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61.
Continuous furnaces are commonly used for steel billet reheating before a rolling operation. It is necessary to perform a number of measurements to set-up and operate the optimization system of the furnaces correctly. A charge temperature measurement using infrared detectors can be one of the usable measurement techniques. This non-contact measurement method is based on the detection of infrared radiation emitted from a measured surface. The radiation intensity depends on the surface temperature and emissivity, which is one of the most important parameters for infrared measurements. Advantages of the non-contact temperature measurement, as well as some problems regarding the surface emissivity, are presented. The direct steel billet temperature measurement procedure using infra-red detectors, emissivity determination procedures, and example results are introduced. It is shown that steel emissivity can vary from approx. 0.17 to 0.8, depending on the surface state, scale formation, and wavelength interval. These problems are critical for the charge temperature measurement using the infra-red detectors, and are discussed in this paper. 相似文献
62.
Yi-Bin Zhao Quan-Shui Fan Gui-Li Xu Zi-Liang Feng Xiao-Jiang Hao 《Journal of carbohydrate chemistry》2013,32(7):401-410
Three new carbohydrates were isolated from the acidic hydrolysis part of the ethyl acetate extract of Cynanchum otophyllum Schneid (Asclepiadaceae) and one new carbohydrate from the ethyl acetate extract of Cynanchum paniculatum Kitagawa. Their structures were determined as methyl 2,6-dideoxy-3-O-methyl-α-D-arabino-hexopyranosyl-(1 → 4)-2,6-deoxy-3-O-methyl-β-D-arabino-hexopyranosyl-(1 → 4)-2,6-dideoxy-3-O-methyl-α-D-arabino-hexopyranoside (1), ethyl 2,6-dideoxy-3-O-methyl-β-D-ribo-hexopyranosyl-(1 → 4)-2,6-dideoxy-3-O-methyl-α-l-lyxo-hexopyranoside (2), met hyl 2,6-dideoxy-3-O-methyl-α-l-ribo-hexopyranosyl-(1 → 4)-2,6-dideoxy-3-O-methyl-β-D-lyxo-hexopyranosyl-(1 → 4)-2,6-dideoxy-3-O-methyl-α-D-arabino-hexopyranoside (3), and 2,6-dideoxy-3-O-methyl-β-D-ribo-hexopyranosyl-(1 → 4)-2,6-dideoxy-3-O-methyl-α-d-arabino-hexopyranosyl-(1 → 4)-2,6-dideoxy-3-O-methyl-α -d-arabino-hexopyranose (4), respectively, by spectral methods. 相似文献
63.
可见/近红外光谱漫透射技术检测西瓜坚实度的研究 总被引:3,自引:3,他引:3
西瓜是一种广受世界各国消费者喜爱的水果,坚实度是西瓜的一个重要品质指标,文章利用可见/近红外漫透射光谱技术进行了西瓜坚实度(FM)的无损检测研究。采用偏最小二乘法(PLS)和主成分回归法(PCR)建立了FM与漫透射光谱的无损检测数学模型,对比分析了不同光谱预处理方法(原始光谱%T,一阶微分处理光谱D1(%T ),二阶微分处理光谱D2(%T )以及光谱的Savitsky-Golay法滤波)对模型预测性能的影响。根据模型相关系数(r)及预测平方根标准偏差(RMSEP)进行了不同模型的预测性能对比,结果表明:光谱经二阶微分处理并使用Savitsky-Golay法滤波后,采用PLS法可以得到最好的FM建模结果(r=0.974,RMSEP=0.589 N)。研究表明:应用可见/近红外漫透射光谱技术检测西瓜的坚实度是可行的,为今后快速无损评价大果形厚果皮类水果坚实度提供了理论依据。 相似文献
64.
M. Sadiq M. Bensitel K. Nohair J. Leglise C. Lamonier 《Journal of Saudi Chemical Society》2012,16(4):445-449
The synthesis of vanadyl phosphate by reaction of an alcoholic solution of V2O5 and o-H3PO4 has been studied. The solids obtained were investigated by various physico-chemical techniques as in situ X-ray diffraction (XRD), thermogravimetric analysis (TGA), and differential thermal analysis (DTA) under inert atmosphere. The compounds have been further characterized by infrared and UV–Visible spectroscopies. The isopropanol conversion is carried out to evaluate the catalytic activity of the samples. The isopropanol conversion increases with the reaction temperature from 433 to 503 K for vanadyl phosphorus oxides calcined at a different temperature. However, the conversion attains 100% at 503 K, and the solid calcined at 973 K exhibits high selectivity towards propene (100% at 503 K). 相似文献
65.
《Journal of Coordination Chemistry》2012,65(6):539-544
Silver(I) complexes of selenones, [LAgNO3] and [AgL2]NO3 (where L is imidazolidine-2-selenone or diazinane-2-selenone and their derivatives) have been prepared and characterized by elemental analysis, IR and NMR (1H, 13C and 107Ag) spectroscopy. An upfield shift in the C=Se resonance of selenones in 13C NMR and a downfield shift in N-H resonance in 1H NMR are consistent with selenium coordination to silver(I). In 107Ag NMR, the AgNO3signal is deshielded by 450-650 ppm on coordination to selenones. Greater upfield shifts in 13C NMR were observed for [LAgNO3] compared to [AgL2]NO3complexes, whereas the opposite trend was observed for 1H and107Ag NMR chemical shifts. 相似文献
66.
《Phosphorus, sulfur, and silicon and the related elements》2013,188(11):2349-2356
Seven new 1-fluorinated-4-phosphopyrazoles 2 have been prepared in 60–94% yield by cyclization of N-(2′,2′,2′-trifluoroethyl) phosphonyl β-hydrazones 1 with triethyl orthoformate in the presence of acetic acid. The IR data, the 1H, 13C, 19F, 31P chemical shifts and coupling constants of the compounds 2 are reported. 相似文献
67.
S. K. Srivastava Shailja Tomar Rupali Rastogi Richa Saxena 《Phosphorus, sulfur, and silicon and the related elements》2013,188(3):634-640
Six new substituted diphenyltin(IV) O,O′-alkylene dithiophosphates, (C6H5)2Sn(X)S(S) POGO [G = —CH2C(CH3)2CH2—, X = Cl (1), SCN (3), ClO4 (5); G = —CH2C (C4H9)(C2H5)CH2—, X = Cl (2), SCN (4), ClO4 (6)], were synthesized by the reaction of the corresponding ammonium salts of the O,O’-alkylene dithiophosphates with an appropriate organotin(IV) chloride. The compounds were characterized on the basis of elemental and spectral analyses (ESI mass spectrometry, IR, 1H, 13C, 31P, and 119Sn NMR). The presence of a four-coordinated Sn atom and monodentate O,O’-alkylene dithiophosphate moiety in compounds 1–4 as well as bidentate O,O’-alkylene dithiophosphate unit in compounds 5,6 is established. 相似文献
68.
In condensed phases, a highly symmetric gas‐phase molecule lowers its symmetry under perturbation of the solvent, which is vital to a variety of structural chemistry related processes. However, the dynamical aspects of solvent‐mediated symmetry‐breaking events remain largely unknown. Herein, direct evidence for two types of solvent‐mediated symmetry‐breaking events that coexist on the picosecond timescale in a highly symmetric anion, namely, hexacyanocobaltate, is presented: 1) an equilibrium symmetry‐breaking event in which a solvent‐bound species having lowered symmetry undergoes a population exchange reaction with the symmetry‐retaining species; 2) a dynamic symmetry‐breaking event that is composed of many dynamic population‐exchange reactions under fluctuating solvent interactions. Ultrafast two‐dimensional infrared spectroscopy is used to simultaneously observe and dynamically characterize these two events. This work opens a new window into molecular symmetry and structural dynamics under equilibrium and non‐equilibrium conditions. 相似文献
69.
70.
Paola Taddei Carla Boga Gabriele Micheletti Barbara Ballarin 《Journal of Raman spectroscopy : JRS》2015,46(1):100-108
Raman and IR spectroscopy were used to investigate the changes induced in yak hair keratin by the straightening treatment based on glyoxylic acid. The amino acidic residues that appeared involved in the reaction with glyoxylic acid were serine and lysine; the involvement of the latter was deduced by the spectroscopic detection of iminic species, resulting from the reaction between the aminic group of lysine and the carbonyl group of glyoxylic acid. The reaction with glyoxylic acid induced conformational rearrangements that mainly involved the fibre bulk rather than the cuticle. Changes in the average tyrosine environment and its hydrogen‐bonding state were detected: at increasing glyoxylic acid incorporation, the tyrosine residues appeared more exposed, probably because of H‐bond interactions with the COOH group. The distribution of the disulfide bridge conformation was also affected, although no cleavage of the S–S bond was detected, in agreement with the shiny and healthy appearance of the fibres. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献