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101.
This paper presents part of the larger study on microstructural features of mortars and it's effects on laser cleaning process. It focuses on the influence of surface roughness, porosity and moisture content of mortars on the removal of graffiti by Nd:YAG laser. The properties of this laser are as follows: wavelength (λ) 1.06 μm, energy: 500 mJ per pulse, pulse duration: 10 ns. The investigation shows that the variation of laser fluence with the number of pulses required for the laser cleaning can be divided into two zones, namely effective zone and ineffective zone. There is a linear relationship observed between number of pulses required for laser cleaning and the laser fluence in the effective zone, while the number of pulses required for the laser cleaning is almost constant even though the laser fluence increases in the ineffective zone. Moreover, surface roughness, porosity and moisture content of mortar samples have influence on the laser cleaning process. The effect of these parameters become however negligible at the high level of laser fluence. The number of pulses required for the laser cleaning is low for smooth surface or less porous mortar. Furthermore, the wetness of the samples facilitates the cleaning process. 相似文献
102.
103.
Bogusław Buszewski Agnieszka Ulanowska Tomasz Ligor Natalia Denderz Anton Amann 《Biomedical chromatography : BMC》2009,23(5):551-556
In this study, 38 samples of expired air were collected and analyzed from 20 non‐smoking volunteers, four passive smokers and 14 smokers (21 women and 17 men). Measurements were carried out using solid‐phase microextraction (SPME) as an isolation and preconcentration technique. The determination and identification were accomplished by gas chromatography coupled with mass spectrometry (GC/MS). Our data showed that ca 32% of all identified compounds in the breath of healthy non‐smokers were saturated hydrocarbons. In the breath of smoking and passive smoking volunteers hydrocarbons were predominant, but also present were more exogenous analytes such as furan, acetonitrile and benzene than in the breath of non‐smokers. Acetonitrile, furan, 3‐methylfuran, 2,5‐dimethylfuran, 2‐butanone, octane and decane were identified in breath of smoking and passive smoking persons. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
104.
Let
r
K
a,b
be a complete bipartite multigraph. We show a necessary and sufficient condition for a multigraph
r
K
a,b
to be arbitrarily decomposable into open trails. We extend the results obtained by Balister for complete graphs (Balister
in Probab Comput 10:463–499, 2001). Moreover we show that a multigraph
r
K
a,b
with even r and a ≥ 3 or b ≥ 3 is arbitrarily decomposable into open and closed trails. 相似文献
105.
106.
This paper proposes a method for solving optimisation problems involving piecewise quadratic functions. The method provides a solution in a finite number of iterations, and the computational complexity of the proposed method is locally polynomial of the problem dimension, i.e., if the initial point belongs to the sufficiently small neighbourhood of the solution set. Proposed method could be applied for solving large systems of linear inequalities. 相似文献
107.
Agnieszka Dziewulska-Kułaczkowska 《Journal of Thermal Analysis and Calorimetry》2010,101(3):1019-1026
The complexes Mn(II), Co(II), Ni(II) and Zn(II) with 4-oxo-4H-1-benzopyran-3-carboxaldehyde were synthesized and characterized
by elemental analysis, infrared and UV spectroscopy, X-ray diffraction patterns, magnetic susceptibility, thermal gravimetric
analysis, conductivity and also solubility measurements in water, methanol and DMF solution at 298 K. They are polycrystalline
compounds with various formula and different ratio of metal ion:ligand. Their formula are following: [MnL2(H2O)](NO3)2·2H2O, [CoL2](NO3)2·3H2O, [NiL2](NO3)2·3H2O, [CuL2](NO3)2·H2O and [ZnL3](NO3)2, where L = C10H6O3. The coordination of metal ions is through oxygen atoms present in 4-position of γ-pyrone ring and of aldehyde group of ligand.
Chelates of Mn(II), Co(II), Ni(II) and Cu(II) obey Curie–Weiss law and they are high-spin complexes with the weak ligand fields.
The thermal stability of analyzed complexes was studied in air at 293–1,173 K. On the basis of the thermoanalytical curves,
it appears that thermal stability of anhydrous analysed chelates changed following: Cu (423 K) < Zn (438 K) ~ Co (440 K) < Ni
(468 K). The gaseous products of thermal decomposition of those compounds in air atmosphere are following: CO2, CO, NO2, N2O, hydrocarbons and in case of hydrates also water. The molar conductance data confirm that the all studied complexes are
1:2 electrolytes in DMF solution. 相似文献
108.
Anna Śmiechowska Witold Przychodzeń Jarosław Chojnacki Piotr Bruździak Jacek Namieśnik Agnieszka Bartoszek 《Structural chemistry》2010,21(5):955-964
Adducts of natural allyl, phenethyl, and benzyl isothiocyanates and 2-amino-1-methylbenzimidazole were synthesized. After
optimization of the reaction conditions, the target 2-benzimidazolylthioureas were obtained in reasonable yields. The detailed
molecular and crystal structures of these compounds were characterized by spectroscopic and X-ray methods. Spectral analysis
demonstrated that N-(1-methylbenzimidazolyl)-N′-allylthiourea, N-(1-methylbenzimidazolyl)-N′-benzylthiourea, and N-(1-methylbenzimidazolyl)-N′-phenethylthiourea exist in solution in an unprecedented three tautomeric forms, whose structures were corroborated unambiguously. 相似文献
109.
Jeong SD Nowak-Król A Kim Y Kim SJ Gryko DT Lee CH 《Chemical communications (Cambridge, England)》2010,46(46):8737-8739
meso-Alkylidene (m-benzi)pentaphyrin containing exocyclic C=C double bonds at two meso-positions is synthesized and fully characterized for the first time. The single crystal X-ray crystallographic analysis shows a concave conformation with two pyrrole rings inverted. The first protonation occurs exclusively at core nitrogen. The synthesized compound displays concentration dependent chromogenic responses for fluoride anion in organic solvent. 相似文献
110.
Agnieszka Czapik Maria Gdaniec 《Acta Crystallographica. Section C, Structural Chemistry》2010,66(7):o356-o360
2,3,5,6‐Tetrafluorobenzene‐1,4‐diol easily forms cocrystals with heteroaromatic bases containing the pyrazine unit. In the 1:1 complexes with pyrazine, C6H2F4O2·C4H4N2, (I), and quinoxaline, C6H2F4O2·C8H6N2, (II), the crystal components are linked via O—H...N hydrogen bonds into one‐dimensional chains. With the largest base, phenazine, the 1:2 benzenediol–phenazine complex, C6H2F4O2·2C12H8N2, (III), was obtained, with the molecules linked via O—H...N interactions into a discrete heterotrimer. In all three cocrystals, the two types of molecules are organized into layers via softer C—H...O and C—H...F interactions and π–π stacking interactions, with stronger hydrogen bonds linking molecules of adjacent layers. In (II) and (III), molecules are arranged into heterostacks, whereas in (I) separate stacks are formed by the heterocyclic base and the benzenediol molecule. 相似文献