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排序方式: 共有264条查询结果,搜索用时 15 毫秒
1.
Luca Valentini 《Polymer》2005,46(17):6715-6718
The adsorption of several types of conducting polymers on carbon nanotubes is investigated by electrical transport measurements. We report the optoelectronic properties occurring in single-walled carbon nanotubes (SWNTs) conjugated polymer, poly(3-octylthiophene), composites. Al/polymer-nanotube composite/indium-tin oxide diodes show photovoltaic behavior proposing that the main reason for this increase is the photoinduced electron transfer at the polymer/nanotube interface. Interesting results were obtained in the case of poly(o-anisidine) (POAS)-multi-walled nanotubes (MWNTs) composites where the increment of monolayers results in a significant improvement of the specific conductivity. POAS-coated MWNTs thin films demonstrated their potentiality as a new class of materials for inorganic vapors detection for environmental applications. 相似文献
2.
Edoardo Zonta Francesco Valentini Andrea Dorigato Luca Fambri Alessandro Pegoretti 《Polymer Engineering and Science》2021,61(1):136-153
The thermomechanical behavior of ethylene propylene diene monomer (EPDM) foams produced with the salt leaching method has been investigated and compared with the behavior of EPDM foams obtained from conventional blowing agents. Moreover, the salt-leaching process has been optimized to minimize salt residues and the influence of different parameters (such as average particle size and particle size distribution) has been investigated. Scanning electron microscopy and density measurements highlighted that salt-leaching leads to the formation of open-cell porosity with cell dimensions of around 60 to 80 μm, while foams obtained with the two traditional foaming agents lead to closed-cell porosity. Compression set values indicate that the behavior of the foams produced with salt leaching are more similar to the unfoamed rubber, characterized by higher elasticity and low residual deformation. Two theoretical models were successfully applied to the compression curves (Mooney-Rivlin and Exponential-Logarithmic) and they highlighted the effect of foaming on the properties of EPDM rubber and in particular the higher chain extensibility obtained through the salt leaching foaming method. 相似文献
3.
A compact two-cuvette dye amplifier capable of pulse amplifying weak cw visible sources by factors in excess of 10(9) has been demonstrated. Seeded with a 300-μW single-frequency He-Ne laser and without the need for a Faraday isolator, the preamplifier yields >40-μJ pulses of 4.5-ns duration and 1.4× transform-limited linewidths around 140 MHz. Subsequent power amplification yields 4-ns FWHM, 2-mJ pulses with excellent pulse-to-pulse stability and linewidths around 170 MHz. Scaling of the operational envelope and extension to pulse amplification of cw single-mode tunable diode lasers is discussed. 相似文献
4.
5.
P Vandoni R Perondi A Saino G Pomidossi M Ciulla R Paliotti G Tortora P Valentini F Magrini 《Canadian Metallurgical Quarterly》1998,49(12):975-984
In order to obtain accurate measurements of coronary sinus blood flow (CSBF), a new catheter (7 French) with a radiopaque, flexible, and basket-shaped tip was developed for guiding a standard 3 Fr Doppler catheter in the coronary sinus (CS) in man. The radiopaque "basket" tip of the catheter allows the operator to stabilize the position of the Doppler transducer in the center of the CS and to accurately measure the CS internal diameter radiologically. CSBF was calculated as the product of CS cross-sectional area by mean CSBF velocity. Doppler-derived CSBF values at rest and during handgrip were compared with those obtained by the local thermodilution technique in 16 patients undergoing diagnostic coronary angiography. During handgrip, mean CSBF increased from 154+/-23 (rest) to 299+/-34 mL/min by the Doppler method and from 148+/-22 to 288+/-32 mL/min by the thermodilution technique. A good correlation (r = 0.86) between the CSBF values with the two techniques was observed. The authors conclude that the intravascular Doppler technique associated with the use of the basket guide catheter provides an accurate and simple tool for monitoring CSBF in patients. 相似文献
6.
Fabiane Bach Cristiane Vieira Helm Marcelo Barba Bellettini Giselle Maria Maciel Charles Windson Isidoro Haminiuk 《International Journal of Food Science & Technology》2017,52(11):2382-2392
The main chemical and biochemical constituents of nine edible mushrooms were evaluated in this study. An enzymatic method was used to determine the α‐ and β‐glucan contents, and the amino acid (AA) profiles were evaluated by RP‐HPLC‐DAD. The recommended dietary allowance (RDA) of the nutrients was evaluated. Finally, principal component analysis (PCA) was used to group the mushrooms according to their AA, glucans and chemical composition. All mushrooms evaluated can be considered as a potential and alternative source of dietary fibre (24.4–46.62%) and protein (16.47–36.96%) in a diet, with low contents of fat (1.40–2.08%). Phosphorus, potassium, iron, copper and zinc were the main minerals found in the mushrooms, whereas sodium concentration was negligible. All essential AA were detected in the mushrooms, with Pleurotus ostreatus (black oyster) representing the main source of essential amino acids among the samples. The contents of β‐glucan ranged from 1.58 to 16.91 mg g?1 of dry matter among the mushrooms and Pleurotus eryngii presented the highest amount of this component. Pleurotus ostreatus (black oyster) and P. eryngii were also grouped together due to similarities in their phosphorous and arginine contents. Among the main results, it can highlight the high concentration of dietary fibre and essential amino acids of the edible mushrooms. 相似文献
7.
Igor Otavio Minatel Fabiane Valentini Francisqueti Camila Renata Corrêa Giuseppina Pace Pereira Lima 《International journal of molecular sciences》2016,17(8)
γ-oryzanol (Orz), a steryl ferulate extracted from rice bran layer, exerts a wide spectrum of biological activities. In addition to its antioxidant activity, Orz is often associated with cholesterol-lowering, anti-inflammatory, anti-cancer and anti-diabetic effects. In recent years, the usefulness of Orz has been studied for the treatment of metabolic diseases, as it acts to ameliorate insulin activity, cholesterol metabolism, and associated chronic inflammation. Previous studies have shown the direct action of Orz when downregulating the expression of genes that encode proteins related to adiposity (CCAAT/enhancer binding proteins (C/EBPs)), inflammatory responses (nuclear factor kappa-B (NF-κB)), and metabolic syndrome (peroxisome proliferator-activated receptors (PPARs)). It is likely that this wide range of beneficial activities results from a complex network of interactions and signals triggered, and/or inhibited by its antioxidant properties. This review focuses on the significance of Orz in metabolic disorders, which feature remarkable oxidative imbalance, such as impaired glucose metabolism, obesity, and inflammation. 相似文献
8.
A method is described to obtain separation of single-walled carbon nanotubes (SWCNTs) on an indium tin-oxide (ITO) substrate by modifying the conducting surface of ITO with amino-silane functional groups. Scanning electron microscopy confirmed that the amino-silane functionalization of the substrate is a critical parameter for the immobilization of separated nanotubes. In particular spin coating the SWCNT solution onto the amino-silane modified ITO surface results in a lower nanotube density with respect to the reference sample obtained on pure ITO together with the immobilization of semiconducting carbon nanotubes onto the substrate. The possibility of using these SWCNT thin films to obtain polymer/nanotube heterojunctions for the development of organic solar cells is considered. 相似文献
9.
ABSTRACTIn the present paper, the mechanical properties and the scratch failure mechanisms of Ni–P electroless coatings are described. The material microstructure was studied in as-deposited and annealed conditions through SEM and EDS analyses. Nanoindentation measurements on the coatings showed a remarkable hardening due to the crystallization and precipitation behaviour produced by annealing. The scratch tests, conducted by increasing the load during scratch, revealed the coating failure mechanisms in a broad range of applied stresses up to delamination. 相似文献
10.
Leite ER Carreño NL Longo E Valentini A Probst LF 《Journal of nanoscience and nanotechnology》2002,2(1):89-94
Here we describe a new route for the synthesis of nanometric Ni particles embedded in a mesoporous silica material with excellent potential for catalytic applications. Mesoporous silica with a surface area in the range of 202-280 m2/g, with narrow pore size distribution and Ni nanoparticles (particles in the range of 3-41 nm) were obtained in a direct process. A different approach was adopted to process such a nanocomposite. This new approach is based on the formation of a polymer with the silicon oxianion and nickel cation chelated to the macromolecule structure and on the control of the pyrolysis step. The CO/CO2 atmosphere resulting from the pyrolysis of the organic material promotes the reduction of the Ni citrate. 相似文献