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The Origin of the Giant Hall Effect in Metal-Insulator Composites

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Open Journal of Composite Materials 2016年第3期6卷 78-90页

作者： joachim.sonntag MEAS Deutschland GmbH a TE Connectivity LTD Company Dortmund Germany

Near the metal-insulator transition, the Hall coefficient R of metal-insulator composites (M-I composite) can be up to 104 times larger than that in the pure metal called Giant Hall effect. Applying the physical model for alloys with phase separation developed in [1] [2], we conclude that the Giant Hall effect is caused by an electron transfer away from the metallic phase to the insulating phase occupying surface states. These surface states are the reason for the granular structure typical for M-I composites. This electron transfer can be described by [1] [2], provided that long-range diffusion does not happen during film production (n is the electron density in the phase A. uA and uB are the volume fractions of the phase A (metallic phase) and phase B (insulator phase). β is a measure for the average potential difference between the phases A and B). A formula for calculation of R of composites is derived and applied to experimental data of granular Cu1-y(SiO2)y and Ni1-y(SiO2)y films.

关键词： Metal-Insulator Composites Granular Metals Hall Coefficient Conductivity Electron Density

High-Temperature Superconductivity—An Electron Transfer Phenomenon

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World Journal of Condensed Matter Physics 2024年第4期14卷 67-76页

作者： joachim.sonntag Dortmund Germany

The increase of the critical temperature Tc for superconductivity in Al1−x(SiO2)x cermets with increasing x correlates with a decrease of the electron density n due to electron transfer, expressed by Tc/Tc,max=1−γ⋅n2(*). Behind the formula (*) and Tc/Tc,max=1−82.6(P−0.16)2, which is characteristic of hole-doped cuprat high-temperature superconductors, lies a general phenomenon, namely electron transfer, which equalizes potential differences in the material and leads to a strong reduction of n. P is the fraction of holes filled by the transferred electrons. A quantitative consideration gives Tc(x)/Tc,max=1−(1−x1−x0)2(**), where x is the doping concentration and x0 is the concentration at which superconductivity begins. At x=xmax=1the electron source is completely depleted and with further growth of x the hole density p starts to increase and Tc decreases until superconductivity disappears completely at x=2−x0. Taking into account the formula (**), the hypothesis arose that for x>xmaxTc/Tc,max=1−γ⋅p2(***), an analogue of the formula (*), and that superconductivity is possible not only by electron-Cooper pairs but also by paired holes. The mechanisms described here for HTSC suggest an analogy to the physics of semiconductors and that of nanocomposites: Electron-hole duality. The “P=1/8” anomaly in YBa2Cu3O6+x is caused by the simultaneous presence of electrons and holes, a consequence of incomplete electron transfer.

关键词： High-Tc Superconductor Electron Transfer Electron Density Hole Density “P = 1/8” Anomaly Jahn-Teller Effect

Electronic Transport in Alloys with Phase Separation (Composites)

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Open Journal of Composite Materials 2019年第1期9卷 21-56页

作者： joachim.sonntag Bertrand Lenoir Pawel Ziolkowski TE Connectivity Sensors Germany GmbH Dortmund Germany Institut Jean Lamour UMR 7198 CNRS-Université de Lorraine 2 Allée André Guinier-Campus ARTEM Nancy Cedex France German Aerospace Center Institute of Materials Research Koln Germany

A measure for the efficiency of a thermoelectric material is the figure of merit defined by ZT = S2T/ρκ, where S, ρ and κ are the electronic transport coefficients, Seebeck coefficient, electrical resistivity and thermal conductiviy, respectively. T is the absolute temperature. Large values for ZT have been realized in nanostructured materials such as superlattices, quantum dots, nanocomposites, and nanowires. In order to achieve further progress, (1) a fundamental understanding of the carrier transport in nanocomposites is necessary, and (2) effective experimental methods for designing, producing and measuring new material compositions with nanocomposite-structures are to be applied. During the last decades, a series of formulas has been derived for calculation of the electronic transport coefficients in composites and disordered alloys. Along the way, some puzzling phenomenons have been solved as why there are simple metals with positive thermopower? and what is the reason for the phenomenon of the “Giant Hall effect”? and what is the reason for the fact that amorphous composites can exist at all? In the present review article, (1), formulas will be presented for calculation of σ = (1/ρ), κ, S, and R in composites. R, the Hall coefficient, provides additional informations about the type of the dominant electronic carriers and their densities. It will be shown that these formulas can also be applied successfully for calculation of S, ρ, κ and R in nanocomposites if certain conditions are taken into account. Regarding point (2) we shall show that the combinatorial development of materials can provide unfeasible results if applied noncritically.

关键词： Hall Effect Giant Hall Effect Seebeck Coefficient (Thermopower) Electron Density Conductivity Thermal Conductivity Composites Nanocomposites Percolation Theory

Earth observation in service of the 2030 Agenda for Sustainable Development

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Geo-Spatial Information Science 2017年第2期20卷 77-96页

作者： Katherine Anderson Barbara Ryan William sonntag Argyro Kavvada Lawrence Friedl Group on Earth Observations GenevaSwitzerland Booz Allen Hamilton WashingtonDCUSA NASA Earth Science Division WashingtonDCUSA

This paper reviews the key role that Earth Observations(EO)play in achieving the Sustainable Development Goals(SDGs)as articulated in the 2030 Agenda document and in monitoring,measuring,and reporting on progress towards the associated *** paper also highlights how the Group on Earth Observations(GEO)would contribute to ensure the actual use of EO in support of the 2030 Agenda;and how the Global Earth Observations System of Systems meets requirements for efficient investments in science and technology and a good return on investment,which is elaborated in the Addis Ababa Action Agenda on development *** a number of examples,we first discuss how extensive EO use would:provide a substantial contribution to the achievements of the SDGs by enabling informed decision-making and by allowing monitoring of the expected results;improve national statistics for greater accuracy,by ensuring that the data are“spatially-explicit”and directly contribute to calculate the agreed SDG Targets and Indicators support the fostering of synergy between the SDGs and multilateral environmental agreements by addressing cross-cutting themes such as climate and energy;and facilitate countries’approaches for working across different development sectors,which is,according to the special adviser on the 2030 Agenda,a key challenge to achieve the *** then focus on the role that GEO could play in enabling actual use of EO in support of the 2030 Agenda by directly addressing the Strategic Development Goal 17 on partnerships.

关键词： Earth observation Group on Earth Observations(GEO) Sustainable Development Goal(SDG) the 2030 Agenda

Impact of renewable energies on the operation and economicsituation of coal fired power stations： Actual situation of coalfired power stations in Germany

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Frontiers in Energy 2017年第2期11卷 119-125页

作者： Hans-joachim KRAUTZ Alexander LISK joachim POSSELT Christian KATZER Department for Power Plant Technology Brandenburg University of Technology Cottbus-Senftenberg 03046 Cottbus Gemany

Due to the fluctuating character of the renewable energy sources the demand of conventional power plants for flexibility is increasing. In the recent years, in Germany there has been a fast rise of production capacity of renewable energies, especially from wind turbines, photovoltaic installations, and biomass plants. The installed nominal power of wind turbines is actually (December 2016) 42 GW and of photovoltaic installations 40 GW. The renewable electric energy production in Germany is about 190 TWh/a, which represents a share of 33% of the yearly demand. The increased need for flexibility affects both the power gradients as well as the minimum load of conventional power plants. Due to this flexibility behaviour, conventional power plants are faced with problems concerning the durability of power plant components, corrosion, more maintenance effort and consequently the overall life expectancy. Another consequence of the increasing share of renewable energies is the decreasing full load operating hours, especially of coal fired and gas power plants. Along with decreasing revenues from the energy exchange market, coal fired power plants are faced with new economically challenges.

关键词： flexible load operation minimal load power gradients power plant maintenance corrosion life expectancy

Combinatorial Dyson-Schwinger equations and inductive data types

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Frontiers of physics 2016年第3期11卷 179-193页

作者： joachim Kock Departament de matemhtiques Universitat Autdnoma de Barcelona Spain

The goal of this contribution is to explain the analogy between combinatorial Dyson-Schwinger equations and inductive data types to a readership of mathematical physicists. The connection relies on an interpretation of combinatorial Dyson-Schwinger equations as fixpoint equations for polynomial functors （established elsewhere by the author, and summarised here）, combined with the now-classical fact that polynomial functors provide semantics for inductive types. The paper is expository, and comprises also a brief introduction to type theory.

关键词： Dyson-Schwinger equations type theory inductive types bialgebras polynomialfunctors

A Fresh Look at Dickinsonia:Removing It from Vendobionta

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Acta Geologica Sinica(English Edition) 2006年第5期80卷 636-642页

作者： joachim REITNER Geowissenschaftliches Zentrum Abteilung Geobiologie Universitt Gttingen 37077 Gttingen Germany

The Ediacaran Dickinsonia is well-known for being the only fossil to be assigned to many phyla,ranging from lichens,Cnidaria,Platyhelminthes,Annelida,and a phylum of its own to a nonmetazoan kingdom.A new specimen from the Ediacaran fine-grained sandstone on the Winter Coast of the White Sea in northern Russia,which has an age of ~555 million years ago,preserved convincing internal anatomies of definite animals,comparable with meridional canals of extant ctenophores(comb jellies).Additionally,we reconsidered Dickinsonia as a biradially symmetrical animal rather than a bilateral one as previously *** animal nature of Dickinsonia is,thus,well established and its affinities are most probably allied to *** research is not only removing Dickinsonia from Vendobionta,but also bringing the fossil record of ctenophores forward to 20 million years before the Cambrian “explosion”.

关键词： Dickinsonia Ctenophora Vendobionta metazoan Ediacara biota Ediacaran

Diverged Copies of the Seed Regulatory Opaque-2 Gene by a Segmental Duplication in the Progenitor Genome of Rice, Sorghum, and Maize

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Molecular Plant 2008年第5期1卷 760-769页

作者： Jian-Hong Xu joachim Messing Waksman Institute of Microbiology Rutgers University 190 Frelinghuysen Road Piscataway NJ 08854 USA

Comparative analyses of the sequence of entire genomes have shown that gene duplications, chromosomal segmental duplications, or even whole genome duplications （WGD） have played prominent roles in the evolution of many eukaryotic species. Here, we used the ancient duplication of a well known transcription factor in maize, encoded by the Opaque-2 （O2） locus, to examine the general features of divergences of chromosomal segmental duplications in a lineagespecific manner. We took advantage of contiguous chromosomal sequence information in rice （Oryza sativa, Nipponbare）, sorghum （Sorghum bicolor, Btx623）, and maize （Zea rnays, B73） that were aligned by conserved gene order （synteny）. This analysis showed that the maize 02 locus is contained within a 1.25 million base-pair （Mb） segment on chromosome 7, which was duplicated ≈56 million years ago （mya） before the split of rice and maize 50 mya. The duplicated region on chromosome I is only half the size and contains the maize OHP gene, which does not restore the O2 mutation although it encodes a protein with the same DNA and protein binding properties in endosperm. The segmental duplication is not only found in rice, but also in sorghum, which split from maize 11.9 mya. A detailed analysis of the duplicated regions provided examples for complex rearrangements including deletions, duplications, conversions, inversions, and translocations. Furthermore, the rice and sorghum genomes appeared to be more stable than the maize genome, probably because maize underwent allotetraploidization and then diploidization.

关键词： WGD Opaque-2

Hepatitis B virus-induced oncogenesis

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World Journal of Gastroenterology 2007年第1期13卷 74-81页

作者： joachim Lupberger Eberhard Hildt Department of Internal Medicine II Hugstetter Str. 55 D-79106 Freiburg Germany

Hepatocellular carcinoma (HCC) is one of the most com- mon cancers in the world with an annual incidence of more than 500 000 in the year 2000. Its incidence is rising in many countries. Recently, it has been estimated that about 53% of HCC cases in the world are related to hepatitis B virus (HBV). The epidemiological association of HBV with HCC is well established. In recent studies, it was revealed that HBsAg carriers have a 25-37 times increased risk of developing HCC as compared to non-infected people. At present, HBV-associated carcinogenesis can be seen as a multi-factorial process that includes both direct and indirect mechanisms that might act synergistically. The integration of HBV DNA into the host genome occurs at early steps of clonal tumor expansion. The integration has been shown in a number of cases to affect a variety of cancer- related genes and to exert insertional mutagenesis. The permanent liver inflammation, induced by the immune response, resulting in a degeneration and regeneration process confers to the accumulation of critical mutations in the host genome. In addition to this, the regulatory proteins HBx and the PreS2 activators that can be encoded by the integrate exert a tumor promoter-like function resulting in positive selection of cells producing a functional regulatory protein. Gene expression profiling and proteomic techniques may help to characterize the molecular mechanisms driving HBV-associated carcino- genesis, and thus potentially identify new strategies in diagnosis and therapy.

关键词： Hepatitis B virus Hepatocellular carcinoma Regulatory proteins Signal transduction