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991.
The single crystal X-ray structures of three structurally related azonaphtharylamide pigments are reported. Two azo pigments derived from 4-amino-3-nitrotoluene as diazo component (1a and b) crystallize in the centrosymmetric space group P21/c while the third (1c), an analogue of 1b but derived from 2,5-dichloroaniline as diazo component, crystallizes in the chiral space group P212121. The compounds adopt the ketohydrazone tautomeric forms with intramolecular, but no intermolecular, hydrogen bonding. The application performance of the products is discussed in relation to the molecular and crystal structures. X-ray powder diffraction, supported by FTIR spectroscopic and DSC analysis, demonstrate that pigment 1a shows polymorphism. The application performances of the two polymorphs of this pigment are compared. 相似文献
992.
Mehran Seyed-Ahmadi Blake Erb Carey J. Simonson Robert W. Besant 《International Journal of Heat and Mass Transfer》2009,52(25-26):6012-6020
Part І of this paper [17] developed and verified the numerical model for simultaneous heat and moisture transfer in the run-around membrane energy exchanger (RAMEE) system to determine the transient behavior of the system under different initial and operating conditions.This paper presents the transient response of the RAMEE system for step changes in the inlet supply air temperature and humidity ratio. Also the system quasi-steady state operating conditions are predicted as the system approaches its asymptotic operating condition. The transient responses are predicted with changes in various parameters. These include: the number of heat transfer units, thermal capacity ratio, heat loss/gain ratio, storage volume ratio and the normalized initial salt solution concentration. It is shown that the storage volume ratio and the initial salt solution concentration have significant impacts on the transient response of the system and heat transfer between the RAMEE system and the surrounding environment can change the system quasi-steady conditions substantially. 相似文献
993.
Three experiments modeled after infant studies were run on four great ape species (Gorilla gorilla, Pongo pygmaeus, Pan troglodytes, Pan paniscus) to investigate their reasoning about solidity and gravity constraints. The aims were: (a) to find out if great apes are subject to gravity biased search or display sensitivity for object solidity, (b) to check for species differences, and (c) to assess if a gravity hypothesis or more parsimonious explanations best account for failures observed. Results indicate that great apes, unlike monkeys, show no reliable gravity bias, that ape species slightly differ in terms of their performance, and that the errors made are best explained by a gravity account. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
994.
RESRES: The story behind the paper “Research in software engineering: An analysis of the literature”
This article is a background report describing a comprehensive study of research in the three computing disciplines Computer Science, Software Engineering, and Information Systems. Findings relate to research topics, approaches, methods, reference disciplines, and levels of analysis. The article informally describes the process used and the research products produced. 相似文献
995.
996.
Penicillium roqueforti grows and sporulates during the ripening period of blue cheeses and it is responsible for the typical blue cheese flavour formation. However, the sporulation (blue veins) is taking place in a fraction of the total mass and the cheese matrix is highly heterogeneous. The aroma profiles regarding the three different sections of Stilton cheese, blue veins outer crust and white core, were studied using solvent extraction GC–MS, a headspace GC–MS technique (SPME GC–MS) and direct headspace analysis (APCI–MS). Cheeses from different dairies were analysed, allowing the question of how similar are different batches of cheese from different dairies. 相似文献
997.
Pingbo Tang Daniel Huber Burcu Akinci Robert Lipman Alan Lytle 《Automation in Construction》2010,19(7):829-843
Building information models (BIMs) are maturing as a new paradigm for storing and exchanging knowledge about a facility. BIMs constructed from a CAD model do not generally capture details of a facility as it was actually built. Laser scanners can be used to capture dense 3D measurements of a facility's as-built condition and the resulting point cloud can be manually processed to create an as-built BIM — a time-consuming, subjective, and error-prone process that could benefit significantly from automation. This article surveys techniques developed in civil engineering and computer science that can be utilized to automate the process of creating as-built BIMs. We sub-divide the overall process into three core operations: geometric modeling, object recognition, and object relationship modeling. We survey the state-of-the-art methods for each operation and discuss their potential application to automated as-built BIM creation. We also outline the main methods used by these algorithms for representing knowledge about shape, identity, and relationships. In addition, we formalize the possible variations of the overall as-built BIM creation problem and outline performance evaluation measures for comparing as-built BIM creation algorithms and tracking progress of the field. Finally, we identify and discuss technology gaps that need to be addressed in future research. 相似文献
998.
999.
The mystery of the lack of a positive relationship between growth and urbanization in sub-Saharan Africa has been raised in
a number of studies. A recent paper by Barrios et al. (Journal of Urban Economics 60:357–371, 2006) provides a compelling explanation for why this occurs. Exploiting a new data source, they show how climate change, specifically
the reduction in rainfall, has driven people from the increasingly impoverished countryside to the city. They also show that
while this is an important factor explaining urbanization in sub-Saharan African countries it does not affect urbanization
elsewhere. Their explanation for this important difference is differences in the patterns of rainfall, as well as the composition
of soil in most sub-Saharan countries. In a word, geographical factors have dominated the unusual pattern observed in the
world’s most rapidly urbanizing continent. In this paper, we extend the work done by Barrios et al. to include more observations
and more detailed geographic variables. We first replicate their results and extend the number of observations to more recent
periods. Then we consider the effects of a range of specific country geographical characteristics, relying on data developed
by other researchers. After discussing our results, we focus on the implications of our findings for policy formulation, particularly
for sub-Saharan African countries. The results indicate that geographical circumstances place significantly more important
constraints on maximization processes. In other words, urbanization in these countries takes place in a profoundly “second-best”
world. We consider what this kind of context implies for the sequencing and implementation of economic reforms which would
allow for an urbanization process that would be more conducive to economic growth. 相似文献