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71.
M. R. Osborne 《Applied physics. B, Lasers and optics》1988,45(4):285-291
An experimental study of the dependence of the output pulse duration of a longpulse, x-ray preionized excimer laser on the halogen donor molecule is reported. Results obtained at the XeCl* wavelength, using a variety of halogen donors, are in agreement with the halogen donor depletion model of discharge instability. The pulse durations of the raregas-fluoride lasers (KrF*, XeF*) have been found to be significantly shorter than would be predicted using this model and the XeCl* data mentioned above. Reasons for this inferior performance are proposed and investigated. In particular, multiple halide ion donation and electrode surface structure effects are discussed in detail. 相似文献
72.
T.D. Fansler B. Stojkovic M.C. Drake M.E. Rosalik 《Applied physics. B, Lasers and optics》2002,75(4-5):577-590
Spectrally resolved visible and ultraviolet emissions are investigated as a basis for wide-range, individual-cycle measurement
of the local fuel concentration in spark-ignition engines. The 388-nm CN emission intensity, normalized by the spark-discharge
energy during the observation interval (typically 150 μs at the start of the glow discharge), is found to be the most useful
measure of fuel concentration when data are required over a wide range. Calibration data for homogeneous propane–air and isooctane–air
mixtures over a wide range of cylinder gas conditions at the time of ignition collapse to a single curve when the fuel concentration
is expressed in terms of the number density of carbon atoms. The carbon number densities measured in this study correspond
to fuel–air equivalence-ratios in the range 0–3 at 95% throttle conditions. Random and systematic errors are 10% or less.
Applied to an engine in which liquid fuel is injected directly into the cylinder, the technique reveals substantial cyclic
fluctuations in the fuel concentration at the spark gap for early fuel injection (intended to produce a homogeneous fuel–air
mixture in the combustion chamber) and large fuel-concentration fluctuations for late fuel injection (which produces a highly
stratified mixture). The results also show that for stratified operation with a fixed fuel-injection timing, a spark timing
that is later than optimum leads to incomplete combustion in many cycles due to fuel–air ratios that are too lean for good
ignition and rapid flame development.
Received: 6 November 2001 / Revised version: 6 May 2002 / Published online: 25 September 2002
RID="*"
ID="*"Corresponding author. Fax: +1-586/986 0176, E-mail: todd.fansler@gm.com 相似文献
73.
在线热裂解/气相色谱-质谱联用技术研究八角茴香油的热裂解行为 总被引:1,自引:0,他引:1
采用在线热裂解/气相色谱-质谱(Py/GC-MS)联用技术分析研究了八角茴香油的主要成分和裂解产物,探讨了氦气氛围中八角茴香油在300,400,500,600,700,800℃下的热裂解行为。结果从八角茴香油中检测出13种组分,其中反式茴香脑占94.848%;从裂解产物中检测出28种物质;八角茴香油组分在低温下(300~500℃)大部分发生转移;高温下(600~800℃)裂解相对比较剧烈,生成一些香味物质及甲苯、乙苯等有害物质;反式茴香脑在500℃时具有最大的转移率。上述结果为八角茴香油在食品中的应用提供了参考。 相似文献
74.
Qiu WG Li ZF Bai GM Meng SN Dai HX He H 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2007,66(4-5):1189-1193
The interaction of a cationic water-soluble porphyrin, 5,10,15,20-tetrakis[4-(3-pyridiniumpropoxy)phenyl]prophyrin tetrakisbromide (TPPOC3Py), with beta-CD and HP-beta-CD in aqueous solution has been studied by UV-vis, 1H NMR, 2D-NOESY and MALDI-TOF MS, and it reveals that a stable 1:1 inclusion complex between TPPOC3Py and HP-beta-CD or beta-CD has formed, in which one of the meso substituents of porphyrin ring has deeply penetrated through the cavity of HP-beta-CD from secondary face. The inclusion constants of the complexes of TPPOC3Py-beta-CD and TPPOC3Py-HP-beta-CD are (1.6+/-0.2)x10(3) M-1 and (8.9+/-0.4)x10(4) M-1, respectively. 相似文献
75.
76.
Laser diagnostics of NO reburning in fuel-rich propene flames 总被引:1,自引:0,他引:1
Absolute NO concentrations were measured by laser-induced fluorescence (LIF) in three different fuel-rich non-sooting propene
flames (φ=1.5, 1.8 and 2.3). The experiments were performed in low-pressure premixed propene flames with 0.2%-1% NO added.
Laser diagnostics was applied as a tool for investigating reburn chemistry. The Q2(25.5) line in the A-X(0,0) band was excited because of the small temperature dependence of its ground state population. The
NO fluorescence lifetimes were measured directly and compared to theoretical values. The initial NO levels are strongly reduced
in all three flames. According to modeling results, the HCN mole fraction increases strongly with stoichiometry. As guidelines
for laser diagnostics applications in such systems, the modeling results were analyzed with respect to the main reaction channels
and reaction partners in fuel-rich flames.
Received: 1 March 2000 / Revised version: 20 April 2000 / Published online: 20 September 2000 相似文献
77.
78.
P.A. Nooren M. Versluis T.H. van der Meer R.S. Barlow J.H. Frank 《Applied physics. B, Lasers and optics》2000,71(1):95-111
We report a series of Raman-Rayleigh-LIF measurements in two turbulent natural-gas jet diffusion flames produced by the Delft
piloted jet diffusion flame burner. The main objective of the Raman-Rayleigh-LIF measurements was to obtain detailed information
on the major species concentrations in the flames. The measurements provide simultaneous data on temperature, the concentrations
of the major species and the radicals OH and NO and mixture fraction. The application of the Raman technique in the undiluted
natural-gas flames proves to be very challenging because of the high fluorescence interference levels. The interference contributions
to the recorded Raman signals are identified and subtracted using empirical correlations between the Raman signals and the
signals on fluorescence interference monitor channels. The calibration and data reduction of the Raman-Rayleigh and LIF signals
are discussed in detail. The resulting dataset compares excellently with data from previous experiments. Because the Raman-Rayleigh-LIF
data provide quantitative concentrations and accordingly quantitative mixture fractions, they form a valuable and useful extension
of the existing database for the Delft piloted jet diffusion flame burner.
Received: 19 October 1999 / Revised version: 31 January 2000 / Published online: 7 June 2000 相似文献
79.
Yiyang Li Erdong Liu Haiping Gu Junwei Lou Yafeng Yang Longhai Ban Wanxi Peng Shengbo Ge 《Molecules (Basel, Switzerland)》2023,28(1)
Energy is indispensable in human life and social development, but this has led to an overconsumption of non-renewable energy. Sustainable energy is needed to maintain the global energy balance. Lignocellulose from agriculture or forestry is often discarded or directly incinerated. It is abundantly available to be discovered and studied as a biomass energy source. Therefore, this research uses Staphylea holocarpa wood as feedstock to evaluate its potential as energy source. We characterized Staphylea holocarpa wood by utilizing FT–IR, GC–MS, TGA, Py/GC–MS and NMR. The results showed that Staphylea holocarpa wood contained a large amount of oxygenated volatiles, indicating that it has the ability to act as biomass energy sources which can achieve green chemistry and sustainable development. 相似文献
80.
The m/n = 2/1 neoclassical tearing modes are first observed in HL-2A low density, low beta plasma with central electron cyclotron resonance heating. The neoclassical tearing modes (NTMs) are triggered by a sawtooth crash with m/n = 1/1 precursors, which are toroidal coupled with a small scale m/n = 2/1 mode. The time history of the island width is compared with the prediction of the NTM theory, showing a good agreement between theory and experiment. 相似文献