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排序方式: 共有314条查询结果,搜索用时 46 毫秒
311.
Federico CarosioGalina Laufer Jenny AlongiGiovanni Camino Jaime C. Grunlan 《Polymer Degradation and Stability》2011,96(5):745-750
A novel method to improve flame retardant properties of textile fabric using multilayered thin films was evaluated. In this work, PET fabrics were coated with silica nanoparticles using layer-by-layer assembly. Five bilayers of positively and negatively charged colloidal silica (<10 nm average thickness) increased time to ignition and decreased heat release rate peak of PET fabric by 45% and 20%, respectively. In vertical burn test, this same nanocoating dramatically reduced burn time and eliminated melt dripping. This study demonstrates the ability to impart flame retardant behavior using a water-based, environmentally-friendly protective coating. 相似文献
312.
Thin silver films were deposited by pulsed laser ablation in a controlled Ar atmosphere and their SERS activity was investigated.
The samples were grown at Ar pressures between 10 and 70 Pa and at different laser pulse numbers. Other deposition parameters
such as laser fluence, target to substrate distance and substrate temperature were kept fixed at 2.0 J/cm2, 35 mm and 297 K. Film morphologies were investigated by scanning and transmission electron microscopies (SEM, TEM). Surface
features range from isolated nearly spherical nanoparticles to larger islands with smoothed edges. Cluster growth is favored
by plume confinement induced by background gas. After landing on the substrate clusters start to aggregate giving rise to
larger structures as long as the deposition goes on. Such a path of film growth allows controlling the surface morphology
as a function of laser pulse number and Ar pressure. These two easy-to-manage process parameters control the number density
and the average size of the as-deposited nanoparticles. We investigated the influence of substrate morphologies on their surface
enhanced Raman scattering properties. Raman measurements were performed after soaking the samples in rhodamine 6G aqueous
solutions over the concentration range between 1.0 × 10−4 and 5.0 × 10−8 M. The sensitivity of the film SERS activity on the surface features is put into evidence. 相似文献
313.
Neri Merhav 《Physica A》2008,387(22):5662-5674
We demonstrate that there is an intimate relationship between the magnetic properties of Derrida’s random energy model (REM) of spin glasses and the problem of joint source-channel coding in Information Theory. In particular, typical patterns of erroneously decoded messages in the coding problem have “magnetization” properties that are analogous to those of the REM in certain phases, where the non-uniformity of the distribution of the source in the coding problem plays the role of an external magnetic field applied to the REM. We also relate the ensemble performance (random coding exponents) of joint source-channel codes to the free energy of the REM in its different phases. 相似文献
314.
Ilaria Neri Sonia Laneri Ritamaria Di Lorenzo Irene Dini Giacomo Russo Lucia Grumetto 《Molecules (Basel, Switzerland)》2022,27(13)
Parabens (PBs) are used as preservatives to extend the shelf life of various foodstuffs, and pharmaceutical and cosmetic preparations. In this work, the membrane barrier passage potential of a subset of seven parabens, i.e., methyl-, ethyl-, propyl- isopropyl, butyl, isobutyl, and benzyl paraben, along with their parent compound, p-hydroxy benzoic acid, were studied. Thus, the Franz cell diffusion (FDC) method, biomimetic liquid chromatography (BLC), and in silico prediction were performed to evaluate the soundness of both describing their permeation through the skin. While BLC allowed the achievement of a full scale of affinity for membrane phospholipids of the PBs under research, the permeation of parabens through Franz diffusion cells having a carbon chain > ethyl could not be measured in a fully aqueous medium, i.e., permeation enhancer-free conditions. Our results support that BLC and in silico prediction alone can occasionally be misleading in the permeability potential assessment of these preservatives, emphasizing the need for a multi-technique and integrated experimental approach. 相似文献