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991.
Leandro Luetkmeyer Maria Inês Bruno Tavares Gisele C. X. Valle José de Souza Nogueira 《Macromolecular Symposia》2007,258(1):108-112
Summary: The focus of this work was to characterize the molecular dynamic of High Impact Polystyrene (HIPS - 5% PB), wood - A (Vochysia divergens) and B (Erisma uncinatum) - and their composites, using solid state nuclear magnetic resonance (NMR), by measuring the proton spin-lattice relaxation time (T1H) using a low field NMR, and by thermal analysis as Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA). DSC and TGA measurements show that both woods present the same molecular behavior. On the other hand, the spin-lattice relaxation time observed that the water is interfering in the packing and arrangements of cellulose chains due to inter and intra hydrogen molecular interactions, promoting the T1H values changed to high values. T1H shows that the sample B presents a higher rigidity than sample A. However, HIPS presents higher T1H values comparing to wood types. Analyzing the relaxation data for the composites, the values indicate that composites present an interaction between both components. 相似文献
992.
Jony Javorski Eckert Ludmila Corrêa de Alkmin e Silva Eduardo dos Santos Costa Fabio Mazzariol Santiciolli Fernanda Cristina Corrêa Franco Giuseppe Dedini 《基于设计的结构力学与机械力学》2019,47(2):175-200
The reduction of vehicle fuel consumption is one of the most important targets for the automotive industry. Plug-in electric vehicles (PHEVs) are considered a viable alternative to improve the vehicle performance and efficiency. This study presents a prototype of a hybridization kit to convert a conventional vehicle into a PHEV that results in an expressive reduction of fuel consumption. Due to this, an interactive adaptive-weight genetic algorithm optimization was applied to find out optimum configurations for the hybridization kit in order to minimize the overall cost to perform FTP-75 and US06 driving cycles and to improve performance. 相似文献
993.
Macêdo R. O. Aragão C. F. S. do Nascimento T. G. Macêdo A. M. C. 《Journal of Thermal Analysis and Calorimetry》1999,56(3):1323-1327
The stability and thermal behaviour of chloramphenicol and various of its mixtures were investigated. The thermogravimetric
and stability constant results showed that the chloramphenicol base is thermally more stable than the tablet in the studied
formulation. The reduction in stability was attributed to the presence of starch in the formulation. The thermal decompositions
of the chloramphenicol base and the tablet obey first-order kinetics.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
994.
Juliana M. Rodrigues Pierre Buisson Joana M. Pereira Inês M. Pinheiro Tamara Fernández-Marcelo M. Helena Vasconcelos Sabine Berteina-Raboin Maria-João R.P. Queiroz 《Tetrahedron》2019,75(10):1387-1397
Novel 8-(het)aryl-6H-pyrano[4′,3′:4,5]thieno[3,2-b]pyridines were prepared in good to high yields by a tandem one-pot procedure of Sonogashira coupling and 6-endo-dig lactonization from 3-bromothieno[3,2-b]pyridine-2-carboxylic acid and (het)arylalkynes. Sonogashira coupling products were also prepared from the corresponding methyl ester giving in the same reaction the corresponding 6-endo-dig compounds as minor products. The Sonogashira phenyl ester product gave cyclization with electrophiles only in low to moderate yields. Nevertheless, halolactonizations using Cu(I) or (II) salts/N-halosuccinimides (NXS) from either the phenyl ester or the carboxylic acid derivatives occurred in good to high yields. The growth inhibition potential of the compounds was evaluated using human tumor cell lines, HCT-15 (colorectal adenocarcinoma) and NCI-H460 (non-small cell lung cancer) and studies of apoptosis induction were performed for the three most promising compounds in HCT-15?cells. Two of them caused almost 40% of cell death by apoptosis when tested at their 1.5?×?GI50 concentrations. The tricyclic lactone with a F atom in the meta position showed to be the most promising one. 相似文献
995.
Ingrid F. Zattoni Lais D. Guanaes Letícia B. Cerqueira Roberto Pontarolo Diogo R.B. Ducatti M. Eugênia R. Duarte Miguel D. Noseda Angela C.L.B. Trindade Alan G. Gonçalves 《Tetrahedron letters》2019,60(40):151129
We have evaluated four 1,4-dihydropyridines (DHPs 1a, 1b, 1c and 1d) as reducing agents, which presented free (hydrogenated) or phenyl-substituted N-1 and C-4 positions of the DHP ring. Reactions combining each of the DHP and different amounts of BF3OEt2 were evaluated for the reduction of imine 2a (N-benzylideneaniline). DHP simultaneously substituted at N-1 and C-4 (1a), and DHP substituted at C-4 (1b) gave lower yields for reduction of 2a in comparison with DHPs 1c and 1d (both unsubstituted at the C-4 position). By evaluating the amount of added BF3OEt2 to the reaction mixture, we have found that DHP 1c (substituted at N-1) provided its best yield for amine 3a (82%) when associated with stoichiometric amounts BF3OEt2, while DHP 1d (N-1- and C-4-unsubstituted derivative) was more effective (90% yield) with catalytic quantities of the Lewis acid. The reaction system using DHP 1c under stoichiometric BF3OEt2 could also be successfully applied with additional imine examples and under reductive amination conditions. 相似文献
996.
Geraldo GarciadeFreitasJunior Tayla M. Florêncio Ricardo J. Mendona Giancarlo R. Salazar‐Banda Robson T. S. Oliveira 《Electroanalysis》2019,31(3):554-559
An electrochemical method for the simultaneous determination of benzene, toluene and xylenes (BTX) in water was developed using square‐wave voltammetry (SWV). The determination of BTX was carried out using a cathodically pre‐treated boron‐doped diamond electrode (BDD) using 0.1 mol L?1 H2SO4 as supporting electrolyte. In the SWV measurements using the BDD, the oxidation peak potentials of the total xylenes‐toluene and toluene‐benzene couples, present in ternary mixtures, display separations of about 100 and 200 mV, respectively. The attained detection limits for the simultaneous determination of benzene, toluene and total xylenes were 3.0×10?7, 8.0×10?7 and 9.1×10?7 mol L?1, respectively. The recovery values taken in ternary mixtures of benzene, toluene and total xylenes in aqueous solutions are 98.9 %, 99.2 % and 99.4 %, respectively. 相似文献
997.
E. B. S. Corrêa C. A. Linhares A. P. C. Malbouisson J. M. C. Malbouisson A. E. Santana 《The European Physical Journal C - Particles and Fields》2017,77(4):261
We study effects coming from finite size, chemical potential and from a magnetic background on a massive version of a four-fermion interacting model. This is performed in four dimensions as an application of recent developments for dealing with field theories defined on toroidal spaces. We study effects of the magnetic field and chemical potential on the size-dependent phase structure of the model, in particular, how the applied magnetic field affects the size-dependent critical temperature. A connection with some aspects of the hadronic phase transition is established. 相似文献
998.
Zoheir Ziani Gaëtan Lévêque Saliya Coulibaly Abdelmajid Taki Abdellatif Akjouj 《Annalen der Physik》2020,532(10):2000240
The route to chaos of a plasmonic dimer formed of two identical nanoparticles with Kerr-type nonlinear response and illuminated by an external electric field is reported. It is shown that this system has a complex dynamical behavior with chaotic nature. This complexity is analyzed using Lyapunov exponents, the Kaplan–Yorke dimension, and correlation dimensions. The existence of familiar period-doubling sequences route to chaos is pointed out, and domains corresponding to the onset of period doubling and chaos in the plane of parameters are evidenced. 相似文献
999.
1000.
da Silva Débora da C. P. de Menezes Lívia R. da Silva Paulo Sérgio R. C. Tavares Maria Inês B. 《Journal of Thermal Analysis and Calorimetry》2021,143(1):165-172
Journal of Thermal Analysis and Calorimetry - Most of the synthetic polymers that are used for packaging industry come from fossil fuel; thus, when their life cycle is complete, they normally... 相似文献