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排序方式: 共有192条查询结果,搜索用时 15 毫秒
61.
Mišan A Mimica-Dukić N Sakač M Mandić A Sedej I Simurina O Tumbas V 《Journal of food science》2011,76(9):C1239-C1244
The antioxidant activity of ethanolic extracts of parsley, buckthorn, mint, caraway, and their mixture "Vitalplant" was evaluated, and the potential of "Vitalplant" mixture extract to retard the process of lipid oxidation in cookies was tested. The antioxidant activity was estimated by 2 direct (ESR) and 4 indirect (spectrophotometric) tests and correlated with the total phenolic and flavonoid content. The potential of "Vitalplant" mixture extract to retard the process of lipid oxidation in cookies was measured by thiobarbituric acid (TBA)-reactive-substances assay (TBARS) and DPPH˙ (1,1-diphenyl-2-picryl-hydrazyl) test. Significantly different (P < 0.05) amounts of total phenolics were found among extracts in the following order: mint > buckthorn > "Vitalplant" > parsley > caraway. Total flavonoid content varied from 0.510% (parsley) to 2.05% ("Vitalplant"). A statistically significant correlation was found between IC(50) values on DPPH˙ and total flavonoid content of the samples (r=- 0.94, P < 0.05) and between IC(50) values on DPPH˙ and IC(50) values on O(2) (·-) scavenging activity (r= 0.89, P < 0.05). A correlation between reducing activity and total phenolic content was found to be positive and statistically significant (r= 0.94, P < 0.05). "Vitalplant" mixture exhibited a relatively high antioxidant activity in most of the tests, which can be explained by synergistic effects of the ingredients of which it is composed. Finally, "Vitalplant" extract addition (2%, 4%, and 6%) improved antioxidant activity and oxidative stability of the cookies in dose-dependent manner. PRACTICAL APPLICATION: Supplementation of cookies with a mixture of Petroselini fructus, Frangulae cortex, Mentha piperitae folium, Carvi fructus can retard the process of lipid oxidation and elevate antioxidant activity of the final product. 相似文献
62.
Reza Hosseini Neda Teimourzadeh Morteza Fathipour 《Journal of Computational Electronics》2014,13(1):170-179
A new type of Gate All Around Nanowire Transistor (GAA NWT) which employs source heterojunction and strained channel is proposed and its electrical characteristics are compared with SiGe GAA NWT and with conventional Silicon GAA NWT. The effect of band-offset energy at the source SiGe/strained-Si heterojunction is to enhance carriers’ kinetic energy when injected from the source into the channel. In this analysis, a quantum mechanical transport approach based on non-equilibrium Green’s function method in the frame work of effective mass theory is employed. Simulation routine consists of self consistent solutions of a three dimensional Poisson’s equation, a Schrodinger equation on the radial direction, and also transport equation. We analyze the electrical characteristics of the source heterojunction strained channel GAA NWT. Also, the advantages of this novel structure in terms of current drive capability and conduction band edge are discussed. It is shown that proposed structure provides a higher on current, lower leakage, lower threshold voltage and lower subthreshold slope in comparison with SiGe GAA NWT and conventional Silicon GAA NWT. 相似文献
63.
This work reports on hydrogen termination of nano-crystalline diamond films and the behavior of polymer SU-8 as passivating layer after plasma treatment performed at low temperature in a novel linear antenna microwave plasma enhanced system. Nano-crystalline diamond films were grown by microwave plasma enhanced chemical vapor deposition and then hydrogen terminated at different substrate temperatures. The results indicate that a temperature as low as 200 °C is sufficient to reliably attain a diamond surface conductivity of the order of 10−7 (Ω/□)−1. An increase in substrate temperature up to 400 °C results in an increase in surface conductivity up to 1.7 × 10−6 (Ω/□)−1. The structural changes of the SU-8 passivating layer, before and after plasma treatment, were investigated by FTIR spectroscopy. 相似文献
64.
We evaluated the sorptive properties of mordenite zeolite (MOR), a copper terephthalate metal–organic framework (MOF), and graphene oxide (GO) and their potential use in treating acid rock drainage (ARD) containing Fe3+, Cu2+, Mn2+, Zn2+, Pb2+, and Cd2+ ions. MOR was prepared via a hydrothermal method, MOF was prepared via a solvothermal method, and few-layered GO nanosheets were synthesized using Hummers’ method. The aqueous contaminants were removed by chemico-physical sorption and ion exchange in batch tests. It proved possible to dramatically improve removal efficiency and sorptive capacity by optimizing experimental conditions. Magnetic MOF crystals were more efficient in removing metals than the MOR and GO. Sorption tests using ARD from the Sungun copper mine and a multi-component solution containing cationic metal species revealed that both GO nanosheets and magnetic MOF have great potential for ARD treatment. 相似文献
65.
Amorphous TaN x thin films (14 and 62 nm) were deposited by reactive sputtering on Si substrates. Crystallization and the metallurgical failure mechanism for Si/TaN x /Cu metallization stacks were investigated by resistivity measurements, X-ray diffraction analysis, detailed electron microscopy and elemental depth profiling on samples annealed in 5 %H2/95 %N2 gas for 30 min at various temperatures ranging from 300 to 900 °C. Amorphous TaN x thin films crystallized at 600 °C to hexagonal Ta2N by a polymorphous transformation. Depending on film thickness, polycrystalline Ta2N diffusion barriers were effective up to 700–800 °C. Failure occurred by diffusion of Cu to the Si/TaN x interface to form Cu3Si particles followed by outdiffusion of Si and formation of Cu3Si and TaSi2 precipitates on the outer surface. The TaN x barriers were integrated in metal–oxide–semiconductor devices (Cu/10 nm TaN x /26 nm SiO2/Si) to evaluate their electrical failure after bias-temperature-stress (BTS) testing using capacitance–voltage and current–voltage measurements. The shift in flat-band voltage and the leakage current were monitored before and after BTS. The electrical test results were compared with compositional and morphological information obtained from elemental depth profiling and electron microscopy. No evidence of Cu diffusion to SiO2 was found for capacitors with large leakage currents. 相似文献
66.
There is a need to obtain highly reliable values of thermophysical properties. The thermal conductivity of solids is often calculated from the thermal diffusivity, specific heat, and density, respectively, measured by the laser-flash method, differential scanning calorimetry, and Archimedes’ method. The laser-flash method is one of the most well-known methods for measuring the thermal diffusivity of solids above room temperature. This method is very convenient to measure the thermal diffusivity without contact in a short time. On the other hand, it is considered as an absolute reference measurement method, in particular, because only measurements of basic quantities such as time, temperature, length, and electrical quantities are required, and because the uncertainty of measurement can be analytically evaluated. However, it could be difficult in some cases to obtain reliable thermal-diffusivity values. The measurement results can indeed depend on experimental conditions; in particular, the pulse heating energy. A procedure to obtain the intrinsic thermal-diffusivity value was proposed by National Metrology Institute of Japan (NMIJ). Here, “intrinsic” means unique for the material, independent of measurement conditions. In this method, apparent thermal-diffusivity values are first measured by changing the pulse heating energy at the same test temperature. Then, the intrinsic thermal diffusivity is determined by extrapolating these apparent thermal diffusivities to a zero energy pulse. In order to verify and examine the applicability of the procedure for intrinsic thermal-diffusivity measurements, we have measured the thermal diffusivity of some materials (metals, ceramics) using the laser-flash method with this extrapolation procedure. NMIJ and Laboratoire National de Metrologie et d’essais (LNE) have laser-flash thermal-diffusivity measurement systems that are traceable to SI units. The thermal diffusivity measured by NMIJ and LNE on four materials shows good agreement, although they used different measurement systems and different analysis methods of the temperature-rise curve. Experimental verification on the procedure was carried out using the measured results. Some problems and considered solutions for laser-flash thermal-diffusivity measurements are discussed. 相似文献
67.
This article addresses advanced available-to-promise (AATP) in mixed-model assembly line sequencing problems. In the developed framework, customers are prioritized with respect to 11 defined criteria using the technique for order of preference by similarity to ideal solution (TOPSIS) method, and order quantities are calculated using a nonlinear mathematical program. Next, a mixed binary nonlinear mathematical program is developed to determine the optimum sequence of the optimized order quantities to minimize the total lateness. Since the proposed models are intractable, a hybrid genetic algorithm–simulated annealing method is also developed. Finally, an industrial case study is reported, the results of which validate the developed AATP framework. 相似文献
68.
69.
Maryam Ranjbar ?mer ?elik S. Heydar Mahmoudi Najafi Shabnam Sheshmani Neda Akbari Mobarakeh 《Journal of Inorganic and Organometallic Polymers and Materials》2012,22(4):837-844
A new lead(II) coordination polymer, [PbBr2(C9H15N5O)]n (1), where C9H15N5O is (2,4-diamino-6-piperidine-1-yl) pyrimidine N-oxide (minoxidil) is synthesized and characterized. Polymer 1 is synthesized in methanol by sonochemical and hydrothermal methods from lead(II) acetate, KBr and the minoxidil ligand. The crystal structure of [PbBr2(C9H15N5O)]n indicates a syndiotactic coordination polymer. The Pb(II) atom lies on a mirror plane; the mirror plane is perpendicular to the pyrimidine ring bisecting the piperidine ring. N–H···O intramolecular and C–H···Br, N–H···N strong intermolecular interactions were observed. Micro-rods of PbO and nano-plates of PbOHBr were prepared by thermal decomposition of the nano-structured [PbBr2(C9H15N5O)]n as a precursor. Characterization of the products was carried out using X-ray crystallography, elemental analysis, FTIR spectroscopy, scanning electron microscopy, energy dispersive X-ray analysis and thermal analysis. The sonochemical method resulted in a significant reduction of reaction time, reaction temperature and particle sizes of the products. 相似文献
70.
Yousef Karimi Neda Maftoonazad Hosahalli S. Ramaswamy Shiv O. Prasher Michele Marcotte 《Food and Bioprocess Technology》2012,5(1):252-264
In this study, the applicability of hyperspectral technique, a fast and non-destructive, novel method was investigated for
the color discrimination of avocados subjected to different treatments. Fruits like avocados are coated with edible films
to extend their shelf life. Using different formulations of coating with varying pectin, beeswax, and sorbitol contents, nine
different coating preparations with potential to influence the ripening behavior of avocados were developed. Avocados were
coated with these formulations, air-dried, and stored at room temperature. Concurrently, the reflectance responses of the
avocado fruits were measured in 2,151 wavebands (350 to 2500 nm) with a field spectroradiometer. To tackle the co-linearity
that exists between the spectral observations, aggregated 10- and 20-nm data sets were used. Using a stepwise procedure, the
most effective wavebands capable of discriminating treatment effects were selected. By applying a discrimination procedure
with a well-chosen subset of the selected wavebands, treatments were correctly classified with more than 92% accuracy. 相似文献