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Anisotropic plastic deformation behavior of as-extruded ZK60 magnesium alloy at room temperature

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Science China(Technological Sciences) 2009年第1期52卷 161-165页

作者： hans j R Department of Materials Science and Engineering Norwegian University of Science and Technology

The anisotropic plastic deformation behavior of as-extruded ZK60 magnesium alloy at room tempera-ture (RT) was investigated by compressive and tensile testing in different directions, i.e. the loading axis oriented at 0°, 45° and 90° to the extrusion direction. The relationship between texture and plastic deformation behavior were examined. The results show that the extruded ZK60 alloy exhibits a strong ring fiber texture. The mechanical properties are strongly orientation dependent. In tension testing, the 0° specimen exhibited higher yield strength and lower elongation. In compression testing, however, ZK60 alloy exhibited almost the same yield strength in three directions. The anisotropic plastic defor-mation behavior is due to strong fiber texture and the lower symmetry of the hexagonal close packed (hcp) structure of ZK60 alloy. The correlation between texture and mechanical behaviour offers the possibility to improve the mechanical properties of magnesium alloy by optimization of the material production process.

关键词： anisotropic plastic deformation behavior ZK60 Mg alloy texture mechanical property

High-resolution Induan-Olenekian boundary sequence in Chaohu, Anhui Province

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Science China Earth Sciences 2005年第3期48卷 291-297页

作者： hans j. hansen Geological Institute Copenhagen University Oster Voldgade 10 DK-1350 Copenhage Denmark

The West Pingdingshan Section in Chaohu, Southeast China’s Anhui Province is one of the potential GSSP candidates for the Induan-Olenekian boundary. Extensive study has been done on the Induan-Olenekian boundary strata at the section to meet the requirements of defining the GSSP precisely. This paper focuses on the boundary strata at the section to present a review of the main results achieved in recent years. The Induan-Olenekian boundary strata here cover an interval of about four meters at the West Pingdingshan Section, in which the key indices of defining the boundary and the chief transitional processes of some parameters at the boundary are included. The relationship between the boundaries defined by ammonoids and by conodonts is well clarified at the section. The magnetic polarity analysis shows that the boundary interval belongs to a normal polarity zone. Both the carbonate and organic carbon isotopes com- positions experienced a significant conversion in the boundary interval.

关键词： Lower Triassic, Induan-Olenekian boundary, GSSP, candidate, Chaohu of China.

Recycling of automotive aluminum

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Transactions of Nonferrous Metals Society of China 2010年第11期20卷 2057-2063页

作者： jirang CUI hans j.ROVEN Department of Materials Science and Engineering Norwegian University of Science and Technology(NTNU)

With the global warming of concern,the secondary aluminum stream is becoming an even more important component of aluminum production and is attractive because of its economic and environmental *** this work,recycling of automotive aluminum is reviewed to highlight environmental benefits of aluminum recycling,use of aluminum alloys in automotive applications,automotive recycling process,and new technologies in aluminum scrap *** survey shows that newly developed techniques such as laser induced breakdown spectroscopy(LIBS) and solid state recycling provide promising alternatives in aluminum scrap *** with conventional remelting and subsequent refinement,solid state recycling utilizing compression and extrusion at room or moderate temperature can result in significant energy savings and higher metal yield.

关键词： recycling automotive aluminum sorting mechanical separation solid state recycling

Estimation of Pool Boiling Heat Transfer Coefficients of Ethanol-Water Mixtures

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Chinese journal of Chemical Engineering 1999年第2期7卷 95-103页

作者：谷俊杰 hans-jrgBart Lehrstuhl fur Thermische Verfahrenstechnik Universitat Kaiserslautern67653 KaiserslauternGermany

Based on the analysis of the principles of heat and mass transfer from the liquid bulk to bubble surface during nucleation, a new estimation method to predict the heat transfer of the nucleate pool boiling in binary mixtures is proposed in this paper by using the heat and mass transfer analogy (Colburn analogy) at the bubble surface transfer layers. With the use of Thome's concept of boiling range, an approximate method is derived to realize the calculation. The predicted results by this method are in good agreement with the experimental data from different sources.

关键词： heat transfer boiling water-ethanol mixture estimation

Micromechanical investigation of granular ratcheting using a discrete model of polygonal particles

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Particuology 2008年第6期6卷 390-403页

作者： Fernando Alonso-Marroquín hans B. Mhlhaus hans j. Herrmann Earth Systems Science Computational Centre & School of Physical Sciences The University of Queensland Earth Systems Science Computational Centre The University of Queensland Institut fr Baustoffe ETH-HenggerbergZrich

We use a two-dimensional model of polygonal particles to investigate granular ratcheting. Ratcheting is a long-term response of granular materials under cyclic loading, where the same amount of permanent deformation is accumulated after each cycle. We report on ratcheting for low frequencies and extremely small loading amplitudes. The evolution of the sub-network of sliding contacts allows us to understand the micromechanics of ratcheting. We show that the contact network evolves almost periodically under cyclic loading as the sub-network of the sliding contacts reaches different stages of anisotropy in each cycle. Sliding contacts lead to a monotonic accumulation of permanent deformation per cycle in each particle. The distribution of these deformations appears to be correlated in form of vortices inside the granular assembly.

关键词： Granular systems Dynamics and kinematics of rigid bodies Molecular dynamics methods

From Single Droplet to Column Design

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Tsinghua Science and Technology 2006年第2期11卷 212-216页

作者： hans-jrg Bart Institute of Thermal Process Engineering TU Kaiserslautern D-67653 Kaiserslautern Germany

The technique state to design counter-current extraction columns is based on the performance of pilot plant experiments. The modelling is then either with the equilibrium or dispersion model, whereas in the latter the dispersion coefficient accounts for all hydrodynamic non-idealities. A new approach uses single droplet experiments to obtain the basic laws and functions governing droplet breakage, coalescence, relative velocity, and axial dispersion when using droplet populance balance models （DPBM）. The hydrodynamics simulation results show that the mean Sauter diameter, hold-up, and concentration profiles could be well predicted, which promotes the use of DPBM models for further applications in industrial scale.

关键词： single droplet column design countercurrent extraction droplet populance balance model

Silurian-Devonian and jurassic Thermal Events in the Ordos Basin, China: Indications from K-Ar Dating on Illites

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Acta Geologica Sinica(English Edition) 1996年第4期70卷 435-446页

作者： hans Ahrendt Klaus Wemmer hans-j rgen Behr Institute of Geology and Dynamics of Lithosphere University of Gttingen G ttingen GermanyInstitute of Geology and Dynamics of LithosphereUniversity of Gttingen G ttingen GermanyInstitute of Geology and Dynamics of LithosphereUniversity of Gttingen G ttingen Germany

In the Ordos basin, two distinct thermal events of different ages have been identified for the first time by means of K-Ar dating combined with illite crystallinity analysis. For the Late Triassic and Late Permian samples, the K-Ar ages of the jurassic; the K-Ar ages of the <2 μm fractions (210-308 Ma) are interpreted as mixed ages of detrital material and authigenic illites. The K-Ar ages of both < 0.2μm and < 2μm fractions of a Middle Cambrian sample (368 Ma and 419 Ma) correspond to the ages of the metamorphism and earliest granite intrusion in the northern Caledonian Qinling fold zone (380-420 Ma) and show a thermal event during Silurian-Devonian time.

关键词： illite K-Ar dating illite crystallinity thermal event Ordos basin

Surveillance colonoscopy practice in Lynch syndrome in the Netherlands:A nationwide survey

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World journal of Gastroenterology 2007年第34期13卷 4658-4659页

作者： jan j Koornstra hans FA Vasen Department of Gastroenterology and Hepatology University Medical Centre Groningen University of Groningen Groningen The Netherlands The Netherlands Foundation for the Detection of Hereditary Tumors Department of Gastroenterology Leiden University Medical Centre Leiden The Netherlands

Lynch syndrome, or hereditary nonpolyposis colorectal cancer (HNPCC), is the most common genetic disorder predisposing to colorectal cancer. As regular colonoscopic surveillance has been shown to reduce the incidence of colorectal cancer, this strategy is recommended worldwide. Recently, several advances in colonoscopic techniques have improved detection rates of neoplasia in Lynch syndrome. In this nationwide survey, we evaluated current surveillance colonoscopy practices for Lynch syndrome in the Netherlands and the extent to which advanced techniques have been adopted in routine clinical practice.

关键词： Lynch syndrome Hereditary nonpolyposiscolorectal cancer Colonoscopy Surveillance Chromoendoscopy

AtGGM2014, an Arabidopsis gene co-expression network for functional studies

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Science China(Life Sciences) 2015年第3期58卷 276-286页

作者： MA ShiSong BOHNERT hans j DINESH-KUMAR Savithramma P Department of Plant Biology and the Genome Center College of Biological Sciences University of California Departments of Plant Biology and of Crop Sciences University of Illinois at Urbana-Champaign

Gene co-expression networks provide an important tool for systems biology studies. Using microarray data from the Array Express database, we constructed an Arabidopsis gene co-expression network, termed At GGM2014, based on the graphical Gaussian model, which contains 102,644 co-expression gene pairs among 18,068 genes. The network was grouped into 622 gene co-expression modules. These modules function in diverse house-keeping, cell cycle, development, hormone response, metabolism, and stress response pathways. We developed a tool to facilitate easy visualization of the expression patterns of these modules either in a tissue context or their regulation under different treatment conditions. The results indicate that at least six modules with tissue-specific expression pattern failed to record modular regulation under various stress conditions. This discrepancy could be best explained by the fact that experiments to study plant stress responses focused mainly on leaves and less on roots, and thus failed to recover specific regulation pattern in other tissues. Overall, the modular structures revealed by our network provide extensive information to generate testable hypotheses about diverse plant signaling pathways. At GGM2014 offers a constructive tool for plant systems biology studies.

关键词： Arabidopsis gene co-expression network graphical Gaussian model plant development stress response hormone response