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371.
José Geraldo de P. Espínola Evandro P. S. Martins Franklin P. Aguiar Haryane R. M. Silva M. G. Fonseca L. N. H. Arakaki Ercules E. S. Teotônio 《Journal of Thermal Analysis and Calorimetry》2011,106(2):601-606
The complex BiCl3·L (L = 1,10-phenanthroline) was synthesized and characterized by elemental analysis and infrared spectroscopy (IR). Infrared
spectroscopy data suggested that the nitrogen atom of the aromatic ring is bonded to the bismuth atom. The kinetic study of
thermal degradation was determined by non-isothermal thermogravimetry. Two methods based on integral equation of Coats-Redfern,
were necessary for determining the kinetic trip: the fitting method, known as the checking model and an iso-conversional method.
The latter gives the activation energy for each degree of conversion and the first, the kinetic model gives activation energy
and the pre-exponential factor for thermal decomposition processes that occur through a single simple mechanism. The kinetic
parameters, E
a and log A for the heating rates of 5, 10, and 15 min K−1, were determined considering the decomposition model denoted by F0/R1 in the range of degree of conversion between 0.065
and 0.71. 相似文献
372.
Using spontaneous optical parametric downconversion, we experimentally demonstrate heralded generation of shaped single photons, whose modes are tailored indirectly by applying amplitude modulation on the pump field that drives the downconversion process. Our experiment opens a door to creating high-quality, mode-shaped single photons at a substantially higher efficiency than is possible with the existing method of direct single-photon shaping. 相似文献
373.
Leonardo H. F. Lima Viviane I. Serpa Flávio R. Rosseto Geraldo Rodrigues Sartori Mario de Oliveira Neto Leandro Martínez Igor Polikarpov 《Cellulose (London, England)》2013,20(4):1573-1585
Cellobiohydrolases hydrolyze cellulose releasing cellobiose units. They are very important for a number of biotechnological applications, such as, for example, production of cellulosic ethanol and cotton fiber processing. The Trichoderma cellobiohydrolase I (CBH1 or Cel7A) is an industrially important exocellulase. It exhibits a typical two domain architecture, with a small C-terminal cellulose-binding domain and a large N-terminal catalytic core domain, connected by an O-glycosylated linker peptide. The mechanism by which the linker mediates the concerted action of the two domains remains a conundrum. Here, we probe the protein shape and domain organization of the CBH1 of Trichoderma harzianum (ThCel7A) by small angle X-ray scattering (SAXS) and structural modeling. Our SAXS data shows that ThCel7A linker is partially-extended in solution. Structural modeling suggests that this linker conformation is stabilized by inter- and intra-molecular interactions involving the linker peptide and its O-glycosylations. 相似文献
374.
Pasquale?AvinoEmail author Geraldo?Capannesi Maurizio?Manigrasso Alberto?Rosada Mario?Vincenzo?Russo 《Chemistry Central journal》2013,7(1):173
Background
Anthropogenic activities introduce materials increasing levels of many dangerous substances for the environmental quality and being hazardous to human health. Major attention has been given to those elements able to alter the environment and endanger human health.The airborne particulate matter pollutant is considered one of the most difficult task in environmental chemistry for its complex composition and implications complicating notably the behavior comprehension. So, for investigating deeply the elemental composition we used two nuclear techniques, Neutron Activation Analysis and Photon Activation Analysis, characterized by high sensitivity, precision and accuracy. An important task has been devoted to the investigation of Quality Control (QC) and Quality Assurance (QA) of the methodology used in this study.This study was therefore extended as far back as possible in time (from 1965 until 2000) in order to analyze the trend of airborne concentration of pollutant elements in connection with the industrial and lifestyle growth during the entire period.Results
Almost all the elements may be attributed to long-range transport phenomena from other natural and/or anthropogenic sources: this behavior is common to all the periods studied even if a very light decreasing trend can be evidenced from 1970 to 2002. Finally, in order to investigate a retrospective study of elements in PM10 and their evolution in relationship with the natural or anthropogenic origins, we have investigated the Enrichment Factors. The study shows the EF trends for some elements in PM10 during four decades.Conclusions
The two nuclear techniques have allowed to reach elevated sensibility/accuracy levels for determining elements at very low concentrations (trace and ultra-trace levels). The element concentrations determined in this study do not basically show a significant level of attention from a toxicological point of view.375.
Large corporations fund their capital and operational expenses by issuing bonds with a variety of indexations, denominations, maturities and amortization schedules. We propose a multistage linear stochastic programming model that optimizes bond issuance by minimizing the mean funding cost while keeping leverage under control and insolvency risk at an acceptable level. The funding requirements are determined by a fixed investment schedule with uncertain cash flows. Candidate bonds are described in a detailed and realistic manner. A specific scenario tree structure guarantees computational tractability even for long horizon problems. Based on a simplified example, we present a sensitivity analysis of the first stage solution and the stochastic efficient frontier of the mean-risk trade-off. A realistic exercise stresses the importance of controlling leverage. Based on the proposed model, a financial planning tool has been implemented and deployed for Brazilian oil company Petrobras. 相似文献
376.
In this paper we prove that, under certain conditions, Nicodemi extensions of compact multilinear operators between Banach spaces are compact as well. An application of this result to the isometric/isomorphic theory of spaces of compact multilinear operators is provided. 相似文献
377.
378.
379.
Vila HV Leal LA Martins JB Skouteris D Magela e Silva G Gargano R 《The Journal of chemical physics》2012,136(13):134319
For the first time in the literature, rigorous time-independent quantum scattering formalism was applied, by means of the ABC program, to the H + Li(2) → LiH + Li reaction. The state-to-state probabilities as a function of the total energy have been computed at zero total angular momentum (J = 0) allowing us to evaluate the effect of vibrational/rotational excitation on the reaction promotion/inhibition, the energetic distribution of products, and the temperature dependence of the J-shifting thermal rate coefficients. 相似文献
380.
Radiation induced mutual grafting of styrene onto polypropylene has been carried using several grafting solutions with different organic solvents and polarity levels. In the mixture of styrene and protic polar solvents high grafting yields were obtained. This behavior suggests that grafting process does not have dependence on swelling of the substrate, something that is expected when a non-polar substrate and a non-polar media are in contact. In this case, the grafting yield may be related to the free radical generation at protic polar solvent; these reactive specimens start the reaction on substrate surface to allow the accessibility of monomer species to active sites. Some reaction mechanisms are proposed. 相似文献