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排序方式: 共有1273条查询结果,搜索用时 15 毫秒
1.
Nonlinear Dynamics - Nonlinear flutter of variable stiffness composite plates—using a reduced-order model benefiting from a large-enough number of modes or degrees of freedom—is the... 相似文献
2.
Application of TiO2-nanotubes/PbO2 as an anode for the electrochemical elimination of Acid Red 1 dye
Santos José Eudes L. de Moura Dayanne Chianca da Silva Djalma Ribeiro Panizza Marco Martínez-Huitle Carlos A. 《Journal of Solid State Electrochemistry》2019,23(2):351-360
Journal of Solid State Electrochemistry - In this study, galvanostatic electrolysis, through the use of the platinum supported on Ti (Ti/Pt) and Ti/TiO2-nanotubes/PbO2 anodes, was conducted in an... 相似文献
3.
We address in this paper the problem of finding an optimal strategy for dealing with bottleneck machines and bottleneck parts in the cell formation process in group technology. Three types of economic decisions are considered: subcontracting, machine duplication and intercell moves. The problem is formulated as a minimum weighted node covering problem in a hypergraph, and we show that it can be solved in polynomial time by finding a maximum weighted stable set in a bipartite graph. We extend this result to cellular manufacturing systems in which the sequence of operations of each part is known in advance. 相似文献
4.
J. L. Souza A. F. Santos L. Polese Marisa S. Crespi C. A. Ribeiro 《Journal of Thermal Analysis and Calorimetry》2007,87(3):673-677
Poly(3-hydroxybutyrate), PHB has been structurally
modified through reaction with maleic anhydride, MA. Transesterification reaction
was carried out fixing the PHB and MA and besides time and temperature the
concentration of the triethylamine (used as catalyst) was changed. Glass transition,
melting and crystallization temperature obtained from DSC curves and thermal
degradation temperatures obtained from TG traces were used to evaluate the
influence of the reaction conditions on the modification of PHB according
to factorial design. On the base of the results the optimum conditions are
to perform the PHB modification reaction with MA reaction at 110°C for
1 h with 5% v/v triethylamine. 相似文献
5.
6.
Dendritic molecular capsules for hydrophobic compounds 总被引:1,自引:0,他引:1
Morgan MT Carnahan MA Immoos CE Ribeiro AA Finkelstein S Lee SJ Grinstaff MW 《Journal of the American Chemical Society》2003,125(50):15485-15489
Reichardt's dye, a highly solvatochromic dye, was encapsulated within poly (glycerol succinic acid) ([Gn]-PGLSA-OH) dendrimers to investigate the interior environment of these dendritic macromolecules. The absorption maximum for the encapsulated Reichardt's dye in water was indicative of a relatively high dielectric constant present within the dye/dendrimer complex. (1)H NMR of the encapsulated complex showed the presence of aromatic protons from Reichardt's dye along with the aliphatic protons of the dendrimer. Additionally, there were substantial changes in T(1) and T(2) times of the encapsulated dye when compared with the free dye, and (1)H NOESY spectra for the complex showed a significant number of intermolecular NOE cross-peaks. These data reveal the close through-space proximity of the dye to the dendrimer and the restricted motion of the encapsulated dye. To demonstrate the potential use of these macromolecules as drug delivery vehicles, the poorly water-soluble anticancer drug 10-hydroxycamptothecin (10HCPT) was encapsulated within a carboxylated PGLSA dendrimer ([G4]-PGLSA-COONa). Cytotoxicity assays with human breast cancer cells showed a significant reduction of cell viability, demonstrating that 10HCPT retains activity upon encapsulation. 相似文献
7.
José Glaüco Ribeiro Tostes 《Theoretical chemistry accounts》1981,59(3):229-235
Certain features of the chemist's molecular structure model, viz. size and shape, are retrieved even in the best non-adiabatic variational calculations thus far carried out for ground states of H
2
+
and H2. Those features do not conflict with the full symmetry of exact molecular eigenstates, once they are properly understood as correlation effects. 相似文献
8.
M. A. V. Ribeiro da Silva C. P. F. Santos M. J. S. Monte C. A. D. Sousa 《Journal of Thermal Analysis and Calorimetry》2006,83(3):533-539
The
standard (p0=0.1
MPa) molar enthalpies of formation, ΔfHm0, for
crystalline phthalimides: phthalimide, N-ethylphthalimide
and N-propylphthalimide were derived from
the standard molar enthalpies of combustion, in oxygen, at the temperature
298.15 K, measured by static bomb-combustion calorimetry, as, respectively,
– (318.0±1.7), – (350.1±2.7) and – (377.3±2.2)
kJ mol–1. The standard molar enthalpies of
sublimation, ΔcrgHm0, at T=298.15
K were derived by the Clausius-Clapeyron equation, from the temperature dependence
of the vapour pressures for phthalimide, as (106.9±1.2) kJ mol–1
and from high temperature Calvet microcalorimetry for phthalimide, N-ethylphthalimide and N-propylphthalimide
as, respectively, (106.3±1.3), (91.0±1.2) and (98.2±1.4)
kJ mol–1.
The derived standard molar enthalpies of formation,
in the gaseous state, are analysed in terms of enthalpic increments and interpreted
in terms of molecular structure. 相似文献
9.
Crespi M. S. Silva A. R. Ribeiro C. A. Oliveira S. C. Santiago-Silva M. R. 《Journal of Thermal Analysis and Calorimetry》2003,72(3):1049-1056
The thermal behavior and non-isothermal kinetics of thermal decomposition of three different kinds of composting of the USR
like: stack with drilled PVC tubes (ST), revolved stack (SR) and stack with material of structure (SM), from the usine of
composing of Araraquara city, Săo Paulo state, Brazil, within a period of 132 days of composting were studied. Results from
TG, DTG and DSC curves obtained on inert atmosphere indicated that the cellulosic fraction present, despite the slow degradation
during the composting process, is thermally less stable than other substances originated from that process. Due to that behavior,
the cellulosic fraction decomposition could be kinetically evaluated through non-isothermal methods of analysis. The values
obtained were: average activation energy, Ea=248, 257 and 259 kJ mol-1 and pre- exponential factor, logA=21.4, 22.5, 22.7 min-1, to the ST, SR and SM, respectively. From Ea and logA values and DSC curves, Málek procedure could be applied, suggesting that the SB (Šesták-Berggren) kinetic model is the appropriated
one to the first thermal decomposition step.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
10.
Optimisation of Supercritical Carbon Dioxide Systems for Complexation of Naproxen : Beta-Cyclodextrin 总被引:1,自引:0,他引:1
Susana Junco Teresa Casimiro Nuno Ribeiro Manuel Nunes Da Ponte Helena M. Cabral Marques 《Journal of inclusion phenomena and macrocyclic chemistry》2002,44(1-4):69-73
Supercritical carbon dioxide (scCO2)offers several attractive scenarios for thepharmaceutical processing as an alternativeto aqueous and organic solvents. In thiswork naproxen, a widely used non steroidalanti-inflammatory drug with analgesic andanti-inflammatory properties, was chosenas a model drug. Its complexation with cyclodextrinsimproves the rate and extent of dissolutionof the drug, increase its rate of absorption and mayreduce the unpleasant side-effects of the drug.The interest in using this supercritical technologyled us to develop an experimental unit for the useof supercritical CO2 as a processing medium forthe complexation of naproxen with beta cyclodextrin (CD). 相似文献