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Ab initio energetic study of oxide ceramics with rare-earth elements

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Rare Metals 2006年第5期25卷 549-555页

作者： Matvei Zinkevich fritz Aldinger Max-Planck-Institut für Metallforschung Institut für Nichtmetallische Anorganische MaterialienUniversitt StuttgartHeisenbergstrasse 3D-70569 StuttgartGermany

Ab initio energetic calculations based on the density functional theory （DFF） and the projector augmented wave method （PAW） for determining the polymorphisms of lanthanide sesquioxides Ln2O3 （where Ln = rare-earth element, Y, and Sc）, LnMO3 perovskites （where M = AI and Ga）, and Ln2B207 pyrochlores （where B = Ti, Zr, and Hf） were reported. The relative lattice stabilities agreed well with the critically assessed results or the experimental results except the C-type Ln2O3 with a cubic structure, for which the calculated total energies were considerably more negative. With the increase of the Ln^3＋-cation radius, the polymorphic structures showed a degenerative tendency. The tendencies and quantities of the enthalpies of formation of the ternary oxide ceramics synthesized from their constituent binary oxides reasonably agreed with the available experimental results, and valuable thermodynamic properties were afforded to the compound, for which no experimental data is available. The enthalpies of formation of both perovskites and pyrochlores tend to become more negative with the increase of the Ln^3＋-cation radius.

关键词： rare earth oxide ceramics ab initio calculation lattice stability enthalpy of formation

Recent progress on ULF wave and its interactions with energetic particles in the inner magnetosphere

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Science China(Technological Sciences) 2008年第10期51卷 1620-1625页

作者： Theodore A. fritz Center for Space Physics Boston University Boston MA 02215 USA

The global distribution properties of Ultra Low Frequency wave (ULF) in the inner magnetospgere and its interactions with energetic particles, such as the wave-particle resonance, modulation, and particle acceleration, are active topics in space physics research. These problems are fundamentally important issues to understand the energy transport from the solar wind into the magnetosphere. In this paper we briefly reviewed the recent research progress on ULF wave and its interactions with energetic particles in the inner magnetosphere; furthermore, we suggested some open questions for future study.

关键词： radiation belt particle particle acceleration ULF wave compressional mode cavity mode poloidal mode toroidal mode Field Line Resonance (FLR) energetic particles modulation

Exploration of chromene-based BioAIEgens

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National Science Review 2024年第3期11卷 47-48页

作者： fritz E.Kühn Department of Chemistry&Catalysis Research Center School of Natural Sciences Technical University of Munich

Photoemission efficiency is usually higher in solution than in solid *** compounds however, display a reverse behavior. Such a behavior is called aggregation-induced emission(AIE).

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Biophoton Emission as a Potential Measure of Organizational Order

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Science China Chemistry 1994年第9期37卷 1099-1112页

作者：顾樵 Popp fritz-Albert Also in Department of Physics Northwest University Xi'an 710069 PRC International Institute of Biophysics Technology Centre 67661 Kaiserslautern Germany

Beginning with the quantum theory of biophoton emission,a c-number equation character- izing the excited-state dynamics of a complex system of collective biomolecules in interaction with both the 'pumping'field and the biophoton field is presented,and then the order-growth process of the system in terms of both determinism and statistics is investigated.A general expression describing the order-growth dynamics of biological systems,which reduces in a limiting case to the well-known growth curve,is ob~ *** a Fokker-Planck equation for probability density function of an order parameter q of the system has been *** solution predicts that the system under consideration can evolute from an arbitrary initial state to a pure state characterized by the steady-state order parameter q_***,the evolution of the maximum entropy of the system is discussed,which shows that the system investigated is to keep an absolute maximum of entropy,and at the same time,to minimize its entropy value by reducing the uncertain- ty of the order ***,some agreements of the theoretical results with the corresponding experi- mental observations of order-growth process demonstrated by the biophoton emission are shown,which indi- cates that biophoton emission may serve as a potential measure of the organizational order.

关键词： biophoton emission complex system nonlinear dynamics organizational order maximum entropy

Long-term seasonal fluctuations of lepidopteran cereal stemborers and their natural enemies on maize and wild host plants in southern Benin

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Insect Science 2009年第4期16卷 329-341页

作者： Saka Gounou Nanqing Jiang fritz Schulthess International Institute of Tropical Agriculture Biological Control Centre for Africa Cotonou Repubfic of Benin Intemational Centre of Insect Physiology and Ecology Nairobi Kenya

The seasonal fluctuation oflepidoptcran cereal stemborers on maize and wild host plants （i.e., grasses and a few sedges） was investigated in southern Benin from 1988 to 1998 by time series analysis and repeated-measures analysis of variance （ANOVA）. In addition, a walk-in light trap was used to study the flight behavior of adult moths. On both cereals and grasses, the noctuid Sesamia calaraistis was the predominant species, followed by the pyralid Eldana saccharina. The noctuid Busseolafusca was rare on both maize and wild host plants. In general, pest populations increased during the course of the year to reach peak densities during the second short rainy season, and then crashed to close to zero during the dry season. On wild host plants, egg masses and other immature stages were collected throughout the year but they were higher on wild grasses than maize during the off-season. Thus wild host plants can be considered as refuge for both borers and natural enemies during the off-season, when maize is not available. However, only four out of the eleven wild host species played a discernable role. S. calamistis egg densities appeared to be influenced by density-dependent factors, suggesting an effect of natural enemies. Temperature and rainfall had a negative effect on egg abundance. Larval parasitism by a Kenyan strain of the braconid Cotesia sesamiae, which was released in southern Benin in the early 1990s, and by the tachinid Sturmiopsisparasitica varied between seasons and years but there were no discernable patterns. For both parasitoids and borer host species, parasitism was positively correlated with trap catches of adult moths. The recovery of C. sesamiae during a 2-year period suggests that the parasitoid has established its population in southern Benin.

关键词： climate lepidopteran stemborers maize parasitoids time series analysis wild host plants

Influence of 3d transition-metal substitution on the oxygen reduction reaction electrocatalysis of ternary nitrides in acid

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Nano Research 2019年第9期12卷 2307-2312页

作者： Kevin E. fritz Yichen Yan Jin Suntivich Department of Material Science and Engineering Cornell UniversityIthacaNew York 14850USA Kavli Institute at Cornell for Nanoscale Science IthacaNew York 14850USA

The development of non-precious,acid-stable,oxygen reduction reaction(ORR)electrocatalysts can significantly aid the commercialization of proton exchange membrane fuel cells(PEMFCs).We report a survey of the ORR electrocatalysis on 3d metal substituted(M=Mn,Fe,Co)molybdenum and tungsten nitrides in acidic *** find that molybdate catalysts are more active than tungstates,with the specific activity depending on the chemistry of the substituted 3d *** both families,more electronegative 3d metals led to higher ORR activity(i.e.,Co>Fe>Mn).We attribute this result to the ability of the more electro negative 3d metal to withdraw electro ns from the Mo-or W-based active sites,effectively oxidizing the metal centers of the *** on our observation,future nitride ORR electrocatalysts can be further optimized by oxidizing the Mo sites further by,for example,addi ng eve n more electro negative dopa nt metals or in corporati ng anion vaca ncies.

关键词： nitrides electrocatalysis fuel cells oxygen reduction

Organorhenium(Ⅶ) oxides

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Rare Metals 2006年第z1期25卷 411-421页

作者： KüHN fritz E. JAIN Kavita R. Department für Chemie der Technischen Universitt München Lichtenbergstrasse 4 D-85747 Garching bei München Germany

Methyltrioxorhenium (MTO) and its derivatives were utilized as catalysts for a broad variety of organic reactions after the discovery of an easy synthetic access way to this class of compounds. Among the numerous characterization techniques, 17O-NMR spectroscopy and vibrational spectroscopy were exemplary discussed. The immobilization of MTO and its derivatives is of significant current interest as is the synthesis of chiral derivatives.

关键词： catalysis epoxidation immobilization olefination rhenium

Bio-inspired tetracarbene compounds as a new family of energy saving catalysts

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Journal of Energy Chemistry 2023年第4期79卷 559-561页

作者： Bo Zhang fritz E.Kühn CAS Key Laboratory of Science and Technology on Applied Catalysis Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023LiaoningChina' University of Chinese Academy of Science Beijing 100049China Molecular Catalysis Catalysis Research Center and Department of ChemistrySchool of Natural SciencesTechnical University of MunichLichtenbergstr 485748 Garching bei MünchenGermany

Efficient use of energy is a pressing *** of chemical processes is currently an important target for energy *** chemical processes are independent of pathways with respect to the final energy output or consumption,the application of catalysts can reduce involved activation energies considerably and therefore save large amounts of energy.

关键词： Catalysis Iron Carbenes Multidentate ligands

Adaptive Neuro-Fuzzy Modeling of Mechanical Behavior for Vertically Aligned Carbon Nanotube Turfs

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Journal of Materials Science & Technology 2011年第4期27卷 301-308页

作者： Mohammad Al-Khedher Charles Pezeshki Jeanne McHale fritz Knorr Mechatronics Division Al-Balqa Applied University School of Mechanical and Materials Engineering Washington State University Department of Chemistry Washington State University

Several characterization methods have been developed to investigate the mechanical and structural properties of vertically aligned carbon nanotubes （VACNTs）. Establishing analytical models at nanoscale to interpret these properties is complicated due to the nonuniformity and irregularity in quality of as-grown samples. In this paper, we propose a new methodology to investigate the correlation between indentation resistance of multi-wall carbon nanotube （MWCNT） turfs, Raman spectra and the geometrical properties of the turf structure using adaptive neuro-fuzzy phenomenological modeling. This methodology yields a novel approach for modeling at the nanoscale by evaluating the effect of structural morphologies on nanomaterial properties using Raman spectroscopy.

关键词： Adaptive neuro-fuzzy Carbon nanotubes Image analysis Nanoindentation Raman spectroscopy