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31.
Sherman David K.; Cohen Geoffrey L.; Nelson Leif D.; Nussbaum A. David; Bunyan Debra P.; Garcia Julio 《Canadian Metallurgical Quarterly》2009,97(5):745
Three studies investigated whether self-affirmation can proceed without awareness, whether people are aware of the influence of experimental self-affirmations, and whether such awareness facilitates or undermines the self-affirmation process. The authors found that self-affirmation effects could proceed without awareness, as implicit self-affirming primes (utilizing sentence-unscrambling procedures) produced standard self-affirmation effects (Studies 1 and 3). People were generally unaware of self-affirmation’s influence, and self-reported awareness was associated with decreased impact of the affirmation (Studies 1 and 2). Finally, affirmation effects were attenuated when people learned that self-affirmation was designed to boost self-esteem (Study 2) or told of a potential link between self-affirmation and evaluations of threatening information (Study 3). Together, these studies suggest not only that affirmation processes can proceed without awareness but also that increased awareness of the affirmation may diminish its impact. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
32.
Nuclear fusion D+D processes are studied by nanosecond pulsed laser interaction with ultra-dense deuterium. This material has a density of 1029 cm?3 as shown in several previous publications. Laser power is <2 W (0.2 J pulses) and laser intensity is <1014 W cm?2 in the 5–10 μm wide beam waist. Particle detection by time-of-flight energy analysis with plastic scintillators is used. Metal foils in the particle flux to the detector remove slow ions, and make it possible to convert and count particles with energy well above 1 MeV. The variation of the signal of MeV particles from D+D fusion is measured as a function of laser power. At relatively weak laser-emitter interaction, the particle signal from the laser focus varies as the square of the laser power. This indicates collisions in the ultra-dense deuterium of two fast deuterons released by Coulomb explosions. During experiments with stronger laser-emitter interaction, the signal varies approximately as the sixth power of the laser power, indicating a plasma process. At least 2 × 106 particles are created by each laser pulse at the maximum intensity used. Our results indicate break-even in fusion at a laser pulse energy of 1 J with the same focusing, in approximate agreement with theoretical results for ignition conditions in ultra-dense deuterium. Radiation loss at high temperature will however require higher laser energy at break-even. 相似文献
33.
Adaptive QRS Detection: A Study of Performance 总被引:2,自引:0,他引:2
Sornmo Leif Paklm Olle Nygards Mats-Erik 《IEEE transactions on bio-medical engineering》1985,(6):392-401
QRS detectors are often evaluated in terms of statistical measures, e.g., rate of false and true detections. These measures are usually calculated for a detector with fixed parameter values. In this paper, detector properties are studied by varying those parameters which seem to have the most profound effect on performance. By applying techniques known from optimal estimation to a stochastic model for the ECG, two different detectors have been derived. The detector structures are described in detail. In order to study and compare the performance of the two detectors, a database of "difficult" ECG's has been collected, containing various "artifacts" of physiological and electrical/mechanical origin. The performance of this database is presented in terms of receiver-operating characteristics (ROC's), and several examples are discussed. 相似文献
34.
Francesca Giuffrida Frédéric Destaillats Maria Herrero Egart Bernadette Hug Pierre-Alain Golay Leif H. Skibsted Fabiola Dionisi 《Food chemistry》2007,101(3):1108-1114
Heat flux differential scanning calorimetry (DSC) and electron spin resonance spectroscopy (ESR) were used to assess the activity and the thermal stability of antioxidants in four vegetable oils. Sunflower oil (SO) and high oleic sunflower oil (HOSO), both rich in diunsaturated fatty acids (FA), low trans oil (LT) and partially hydrogenated palm oil (PHPO), both containing monounsaturated FA, were analyzed by isothermal heat flux DSC, with or without 300 mg/kg of antioxidant: ascorbyl palmitate (AP), α-tocopherol (αT), δ-tocopherol (δT) and propyl gallate (PG). DSC experiments showed that δT is the most effective antioxidant for SO and PG for the less unsaturated oils. SO and PHPO were also analyzed by ESR at 120 and 145 °C, respectively. ESR results confirm the strongest antioxidant activity of δT and PG for SO and PHPO, respectively. Therefore, the present study demonstrates that DSC and ESR are valuable technologies to study activity and stability of antioxidants at high temperature. Moreover, experiments performed in the presence of the spin-trap N-tert-butyl-α-phenylnitrone (PBN), suggest that δT delay lipid oxidation through a different reaction mechanism when compared to αT. A different mechanism between tocopherols isomers in delaying lipid oxidation has been hypotized. 相似文献
35.
Enhancing mechanical and fracture properties of sandwich composites using nanoparticle reinforcement 总被引:1,自引:0,他引:1
Justin K. Stewart Hassan Mahfuz Leif A. Carlsson 《Journal of Materials Science》2010,45(13):3490-3496
Polyurethane (PU) foam is reinforced with SiC nanoparticles to develop core materials for sandwich composites. Isocyanate
component (Part A) of PU foam was dispersed with SiC nanoparticles, and then mixed with polyol (Part B) to manufacture nanophased
core materials. Nanoparticle reinforcement varied from 0.1 to 2.0 wt% of the total polymer. Both pristine and silane functionalized
SiC nanoparticles were used in the investigation. Nanophased foams were tested in compression and flexure to determine the
mechanical properties. Fracture toughnesses K
IC and G
IC were determined using the SENB test. Sandwich panels were fabricated and tested for face-core debond fracture toughness using
the tilted sandwich debond test. The study has revealed that reinforcement of the foam by pristine nanoparticles substantially
enhances mechanical properties but degrades fracture toughness. This loss in fracture toughness, however, may be recovered
with the use of functionalized nanoparticles. Small concentrations (0.1–0.2 wt%) of functionalized nanoparticles provided
large improvement in debond fracture toughness of sandwich specimens. 相似文献
36.
37.
In this study we analyze the life cycle primary energy use of a wood-frame apartment building designed to meet the current Swedish building code, the Swedish building code of 1994 or the passive house standard, and heated with district heat or electric resistance heating. The analysis includes the primary energy use during the production, operation and end-of-life phases. We find that an electric heated building built to the current building code has greater life cycle primary energy use relative to a district heated building, although the standard for electric heating is more stringent. Also, the primary energy use for an electric heated building constructed to meet the passive house standard is substantially higher than for a district heated building built to the Swedish building code of 1994. The primary energy for material production constitutes 5% of the primary energy for production and space heating and ventilation of an electric heated building built to meet the 1994 code. The share of production energy increases as the energy-efficiency standard of the building improves and when efficient energy supply is used, and reaches 30% for a district heated passive house. This study shows the significance of a life cycle primary energy perspective and the choice of heating system in reducing energy use in the built environment. 相似文献
38.
Aline M. C. Racanicci Bente Danielsen Leif H. Skibsted 《European Food Research and Technology》2008,227(1):255-260
Aqueous extract of mate, made from dried leaves of Ilex paraguariensis, St. Hilaire, was shown to be effective during chilled storage for up to 10 days in protecting lipids and vitamin E against oxidation in pre-cooked meat balls made from chicken breast added 0.5% salt and packed in atmospheric air. Extracts made with water, methanol, ethanol or 70% aqueous acetone were evaluated by comparing (1) total phenolic content, (2) radical scavenging capacity, (3) effect on lipid oxidation in a food emulsion model, and in liposomes. Based on the three-step evaluation, aqueous mate extract was preferred for food use. Dried leaves were further compared to dried rosemary leaves in chicken meat balls, and mate (0.05 and 0.10%) found to yield equal or better protection than rosemary at the same concentration against formation of secondary lipid oxidation products. 相似文献
39.
Jonas Eskhult Christian Ulrich Fredrik Björefors Leif Nyholm 《Electrochimica acta》2008,53(5):2188-2197
It is demonstrated that current oscillations can be observed during chronoamperometric and cyclic voltammetric experiments in solutions containing 0.4 M CuSO4 and 1.2 M citrate at pH 11 and 50 °C. The oscillations, which are shown to originate from local variations in the pH, result in the deposition of nanostructured Cu and Cu2O materials. It is concluded that the current oscillations are analogous to the previously described potential oscillations obtained under controlled current conditions in alkaline Cu(II)-lactate, -tartrate and -citrate solutions. Rotating disk electrode results clearly show that the reduction of the Cu(II)-complexes is kinetically controlled and that the rate of the reduction increases with increasing pH and temperature. It is also shown that the presence of a cathodic peak on the anodic scan in the cyclic voltammograms can be used to identify the experimental conditions leading to the spontaneous current (or potential) oscillations. Electrochemical quartz crystal microbalance results indicate that the cathodic peak stems from an increased rate of the reduction of the Cu(II)-citrate complexes due to a rapid increase in the local pH. This causes Cu2O rather than Cu to be deposited which, however, results in a decrease in the local pH and a decreasing current. In situ ellipsometry data confirm that Cu2O deposition replaces that of Cu in the potential region of the cathodic peak. The present findings should facilitate syntheses of nanolayered materials based on spontaneous potential or current oscillations. 相似文献
40.
The behaviour of paperboard beams subjected to pure bending is analysed and related to tensile and compression stress-strain behaviour. Since the compression strength is lower than the tensile strength, beam failure occurs in compression. However, beam failure does not occur when the ultimate strain in pure compression is reached in the surface fibres. A plastic yielding in compression, which gives good agreement between experimentally-determined and theoretically-calculated bending moments up to failure is therefore suggested. At failure, the elastic energy stored in the sample causes propagation of an interlaminar crack at the compression side, which is observed in scanning electron micrographs. 相似文献