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排序方式: 共有137条查询结果,搜索用时 15 毫秒
1.
Jeannine Saint Jean Paulin 《International Journal of Engineering Science》1985,23(8):839-847
The core of the electric cable is a heterogeneous medium; the conducting wires are periodically distributed and the period is small compared with the diameter of the core. Moreover, the insulating medium is not perfectly thermally insulating but its thermic conductivity is small. We study the evolution of the global temperature in the core and find two different types of results, depending upon how small are the two small parameters. 相似文献
2.
McIntosh Daniel N.; Silver Roxane Cohen; Wortman Camille B. 《Canadian Metallurgical Quarterly》1993,65(4):812
Parents (N?=?124) who had lost an infant to sudden infant death syndrome were interviewed 3 wks and 18 mo postloss. Two components of religion (religious participation and religious importance) were assessed, and their relations with 3 coping-process variables (perceived social support, cognitive processing of the loss, and finding meaning in the death) were examined. Greater religious participation was related to increased perception of social support and greater meaning found in the loss. Importance of religion was positively related to cognitive processing and finding meaning in the death. Furthermore, through these coping-process variables, religious participation and importance were indirectly related to greater well-being and less distress among parents 18 mo after their infants' deaths. Results suggest that further study of the social and cognitive aspects of religion would be profitable. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
3.
Roxane Detry Vera Van Hoed Jérôme Sterckx Catherine Deledicque Kiyotaka Sato Christophe Blecker Sabine Danthine 《European Journal of Lipid Science and Technology》2021,123(1):2000155
Developing trans-free alternative fat solutions suitable for specific applications remains a challenge in edible fats and other domains. This is particularly true for palm oil-based puff pastry margarines, which suffer from post crystallization problems, leading to dramatic loss of functionality. This research is aimed at investigating the influence of triacylglycerol (TAG) compositions of palm oil-based puff pastry margarines on the physical properties of the fat crystal network, which determine the functionality of such products. Three model puff pastry margarines are produced at pilot scale under the same crystallization conditions. They share the same fatty acid composition and close solid fat content (SFC) profiles, whereas the proportions of major TAG (tripalmitoylglycerol (PPP), 1,3-di-palmitoyl-2-oleoylglycerol (POP), 1,2-di-palmitoyl-3-oleoylglycerol (PPO), 1,2-dioleoyl-3-palmitoylglycerol (POO)) are different. Polymorphism, melting profile, hardness, microscopic structures, and baking performance (puffing effect) of the model fats are examined during a period of 6 months. The following results are obtained: 1) The TAG composition significantly influences the post crystallization processes occurring in palm oil-based margarines. 2) High amounts of POP show negative influences. 3) The proportions of POP, PPO, and PPP should be carefully balanced to prevent detrimental crystal network rearrangements, leading to textural modifications (hardness increase) and significant reduction in baking performance. Practical Applications : The results presented in this work could be helpful for edible fat products developers, especially for roll-in fat applications. This research provides an overview of the relevant properties to study for the assessment of puff pastry margarine functionality. It also highlights the importance of ensuring long-term stability of palm oil-based fat products. Finally, it emphasizes that certain combinations of fat materials should be avoided to maintain the quality of palm oil-based puff pastry margarines. 相似文献
4.
We characterize the amount of alternation between blocks of Boolean quantifiers (having both existential and universal), blocks
of real existential quantifiers, and blocks of real universal quantifiers that can be decided in parallel polynomial time
over the reals. We do so under the assumption that blocks have a uniform bound on their size, both for the case of this bound
to be polynomial and constant. On the way towards this characterization we prove a real version of Savitch’s Theorem. 相似文献
5.
Physically based rendering needs numerical models from real measurements, or analytical models from material definitions, of the Bidirectional Reflectance Distribution Function (BRDF). However, measured BRDF data sets are too large and provide no functionalities to be practically used in Monte Carlo path tracing algorithms. In this paper, we present a wavelet‐based generic BRDF model suitable for both physical analysis and path tracing. The model is based on the separation of spectral and geometrical aspect of the BRDF and allows a compact and efficient representation of isotropic, anisotropic and/or spectral BRDFs. After a brief survey of BRDF and wavelet theory, we present our software architecture for generic wavelet transform and how to use it to model BRDFs. Then, modelling results are presented on real and virtual BRDF measurements. Finally, we show how to exploit the multiresolution property of the wavelet encoding to reduce the variance by importance sampling in a path tracing algorithm. ACM CSS: I.3.7 Computer Graphics—Three‐Dimensional Graphics and Realism 相似文献
6.
Deferred Splatting 总被引:2,自引:0,他引:2
7.
Nitrogen transformations and retention in planted and artificially aerated constructed wetlands 总被引:9,自引:0,他引:9
Gabriel Maltais-Landry Roxane Maranger Jacques Brisson Florent Chazarenc 《Water research》2009,43(2):535-545
Nitrogen (N) processing in constructed wetlands (CWs) is often variable, and the contribution to N loss and retention by various pathways (nitrification/denitrification, plant uptake and sediment storage) remains unclear. We studied the seasonal variation of the effects of artificial aeration and three different macrophyte species (Phragmites australis, Typha angustifolia and Phalaris arundinacea) on N processing (removal rates, transformations and export) using experimental CW mesocosms. Removal of total nitrogen (TN) was higher in summer and in planted and aerated units, with the highest mean removal in units planted with T. angustifolia. Export of ammonium (NH4+), a proxy for nitrification limitation, was higher in winter, and in unplanted and non-aerated units. Planted and aerated units had the highest export of oxidized nitrogen (NOy), a proxy for reduced denitrification. Redox potential, evapotranspiration (ETP) rates and hydraulic retention times (HRT) were all predictors of TN, NH4+ and NOy export, and significantly affected by plants. Denitrification was the main N sink in most treatments accounting for 47-62% of TN removal, while sediment storage was dominant in unplanted non-aerated units and units planted with P. arundinacea. Plant uptake accounted for less than 20% of the removal. Uncertainties about the long-term fate of the N stored in sediments suggest that the fraction attributed to denitrification losses could be underestimated in this study. 相似文献
8.
Shallow landslides and slope failures have been studied from several points of view (inventory, heuristic, statistic, and deterministic). In particular, numerous methods embedded in Geographic Information Systems (GIS) applications have been developed to assess slope stability. However, little work has been done on the systematic comparison of different techniques and the incorporation of vertical contrasts of geotechnical properties in multiple soil layers. In this research, stability is modeled by using LOGISNET, an acronym for Multiple Logistic Regression, Geographic Information System, and Neural Network. The main purpose of LOGISNET is to provide government planners and decision makers a tool to assess landslide susceptibility. The system is fully operational for models handling an enhanced cartographic–hydrologic model (SINMAP) and multiple logistic regression. The enhanced implementation of SINMAP was tested at regional scale in the Highway 101 corridor in Del Norte County, California, and its susceptibility map was found to have improved factor of safety estimates based on comparison with landslide inventory maps. The enhanced SINMAP and multiple logistic regression subsystems have functions that allow the user to include vertical variation in geotechnical properties through summation of forces in specific soil layers acting on failure planes for a local or regional-scale mapping. The working group of LOGISNET foresees the development of an integrated tool system to handle and support the prognostic studies of slope instability, and communicate the results to the public through maps. 相似文献
9.
High-Quality Adaptive Soft Shadow Mapping 总被引:5,自引:0,他引:5
The recent soft shadow mapping technique [ [GBP06] ] allows the rendering in real-time of convincing soft shadows on complex and dynamic scenes using a single shadow map. While attractive, this method suffers from shadow overestimation and becomes both expensive and approximate when dealing with large penumbrae. This paper proposes new solutions removing these limitations and hence providing an efficient and practical technique for soft shadow generation. First, we propose a new visibility computation procedure based on the detection of occluder contours, that is more accurate and faster while reducing aliasing. Secondly, we present a shadow map multi-resolution strategy keeping the computation complexity almost independent on the light size while maintaining high-quality rendering. Finally, we propose a view-dependent adaptive strategy, that automatically reduces the screen resolution in the region of large penumbrae, thus allowing us to keep very high frame rates in any situation. 相似文献
10.