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51.
Italo Tamanini 《Annali dell'Universita di Ferrara》1988,34(1):183-217
Summary We establish a new regularity result for boundaries of sets minimizing the area functional perturbed by a curvature term,
and subject to a mass constraint of the type
, with a fixed, strictly positive integrable functiong(x). The existence of Lagrange parameters is also considered.
A preliminary version of the paper was presented at the meeting on “Partial Differential Equations”, Ferrara (Italy), October
13–16, 1986. Work partially supported by the Italian M.P.I. 相似文献
52.
Fleming GD Golsio I Aracena A Celis F Vera L Koch R Campos-Vallette M 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2008,71(3):1049-1055
This paper reports a DFT modelling of SERS spectra for benzene and benzonitrile on the basis of a simple noncoordinate substrate-adsorbate model. Assignment of normal modes was obtained from internal force constants and potential energy distribution matrices and used to identify, according the SERS selection rules, the orientation of the optimized molecules on the metallic surface. Calculated band enhancements are in good agreement with experimental observations. The optimized geometry parameters of the molecule-Ag system, changes of HOMO-LUMO energies are discussed to give insight in the different SERS mechanisms for both molecules. 相似文献
53.
54.
Annali di Matematica Pura ed Applicata (1867-1897) - 相似文献
55.
Viviana Scognamiglio Italo Pezzotti Gianni Pezzotti Juan Cano Ivano Manfredonia Katia Buonasera Fabiana Arduini Danila Moscone Giuseppe Palleschi Maria Teresa Giardi 《Analytica chimica acta》2012
In this paper we propose the construction and application of a portable multi-purpose biosensor array for the simultaneous detection of a wide range of endocrine disruptor chemicals (EDCs), based on the recognition operated by various enzymes and microorganisms. The developed biosensor combines both electrochemical and optical transduction systems, in order to increase the number of chemical species which can be monitored. Considering to the maximum residue level (MRL) of contaminants established by the European Commission, the biosensor system was able to detect most of the chemicals analysed with very high sensitivity. In particular, atrazine and diuron were detected with a limit of detection of 0.5 nM, with an RSD% less than 5%; paraoxon and chlorpyrifos were revealed with a detection of 5 μM and 4.5 μM, respectively, with an RSD% less than 6%; catechol and bisphenol A were identified with a limit of detection of 1 μM and 35 μM respectively, with an RSD% less than 5%. 相似文献
56.
Fábio Dos Santos Grasel Tiago Charão De Oliveira Luiz Antonio Mazzini Fontoura Italo José Da Cruz Rigotti Paulo Augusto Netz 《International journal of quantum chemistry》2012,112(6):1678-1687
Amides and carbamates present an energetic barrier associated to N? C(O) bond rotation, which determines two different equilibrium geometries. In this work, the conformational equilibrium of formanilide, acetanilide, methyl and t‐butyl phenylcarbamates, and their N‐methylderivatives was studied by AM1 and B3LYP/6‐31G(d,p) calculations. The effect of aryl p‐substituents (MeO, Me, Cl, Br, CN, and NO2) was also studied. Amide barriers were found by DFT calculation between 12 and 21 kcal/mol. Carbamates, on the other hand, showed barriers between 11 and 15 kcal/mol. AM1 underestimates the energetic barriers and provides values around half those obtained by B3LYP/6‐31G(d,p) calculations. Electron withdrawing substituents on aryl group decrease the barrier. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2012 相似文献
57.
We consider a discrete-time version of the model proposed by Lamantia and Radi [15] to describe a fishery where a population regulated by a logistic growth function is exploited by a pool of agents that can choose, at each time period, between two different harvesting strategies according to a profit-driven evolutionary selection rule. The resulting discrete dynamical system, represented by a two-dimensional nonlinear map, is characterized by the presence of invariant lines on which the dynamics are governed by one-dimensional restrictions that represent pure, i.e. adopted by all players, strategies. However, interesting dynamics related to interior attractors, where players playing both strategies coexist, are evidenced by analytical as well as numerical methods that reveal local and global bifurcations. 相似文献
58.
M Wang J Zhu W Zhu B Zhu J Liu X Zhu Y Pu P Sun Z Zeng X Li D Yuan S Zhu G Pezzotti 《Angewandte Chemie (International ed. in English)》2012,51(36):9123-9127
The dielectric constant and electrical conductivity of a composite of two insulators, poly(1,1-difluoroethylene) (yellow) and K(2) CO(3) (white), increased dramatically near the percolation threshold?f(c) (f=concentration of K(2) CO(3) ). This intriguing phenomenon can be interpreted in terms of interface percolation caused by the formation of chemically activated interfaces. 相似文献
59.
Using the eigenvalues and eigenvectors of correlations matrices of some of the main financial market indices in the world, we show that high volatility of markets is directly linked with strong correlations between them. This means that markets tend to behave as one during great crashes. In order to do so, we investigate financial market crises that occurred in the years 1987 (Black Monday), 1998 (Russian crisis), 2001 (Burst of the dot-com bubble and September 11), and 2008 (Subprime Mortgage Crisis), which mark some of the largest downturns of financial markets in the last three decades. 相似文献
60.
Yasuhito Takahashi Takaaki Shishido Kengo Yamamoto Yasunobu Sawaji Jun Nishida Giuseppe Pezzotti 《Journal of Raman spectroscopy : JRS》2015,46(11):1166-1172
Near‐infrared (NIR) Raman microprobe spectroscopy has been applied to the non‐invasive characterization of the biochemical structure of extracellular matrix in articular cartilage, a step forward along the path of in vivo diagnostic application of chondropathy. In most studies handling ex vivo cartilage specimens, formalin fixation or freeze‐thaw treatments have been applied in order to stabilize tissue and cell constituents prior to spectroscopic measurements. However, these pre‐processing manipulations might significantly affect certain target bands of the cartilage spectra, thus introducing biases in the characterizations, and potentially leading to data misinterpretation. In this study, we evaluated how formalin fixing and freeze‐thaw processes affect Raman spectra from human femur cartilage. Healthy cartilage specimens were fixed/stored either in a 10% neutral buffered formalin solution or in a deep freezer set at −80 °C. The results of this study show that formalin fixation significantly affects the NIR Raman spectra of cartilage specimens due to concurrent formalin absorption and water dehydration within both collagen and glycosaminoglycan macromolecules. Water dehydration was also confirmed in the amide I structure in the frozen‐thawed specimen, but to a much lesser extent. Furthermore, soaking the tissues in phosphate‐buffered saline solution minimized the storage‐induced Raman artifacts, but its immersion had limited effectiveness in formalin‐fixed specimens, predominantly due to an overlap of signals from the formalin liquid (i.e. emitting at 1046 and 1492 cm−1). Therefore, to provide a highly accurate biochemical evaluation of extracellular matrix using NIR Raman spectroscopy, freeze‐thaw processes are more suitable for ex vivo samples of human cartilage than formalin fixation. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献