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1.
Verbruggen Frederick; Liefooghe Baptist; Vandierendonck André; Demanet Jelle 《Canadian Metallurgical Quarterly》2007,33(2):342
In the task-switching literature, it has frequently been demonstrated that although advance task preparation reduces the switch cost, it never really eliminates the switch cost. This remaining residual switch cost received much attention, and it has been argued that advance preparation is restricted in nature. In the present study, the role of task-cue presentation in the establishment of the residual switch cost was investigated. In 4 experiments, the cue was removed during the preparation interval, and it was hypothesized that this would encourage participants to complete advance task preparation. The results of all 4 experiments provided support for this hypothesis: When the cue was presented for a short time and then removed, the residual switch cost completely disappeared. This was found for different cue types. Furthermore, Experiment 3 demonstrated that it was not the presence of the cue itself but merely differences in advance task preparation that caused the effects. This suggests that advance task preparation is not as restricted in nature as previously assumed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
2.
Floodplain roughness parameterization using airborne laser scanning and spectral remote sensing 总被引:1,自引:0,他引:1
Floodplain roughness parameterization is one of the key elements of hydrodynamic modeling of river flow, which is directly linked to exceedance levels of the embankments of lowland fluvial areas. The present way of roughness mapping is based on manually delineated floodplain vegetation types, schematized as cylindrical elements of which the height (m) and the vertical density (the projected plant area in the direction of the flow per unit volume, m− 1) have to be assigned using a lookup table. This paper presents a novel method of automated roughness parameterization. It delivers a spatially distributed roughness parameterization in an entire floodplain by fusion of CASI multispectral data with airborne laser scanning (ALS) data. The method consists of three stages: (1) pre-processing of the raw data, (2) image segmentation of the fused data set and classification into the dominant land cover classes (KHAT = 0.78), (3) determination of hydrodynamic roughness characteristics for each land cover class separately. In stage three, a lookup table provides numerical values that enable roughness calculation for the classes water, sand, paved area, meadows and built-up area. For forest and herbaceous vegetation, ALS data enable spatially detailed analysis of vegetation height and density. The hydrodynamic vegetation density of forest is mapped using a calibrated regression model. Herbaceous vegetation cover is further subdivided in single trees and non-woody vegetation. Single trees were delineated using a novel iterative cluster merging method, and their height is predicted (R2 = 0.41, rse = 0.84 m). The vegetation density of single trees was determined in an identical way as for forest. Vegetation height and density of non-woody herbaceous vegetation were also determined using calibrated regression models. A 2D hydrodynamic model was applied with the results of this novel method, and compared with a traditional roughness parameterization approach. The modeling results showed that the new method is well able to provide accurate output data. The new method provides a faster, repeatable, and more accurate way of obtaining floodplain roughness, which enables regular updating of river flow models. 相似文献
3.
Matilda Zemanov Emmanuel Lecomte Pavol
ajgalík Ralf Riedel 《Journal of the European Ceramic Society》2002,22(16):2963-2968
The pyrolised polysilazanes poly(hydridomethyl)silazane NCP 200 and poly(urea)silazane CERASET derived Si–C–N amorphous powders were used for preparation of micro/nano Si3N4/SiC composites by hot pressing. Y2O3–Al2O3 and Y2O3–Yb2O3 were used, as sintering aids. The resulting ceramic composites of all compositions were dense and polycrystalline with fine microstructure of average grain size <1 μm of both Si3N4 and SiC phases. The fine SiC nano-inclusions were identified within the Si3N4 micrograins. Phase composition of both composites consist of , β modifications of Si3N4 and SiC. High weight loss was observed during the hot pressing cycle, 12 and 19 wt.% for NCP 200 and CERASET precursors, respectively. The fracture toughness of both nanocomposites (NCP 2000 and CERASET derived) was not different. Indentation method measured values are from 5 to 6 MPa m1/2, with respect to the sintering additive system. Fracture toughness is slightly sensitive to the SiC content of the nanocomposite. Hardness increases with the content of SiC in the nanocomposite. The highest hardness was achieved for pyrolysed CERASET precursor with 2 wt.% Y2O3 and 6 wt.% Yb2O3, HV 23 GPa. This is a consequence of the highest SiC content as well as the chemical composition of additives. 相似文献
4.
Several theories of task switching assume that basic task processes such as stimulus identification and response selection do not contribute to task-switch costs. This conclusion is mainly based on the finding that stimulus-identification manipulations have no influence on the size of the switch cost. The present study tested the influence of response-selection manipulations on the size of the switch cost. The authors manipulated the difficulty of response selection by using a semantically based response-side effect that is associated with numerical-judgement tasks, namely the Spatial Numerical Association of Response Codes (SNARC) effect. The authors observed a SNARC effect and a switch cost, but no interaction between the two: the task-switch cost did not differ between SNARC-compatible and -incompatible responses. The authors conclude that response selection does not contribute to the switch cost on the current trial, which provides further support for the idea that basic task processes and task-switch processes are separate. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
5.
Anna Kramers Jens Malmodin Matilda Gennvi Gustafsson 《中国新通信》2008,10(17):5-10
近年来,有关全球变暖的原因开始显得越发明显,特别是对温室效应来说。四大商业因素——建筑,履行,交通,以及食物(肉制品极其重要)——占据了全球能源消耗以及二氧化碳排放的四分之三。通讯技术无力独自改变现状,但ICT却是未来低碳世界的一个关键。就中短期而言,我们相信ICT可以提供5%-20%的削减量。最近的研究表明,在全球变暖中,ICT的直接二氧化碳排放量大概占据2%的份额。其中移动通讯占了0.2%,而固定电话(包括宽带)则是0.3%。就全球变暖而言,ICT领域中,电脑以及互联网(特别是数据中心)才是最大最重要的肇事者。 相似文献
6.
AU ChakTong 《中国科学:信息科学(英文版)》2010,(2)
Ni-doped ZnO thin films (Ni concentration up to 10 mol%) were generated on Si (100) substrates by a sol-gel technique. The films showed wurtzite structure and no other phase was found. The chemical state of Ni was found to be bivalent by X-ray photoelectron spectroscopy. The results of magnetic measurements at room temperature indicated that the films were ferromagnetic, and magnetic moment decreased with rise of Ni concentration. The magnetization of Ni (10 mol%)-doped ZnO film annealed in nitrogen was low... 相似文献
7.
Three sorts of apple (Idared, Golden Delicious and Jonathan) were dried in a laboratory-type fluidized bed dryer. Apples were cleaned, cored, peeled and cut into 10 × 10 × 10 mm cubes or into slices 5 × 3 mm thick and 40 mm long. A part of the samples was dipped for 3 min prior to drying in 0.1% ascorbic acid solution. Drying temperature was 80 °C. Some physicochemical and sensory properties of fresh and dried apples were determined. Moisture content in dried samples varied between 9 and 12%. Greater quantity of water results in lower sensory characteristics. The sensory characteristics of apples were determined by a scoring system with weighed factors in a 20-point scale. Glucose, fructose, saccharose, citric acid, malic acid and ascorbic acid levels were analysed by enzymatic methods. Contents of glucose, fructose and saccharose in dried apples were substantially unchanged compared to fresh apples. The drying process had the most influence on contents of citric and malic acids. Higher rehydration ratios were measured in spaghetti-like sclices and in ascorbic acid treated samples. Idared had the best characteristics with regard to physicochemical and sensory results. 相似文献
8.
9.
Matilda Grüner Marija Horvati Milica Ga
i Mara Banovi 《Journal of the science of food and agriculture》1996,70(3):355-358
The phytic acid content and distribution of phosphorus during cereal flaking were determined as well as the level of some minerals, and the molar ratios of phytic acid: zinc were calculated. Statistical analyses showed that there were no differences in the amount of total phosphorus, between oats and wheat and between rye and barley. The phytic/non-phytic phosphorus ratio was about 3 in wheat and oats, about 2 in barley and about 13 in rye. The technological processing did not affect ( P< 0·05) phytic acid content. The molar ratio of phytic acid: zinc for the flakes was only slightly below that of the whole grain, indicating that the technological process, primarily a hydrothermal treatment and flaking, did not improve zinc availability. 相似文献
10.
Elie Fereche Itoba-Tombo Seteno Karabo Obed Ntwampe Jonathan James Andrew Bell John Baptist Nzukizi Mudumbi Tolbert Mhlangabezi Golela 《The International journal of environmental studies》2017,74(1):28-41
In recent years, developing countries have increased their cassava (Manihot esculenta) production for food security. Cassava contains cyanogen glycosides, mainly as linamarin, which through bio-catalysis, i.e. enzyme hydrolysis, results in hydrogen cyanide (HCN). HCN is released into the environment through numerous ways with subsequent volatilisation. Thus, the HCN released during the period 2002–2013 was estimated between 0.025?×?10?3 to 6.71 ppq (African), 0.012?×?10?3 to 1.01 ppq (Asian) and 0.007?×?10?3 to 0.920?×?10?3 ppq (South American). Furthermore, a decade’s (2014–2024) projection of HCN volatilisation displays increases of 60.5% (Africa), 57.7% (Asia) and 50.5% (South America) when compared with the current production. Furthermore, gas released during cassava plants’ growth, i.e. HCN, NH3, and NO2, was quantified in healthy plants. Varying concentrations of HCN were released. These further indicated the presence of a pseudo-halogenic gas in the environment – a contributor to climate change. 相似文献