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901.
Interaction of Nd:YAG laser, operating at 1064 or 532 nm wavelength and a pulse duration of 40 ps, with AISI 1045 steel was studied. Surface damage thresholds were estimated to be 0.30 and 0.16 J/cm2 at the wavelengths of 1064 and 532 nm, respectively. The steel surface modification was studied at the laser energy density of 10.3 J/cm2 (at 1064 nm) and 5.4 J/cm2 (at 532 nm). The energy absorbed from Nd:YAG laser beam is partially converted to thermal energy, which generates a series of effects, such as melting, vaporization of the molten material, shock waves, etc. The following AISI 1045 steel surface morphological changes and processes were observed: (i) both laser wavelengths cause damage of the steel in the central zone of irradiated area; (ii) appearance of a hydrodynamic feature in the form of resolidified droplets of the material in the surrounding outer zone with 1064 nm laser wavelength; (iii) appearance of periodic surface structures, at micro- and nano-level, with the 532 nm wavelength and, (iv) development of plasma in front of the target. Generally, interaction of laser beam with the AISI 1045 steel (at 1064 and 532 nm) results in a near-instantaneous creation of damage, meaning that large steel surfaces can be processed in short time. 相似文献
902.
Paola Deplano Luciano Marchiò Flavia Artizzu Maria Laura Mercuri Luca Pilia Gloria Pintus Angela Serpe Eduard B. Yagubskii 《Monatshefte für Chemie / Chemical Monthly》2009,140(7):775-781
Abstract The novel [Ni(Me2pipdt)(dddt)] complex based on the Me2pipdt (1,4-dimethylpiperazine-3,2-dithione) and dddt (5,6-dihydro-1,4-dithine-2,3-dithiolate) ligands has been synthesised
and characterised. Structural data, vibrational marker, solvatochromic behaviour of the typical absorption in the near infrared
region, and approximate theoretical calculations suggest that an unbalanced electron distribution at the dithiolene core occurs
in the ground and excited states. In particular, the dddt ligand gives a prevailing contribution to the HOMO, and Me2pipdt to the LUMO. The charge-transfer character of the HOMO–LUMO transition makes this complex a potential second-order non-linear
optic chromophore.
Graphical Abstract
相似文献
903.
A feasible procedure of using methyl formate as cheap reagent for the conversion of aliphatic and aromatic amines into formamides with high yields is reported. The improved amine formylation method proceeds mainly at room temperature and in presence of bicyclic guanidines as catalysts. A verifiable key intermediate of outstanding formylating activity is generated from methyl formate and the catalyst in the reaction mixture. 相似文献
904.
It is known that, if u is a real valued function on ?N of bounded variation, then its total variation decreases under polarization. In this paper we identify the difference between the total variation of u and that one of its polar uΠ (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
905.
906.
907.
Jana Brania Angela Kleinov Klaudia Jomov Rbert Weissabel Marcel Cvik Zuzana Braniov Mria Porubsk 《Molecules (Basel, Switzerland)》2021,26(17)
The effect of humidity on sheep wool during irradiation by an accelerated electron beam was examined. Each of the samples with 10%, 53%, and 97% relative humidity (RH) absorbed a dose of 0, 109, and 257 kGy, respectively. After being freely kept in common laboratory conditions, the samples were subjected to batch Co(II) sorption experiments monitored with VIS spectrometry for different lapses from electron beam exposure. Along with the sorption, FTIR spectral analysis of the wool samples was conducted for cysteic acid and cystine monoxide, and later, the examination was completed, with pH measuring 0.05 molar KCl extract from the wool samples. Besides a relationship to the absorbed dose and lapse, the sorptivity results showed considerable dependence on wool humidity under exposure. When humidity was deficient (10% RH), the sorptivity was lower due to limited transformation of cystine monoxide to cysteic acid. The wool pre-conditioned at 53% RH, which is the humidity close to common environmental conditions, demonstrated the best Co(II) sorptivity in any case. This finding enables the elimination of pre-exposure wool conditioning in practice. Under excessive humidity of 97% RH and enough high dose of 257 kGy, radiolysis of water occurred, deteriorating the sorptivity. Each wool humidity, dose, and lapse showed a particular scenario. The time and humidity variations in the sorptivity for the non-irradiated sample were a little surprising; despite the absence of electron irradiation, relevant results indicated a strong sensitivity to pre-condition humidity and lapse from the start of the monitoring. 相似文献
908.
Romo Arago Dougu Kentsop Valeria Iobbi Giuliana Donadio Barbara Ruffoni Nunziatina De Tommasi Angela Bisio 《Molecules (Basel, Switzerland)》2021,26(17)
Salvia corrugata Vahl. is an interesting source of abietane and abeo-abietane compounds that showed antibacterial, antitumor, and cytotoxic activities. The aim of the study was to obtain transformed roots of S. corrugata and to evaluate the production of terpenoids in comparison with in vivo root production. Hairy roots were initiated from leaf explants by infection with ATCC 15834 Agrobacterium rhizogenes onto hormone-free Murashige and Skoog (MS) solid medium. Transformation was confirmed by polymerase chain reaction analysis of rolC and virC1 genes. The biomass production was obtained in hormone-free liquid MS medium using Temporary Immersion System bioreactor RITA®. The chromatographic separation of the methanolic extract of the untransformed roots afforded horminone, ferruginol, 7-O-acetylhorminone and 7-O-methylhorminone. Agastol and ferruginol were isolated and quantified from the hairy roots. The amount of these metabolites indicated that the hairy roots of S. corrugata can be considered a source of these compounds. 相似文献
909.
910.
Nicola Marchi Qingshan Teng Minh T Nguyen Linda Franic Nirav K Desai Thomas Masaryk Peter Rasmussen Silvia Trasciatti Damir Janigro 《BMC neuroscience》2010,11(1):34