrum shows a very good signal-to-noise ratio with clearly resolved rotational structures of theP andR triplets. The dependence of the signal on the pump-beam polarization was also studied. The spatial distribution of the signal from C2 radicals in the flame was measured as a demonstration of the use of polarization spectroscopy in combustion diagnostics. 相似文献
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Oleg P. Korobeinichev Alexander A. Paletsky Tatyana A. Bolshova Vadim D. Knyazev 《Combustion Theory and Modelling》2013,17(5):927-939
The phenomenon of superadiabatic flame temperature (SAFT) was discovered and investigated in a low-pressure HN3/N2 flame using numerical modelling. A previously developed mechanism of chemical reactions in the HN3/N2 flame at the pressure 50 Torr and the initial temperature T0 = 296 K was revised. Rate constants of several important reactions involving HN3 (HN3 (+N2) = N2 + NH (+N2), R1; HN3 (+HN3) = N2 + NH (+HN3), R2; HN3 + H = N2 + NH2, R4; HN3 + N = N2 + NNH, R5; and HN3 + NH2 = NH3 + N3, R7) were calculated using quantum chemistry and reaction rate theories. Modified Arrhenius expressions for these reactions are provided for the 300–3500 K temperature range. Modelling of the flame structure and flame propagation velocity of the HN3/N2 flame at p = 50 Torr and T0 = 296 K was performed using the revised mechanism. The results demonstrate the presence of the SAFT phenomenon in the HN3/N2 flame. Analysis of the flame structure and the kinetic mechanism indicates that the cause of SAFT is in the kinetic mechanism: exothermic reactions of radicals with hydrogen atoms occur in the post flame zone, which results in the formation of super equilibrium H2 concentrations. The flame propagation velocity is largely determined by the second-order HN3 decomposition reaction and not by the reaction of HN3 with H, as was previously assumed. Calculation of the flame propagation velocity according to the Zeldovich-Frank-Kamenetsky theory with the decomposition reaction as a limiting stage yielded a value that agrees with that obtained in numerical modelling using the complete reaction mechanism. 相似文献