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排序方式: 共有535条查询结果,搜索用时 15 毫秒
431.
Cristina Cruz‐Teno Pablo Pérez‐Martínez Javier Delgado‐Lista Elena M. Yubero‐Serrano Antonio García‐Ríos Carmen Marín Purificación Gómez Yolanda Jiménez‐Gómez Antonio Camargo Fernando Rodríguez-Cantalejo Maria M. Malagón Francisco Pérez‐Jiménez Helen M. Roche José López‐Miranda 《Molecular nutrition & food research》2012,56(6):854-865
432.
Susana Silva Martínez Josefina Vergara SánchezJorge Rogelio Moreno Estrada Roberto Flores Velásquez 《Solar Energy Materials & Solar Cells》2011,95(8):2010-2017
FeIII supported on ceria as an effective catalyst for oxidation was prepared and used for the degradation of basic orange 2 azo textile dye (BO2). BO2 was chosen as a model pollutant and the catalytic oxidation was carried out in a batch reactor using hydrogen peroxide as the oxidant at pH 3. The influent factors on BO2 oxidation, such as catalyst dosage, H2O2 concentration, and BO2 concentration were studied by considering the BO2 conversion and chemical oxygen demand (COD) removal. The FeIII-ceria catalyst showed a high catalytic activity for the oxidation of BO2 in aqueous solution. It was observed that the solution became colorless after 5 h of oxidation and over 90% COD removal was achieved with all the FeIII-ceria catalysts used under dark conditions in the catalytic oxidation system. The catalytic removal of BO2 during BO2 oxidation was improved under solar radiation, which notably increased the BO2 degradation rate. Consecutive BO2 oxidation cycles carried out with the same FeIII-ceria catalyst and untreated fresh dyestuff solution showed that the catalyst had good stability and good degradation performance, thus evidencing the possibility of being used in continuous processes. This study showed that the FeIII-ceria catalytic oxidation process is an efficient method for the treatment of BO2 aqueous solutions. 相似文献
433.
Yolanda Campos-Roca Belén Amado-Rey Sandrine Wagner Arnulf Leuther Axel Bangert Rafael Gómez-Alcalá Axel Tessmann 《Journal of Infrared, Millimeter and Terahertz Waves》2017,38(5):596-608
The behaviour of grounded coplanar waveguide (GCPW) structures in the upper millimeter-wave range is analyzed by using full-wave electromagnetic (EM) simulations. A methodological approach to develop reliable and time-efficient simulations is proposed by investigating the impact of different simplifications in the EM modelling and simulation conditions. After experimental validation with measurements on test structures, this approach has been used to model the most critical passive structures involved in the layout of a state-of-the-art 200-GHz power amplifier based on metamorphic high electron mobility transistors (mHEMTs). This millimeter-wave monolithic integrated circuit (MMIC) has demonstrated a measured output power of 8.7 dBm for an input power of 0 dBm at 200 GHz. The measured output power density and power-added efficiency (PAE) are 46.3 mW/mm and 4.5 %, respectively. The peak measured small-signal gain is 12.7 dB (obtained at 196 GHz). A good agreement has been obtained between measurements and simulation results. 相似文献
434.
435.
Miguel A. Guerrero Yolanda Villacampa Andrés Montoyo 《International Journal of Project Management》2014
The literature states that project duration is affected by various scope factors. Using 168 building projects carried out in Spain, this paper uses the multiple regression analysis to develop a forecast model that allows estimating project duration of new builds. The proposed model uses project type, gross floor area (GFA), the cost/GFA relationship and number of floors as predictor variables. The research identified the logarithmic form of construction speed as the most appropriate response variable. GFA has greater influence than cost on project duration but both factors are necessary to achieve a forecast model with the highest accuracy. We developed an analysis to verify the stability of forecasted values and showed how a model with high values of fit and accuracy may display an anomalous behavior in the forecasted values. The sensitivity of the proposed forecast model was also analyzed versus the variability of construction costs. 相似文献
436.
Gisela Pujol Yolanda Vidal Leonardo Acho Alessandro N. Vargas 《International Journal of Numerical Modelling》2016,29(2):192-204
This paper presents an improved model for an automotive electronic throttle inspired on the behaviour observed in real‐time experiments. Due to a number of issues, particularly the return‐spring, the performance of the throttle valve depends on whether it is opening or closing. This asymmetric behaviour was taken into account to design a mathematical model of the throttle body and to derive a nonlinear asymmetric Proportional Integral controller. The experimental demonstration suggests that considering an asymmetric term dramatically improves the performance of the controller. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
437.
Gonzalez S Gilaberte Y Philips N Juarranz A 《International journal of molecular sciences》2011,12(12):8466-8475
Many phytochemicals are endowed with photoprotective properties, i.e., the capability to prevent the harmful effects of excessive exposure to ultraviolet (UV) light. These effects include photoaging and skin cancer, and immunosuppression. Photoprotection is endowed through two major modes of action: UV absorption or reflection/scattering; and tissue repair post-exposure. We and others have uncovered the photoprotective properties of an extract of the fern Polypodium leucotomos (commercial name Fernblock). Fernblock is an all-natural antioxidant extract, administered both topically (on the skin) or orally. It inhibits generation of reactive oxygen species (ROS) production induced by UV including superoxide anion. It also prevents damage to the DNA, inhibits UV-induced AP1 and NF-κB, and protects endogenous skin natural antioxidant systems, i.e., CAT, GSH, and GSSR. Its photoprotective effects at a cellular level include a marked decrease of UV-mediated cellular apoptosis and necrosis and a profound inhibition of extracellular matrix remodeling. These molecular and cellular effects translate into long-term inhibition of photoaging and carcinogenesis that, together with its lack of toxicity, postulate its use as a novel-generation photoprotective nutriceutical of phytochemical origin. 相似文献
438.
Hydrogenation of phenol to cyclohexanone in aqueous phase, under mild conditions, has been carried out using palladium on different supports such as hydroxyapatite (HA), carbon (C), alumina (γ-Al2O3) and Al2O3-CWE synthesized with high surface area. High activity (100%) and selectivity (98%) to cyclohexanone was obtained using Pd/ Al2O3-CWE catalyst in 50 min under mild reaction conditions. 相似文献
439.
440.
Luís F.Vilches Yolanda Luna Rodrigo Poblete Juan M.García-Maya Constantino Fernández-Pereira 《中国化学工程学报》2013,21(9):1062-1068
Municipal wastewater treatment plants typically exhibit two classic problems: high ammonium concen- tration in water after conventional biological treatment and, in some cases, poor activated sludge sediment ability. Potential solutions to these problems were investigated by adding a synthetic zeolite obtained from coal fly ash to different steps of activated sludge treatment. The experimental results for ammonium removal fit well with the theoretical adsorption isotherms of the Freundlich model with a maximum adsorption capacity of 13.72 mg.g-'. Utiliza- tion of this kind of zeolite to improve activated sludge sediment ability is studied for the first time in this work. It is found that the addition of the zeolite (1 g. L-1) to an activated sludge with settling problems significantly enhances its sediment ability and comoact ability. This is confirmed by the sludge volume index (SVI), which was reduced from 163 ml.g-1 to 70 ml.g-r, the V60 value, which was reduced from 894 ml.L-1 to 427 ml.L-1, and the zeta poten- tial (0, which was reduced from -19.81 mV to -14.29 mV. The results indicate that the addition of this synthetic zeolite to activated sludge, as an additional waste management practice, has a positive impact on both ammonium removal and sludge settleability. 相似文献