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1.
H.D. Fonseca Filho R. Prioli M.P. Pires A.S. Lopes P.L. Souza F.A. Ponce 《Applied Physics A: Materials Science & Processing》2007,89(4):945-949
Atomic-force nanolithography was used to control the nucleation sites of InAs nanostructures on InP substrates. Indentations
with a wide range of dimensions were produced on InP. InAs nanostructures were selectively grown by metal organic vapor phase
epitaxy. It is shown that the number of active nucleation sites depends on the normal force applied during nanoindentation.
Crystalline defects introduced by nanoindentation are shown to be nucleation sites for these nanostructures. The presence
of screw dislocations within the grown nanostructures further supports this observation.
PACS 81.07.-b; 68.37.Ps; 81.16.Nd 相似文献
2.
E. Matsinos J. Guy E. Simopoulou W. Venus P. Allport M. Berggren M. Calicchio T. Coghen A. M. Cooper-Sarkar O. Erriquez N. Giannakopoulos G. T. Jones P. Marage M. M. Mobayyen D. R. O. Morrison S. O'Neale M. A. Parker J. Sacton R. A. Sansum N. Schmitz G. W. Van Apeldoorn K. Varvell A. Vayaki H. Wachsmuth W. Wittek BEBC WA Collaboration 《Zeitschrift fur Physik C Particles and Fields》1989,44(1):79-87
Backward proton and pion production is studied in ν and \(\bar v\) charged current interactions in neon. The results are compared with other experiments and theory. The complete backward proton data is compatible with protons produced by reinteractions in the nucleus. However in events with only one proton, muon variables appear correlated to those for the backward proton, as expected by the two-nucleon correlation model. 相似文献
3.
Zein films plasticized with oleic acid were formed by solution casting, by the stretching of moldable resins, and by blown film extrusion. The effects of the forming process on film structure were investigated by X-ray diffraction. Wide-angle X-ray scattering (WAXS) patterns showed d-spacings at 4.5 and 10 A, which were attributed to the zein alpha-helix backbone and inter-helix packing, respectively. The 4.5 A d-spacing remained stable under processing while the 10 A d-spacing varied with processing treatment. Small-angle X-ray scattering (SAXS) detected a long-range periodicity for the formed films but not for unprocessed zein, which suggests that the forming process-promoted film structure development is possibly aided by oleic acid. The SAXS d-spacing varied among the samples (130-238 A) according to zein origin and film-forming method. X-ray scattering data suggest that the zein molecular structure resists processing but the zein supramolecular arrangements in the formed films are dependent on processing methods. Structural model for a zein molecular aggregate (based on Matsushima et al.10). Rectangular prisms of individual zein molecules are hexagonally aligned parallel to each other. 相似文献
4.
C. G. L. Canellas S. M. F. Carvalho E. F. O. De Jesus M. J. Anjos R. T. Lopes 《Journal of Radioanalytical and Nuclear Chemistry》2006,269(3):631-634
Summary Major and trace elements were determined in serum of patients with chronic myelogenous leukemia (CML) using total reflection
X-ray fluorescence induced by synchrotron radiation (SRTXRF). CML affects 1 to 2 people per 100,000 and accounts for 7-20%
cases of leukemia. It was possible to determine the concentrations of the following elements: P, S, Cl, K, Ca, Cr, Mn, Fe,
Ni, Cu, Zn, Br and Rb. Using analysis of variance (ANOVA) it was observed that the contents of the P, S, Ca, Cr, Mn, Fe, Cu
and Rb elements differed significantly at a = 0.05 between groups of healthy subjects and CML patients and also genders (males
and females). 相似文献
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7.
Cestari AR Vieira EF Pinto AA Lopes EC 《Journal of colloid and interface science》2005,292(2):363-372
In this work, a hybrid silica/chitosan was synthesized and characterized by nitrogen elemental analysis and thermal analysis (TG, DTG, DTA, and DSC) and BET surface area. The hybrid was used in adsorption studies of two anionic dyes from aqueous solutions. A rise of temperature accelerates mass transfer of dyes into the hybrid. However, the maximum adsorption capacities reach similar values from 25 to 55 degrees C. The kinetic data were first evaluated in relation to the decrease of the time-related residual concentration of the dyes in solution, where the second-order model has presented the best fitting. The solid-phase interaction of dye data presents a rough fitting to the traditional first-order Lagergren kinetic model. However, a modified Avrami kinetic equation was successfully fitted to the kinetic quantities, where from five to seven kinetic regions were found. A pore-diffusion model has also demonstrated that the diffusion is the rate-controlling interaction mechanism. However, the experimental-calculated comparative values are the best way to evaluate a specific aqueous- or solid-phase kinetic model. 相似文献
8.
A phytochemical investigation in plantlets of the Brazilian medicinal tree Virola surinamensis resulted in the isolation and structural determination of four new compounds: 3-hydroxy-4-methyl-2-(11'-piperonyl-n-undecyl)-butenolide; 3-hydroxy-4-methyl-2-(7'-piperonyl-n-heptyl)-butanolide; 9'-(3,4-methylenedioxy-phenyl)-nonanoic acid and 13'-(3,4-methylene-dioxyphenyl)-tridecanoic acid. Thirteen compounds previously isolated from seeds and adult plants were also reported. 相似文献
9.
Studies on the encapsulation of diclofenac in small unilamellar liposomes of soya phosphatidylcholine 总被引:5,自引:0,他引:5
Lopes LB Scarpa MV Silva GV Rodrigues DC Santilli CV Oliveira AG 《Colloids and surfaces. B, Biointerfaces》2004,39(4):151-158
The encapsulation of acid (AD) and sodium diclofenac (SD) in small unilamellar liposomes (SUV) as well as the interactions of the drug with the bilayer was studied. SUV was prepared by sonication from multilamellar liposomes containing soya phosphatidylcholine and diclofenac at various proportions. The size distribution obtained from dynamic light scattering showed that the incorporation of SD decreases significantly the size of the liposomes suggesting that the drug interacts with the bilayer of the liposomes. This size decrease is related with the phase transition of liposomes to mixed micelar solution. The encapsulation of the hydrophilic dye indocyanine green in the aqueous compartment of liposomes showed that the rate of captured dye decreases with SD concentration suggesting the transition of liposomes to mixed micelles. The (31)P NMR analysis indicates that SD interacts with the phosphate of phosphatidylcholine head groups. A schematic model for interaction of SD with phosphatidylcholine of the liposomes in which the diclofenac anion interacts with the ammonium group of the phospholipid and the dichlorophenyl ring occupies a more internal site of bilayer near phosphate group was proposed. 相似文献
10.
Fátima Nunes Serralha José Madeira Lopes Francisco Lemos Duarte Prazeres Maria Aires-Barros Joo Rocha Joaquim Cabral Fernando Ramôa Ribeiro 《Reaction Kinetics and Catalysis Letters》2000,69(2):217-222
Novel [CrIII(amp)(bipy)(Cl)] (1) (H2amp = N-(hydroxyphenyl)salicyldimine; bipy = 2,2-bipyridyl) and [CrIII(app)(bipy)(Cl)]+ (2) (H2app = N-(hydroxyphenyl)pyridine-2-carboxaldimine; bipy = 2,2-bipyridyl) complexes have been synthesized and characterized by physico-chemical methods. Complexes 1 and 2 have been employed as catalysts in the oxidation of both saturated and unsaturated hydrocarbons using tert-butylhydroperoxide (t-BuOOH). The significance of the results with respect to oxo-functionalization of C-H bonds both in unsaturated and saturated hydrocarbons is noted. 相似文献