检索结果-南通市图书馆

Two pedogenic models for paleoclimatic records of magnetic susceptibility from Chinese and Siberian loess

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Earth Sciences 2008年第2期51卷 284-293页

作者： Paul hesse Jiri CHLACHULA Department of Physical Geography Macquarie University NSW 2109 Australia Key Laboratory of Desert and Desertification Institute of Cold and Arid Regions Environmental and Engineering Chinese Academy of Sciences Lanzhou 730000 China

The magnetic susceptibility (MS) of Chinese loess showing a general proportional relationship to pedogenic grade has been widely recognized and used for reconstruction of paleoclimate by Quaternary scientists. The in-... 详细信息

关键词： Siberian loess Chinese loess paleoclimate magnetic susceptibility magnetic mineralogy environmental magnetism

维普期刊数据库

Hydrochemistry,Origin and Evolution of Sedimentary Sub- surface Fluids:*** diagenetic pore- water evolution in low-sedimentation rate offshore basins

在线全文

学校读者我要写书评

暂无评论

Acta Geochimica 1986年第4期5卷 297-319页

作者： REINHARD hesse Department of Geological Sciences McGill University Montreal. Quebec H3A 2A7 Canada

Pore water studies enable (1) the detection of diagenetic reactions actively occurring in the sediment atthe time of sampling,(2) the distinction between principal modes of solute transport, i.e., between advection(convection) and diffusion, and (3) the assessment of mineral-solution equilibria, Pore waters are, therefore,preferred diagnostic objects in the study of diagenesis, particularly early diagenesis. The single most important factor for pore-fluid evolution in modern offshore basins is sedimentationrate which is closely correlated with organtic matter content of the sediment. Organic matter represents themost reactive sediment constituent which, through bacterial decomposition, provides some of the mainsolutes involved in early diagenetic mineralization reactions. On the basis of sedimentation rate and organicmatter content, it is convenient to distinguish two end-members of basins (environments) with respect toearly diagenesis: Ⅰ. Low to in termediate-sedimentation rate basins with convection or diffusion-controlledpore-water profiles and Ⅱ. high-sedimentation rate basins with reaction-controlled pore-water profiles. The first group of basins or environments, which is the subject of this paper, is typically represented bypelagic sediments. Three principally different trends of pore-water evolution occur: 1. convection-controlledprofiles with no pronounced vertical gradients for the dissolved species; 2. diffusion-controlled profiles withvertical gradients but linear correlations between major ions, especially Ca and Mg, and 3. profiles withgradients but no linear correlation between the major ions. The later are transitional to the trends seen inhigh-sedimentation rate basins. With respect to redox-potentials, the diagenetic environments of low-sedimentation rate basins are generally oxic to suboxic.

关键词： Hydrochemistry,Origin and Evolution of Sedimentary Sub surface Fluids water evolution in low-sedimentation rate offshore basins rate

Hydrochemistry, Origin and Evolution of Sedimentary Subsurface Fluids:——Ⅱ. Early diagenetic pore-water evolution in high sedimentation-rate offshore basins

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Acta Geochimica 1987年第1期6卷 1-18页

作者： REINHARD hesse Department of Geological Sciences McGill University Montreal Quebec H3A 2A7 Canada

High sedimentation-rate basins are characteristic of the continental margins, where sedimentation ratesup to 500m/Ma and more are no exception. The sediments are rich in organic matter and undergo awell-established sequence of bacterial oxidation reactions, starting at the sediment/water interface with:（1）the oxidation zone （absent in euxinic basins）, which is followed downwards by （2） the nitrate reduction zone,（3） the sulfate reduction zone, （4） the carbonate reduction zone, （5） the fermentation zone and （6） thedecarboxylation zone, which marks the onset of thermocatalytic reactions characteristic of the intermediatestage （and deeper stages） of diagenesis. This sequence of bacterially mediated organic-matter decomposition reactions in rapidly depositedsediments on the continental margins is well reflected in the vertical trends of pore-water chemistry. Carbonisotopic fractionation permits to distinguish between zones （1） to （3） with negative δ;C values for the CO;generated, and between zones （4） and （5） with increasingly heavier carbon-isotopes in CO;(up to + 15 to+ 25‰δ;C). The formation of gas-hydrates causes characteristic chemical and isotopic signatures in porewaters retrieved from hydrate-beating sediments. After hydrate decomposition （in the sampling process orat the base of hydrate zones） marked chlorimity decreases accompanied by increases in heavy oxygenisotopes are observed. These are distinctly different from the effects of meteoric water influx, which are notaccompanied by positive δ;O values. The opposite trend of increasing salinity at shallow burial depths,rather than pore-waters freshening, is observed in the vicinity of evaporites.

关键词： Origin and Evolution of Sedimentary Subsurface Fluids Early diagenetic pore-water evolution in high sedimentation-rate offshore basins Hydrochemistry rate high

Analysis on variety and characteristics of maghemite

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China Earth Sciences 2010年第8期53卷 1153-1162页

作者： SHAW John BLOEMENDAL Jan hesse Paul ROLPH Tim Department of Earth Sciences University of Liverpool Department of Geography University of Liverpool Department of Environment and Geography Macquarie University Department of Geology University of Newcastle

Maghemite (γ-Fe2O3) is a very common mineral at the earth’s surface and also an important material for making music and video tapes. Maghemite is usually synthesized from magnetite under oxidizing conditions after a few hours or a few days below a temperature of 300°C. The magnetic property of thermal instability and the chemical action after heating is an important character for maghemite. That is, it will become hematite in certain proportion after being heated above 250°C. Maghemite is therefore actually unable to have its Curie temperature measured. But late using synthetic sample, maghemite was further found partially thermal stable with a measurable Curie temperature ~645°C. During our thermally magnetic experiments for a set of synthetic magnetite, we found that extra fined grain size (pseudo single domain (PSD) and small multi-domain (MD), mainly 1-10 μm) magnetite was formed to a completely thermally stable maghemite. This maghemite can also be produced by heating the same powder up to 700°C in an oven and keeping this temperature for 10 min, then cooling it down. When the generated maghemite by these two ways is heated from room temperature to 700°C, it shows almost fully reversible, or thermally stable. We used X-ray powder diffraction and Mssbauer spectroscopy to confirm the identity of this maghemite and compared its magnetic hysteresis, high temperature magnetization, low temperature thermal demagnetization, and low temperature susceptibility with those of the original preheated magnetite. Such quickly oxidized maghemite by heating to high temperature implies some types of maghemite formed in certain natural condition can carry a thermal remnant magnetization (TRM). Four types of maghemite were characterized and discussed according to their thermal stability. Among them, partially stable and fully thermally stable maghemite after heating should possess capability of carrying TRM. There is possibly a compensation of synthetizing maghemite between heatin

关键词： maghemite paleomagnetism environmental magnetism magnetic mineral thermal stability TRM

维普期刊数据库

Controlling the electro-optic response of a semiconducting perovskite coupled to a phonon-resonant cavity

在线全文

学校读者我要写书评

暂无评论

Light(Science & Applications) 2023年第9期12卷 1749-1756页

作者： Lucia Di Virgilio Jaco J.Geuchies Heejae Kim Keno Krewer Hai Wang Maksim Grechko mischa Bonn Max Planck Institute for Polymer Research Ackermannweg 1055128 MainzGermany Pohang University of Science and Technology Department of Physics37673 PohangKorea

Optical cavities,resonant with vibrational or electronic transitions of material within the cavity,enable control of light-matter *** studies have reported cavity-induced modifications of chemical reactivity,fluorescence,phase behavior,and charge ***,we explore the effect of resonant cavity-phonon coupling on the transient photoconductivity in a hybrid organic-inorganic *** this end,we measure the ultrafast photoconductivity response of perovskite in a tunable Fabry–Pérot terahertz cavity,designed to be transparent for optical *** terahertz-cavity field-phonon interaction causes apparent Rabi splitting between the perovskite phonon mode and the cavity *** explore whether the cavity-phonon interaction affects the material’s electron-phonon interaction by determining the charge-carrier mobility through *** the apparent hybridization of cavity and phonon modes,we show that the perovskite properties in both ground(phonon response)and excited(photoconductive response)states remain unaffected by the tunable light-matter *** the response of the integral perovskite-terahertz optical cavity system depends critically on the interaction strength of the cavity with the phonon:the transient terahertz response to optical excitation can be increased up to threefold by tuning the cavity-perovskite interaction *** results enable tunable switches and frequency-controlled induced transparency devices.

关键词： tunable cavity tuning

Does Aristotelian Magnanimity Exclude Women？

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Philosophy Study 2012年第7期2卷 463-474页

作者： mischa Beckett Simmons College

This article studies whether Aristotle＇s understanding of magnanimity excludes women. I examine Aristotle＇s concept of the biological, moral, and intellectual capacities of women in theory and practice. Although Aristotle＇s biology describes key differences between the sexes, it does not exclude women from magnanimity. While the ethical and political writings also note key differences between men and women, they leave the theoretical possibility of attaining magnanimity open. Practically, the lack of leadership opportunities available to actual women may hinder the development of prudence, leading to an inability to achieve complete virtue and hence magnanimity. Thus, if women are unable to be magnanimous, this is due to practical political and familial arrangements, not to innate feminine defects. This finding provides a unique argument for feminine leadership and political participation. Truly exceptional women may need to actively seek out leadership opportunities and political involvement in order to complete their virtue

关键词： Aristotle Nicomachean Ethics Politics women virtue magnanimity

Modeling Magma Dynamics with a Mixed Fourier Collocation-Discontinuous Galerkin Method

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications in Computational Physics 2011年第7期10卷 433-452页

作者： Alan R.Schiemenz Marc A.hesse Jan S.Hesthaven Department of Geological Sciences Brown UniversityProvidenceRI 02910USA Division of Applied Mathematics Brown UniversityProvidenceRI 02910USA Department of Geological Sciences University of Texas at AustinAustinTX 78712USA Department of Earth and Environmental Sciences GeophysicsMunich UniversityTheresienstr.4180333 MunichGermany

A high-order discretization consisting of a tensor product of the Fourier collocation and discontinuous Galerkin methods is presented for numerical modeling of magma *** physical model is an advection-reaction type system consisting of two hyperbolic equations and one elliptic *** high-order solution basis allows for accurate and efficient representation of compaction-dissolution waves that are predicted from linear *** discontinuous Galerkin method provides a robust and efficient solution to the eigenvalue problem formed by linear stability analysis of the physical *** insights into the processes of melt generation and segregation,such as melt channel bifurcation,are revealed from two-dimensional time-dependent simulations.

关键词： Magma dynamics discontinuous Galerkin method Fourier collocation method numerical simulations linear stability analysis

Synchrotron microtomography reveals insights into the degradation kinetics of bio-degradable coronary magnesium scaffolds

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Bioactive Materials 2024年第2期32卷 1-11页

作者： Roman Menze Bernhard hesse Maciej Kusmierczuk Duote Chen Timm Weitkamp Stephanie Bettink Bruno Scheller MeKo Manufacturing e.K. Im Kirchenfelde 12-1431157SarstedtGermany Xploraytion GmbH Bismarckstr.10-1210625BerlinGermany Synchrotron SOLEIL L’Orme des MerisiersDépartementale 12891190Saint-AubinFrance InnoRa GmbH Robert-Koch-Platz 410115BerlinGermany Universität des Saarlandes Campus Homburg66421HomburgGermany

Bioresorbable magnesium scaffolds are a promising future treatment option for coronary artery stenosis,especially for young *** to the degradation of these scaffolds(<1 year),long-term device-related clinical events could be reduced compared to treatments with conventional drug eluting *** clinical trials indicate a return of vasomotion after one year,which may be associated with improved long-term clinical ***,even after decades of development,the degradation process,ideal degradation time and biological response in vivo are still not fully *** present study investigates the in vivo degradation of magnesium scaffolds in the coronary arteries of pigs influenced by different strut thicknesses and the presence of antiproliferative *** to high 3D image contrast of synchrotron-based micro-CT with phase contrast(SR-μCT),a qualitative and quantitative evaluation of the degradation morphology of magnesium scaffolds was *** the segmentation of theμCT images a convolutional network architecture(U-net)was exploited,demonstrating the huge potential of merging high resolution SR-μCT with deep learning(DL)supported data *** total,30 scaffolds,made of the rare earth alloy Resoloy^(®),with different strut designs were implanted into the coronary arteries of 10 domestic pigs for 28 days using drug-coated or uncoated angioplasty balloons for *** degradation morphology was analyzed using scanning electron microscopy,energy dispersive x-ray spectroscopy and SR-μ*** data from these methods were then related to data from angiography,optical coherence tomography and histology.A thinner strut size(95 vs.130μm)and the presence of paclitaxel indicated a slower degradation rate at 28 d in vivo,which positively influences the late lumen loss(0.5 and 0.6 mm vs.1.0 and 1.1 mm)and recoil values(0 and 1.7%vs.6.1 and 22%).

关键词： Resoloy Magnesium scaffold DCB Paclitaxel Degradation Inflammation Artificial intelligence

Tuning Ice Nucleation by Mussel-Adhesive Inspired Polyelectrolytes:The Role of Hydrogen Bonding

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

CCS Chemistry 2022年第9期4卷 2980-2990页

作者： Jing Chen Yongkang Wang Benjamin Leibauer Takakazu Seki Konrad Meister Yuki Nagata mischa Bonn Department of Chemistry School of ScienceTianjin University of Science&TechnologyTianjin 300457 Max Planck Institute for Polymer Research Mainz 55128 School of Mechanical Engineering Southeast UniversityNanjing 211189 School of Arts&Sciences University of Alaska SoutheastJuneauAlaska 99801

Heterogeneous ice nucleation(HIN)on foreign surfaces plays a crucial role across a wide range of environmental and biological processes,and control of HIN is highly *** surfaces to control HIN poses interesting scientific challenges and holds great potential for technological ***,we combine the ice nucleation tuning capability of polyelectrolytes withmussel-inspired adhesives to obtain robust surface functionalization with HIN control.

关键词： ice nucleation polyelectrolyte catechol sum-frequency generation hydrogen bonding