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51.
The kinetic parameters of the selective isothermal adsorption of ethanol from an aqueous solution onto a hydrophobic zeolite type NaZSM‐5 were determined using a series of the so‐called standard methods (the initial rate, the saturation rate and the maximum rate methods). The kinetic model of ethanol adsorption was determined by the “model fitting” method. The dependence of the kinetic parameters on the degree of adsorption and the presence of a compensation effect were determined by the isoconversional method. The complex changes of the activation energy and pre‐exponential factor with the degree of adsorption were explained by the model of the activation energy distribution of elemental adsorption processes. 相似文献
52.
Tea Kulisic-Bilusic Kerstin Schnäbele Ingrid Schmöller Verica Dragovic-Uzelac Anita Krisko Branka Dejanovic Mladen Milos Greta Pifat 《European Food Research and Technology》2009,228(3):417-424
The antioxidant activity (free radical scavenging ability and lipid oxidation inhibitory activity) and the activity in cell
culture [influence on HT-29 human colon cancer cell viability and nuclear factor kappa B (NF-κB) activation] of natural fruit
juices from red grape, strawberry, cherry and sour cherry were investigated in vitro. Analysis of polyphenolic composition
of fruit juices showed the dominant presence of anthocyanins (cyanidin-3-glucoside, cyanidin-3-rutinoside, peonidin-3-rutinoside,
pelargonidin-3-glucoside), anthocyanidins (procyanidins B1, B2 and B3), flavonoids (glucosides of myricetin, quercetin and
kaempferol), and phenolic acids (neochlorogenic acid, chlorogenic acid, ellagic acid, p-coumaroylquinic acid) in juices. DPPH test and β-carotene bleaching method indicated that grape, strawberry, cherry and sour
cherry natural juices (at the concentration of 2.5%) showed very strong free radical scavenging (75–92%) and antioxidant activity
(71–94%). In addition, at the concentration of 0.01% they showed complete inhibition of copper-induced oxidation of human
LDL (low density lipoprotein). In contrast, selected fruit juices did not show cytotoxic effects on HT-29 cells and NF-κB
inhibitory activity (at the concentrations of 0.5 and 2%). Results of this study showed no correlation between the antioxidant
activity of natural fruit juices from red grape, strawberry, cherry and sour cherry and their effect on HT-29 cell viability
and NF-κB inhibitory activity. 相似文献
53.
Gerald Zach Milos Davidovic Horst Zimmermann 《Analog Integrated Circuits and Signal Processing》2011,68(1):59-68
This work describes time-of-flight distance measurements with a line sensor based on the correlation principle. It is capable
of suppressing maximum bright sunlight and even more electronically in each pixel autonomously without using any optical filters.
The optical fill factor of a pixel is 58% embodying a 100 × 100 μm2 photodiode. Working principle of the pixel circuit and
the mechanism for suppression of ambient illumination as well as physical limitation of accuracy are discussed. Characterizations
of the single-pixel performance with 650 nm laser and 850 nm LED sources with optical output powers of 1 mW and 900 mW, respectively,
are presented. Finally, measured characteristics of the line sensor for distances up to 3.2 m are shown. The standard deviation
is below 2 cm up to 1.2 m at a measurement time of 50 ms per distance point and the near-infrared LED illumination. 相似文献
54.
55.
Soini HA Bruce KE Klouckova I Brereton RG Penn DJ Novotny MV 《Analytical chemistry》2006,78(20):7161-7168
This report describes a rolling stir bar sampling procedure for volatile organic compounds (VOCs) present on various biological surfaces. In combination with thermal desorption/gas chromatography/mass spectrometry, this analytical technique was initially tested for quantitative profiling of human skin VOCs. It is also applicable to additional hydrophobic surfaces such as agricultural products, plant materials, and bird feathers. Use of embedded internal standards provides highly reproducible and quantitative results for a wide variety of sampled trace components. The samples of collected human skin VOCs and standards were found stable under cool storage conditions for at least 14 days, making this approach suitable for field biological and agricultural studies. Additionally, this methodology appears to have potential for forensic and toxicological investigations, as suggested through the analyses of VOC profiles of the human thumb prints recovered from a nonbiological smooth surface. 相似文献
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58.
Ambient Protection of Few‐Layer Black Phosphorus via Sequestration of Reactive Oxygen Species 下载免费PDF全文
Sumeet Walia Sivacarendran Balendhran Taimur Ahmed Mandeep Singh Christopher El‐Badawi Mathew D. Brennan Pabudi Weerathunge Md. Nurul Karim Fahmida Rahman Andrea Rassell Jonathan Duckworth Rajesh Ramanathan Gavin E. Collis Charlene J. Lobo Milos Toth Jimmy Christopher Kotsakidis Bent Weber Michael Fuhrer Jose M. Dominguez‐Vera Michelle J. S. Spencer Igor Aharonovich Sharath Sriram Madhu Bhaskaran Vipul Bansal 《Advanced materials (Deerfield Beach, Fla.)》2017,29(27)
Few‐layer black phosphorous (BP) has emerged as a promising candidate for next‐generation nanophotonic and nanoelectronic devices. However, rapid ambient degradation of mechanically exfoliated BP poses challenges in its practical deployment in scalable devices. To date, the strategies employed to protect BP have relied upon preventing its exposure to atmospheric conditions. Here, an approach that allows this sensitive material to remain stable without requiring its isolation from the ambient environment is reported. The method draws inspiration from the unique ability of biological systems to avoid photo‐oxidative damage caused by reactive oxygen species. Since BP undergoes similar photo‐oxidative degradation, imidazolium‐based ionic liquids are employed as quenchers of these damaging species on the BP surface. This chemical sequestration strategy allows BP to remain stable for over 13 weeks, while retaining its key electronic characteristics. This study opens opportunities to practically implement BP and other environmentally sensitive 2D materials for electronic applications. 相似文献
59.
Parallel structured milling machines with long X travel 总被引:1,自引:0,他引:1
The paper presents research and development results of one parallel structured milling machine with long X travel. The developed milling machine experimental prototype is based on a newly developed 3-DOF spatial parallel mechanism. In comparison with similar developed machines, it has several advantages such as: rather regular shape of the workspace similar to serial machines, greater stiffness by nature of strut arrangement and good force and speed ratio through the entire machine's workspace. 相似文献
60.