Author Keywords: Infrared spectrometry; Fourier transform; Wall and canvas painting analysis; Restoration/conservation of works of art 相似文献
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981.
DTA/TG and TG/DTG thermal studies and XRD investigations were carried out on pastes of lime-pozzolan binders to examine the
relative hydration process. The binders were prepared with two natural pozzolans and hydrated lime, mixed together in different
proportions. The main hydrated phases formed in the pastes are calcium silicate hydrate (CSH) and mono-carboaluminate. The
growth of CSH was greater for the paste of the pozzolan richer in reactive constituents. For pastes with a higher lime/pozzolan
ratio, a slowing of the formation of CSH was observed, while the formation of monocarboaluminate was more intense. The calcium
hydroxide contents of the pastes obtained by thermogravimetric analysis made it possible to determine the pozzolanic activities
of the two pozzolans under examination. The mortars for the various lime-pozzolan binders displayed characteristic hardening.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
982.
The 1,2-diphcnylethyl radical and derivatives were generated from photolysis of tran-f-stilbene and its derivatives 1–13 with secondary amines as quenchers. The 1,2-diphenylelhyl radicals that escaped from the solvent cage were trapped by 2-methyl-2-nitrosopropane (MNP) and were detected by the HPLCEPR method. The yield of the spin adduct is greater for tertiary amines. The smaller yields of the spin adduct formed from secondary amines are ascribed to greater reactivities of the 1,2-diphenylethyl and dialkylamino radicals within the solvent cage. 相似文献
983.
984.
Balek V. Mitsuhashi T. Šubrt J. Bakardjieva S. Málek Z. 《Journal of Thermal Analysis and Calorimetry》2003,72(1):119-127
Emanation thermal analysis (ETA) was used for characterization of thermal behaviour of SiCf/SiC composites on heating in argon and air, respectively. Effect of gas environment (argon, air) and helium ions implantation
on the microstructure development of the SiCf/SiC composite prepared by chemical vapour infiltration (CVI) from Nicalon CG fibres was investigated under in situ conditions
of heating. The annealing of near surface structure irregularities was observed in the range 280-700°C and evaluated by means
of the mathematical model, assuming that the structure irregularities served as diffusion paths for radon. The ETA reflected
the formation of amorphous silica and its subsequent crystallization to crystoballite. Morphology of the SiCf/SiC samples before and after the heat treatments was characterized by means of SEM.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
985.
YipingZhang DongjieWang JinhuaFei XiaomingZheng 《天然气化学杂志》2003,12(2):145-149
Mo/HZSM-5 is a good catalyst for methane aromatization, and the reaction performance of Mo/HZSM-5 and Cu modified Mo/HZSM-5 catalysts under various pretreatment conditions has been studied. The results indicate that the catalyst presented a distinguished catalytic activity, benzene selectivity and a high stability when the bed temperature was raised in N2 atmosphere. 相似文献
986.
Brunella Cappello Clelia Di Maio Maria Iervolino 《Journal of inclusion phenomena and macrocyclic chemistry》2002,43(3-4):251-257
The interactions of Bendazac, a topical non-steroidal anti-inflammatory drug, with-cyclodextrin, hydroxypropyl--cyclodextrin and -cyclodextrinwere investigated to evaluate possibilities to improve the drug's poor water solubilityand eventually to enhance the topical delivery of Bendazac. Phase solubility studiesdemonstrated the ability of the selected cyclodextrins to complex with Bendazac andincrease drug solubility. The amount of solubilized Bendazac increased linearly withthe addition of each cyclodextrin according toAL type plots. 13C-NMR studiesshowed that the Bendazac A-ring was included in the cavity of the three cyclodextrins.The -cyclodextrin was also able to include the B-ring of Bendazac, forminga complex where one drug molecule fitted into two cyclodextrin molecules. Equimolarsolid systems of the drug with each cyclodextrin carrier were prepared using varioustechniques (physical mixing, spray-drying and freeze-drying). The results of differential scanning calorimetry and Fourier transform infrared analysis, performed on the solid systems, demonstrated that freeze-dried and spray-dried products had a high degree of amorphization and agreed with the hypothesis of the existence of drug–cyclodextrin interaction in the solid state. The cyclodextrins tested were able to improve the dissolution of Bendazac. The dissolution profile of the drug was also affected by the physico-chemical properties of each solid system, the freeze-dried products being the most rapidly dissolving forms. 相似文献
987.
M. T. Dom nech Carb F. Bosch Reig J. V. Gimeno Adelantado V. Periz Martí nez 《Analytica chimica acta》1996,330(2-3):207-215
This paper is a study of the analytical capacity of Fourier transform infrared spectroscopy (FT-IR) for any type of samples from works of art. The analytical information obtained with this technique on organic and inorganic compounds is extremely useful in the preliminary studies necessary for diagnosis and to decide on the conservation process. This paper reports the analysis and study with FT-IR on samples extracted from the microlayers in several works of art from different periods (16th to 18th century) comprising wall paintings and canvas. The most outstanding of these being the frescoes by A. Palomino from two ceilings in the Santos Juanes church. The analytical procedures for the different components of the works studied such as
1. (a) varnish applied to wood panels and canvas paintings,
2. (b) binding media and pigments used by the artists,
3. (c) inerts, mortars, stuccos and grounds have been optimized. The FT-IR technique offers a quick analysis of microsamples (less than 0.5 mg) and is able to characterise the different molecular groups which provide information on the nature of the different materials of organic and inorganic origin used by the artist and thus permits the diagnosis of pathologies requiring conservation treatment.
988.
S. G. Zlotin M. V. Sharashkina Yu. A. Strelenko O. A. Luk'yanov M. O. Dekaprilevich Yu. T. Struchkav 《Russian Chemical Bulletin》1994,43(7):1220-1226
Methods for the synthesis of polyfunctionalN-phosphoryl- andN-phosphonoyldiazeneN-oxides containing hydroxyl, acetoxyl, and nitrate groups, and dibromoallyl and dibromopropyl fragments have been developed. The molecular structure ofN-(2,2-dimethyl-5-nitro-1,3-dioxan-5-yl)-N-[methoxy(phenyl)phosphoryl)diazeneN-oxide was established by X-ray structural analysis.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1284–1289, July, 1994. 相似文献
989.
河豚鱼脂肪酸的气相色谱—质谱分析 总被引:10,自引:0,他引:10
采用GC/MS技术对2种河豚鱼(黄鳍、红鳍)脂肪提取物中的脂肪酸进行定性定量分析,共鉴别出24种脂肪酸。多不饱和脂肪酸尤其是二十二碳六烯酸(DHA)的含量很高,在黄猪中相对含量达32.32%,在红鳍中达24.11%。检出了在其它海产品中较少发现的15-二十四烯酸(神经酸),是人体生长发育不可缺少的一种脂肪酸。对鱼肉脂肪提取方法及不同极性毛细管柱分离情况进行了讨论。 相似文献
990.
眼镜蛇蛇油中甘油三酸酯的成分研究 总被引:1,自引:0,他引:1
用AgNO3-硅胶薄层板,氯仿+丙酮(20+1)为展开剂,将蛇油中甘油三酸酯分离为5个组分,并用同样的色谱固定相和石油醚-氯仿-丙酮溶剂系统进行制备性分离。用质谱法对甘油三酸酯进行分子一级水平的化学研究,确定了眼镜蛇蛇油中5个主要的甘油三酸酯成分的结构形式为:16∶0-18∶0-18∶0,16∶0-18∶0-18∶1,16∶0-18∶2-18∶1,18∶2-18∶2-18∶0,18∶2-18∶2-18∶1。 相似文献