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81.
Von Walter Mchtle 《大分子材料与工程》1971,15(1):17-23
The specific refractive index increments of a random methylmethacrylate/ benzylacrylate/styrene-terpolymer and of the three corresponding homopolymers was measured in several solvents and at six different wavelengths. With the known terpolymer composition and the specific refractive index increments of the homopolymers the specific refractive index increment of the terpolymer is calculated by means of an equation formerly derived. Calculated and experimental values are compared. 相似文献
82.
Funke SA Otte N Eggert T Bocola M Jaeger KE Thiel W 《Protein engineering, design & selection : PEDS》2005,18(11):509-514
Chiral compounds can be produced efficiently by using biocatalysts. However, wild-type enzymes often do not meet the requirements of a production process, making optimization by rational design or directed evolution necessary. Here, we studied the lipase-catalyzed hydrolysis of the model substrate 1-(2-naphthyl)ethyl acetate both theoretically and experimentally. We found that a computational equivalent of alanine scanning mutagenesis based on QM/MM methodology can be applied to identify amino acid positions important for the activity of the enzyme. The theoretical results are consistent with concomitant experimental work using complete saturation mutagenesis and high-throughput screening of the target biocatalyst, a lipase from Bacillus subtilis. Both QM/MM-based calculations and molecular biology experiments identify histidine 76 as a residue that strongly affects the catalytic activity. The experiments demonstrate its important influence on enantioselectivity. 相似文献
83.
J. F. Toro-Vazquez Alejandro Rocha-Uribe 《Journal of the American Oil Chemists' Society》1993,70(6):589-594
The adsorption of peroxides, unsaturated carbonyls, free fatty acids and carotenoids from unrefined sesame oil on vegetable
carbon (5%, w/w) in a miscella system was studied. Three different solvent conditions (hexane/ethanol, 100:0, 95:5 and 75:25,
vol/vol), combined in a factorial design with five levels of solvent (0, 10, 20, 30 and 40%, w/w), were used to develop the
miscella. Equilibrium adsorption was not achieved during the 100 min of adsorption, mainly because the oil components were
involved in oxidation reactions during the adsorption process. However, for a given solvent concentration, adsorption of the
oil components showed a significant linear regression on their respective initial concentration in the miscella (Ci). Peroxides and carbonyls showed, at all solvent levels investigated, an affinity for the carbon more independent of their
Ci than free fatty acids and carotenoids. In general, at the same Ci, a higher adsorption was achieved as solvent concentration increased. The results indicated that free fatty acid adsorption
may depend on competitive adsorption based on molecule hydrophobicity. However, in spite of the higher hydrophobicity of carotenoids,
compared with free fatty acids, they might not be competing for the same adsorbing sites. Ethanol showed a prooxidant effect
that increased peroxide production during adsorption but did not affect the reaction involved in carbonyl production. 相似文献
84.
Fábio J. P. Sousa Jan C. Aurich Walter L. Weingaertner Orestes E. Alarcon 《Journal of the American Ceramic Society》2007,90(11):3468-3477
Several kinds of glossiness pattern can be seen on the surface of porcelain stoneware tiles right after the polishing process, as a function of the kinematics performed by the polishing heads. For the newest generation of industrial polishing trains, where a transverse oscillation is included, there is still a great need for literature about the resulting patterns. This paper intends to find the spatial distribution of time under polishing analytically using the kinematics equations involved in the polishing process. The measured values of glossiness collected from three polished tiles are also presented. The importance of adopting a good kinematics for the polishing process has been highlighted, and the equations developed herein are useful tools for further attempts at optimizing the polishing process. 相似文献
85.
Effect of DAG on milk fat TAG crystallization 总被引:1,自引:0,他引:1
Amanda J. Wright Alejandro G. Marangoni 《Journal of the American Oil Chemists' Society》2002,79(4):395-402
The effect of milk fat and standard DAG on the crystallization behavior of milk fat TAG (MF-TAG) was investigated. When milk
fat DAG were added to MF-TAG at the 0.1 wt% level, crystallization was delayed. Racemic purity was shown to be an important
factor in the ability of DAG to influence TAG crystallization. Only sn-1,2 isomers of blends of MF-TAG with 0.1 wt% of the racemic mixtures of dipalmitin and diolein increased the activation free
energy barrier to MF-TAG nucleation (ΔG
c
) and delayed the subsequent crystallization process by increasing the crystallization induction time (τSFC) determined from solid fat content-time measurements. Although crystallization kinetics were affected, the properties of
the resulting network structures remained unchanged upon addition of milk fat minor components at the 0.1 wt% level 相似文献
86.
We study asynchronously communicating open systems modeled as Petri nets with an interface. An accordance preorder describes when one open system can be safely replaced by another open system without affecting some behavioral property of the overall system. Although accordance is decidable for several behavioral properties if we assume a previously known bound on the maximal number of pending messages, we show that it is not decidable without this assumption. 相似文献
87.
Bart Deronde Walter Debruyn Eric Gontier Erwin Goor Tim Jacobs Sara Verbeiren 《International journal of remote sensing》2014,35(7):2402-2420
Throughout the VEGETATION programme, the Flemish Institute for Technological Research (VITO) uninterruptedly hosted the prime user segment of both VEGETATION 1 and VEGETATION 2 multispectral instruments on board the Satellite Pour l’Observation de la Terre 4 (SPOT 4) and SPOT 5 satellites. Operational since the launch of SPOT 4 in March 1998, and foreseen to continue at least until the end of the SPOT 5 mission (anticipated in spring 2014), this user segment comprises a processing facility (PF), actively receiving, processing, correcting, archiving, and distributing the VEGETATION data and derived added-value products. First and foremost, the VEGETATION programme has been serving the needs of operational users – both institutional and commercial – requesting data in near-real time. However, scientific and educational users too benefited significantly, in particular from VEGETATION’s unique time series of the Earth’s land cover, and more specifically the vegetation cover. Over the years, the centralized archive houses processed data covering the equivalent of 11,000 times the Earth’s surface, and delivered more than 50 terapixels to around 10.000 users. As such, VEGETATION’s mission is a prime example of what Europe wants to achieve through the Global Monitoring for Environment and Security (GMES) initiative: truly operational services providing reliable and up-to-date information.This article describes the processing facility, the way the data and products are archived, the different dissemination channels as well as the data policy adopted and the users served. One of the recent evolutions, the development of an entirely new product distribution facility (PDF), implemented as part of the Project for On-Board Autonomy – Vegetation (PROBA-V) user segment is discussed. 相似文献
88.
Carsten Dachsbacher Jaroslav Křivánek Miloš Hašan Adam Arbree Bruce Walter Jan Novák 《Computer Graphics Forum》2014,33(1):88-104
Recent years have seen increasing attention and significant progress in many‐light rendering, a class of methods for efficient computation of global illumination. The many‐light formulation offers a unified mathematical framework for the problem reducing the full lighting transport simulation to the calculation of the direct illumination from many virtual light sources. These methods are unrivaled in their scalability: they are able to produce plausible images in a fraction of a second but also converge to the full solution over time. In this state‐of‐the‐art report, we give an easy‐to‐follow, introductory tutorial of the many‐light theory; provide a comprehensive, unified survey of the topic with a comparison of the main algorithms; discuss limitations regarding materials and light transport phenomena and present a vision to motivate and guide future research. We will cover both the fundamental concepts as well as improvements, extensions and applications of many‐light rendering. 相似文献
89.
Behzad Biglarbegian Mohammad‐Reza Nezhad‐Ahmadi Amin Enayati Guy A. E. Vandenbosch Walter De Raedt Safieddin Safavi‐Naeini 《国际射频与微波计算机辅助工程杂志》2014,24(2):155-160
A new millimeter‐wave antenna structure on a low‐cost, production platform integrated passive device technology is presented. The antenna consists of a 2‐by‐1 array of slot antennas at 60 GHz. An in‐house developed on‐chip antenna measurement setup was used to characterize the fabricated antenna. The measurement results show an antenna gain of more than 5 dBi with a return loss of 18 dB at 60 GHz. The better‐than‐10‐dB impedance bandwidth of the antenna covers the 60‐GHz unlicensed band from 57 to 64 GHz. The 3‐dB beamwidths of the antenna are 105° and 76° at E‐plane and H‐plane at 60 GHz, respectively. The size of the die of the antenna is 2 mm × 4.5 mm. © 2013 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:155–160, 2014. 相似文献
90.
Sri-Kaushik Pavani David Delgado-Gomez Alejandro F. Frangi 《Pattern Analysis & Applications》2014,17(2):441-449
This paper presents a fast training strategy for the Viola–Jones (VJ) type object-detection systems. The VJ object- detection system, popular for its high accuracy at real-time testing speeds, has a drawback that it is slow to train. A face detector, for example, can take days to train. In content-based image retrieval (CBIR), where search needs to be performed instantaneously, VJ’s long training time is not affordable. Therefore, VJ’s method is hardly used for such applications. This paper proposes two modifications to the training algorithm of VJ-type object detection systems which reduces the training time to the order of seconds. Firstly, Laplacian clutter (non-object) models are used to train the weak classifier, thus eliminating the need to read and evaluate thousands of clutter images. Secondly, the training procedure is simplified by removing the time-consuming AdaBoost-based feature selection procedure. An object detector, trained with 500 images, approximately takes 2 s for training in a conventional 3 GHz machine. Our results show that the accuracy of the detector, built with the proposed approach, is inferior to that of VJ for difficult object class such as frontal faces. However, for objects with lesser degree of intra-class variations such as hearts, state-of-the-art accuracy can be obtained. Importantly, for CBIR applications, the fast testing speed of the VJ type object detector is maintained. 相似文献