排序方式: 共有34条查询结果,搜索用时 15 毫秒
1.
Jonathan B. Ball Margaret G. Wong Benny Capuano Jacqueline M. Gulbis Maureen F. Mackay Paul F. Alewood 《Journal of heterocyclic chemistry》1990,27(2):279-286
The constrained dipeptide mimic 1 was synthesized from 2 in three steps with 65% overall yield. Analyses of the 1H nmr data of a number of 3-amino-2,5-dioxo-2,3,4,5-tetrahydro-1H-1-benzazepine derivatives led to the conclusion that these compounds adopt a similar conformation and that this ring system is rigid. X-ray crystallography was used to define the structure of 3 , and computer-aided energy minimization of 6 gave a preferred conformation similar to that observed in the crystal of 3 . 相似文献
2.
Corrado Di Natale Roberto Paolesse Eugenio Martinelli Rosamaria Capuano 《Analytica chimica acta》2014
The analysis of volatile compounds is an efficient method to appraise information about the chemical composition of liquids and solids. This principle is applied to several practical applications, such as food analysis where many important features (e.g. freshness) can be directly inferred from the analysis of volatile compounds. 相似文献
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4.
Roberta M. Rosa Ricardo L. Szulc Rosamaria W. C. Li Jonas Gruber 《Macromolecular Symposia》2005,229(1):138-142
Summary: Poly(2-bromo-5-hexyloxy-p-phenylenevinylene), BHPPV, was electrochemically synthesized in 81% yield. The polymer presented high solubility in organic solvents, in spite of its relatively high molar weight ( = 80 000), and showed to be thermally resistant up to 130 °C. Gas sensors made from thin films of CSA doped BHPPV, deposited on interdigitated electrodes, responded to five different solvents. Plots of relative response versus relative recovery showed good discrimination of the five solvents. 相似文献
5.
Androić D Armstrong DS Arvieux J Bailey SL Beck DH Beise EJ Benesch J Benmokhtar F Bimbot L Birchall J Bosted P Breuer H Capuano CL Chao YC Coppens A Davis CA Ellis C Flores G Franklin G Furget C Gaskell D Gericke MT Grames J Guillard G Hansknecht J Horn T Jones MK King PM Korsch W Kox S Lee L Liu J Lung A Mammei J Martin JW McKeown RD Micherdzinska A Mihovilovic M Mkrtchyan H Muether M Page SA Papavassiliou V Pate SF Phillips SK Pillot P Pitt ML Poelker M Quinn B Ramsay WD Real JS Roche J 《Physical review letters》2012,108(12):122002
The parity-violating (PV) asymmetry of inclusive π- production in electron scattering from a liquid deuterium target was measured at backward angles. The measurement was conducted as a part of the G0 experiment, at a beam energy of 360 MeV. The physics process dominating pion production for these kinematics is quasifree photoproduction off the neutron via the Δ0 resonance. In the context of heavy-baryon chiral perturbation theory, this asymmetry is related to a low-energy constant d(Δ)- that characterizes the parity-violating γNΔ coupling. Zhu et al. calculated d(Δ)- in a model benchmarked by the large asymmetries seen in hyperon weak radiative decays, and predicted potentially large asymmetries for this process, ranging from A(γ)-=-5.2 to +5.2 ppm. The measurement performed in this work leads to A(γ)-=-0.36±1.06±0.37±0.03 ppm (where sources of statistical, systematic and theoretical uncertainties are included), which would disfavor enchancements considered by Zhu et al. proportional to V(ud)/V(us). The measurement is part of a program of inelastic scattering measurements that were conducted by the G0 experiment, seeking to determine the N-Δ axial transition form factors using PV electron scattering. 相似文献
6.
Fabio Capuano Gaetano Mangiapia Ornella Ortona Gerardino d’Errico Roberto Sartorio 《Journal of solution chemistry》2007,36(5):617-629
The molar conductivities of NaCl in several poly(ethylene glycol)(PEG)–water “mixed solvents” are presented as a function
of the PEG content in solution. Three different PEG samples, a monodispersed one and two polydispersed ones, have been used.
The comparison between the molar conductivity values in the mixed solvents and the corresponding ones in pure water shows
that the only effect of PEG on the ions’ motions is an obstruction effect despite the variation of the macroscopic dielectric
constant induced by PEG itself. A comparison between the molar conductivities and the corresponding mutual main diffusion
coefficients shows a tight correlation between the two quantities. This correlation is possible only in the absence of electrostatic
effects due to the presence of PEG. 相似文献
7.
Manuela Jörg Mark Agostino Elizabeth Yuriev Frankie S. Mak Neil D. Miller Jonathan M. White Peter J. Scammells Ben Capuano 《Structural chemistry》2013,24(4):1241-1251
Herein, we describe the synthesis of the adenosine A2A antagonist ZM 241385 (9) starting from commercially available 2-furanhydrazide (1) and including a comprehensive structural characterization of all the intermediates and the final product. In addition, extensive NMR analysis, including temperature and concentration-dependent experiments, are reported as well as the first single-crystal structure of the compound ZM 241385 (9) as the trihydrate. Furthermore, an extensive structural comparison of the single-crystal structure with the published protein bound X-ray structures is reported. 相似文献
8.
Capuano G Filippone G Romeo G Acierno D 《Langmuir : the ACS journal of surfaces and colloids》2012,28(12):5458-5463
We study the structure and linear viscoelasticity of interacting polymer nanocomposites based on mixtures of poly(ethylene oxide) and fumed silica particles. The filler is dispersed within the polymer using two different techniques which lead to different dispersion states. The analysis of the dynamic response of our systems highlights the formation of a stress-bearing network above a critical volume fraction, Φ(c). Extending a two-phase model used to describe weakly interacting systems, we show that above Φ(c) the melt-state elasticity of the composites arises from the independent contributions of a polymer-particle network and a viscous matrix. We also find that, although Φ(c) depends on the initial state of dispersion, the network elasticity scales with volume fraction following a universal power-law, with an exponent ν ≈ 1.8. Such a scaling law has been recently predicted for the stress-bearing mechanism governed by polymer-mediated interactions. 相似文献
9.
Helicity is the scalar product between velocity and vorticity and, just like energy, its integral is an inviscid invariant of the three-dimensional incompressible Navier-Stokes equations. However, space- and time-discretization methods typically corrupt this property, leading to violation of the inviscid conservation principles. This work investigates the discrete helicity conservation properties of spectral and finite-differencing methods, in relation to the form employed for the convective term. Effects due to Runge-Kutta time-advancement schemes are also taken into consideration in the analysis. The theoretical results are proved against inviscid numerical simulations, while a scale-dependent analysis of energy, helicity and their non-linear transfers is performed to further characterize the discretization errors of the different forms in forced helical turbulence simulations. 相似文献
10.
One‐step synthesis of poly(lactic‐co‐glycolic acid)‐g‐poly‐1‐vinylpyrrolidin‐2‐one copolymers 下载免费PDF全文
Elisabetta Ranucci Giovanna Capuano Amedea Manfredi Paolo Ferruti 《Journal of polymer science. Part A, Polymer chemistry》2016,54(13):1919-1928
The radical polymerization of 1‐vinylpyrrolidin‐2‐one (NVP) in poly(lactic‐co‐glycolic acid) (PLGA) 50:50 at 100 °C leads to amphiphilic PLGA‐g‐PVP copolymers. Their composition is determined by FT‐IR spectroscopy. Thermogravimetric analyses agree with FT‐IR determinations. Saponification of the PLGA‐g‐PVP polyester portion allows isolating the PVP side chains and measuring their molecular weight, from which the average chain transfer constant (CT) of the PLGA units is estimated. The MALDI‐TOF spectra of PVP reveal the presence at one chain end of residues of either glycolic acid‐ or lactic acid‐ or lactic/glycolic acid dimers, trimers and one tetramer, the other terminal being hydrogen. This unequivocally demonstrates that grafting occurred. Accordingly, the orthogonal solvent pair ethyl acetate—methanol, while separating the components of PLGA/PVP intimate mixtures, fails to separate pure PVP or PLGA from the reaction products. All PLGA‐g‐PVP and PLGA/PLGA‐g‐PVP blends, but not PLGA/PVP blends, give long‐time stable dispersions in water. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 1919–1928 相似文献