Nanocrystalline particles of MnxZn1−xFe2O4 were prepared by chemical precipitation of hydroxides, followed by hydrothermal processing and freeze–drying. The synthesis involves the hydrolysis of aqueous metal precursors by using ammonia as precipitating agent. The chlorine ion concentration in the solution and the pH of the precipitation, are shown to play a crucial role in retaining the initial stoichiometry of the solution to the nanoparticles. The obtained products exhibited some interesting and unique features: they consisted of nanoparticles with sizes ranging from 5 to 25 nm, they had surface areas between 60 and 110 m2 g−1 and pore sizes in the mesopore region (i.e. 8–20 nm). The produced materials were examined by powder X-ray diffraction for crystalline phase identification, scanning electron microscopy for grain morphology, high resolution transmission electron microscopy for particle size distribution and nitrogen sorption for surface area, pore volume and pore size distribution determination. The sintering of the ferrite powders was also studied by thermogravimetric analysis and dilatometry of the powders mixed with an organic binder to improve their compaction properties. 相似文献
A low-in-oil dressing-type o/w emulsion incorporating a rich-in-fiber orange pulp commercial product, either in crude form or following comminution, was prepared and the rheological properties and physicochemical stability of the emulsion were studied. Interactions between the adsorbed at the droplet surfaces yolk proteins and the pulp surface constituents, possibly electrostatic in nature, resulted in extensive droplet aggregation. This was reflected in the dramatic increase of emulsion rheological parameter values, derived by applying the power or the Casson equation to shear stress-rate of shear data. Pulp incorporation resulted in an improvement of emulsion stability against creaming while the stability against droplet coalescence was only marginally affected. In addition, the rheological parameter values of the fortified with pulp emulsion exhibited an appreciable increase with storage, especially in the case of emulsions incorporating the crude pulp. These findings are combined with oil droplet or pulp particle size and ζ-potential data to probe the emulsion structure and explain its behavior during aging. 相似文献
The pathogenesis of sepsis involves complex interactions and a systemic inflammatory response leading eventually to multiorgan failure. Autotaxin (ATX, ENPP2) is a secreted glycoprotein largely responsible for the extracellular production of lysophosphatidic acid (LPA), which exerts multiple effects in almost all cell types through its at least six G-protein-coupled LPA receptors (LPARs). Here, we investigated a possible role of the ATX/LPA axis in sepsis in an animal model of endotoxemia as well as in septic patients. Mice with 50% reduced serum ATX levels showed improved survival upon lipopolysaccharide (LPS) stimulation compared to their littermate controls. Similarly, mice bearing the inducible inactivation of ATX and presenting with >70% decreased ATX levels were even more protected against LPS-induced endotoxemia; however, no significant effects were observed upon the chronic and systemic transgenic overexpression of ATX. Moreover, the genetic deletion of LPA receptors 1 and 2 did not significantly affect the severity of the modelled disease, suggesting that alternative receptors may mediate LPA effects upon sepsis. In translation, ATX levels were found to be elevated in the sera of critically ill patients with sepsis in comparison with their baseline levels upon ICU admission. Therefore, the results indicate a role for ATX in LPS-induced sepsis and suggest possible therapeutic benefits of pharmacologically targeting ATX in severe, systemic inflammatory disorders. 相似文献
The prediction of the average size of fragments in blasted rock piles produced after blasting in aggregate quarries is essential for decresing the cost of crushing and secondary breaking. There are several conventional and advanced processes to estimate the size of blasted rocks. Among these, the empirical prediction of the expected fragmentation in most cases is carried out by Kuznetsov’s equation (Sov Min Sci 9:144–148, 1973), modified by Lilly (1986) and Cunningham (1987). The present research focuses on the effect of the engineering geological factors and blasting process on the blasted fragments using a more powerful, advanced computational tool, an artificial neural network. In particular, the blast database consists of the blastability index of limestone on the pit face, the quantities of the explosives and of the blasted rock pile, assessing the interaction of these parameters on the blasted rocks. The data were collected from two aggregate quarries, Drymos and Tagarades, near Thessaloniki, in the Central Macedonia region of Greece. This approach indicates significant performance stability, providing the fragmentation size with high accuracy.
VLSI systolic and wavefront array processors' architectures for the block implementation of infinite impulse response digital filters with very high sample rates are presented. The proposed systolic array processor achieves the maximum possible throughput rate and requires only local data transfers. The asynchronous wavefront array processor operates at the same maximum throughput rate and, moreover, it is characterized by a substantial reduced latency. The throughput rate of the proposed array processor structures is a linear function of the block lengthL and theoretically it may be arbitrary high; however, it is limited only by a number of practical implications. 相似文献
The biggest false assumption made when attempting to model automatically acquired legal knowledge is that methodological and procedural legal knowledge is also contained in the text of law. Although the legal profession Intuitively knows the falsity of this assumption, researchers in the area of automatic knowledge acquisition are still confident in implementing systems that use only the text of laws as their main source of knowledge. Knowledge engineers are then forced to make their own interpretations of this knowledge, thus resulting in erroneous and legally unacceptable interpretations of the law. The aim of Nomos (an EC supported project under the ESPRIT II initiative) was to assist the knowledge engineer by providing tools that perform semiautomatic knowledge acquisition from legal texts in Italian and French. This paper uses the implementation of Nomos‐advisor, a legal expert system that uses Nomos's results as an input, as a proof of the falsity of the above assumption and discusses possible solutions. 相似文献
Traditional approaches to addressing historical queries assume asingle line of time evolution; that is, a system (database, relation) evolves over time through a sequence of transactions. Each transaction always applies to the unique, current state of the system, resulting in a new current state. There are, however, complex applications where the system's state evolves intomultiple lines of evolution. In general, this creates a tree (hierarchy) of evolution lines, where each tree node represents the time evolution of a particular subsystem. Multiple lines create novel historical queries, such asvertical orhorizontal historical queries. The key characteristic of these problems is that portions of the history are shared; answering historical queries should not necessitate duplication of shared histories as this could increase the storage requirements dramatically. Both the vertical and horizontal historical queries have two parts: a search part, where the time of interest is located together with the appropriate subsystem, and a reconstruction part, where the subsystem's state is reconstructed for that time. This article focuses on the search part; several reconstruction methods, designed for single evolution lines can be applied once the appropriate time of interest is located. For both the vertical and the horizontal historical queries, we present algorithms that work without duplicating shared histories. Combinations of the vertical and horizontal queries are possible, and enable searching in both dimensions of the tree of evolutions. 相似文献