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61.
An adaptive receiver solution for an asynchronous DS-CDMA system in an indoor powerline network is proposed. A combination of different receiver structures with binary and complex-polyphase sequences is evaluated and compared in terms of bit error rate. The simulation results based on a complete powerline channel model are reported. 相似文献
62.
Jean-José Jacq Thierry Cresson Valérie Burdin Christian Roux 《IEEE transactions on bio-medical engineering》2008,55(5):1620-1633
This paper addresses the problem of the robust registration of multiple observations of the same object. Such a problem typically arises whenever it becomes necessary to recover the trajectory of an evolving object observed through standard 3-D medical imaging techniques. The instances of the tracked object are assumed to be variously truncated, locally subject to morphological evolutions throughout the sequence, and imprinted with significant segmentation errors as well as significant noise perturbations. The algorithm operates through the robust and simultaneous registration of all surface instances of a given object through median consensus. This operation consists of two interwoven processes set up to work in close collaboration. The first one progressively generates a median and implicit shape computed with respect to current estimations of the registration transformations, while the other refines these transformations with respect to the current estimation of their median shape. When compared with standard robust techniques, tests reveal significant improvements, both in robustness and precision. The algorithm is based on widely-used techniques, and proves highly effective while offering great flexibility of utilization. 相似文献
63.
Calculations have been performed on spray scrubbers for two purposes: firstly, to determine the limiting performance set by the complete evaporation of the irrigating liquid on the basis of the initial parameters of the gases to be cooled, and secondly, determining the optimal geometrical parameters (diameter and height). Nomograms are derived for determining the water content increment in an air-water system and the minimum possible gas temperature at the outlet in relation to the initial temperature and water content of the gases to be cooled. 相似文献
64.
D. A. Ivanov I. V. Litvintseva G. E. Val’yano L. V. Fateeva 《Refractories and Industrial Ceramics》2000,41(8):264-269
The method of directed reaction impregnation (DRI), known as a Lanxide process in foreign countries, provides a wide spectrum
of ceramic composite materials with a variable content of metallic phase, which possess high physicomechanical properties.
An important advantage of the method is the absence of shrinkage, which diminishes substantially the amount of heat-treatment
rejects and the cost of the finishing mechanical treatment. The structural characteristics of composites obtained by impregnation
of the pore space of \-SiC and A12O3 ceramic matrices with an aluminum alloy with 5 wt.% Si and 2 wt.% Mg are presented. The former matrix is obtained by free
pouring of a granular powder of silicon carbide, and the latter matrix is represented by a densely sintered alumina preform
with through cylindrical channels. The process is conducted at 1150 – 1200‡C for 24 h in air. The structure of the composites
bears Al2O3 crystals and a mixed Al/Al2O3 phase formed from the metallic melt. The microhardness of the phases that compose the structure of the composite with a silicon
carbide matrix is determined (HV = 28.4 – 73.2 GPa for Al2O3,HV = 10.3 – 19.7 GPa for SiC, andHV = 0.5 – 0.8 GPa for A1/A12O3). Directed reaction impregnation through cylindrical channels of the aluminum oxide matrix yields highly porous fibers with
a typical dimple structure. The impregnation process in this composite is considered from the standpoint of equilibrium (the
Le Chatelier principle). Its occurrence in different stages is considered from the standpoint of thermodynamics.
Transleted from Ogneupory i Technicheskaya Keramika, No. 8, pp. 14 – 20, August, 2000. 相似文献
65.
Claire Bourlieu Mariana Ferreira Bruno Barea Valérie Guillard Pierre Villeneuve Stéphane Guilbert Nathalie Gontard 《European Journal of Lipid Science and Technology》2009,111(5):489-498
Four acetostearin products with increasing acetylation degree were synthesized by chemical interesterification followed by fractionation/blending stages. Their physical properties and functional barrier properties were studied and compared to the properties of technical tristearin. Increasing acetylation degree (AD) modified the triacylglycerols crystal habits and probably led to an increase in acyl chain fluidity, which induced, at macroscopic levels, a decrease in solid fat content (SFC), in melting point, in surface and bulk material hydrophobicity, and an increased moisture effective diffusivity. Water vapor permeability (WVP) coefficients of the materials were partially influenced by the AD factor, but also by the development of macroscopic cracks in lipids presenting high SFC. Acetylated stearin up to 47% (acetyl mol/mol of esterified chain) presented the lowest WVP at 20 °C resulting from an adequate balance between hydrophobicity and mechanical properties of the material. 相似文献
66.
One Question,Multiple Answers: Biochemical and Biophysical Screening Methods Retrieve Deviating Fragment Hit Lists
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Dr. Johannes Schiebel Nedyalka Radeva Dr. Helene Köster Dr. Alexander Metz Timo Krotzky Dr. Maren Kuhnert Prof. Wibke E. Diederich Prof. Andreas Heine Dr. Lars Neumann Dr. Cedric Atmanene Dominique Roecklin Dr. Valérie Vivat‐Hannah Dr. Jean‐Paul Renaud Dr. Robert Meinecke Dr. Nina Schlinck Dr. Astrid Sitte Franziska Popp Dr. Markus Zeeb Prof. Gerhard Klebe 《ChemMedChem》2015,10(9):1511-1521
Fragment‐based lead discovery is gaining momentum in drug development. Typically, a hierarchical cascade of several screening techniques is consulted to identify fragment hits which are then analyzed by crystallography. Because crystal structures with bound fragments are essential for the subsequent hit‐to‐lead‐to‐drug optimization, the screening process should distinguish reliably between binders and non‐binders. We therefore investigated whether different screening methods would reveal similar collections of putative binders. First we used a biochemical assay to identify fragments that bind to endothiapepsin, a surrogate for disease‐relevant aspartic proteases. In a comprehensive screening approach, we then evaluated our 361‐entry library by using a reporter‐displacement assay, saturation‐transfer difference NMR, native mass spectrometry, thermophoresis, and a thermal shift assay. While the combined results of these screening methods retrieve 10 of the 11 crystal structures originally predicted by the biochemical assay, the mutual overlap of individual hit lists is surprisingly low, highlighting that each technique operates on different biophysical principles and conditions. 相似文献
67.
68.
Malher X Simon M Charnay V Déserts RD Lehébel A Belloc C 《International journal of food microbiology》2011,150(1):8-13
A study was conducted in 2009 to identify risk factors of Campylobacter spp. transmission from the digestive tract to the carcasses of standard broilers (slaughter age: 37 day, carcass weight: 1.3 kg on average). Counts of Campylobacter were performed on pools of 10 ceca and 10 neck-skins from 108 Campylobacter ceca-positive batches in three slaughterhouses. Technical and health data also was collected on the broilers: age, size, carcass weight (mean and standard deviation), condemnation rate, mortality rate and nature of treatment during the rearing period.Cecal counts varied from 4.8 to 10.2 log10 cfu/g. In seventeen batches (15.7%), the skin count was below the detection limit. In the 91 batches with positive neck-skin test results, the counts varied from 2.0 to 5.2 log10 cfu/g. Standard deviation of carcass weight, condemnation rate, slaughter rate and cecal count were significantly lower and growth rate higher in the 17 batches where neck-skin results were not detected positive. Multivariate analysis showed that batches with higher standard deviation of carcass weight were 5 to 9 fold more at risk of having detectable carcass contamination. Among the 91 positive neck-skin batches, only slaughter rate and cecal counts were found to have a significant but limited effect on the level of neck-skin contamination. As far as body weight homogeneity may be affected by disease, better health control can contribute to a reduction of the contamination of the broiler carcasses in Campylobacter carrier batches. 相似文献
69.
Thierry Durand Valérie Bultel-Poncé Alexandre Guy Susanne Berger Martin J. Mueller Jean-Marie Galano 《Lipids》2009,44(10):875-888
In animals and plants, fatty acids with at least three double bonds can be oxidized to prostaglandin-like compounds via enzymatic
and non-enzymatic pathways. The most common fatty acid precursor in mammals is arachidonic acid (C20:4) (AA) which can be
converted through the cyclooxygenase pathway to a series of prostaglandins (PG). Non-enzymatic cyclization of arachidonate
yields a series of isoprostanes (IsoP) which comprises all PG (minor compounds) as well as PG isomers that cannot be formed
enzymatically. In contrast, in plants, α-linolenic acid (C18:3) (ALA) is the most common substrate for the allene oxide synthase
pathway leading to the jasmonate (JA) family of lipid mediators. Non-enzymatic oxidation of linolenate leads to a series of
C18-IsoPs termed dinor IsoP or phytoprostanes (PP). PP structurally resemble JA but cannot be formed enzymatically. We will
give an overview of the biological activity of the different classes of PP and also discuss their analytical applications
and the strategies developed so far for the total synthesis of PP, depending on the synthetic approaches according to the
targets and which key steps serve to access the natural products. 相似文献