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排序方式: 共有311条查询结果,搜索用时 15 毫秒
1.
Roberson Debi; Davidoff Jules; Davies Ian R. L.; Shapiro Laura R. 《Canadian Metallurgical Quarterly》2004,133(4):554
This study unites investigations into the linguistic relativity of color categories with research on children's category acquisition. Naming, comprehension, and memory for colors were tracked in 2 populations over a 3-year period. Children from a seminomadic equatorial African culture, whose language contains 5 color terms, were compared with a group of English children. Despite differences in visual environment, language, and education, they showed similar patterns of term acquisition. Both groups acquired color vocabulary slowly and with great individual variation. Those knowing no color terms made recognition errors based on perceptual distance, and the influence of naming on memory increased with age. An initial perceptually driven color continuum appears to be progressively organized into sets appropriate to each culture and language. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
2.
Jules Sadefo Kamdem 《Computing and Visualization in Science》2007,10(4):197-210
In this paper, we generalize the Linear VaR method from portfolios with normally distributed risk factors to portfolios with
mixture of elliptically distributed ones. We treat both the Expected Shortfall and the Value-at-Risk of such portfolios. Special
attention is given to the particular case of a mixture of multivariate t-distributions.
This is a part of J. SADEFO-KAMDEM PhD Thesis[12] of the Université de Reims, France . It has been presented at the workshop
on modelling and computation in Financial Engineering at Bad Herrenalb, Germany May 6-8, 2003. The author is an associate
professor at the Department of mathematics, université d’Evry Val d’Essonne. 相似文献
3.
When shortwave (SW) broadcasts are received on self-contained receivers indoors, there generally is a reduction in signal strength and an increase in the speed and depth of fading in comparison with reception in open spaces outdoors. Even when the received signal level is adequate, the quality of reception indoors is degraded. This comes about because the fields indoors are a superposition of components of radiated signal from the distant transmitter plus other components representing energy reradiated or scattered by nearby conductors such as house wiring or plumbing. Since many of the near-field components originate very close to the receiver, it is possible to reduce their effect by deriving the receiver input from two or more probes-i.e., pickup devices specially designed to respond to fields in their immediate vicinity without disturbing those fields. To achieve the desired probe action, advantage can be taken of the high input impedance of portable, battery-powered receivers designed for use with small telescoping whip antennas. Spacing of multiple probes in the order of a few tens of centimeters suffices to give an output significantly smoother and of higher quality than that obtainable with the receiver's whip antenna by itself. The high signal levels of many SW broadcasts make it practical to use small, inefficient antennas. This article describes an Anti-Fading Probe Antenna (APA), which produces a worthwhile improvement in reception quality indoors. It is simple to build, requires no adjustment, and may even improve received signal quality in some outdoor situations 相似文献
4.
Man-Hee HanJung-Whan Kim Jinwon KimJung Yoon Ko Jules J. MagdaIn Suk Han 《Polymer》2003,44(16):4541-4546
The acrylic comonomers hydroxypropyl methacrylate (HPMA) and N,N-dimethylaminoethyl methacrylate (DMA) have been used in several earlier studies to produce pH-responsive hydrogels. However, these same monomers can also be used to prepare hydrogels that are highly responsive to temperature. One manifestation of this temperature sensitivity is a sharp decrease in hydrogel optical transparency that occurs when the temperature exceeds a critical transition value. For example, a hydrogel that exhibits a swelling transition at the physiological pH value of 7.4 has a transition temperature of about 45 °C when the environmental salt concentration is 0.15 M. The value of the transparency transition temperature is shown to depend on hydrogel synthesis parameters such as comonomer mole ratio, crosslinker mole ratio, and even initiator concentration. By reducing the mole ratio of the crosslinker tetraethylene glycol dimethacrylate (TEGDMA), the transition temperature can be lowered by as much as 15 °C. Environmental salt concentration and solvent polarity are also shown to influence the transition temperature. 相似文献
5.
Anna Whipkey James E. Simon Jules Janick 《Journal of the American Oil Chemists' Society》1988,65(6):979-984
Seeds of 13 accessions of borage (Borago officinalis) varied in total fatty acid content from 28.6 to 35.1% seed weight, with linoleic, γ-linolenic, oleic and palmitic as the
predominant fatty acids, averaging 38.1%, 22.8%, 16.3% and 11.3% of total fatty acids, respectively. There was an inverse
relation between γ-linolenic acid (25.0 to 17.6%) and oleic acid (14.5 to 21.3%). Fatty acid content of leaf tissues was 9.1%
dry weight, with α-linolenic acid 55.2% and γ-linolenic acid 4.4% of total fatty acids. Cotyledons were the major source of
fatty acids in seeds. Seed fatty acid content increased from <1 mg at six days postanthesis to about seven mg at maturity
(22 to 24 days). Individual fatty acid content of seed was relatively constant after day 8. When immature embryos from 6 to
16 days postanthesis were cultured in a liquid or semisolid basal medium, fatty acid composition was similar to that of in
vivo-grown seeds. Growth of cultured embryos decreased as sucrose concentration was increased from 3 to 20% in the basal medium,
and most embryos did not survive 30% sucrose; fatty acid as a percentage of dry weight was maximal at 6% sucrose. 相似文献
6.
The Sanaga River is one of Sub‐Saharan Africa's largest and greatly regulated rivers. Available flow data for this hydrosystem largely cover the pre‐ and post‐regulation periods. From comparisons between unregulated (hypothetical) and observed scenarios, it has been possible to separate and to quantify hydro‐climatic (groundwater + rainfall) change effects from anthropogenic impacts (especially dam‐related alterations). To appreciate shifts in the river regime, discontinuity detection tests and the IHA model were applied to discharge data series reflecting average and extreme flow conditions, respectively. Results obtained principally from the Hubert segmentation method reveal that a major discontinuity occurred in 1970–1971 separating a surplus phase between 1945–1946 and 1969–1970, and a deficient and much contrasted one, from 1971/1972. This implies that the Sanaga catchment is dominantly affected by hydro‐climatic changes. However, wide land cover/land use changes experienced here since 1988 have resulted in an increase in surface runoff. Additional quickflows linked to these changes may have partly compensated for the substantial decline in the dry season rainfall and groundwater inputs observed from this date. Although at the monthly scale, dam‐related impacts on average flows increase with stage of regulation, the seasonal variability of the river regime remains generally unaffected. A comparison of the IHA statistics, calculated from unregulated and observed streamflow data, show that hydrologic shifts occurring in maximum and minimum discharges are mostly significant from 1971/1972 and are mainly due to the action of dams. Minimum flows appear, however, widely impacted, thus reflecting the prime objective assigned to the existing reservoirs, constructed to supplement flows for hydroelectricity production during the dry season. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
7.
Microfluidic Manipulation of Core/Shell Nanoparticles for Oral Delivery of Chemotherapeutics: A New Treatment Approach for Colorectal Cancer 下载免费PDF全文
Mohammad Mahdi Hasani‐Sadrabadi Shahrouz Taranejoo Erfan Dashtimoghadam Ghasem Bahlakeh Fatemeh Sadat Majedi Jules John VanDersarl Mohsen Janmaleki Fatemeh Sharifi Arnaud Bertsch Kerry Hourigan Lobat Tayebi Philippe Renaud Karl I. Jacob 《Advanced materials (Deerfield Beach, Fla.)》2016,28(21):4134-4141
8.
9.
Felipe Gutierrez-Mora Jules L. Routbort 《Journal of the American Ceramic Society》2002,85(9):2370-2372
Pieces of saw-cut La0.85 Sr0.15 MnO3 were joined at 1150° and 1250°C under a compressive stress. The strains to form the joints were ∼0.1. Joints formed by plastic deformation were examined using scanning electron microscopy, and they were indistinguishable from the bulk. The room-temperature direct-current resistivity of the joined pieces was identical to that measured in the bulk material. This indicated that a sound, electrically conducting joint could be formed using plastic deformation (grain-boundary sliding) with little surface preparation. 相似文献
10.
Discrete element methods (DEMs) provide new numerical means to study the behavior of soil-inclusion systems. In some cases, however, the classic DEM fails to model specific aspects of the inclusions. That is why a model based on spar elements is introduced, designed specifically for inclusions. In this model, the movement of the inclusion is considered as a dynamic process and is computed step by step in the same way as in the DEM. The model can be coupled with a DEM code, thus enabling one to simulate the interaction between an inclusion and a disk assembly. Contact laws at the contacts between disks and spar elements describe the interface constitutive behavior. Finally, the results obtained by simulating a geosynthetic anchorage in two different ways are reported. In the first case the inclusion is represented by disks, while in the last case it is represented by spar elements. The comparison shows that spar elements are much more versatile and can simplify the calibration of the discrete models used to simulate soil-inclusion systems. 相似文献