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Phase Stability, Kinetic Diagrams and Diffusion Path in High Temperature Oxidation of Binary Solid-Solution Alloys

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Journal of Materials Science & Technology 2003年第6期19卷 545-552页

作者： YanNIU f.Gesmundo StateKeyLaboratoryforCorrosionandProtection InstituteofMetalResearchShenyang110016China DipartimentodiIngegneriaChimicaediProcesso UniversityofGenova16129GenovaItaly

The phase diagrams of ternary systems involving two metal components and one oxidant are considered first, the limitations to their use is discussed in relation to the high temperature oxidation of binary alloys. Kinetic diagrams, which are useful to predict the conditions for the stability of the two mutually insoluble oxides as the external scale, are then calculated on the basis of thermodynamic and kinetic data concerning both the alloys and the oxides, assuming the validity of the parabolic rate law. A combination of the two types of diagrams provides a more detail information about the oxidation behavior of binary alloys. The calculation of the diffusion paths, which relate the oxidant pressure to the composition of the system in terms of the alloy components both in the alloy and in the scale during an initial stage of the reaction in the presence of the parabolic rate law, is finally developed.

关键词： Binary alloys Oxidation Therniodynamic and kinetic diagrams Diffusion path

A closed form of a kurtosis parameter of a hypergeometric-Gaussian type-Ⅱ beam

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Chinese Physics B 2016年第4期25卷 154-160页

作者： Khannous f Ebrahim A A A Belafhal A adida Morocco

Based on the irradiance moment definition and the analytical expression of waveform propagation for hypergeometric- Gaussian type-II beams passing through an ABCD system, the kurtosis parameter is derived analytically and illustrated numerically. The kurtosis parameters of the Gaussian beam, modified Bessel modulated Gaussian beam with quadrature radial and elegant Laguerre-Gaussian beams are obtained by treating them as special cases of the present treatment. The obtained results show that the kurtosis parameter depends on the change of the beam order m and the hollowness parameter p, such as its decrease with increasing m and increase with increasing p.

关键词： Kurtosis parameter hypergeometric-Gaussian type-II beams paraxial optical ABCD system

fifty years of character compatibility concepts at work

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植物分类学报 2008年第2期46卷 109-129页

作者： George f.ESTABROOK Department of Ecology and Evolutionary Biology The University of Michigan Ann Arbor MI 4809-1048 USA

In the mid 19th century, systematic biologists realized that observable similarities and differences among a group of related species could be the basis for hypotheses about the evolutionary relationships among the species and their ancestors. Such hypotheses can be expressed as characters. A character is comprised of two or more character states of species considered to be similar with respect to a basis for comparison. The states of a character may also be arranged into a character state tree to hypothesize speciation events associated with changes from one character state to another. In the mid 20th century, some systematists realized that sometimes pairs of characters （or character state trees） could be incompatible as hypotheses, i.e., they could not both be true. Through the 1950s, ＇60s and ＇70s, tests for, and ways to resolve, incompatibilities were used to estimate an ancestor rela-tion based on mutually compatible characters. An estimate was often shown as a diagram connecting ancestors to their immediate descendants （not quite correctly） called a phylogenetic tree. More recently, other applications of compatibility concepts have been developed, including： identify characters that appear to be random in the context of their data set; combine estimates of ancestor relations for subsets of taxa in a larger collection into a single estimate （a so-called supertree） for the whole collection; and interpret geographic patterns in an evolutionary context.

关键词： biogeography character compatibility character evaluation convex groups phylogenetic trees,reciprocal illumination speciation supertrees

Inference of phylogenetic relationships among key angiosperm lineages using a compatibility method on a molecular data set

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植物分类学报 2008年第2期46卷 130-141页

作者： George f.ESTABROOK Department of Ecology & Evolutionary Biology The University of Michigan Ann Arbor MI 48109-1048 USA

Phylogenetic relationships among the five key angiosperm lineages, Ceratophyllum, Chloranthaceae, eudicots, magnoliids, and monocots, have resisted resolution despite several large-scale analyses sampling taxa and characters extensively and using various analytical methods. Meanwhile, compatibility methods, which were explored together with parsimony and likelihood methods during the early development stage of phylogenetics, have been greatly under-appreciated and not been used to analyze the massive amount of sequence data to recon-struct the basal angiosperm phylogeny. In this study, we used a compatibility method on a data set of eight genes (mitochondrial atp1, matR, and nad5, plastid atpB, matK, rbcL, and rpoC2, and nuclear 18S rDNA) gathered in an earlier study. We selected two sets of characters that are compatible with more of the other characters than a random character would be with at probabilities of pMf the 8 gene pMf other compatible site matrices produced different topologies that were all weakly sup-ported. The topology reconstructed in the parsimony analyses agrees with the one recovered in the previous study using both parsimony and likelihood methods when no character was eliminated. Parts of this topology have also been recovered in several earlier studies. Hence, this topology plausibly reflects the true relationships among the five key angiosperm lineages.

关键词：系统发育被子植物形态特征数据库

Xylose: absorption, fermentation, and post-absorptive metabolism in the pig

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Journal of Animal Science and Biotechnology 2018年第1期9卷 1-9页

作者： Nichole f.Huntley John f.Patience Department of Animal Science 213 Kildee HallIowa State University Department of Animal Science 201B Kildee HallIowa State University

Xylose, as β-1,4-linked xylan, makes up much of the hemicel ulose in cel wal s of cereal carbohydrates fed to pigs. As inclusion of fibrous ingredients in swine diets continues to increase, supplementation of carbohydrases, such as xylanase,is of interest. However, much progress is warranted to achieve consistent enzyme efficacy, including an improved understanding of the utilization and energetic contribution of xylanase hydrolysis product（i.e. xylooligosaccharides or monomeric xylose）. This review examines reports on xylose absorption and metabolism in the pig and identifies gaps in this knowledge that are essential to understanding the value of carbohydrase hydrolysis products in the nutrition of the pig. Xylose research in pigs was first reported in 1954, with only sporadic contributions since. Therefore, this review also discusses relevant xylose research in other monogastric species, including humans. In both pigs and poultry, increasing purified D-xylose inclusion general y results in linear decreases in performance, efficiency, and diet digestibility. However,supplementation levels studied thus far have ranged from 5% to 40%, while theoretical xylose release due to xylanase supplementation would be less than 4%. More than 95% of ingested D-xylose disappears before the terminal ileum but mechanisms of absorption have yet to be ful y elucidated. Some data support the hypothesis that mechanisms exist to handle low xylose concentrations but become overwhelmed as luminal concentrations increase. Very little is known about xylose metabolic utilization in vertebrates but it is wel recognized that a large proportion of dietary xylose appears in the urine and significantly decreases the metabolizable energy available from the diet. Nevertheless, evidence of labeled D-xylose-1-^（14）C appearing as expired^（14）CO_2 in both humans and guinea pigs suggests that there is potential,although small, for xylose oxidation. It is yet to be determined if pigs develop increased xy

关键词： Pentose utilization Swine Threitol Xylose absorption Xylose metabolism

Implementation of a Roughness Element to Trip Transition in Large-eddy Simulation

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Journal of Thermal Science 2015年第1期24卷 30-36页

作者： J.Boudet J.-f.Monier f.Gao LMfA Ecole Centrale de Lyon Université de Lyon–UMR CNRS 5509 69134 Ecully Cedex France PhD.Candidate Université de Lyon–UMR CNRS 5509 69134 Ecully Cedex France

In aerodynamics, the laminar or turbulent regime of a boundary layer has a strong influence on friction or heat transfer. In practical applications, it is sometimes necessary to trip the transition to turbulent, and a common way is by use of a roughness element （e.g. a step） on the wall. The present paper is concerned with the numerical im- plementation of such a trip in large-eddy simulations. The study is carried out on a flat-plate boundary layer con- figuration, with Reynolds number Rex=l.3x 106. first, this work brings the opportunity to introduce a practical methodology to assess convergence in large-eddy simulations. Second, concerning the trip implementation, a volume source term is proposed and is shown to yield a smoother and faster transition than a grid step. Moreover, it is easier to implement and more adaptable. finally, two subgrid-scale models are tested： the WALE model of Nic0ud and Ducros （flow Turbul. Combust., vol. 62, 1999） and the shear-improved Smagorinsky model of Ldv^que et al. （J. fluid Mech., vol. 570, 2007）. Both models allow transition, but the former appears to yield a faster transition and a better prediction of friction in the turbulent regime.

关键词： large-eddy simulation boundary layer roughness element transition tripping

EffECT Of GAMMA RAYS IN THE PREPARATION Of POLYMER AND HYDROGEL fROM ACRYLAMIDE MONOMER

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Chinese Journal of Polymer Science 2003年第4期21卷 437-442页

作者： M.M.Alam M.f.Mina f.Akhtar NRCD INST AERE GPO Box-3787 Dhaka BangladeshNRCD INST AERE GPO Box-3787 Dhaka BangladeshNRCD INST AERE GPO Box-3787 Dhaka Bangladesh

The formation of polymer and hydrogel from aqueous solutions having 20, 30 and 40% concentrations ofacrylamide monomer by γ-ray irradiation processing in the dose range 0.06-30 kGy using a Co-60 source and theircharacterization have been observed. Polymer conversion and gel fraction are found to depend on radiation doses. Polymerconversion increases with the increase of dose, depending on the solution concentration, where maximum conversion isachieved at 0.18, 0.16 and 0.10 kGy for 20%, 30% and 40% concentrations, respectively. On the other hand, gel fractionincreases with dose from the gel point (0.12 kGy) for all concentrations, where 100% conversion of gel occurs at doses≥5 kGy. Tensile strength, viscosity and molecular weight (M_w) of polymer samples increase with both the dose and theconcentration, showing a high value of M_w up to≈10~8. Swelling of hydrogels under water with respect to time varies due tothe variation of cross-linking density formed in the gels and the maximum swelling mainly occurs within 24 h. A remarkable change of surface morphology reveals characteristic features of monomer, polymer and hydrogel films.

关键词： Polymer Hydrogel γ-Radiation Cross-linking Swelling

Catalytic combustion of soot over Ru-doped mixed oxides catalysts

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Journal of Rare Earths 2014年第7期32卷 610-620页

作者： L.f.Nascimento R.f.Martins O.A.Serra Department of Chemistry Faculdade de FilosofiaCiências e Letras de Ribeirao PretoUniversity of Sao PauloAv.Bandeirantes 3900CEP 14040-901 Ribeirao PretoSPBrazil

We employed modified substrates as outer heterogeneous catalysts to reduce the soot originating from the incomplete diesel combustion. Here, we proposed that ceria（CeO2）-based catalysts could lower the temperature at which soot combustion occurred from 610 oC to values included in the operation range of diesel exhausts（270–400 oC）. Here, we used the sol-gel method to synthesize catalysts based on mixed oxides（ZnO：CeO2） deposited on cordierite substrates, and modified by ruthenium nanoparticles. The presence of ZnO in these mixed oxides produced defects associated with oxygen vacancies, improving thermal stability, redox potential, sulfur resistance, and oxygen storage. We evaluated the morphological and structural properties of the material by X-ray diffraction（XRD）, Brumauer-emmett-teller method（BET）, temperature programmed reduction（H2-TPR）, scanning electron microscopy（SEM）, and transmission electron microscopy（TEM）. We investigated how the addition of Ru（0.5 wt.%） affected the catalytic activity of ZnO：CeO2 in terms of soot combustion. Thermogravimetric analysis（TG/DTA） revealed that presence of the catalyst decreased the soot combustion temperature by 250 oC, indicating that the oxygen species arose at low temperatures, which was the main reason for the high reactivity of the oxidation reactions. Comparative analysis of soot emission by diffuse reflectance spectroscopy（DRS） showed that the catalyst containing Ru on the mixed oxide-impregnated cordierite samples efficiently oxidized soot in a diesel stationary motor： soot emission decreased 80%.

关键词： soot combustion ceria mixed oxides ruthenium nanoparticles rare earths

Nitric oxide:a newly discovered function on wound healing

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Acta Pharmacologica Sinica 2005年第3期26卷 259-264页

作者： Alex f CHEN Departments of Pharmacology and Neurology and the Neuroscience Program Michigan State University East Lansing MI 48824-1317 USA

Wound healing impairment represents a particularly challenging clinical problemto which no efficacious treatment regimens currently *** factors ensuringappropriate intercellular communication during wound repair are not *** protein-type mediators are well-established players in thisprocess,emerging evidence from both animal and human studies indicates thatnitric oxide (NO) plays a key role in wound *** beneficial effects of NO onwound repair may be attributed to its functional influences on angiogenesis,inflammation,cell proliferation,matrix deposition,and *** find-ings from in vitro and in vivo studies of NO on wound repair are summarized inthis *** unveiled novel mechanisms support the use of NO-containingagents and/or NO synthase gene therapy as new therapeutic regimens for im-paired wound healing.

关键词： angiogenesis inflammation nitric oxide proliferation wound healing