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11.
On-line graph drawing deals with huge graphs which are partially unknown. At any time, a tiny part of the graph is displayed on the screen. Examples include web graphs and graphs of links in distributed file systems. This paper discusses issues arising in the presentation of such graphs. The paper describes a system for dealing with web graphs using on-line graph drawing.  相似文献   
12.
The mucosubstances secreted in various tissues of pregnant Syrian hamsters exhibit a wide range of histochemical characteristics. When sections of fixed tissues containing these mucosubstances are treated with a methanolic solution of thionyl chloride for four hours at room temperature, nucleic acid phosphate groups, protein and sialomucin carboxyl groups, and the sulphate groups of many sulphomucins are apparently esterified. In sulphomucins believed to contain carboxyl and sulphate groups, only the sulphate is esterified; the carboxyls (uronic acid groups ?) are left free. If such methylated mucins are saponified (to remove their ester methyl groups) some, but not all, of their histochemical reactions for “free” sulphate are restored. Some desulphation, however, usually occurs during the methylation process. A few sulphated mucins, such as those in the goblet cells of the small intestine, are desulphated completely. The ability to esterify many sulphated mucins without either desulphating them completely or extracting them from the tissue distinguishes methanolic thionyl chloride from the hot methanolic solutions of hydrochloric acid usually used for methylating tissue sections. Moreover, methanolic thionyl chloride solutions are much easier to use. The little chemistry that is at present known about the reactions between methanol and thionyl chloride is insufficient to explain how methanolic thionyl chloride solutions actually methylate polyanionic substances in tissue sections.  相似文献   
13.
Reflectance factors of a rough ocean surface with and without foam are presented. They are calculated from the Cox-Munk model for an ocean without foam. The isotropic reflectance of oceanic foam is added as function of the wind speed. The effective reflectance of foam patches is taken into account  相似文献   
14.
IS DETROIT DEAD?     
An effective way to understand the slow death of the city of Detroit is through the prism of the course of a terminal disease, tracing the stages of symptom assessment, diagnosis, and curative intervention. This essay explores that notion by taking off from several recent books about Detroit's catastrophic decline that employ the language of urban morbidity and mortality to describe the city's condition. Urban death is a function of the withering or failure of crucial vital urban functions involving, principally, governance and economic opportunity. By that standard the essay concludes that it is becoming hard to call Detroit a living city anymore.  相似文献   
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16.
In this paper the application of a PI observer technique to dynamical systems with nonlinearities is proposed. The PI observer has two feedback loops, a proportional loop and an integral loop of the estimation error. In this way the PI observer combines the structures of the practical orientated nonlinearity observer developed by the third author and the classical Luenberger observer. The structure and the estimation performance of the PI observer are discussed and analysed. The results show that the PI observer can estimate the states not only of linear systems, but also, more significantly, of systems with any arbitrary external input which appear as unknown input, nonlinearity or unmodelled dynamics. It is shown that the PI observer works with weak assumptions, which can be fulfilled by many classes of systems to be observed. Owing to the weak assumptions it can improve many observer-based technical solutions as diagnosis or control based on observers. In the paper the conditions are given and proved. The design method is declared and carried out with illustrative examples of a linear system and of a nonlinear system of a link manipulator with flexible joints. The results are good and they show the efficiency of the PI observer. In the case of nonlinear systems the advantages of ‘robustness’ and the model independency of the proposed observer scheme can be shown clearly.  相似文献   
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18.
Lithium‐ion battery performance is intrinsically linked to electrode microstructure. Quantitative measurement of key structural parameters of lithium‐ion battery electrode microstructures will enable optimization as well as motivate systematic numerical studies for the improvement of battery performance. With the rapid development of 3‐D imaging techniques, quantitative assessment of 3‐D microstructures from 2‐D image sections by stereological methods appears outmoded; however, in spite of the proliferation of tomographic imaging techniques, it remains significantly easier to obtain two‐dimensional (2‐D) data sets. In this study, stereological prediction and three‐dimensional (3‐D) analysis techniques for quantitative assessment of key geometric parameters for characterizing battery electrode microstructures are examined and compared. Lithium‐ion battery electrodes were imaged using synchrotron‐based X‐ray tomographic microscopy. For each electrode sample investigated, stereological analysis was performed on reconstructed 2‐D image sections generated from tomographic imaging, whereas direct 3‐D analysis was performed on reconstructed image volumes. The analysis showed that geometric parameter estimation using 2‐D image sections is bound to be associated with ambiguity and that volume‐based 3‐D characterization of nonconvex, irregular and interconnected particles can be used to more accurately quantify spatially‐dependent parameters, such as tortuosity and pore‐phase connectivity.  相似文献   
19.
The individual and combined effects of muscle vitamin E level, cooking conditions (duration, temperature and rate) and packaging on lipid oxidation in refrigerated cooked pork were examined. Oxidative stability following cooking was higher in pork with a higher vitamin E level (p<0.01), cooked at a lower cooking temperature (p<0.01), cooked for a shorter time (p<0.01), cooked at a faster cooking rate (p<0.05) or stored in vacuum packs (p<0.01). Significant two-way and three-way interactions were observed between the effects of muscle vitamin E level, cooking conditions and packaging on lipid oxidation. Adopting more than one of these approaches to minimize lipid oxidation was more effective than adopting a single approach.  相似文献   
20.
Using X-ray diffraction techniques, thermal expansion and compressibility were measured on the orthorhombic compounds HfTiO4, Hf1.26Ti0.74O4, and ZrTiO4 (both quenched and cooled slowly from 1300°C). The thermal expansion of HfTiO4 is highly anisotropic; the thermal expansion coefficients along the crystallographic axes are α a =+(8.7±0.5)×10−6°C−1, α b =−(5.2±0.5)×10−6°C−1, and α c =+ (5.3±0.5)×10−6°C−1. The thermal expansion of Hf1.26Ti0.74O4 was similar to that of HfTiO4 but that of ZrTiO4 was markedly less anisotropic. The compressibilities of HfTiO4 and ZrTiO4 also differed markedly. All compounds investigated, however, behaved similarly in exhibiting a polymorphic transition to a high-pressure phase having the monoclinic baddeleyite (ZrO2) structure. The polymorphism can be explained qualitatively on the basis of crystal structure.  相似文献   
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