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21.
An alternating direction scheme on a nonuniform mesh for reaction-diffusion parabolic problems 总被引:1,自引:0,他引:1
Clavero C; Jorge JC; Lisbona F; Shishkin={paragraph} GI 《IMA Journal of Numerical Analysis》2000,20(2):263-280
In this paper we develop a numerical method for two-dimensionaltime-dependent reaction-diffusion problems. This method, whichcan immediately be generalized to higher dimensions, is shownto be uniformly convergent with respect to the diffusion problems.This method, which can immediately be generalized to higherdimensions, is shown to be uniformly convergent with respectto the diffusion parameter. 相似文献
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OK Yoon WG Hwang JC Choe MS Kim 《Rapid communications in mass spectrometry : RCM》1999,13(14):1515-1521
A technique to investigate photodissociation kinetics on a nanosecond time scale has been devised for molecular ions generated by multiphoton ionization (MPI) using mass-analyzed ion kinetic energy spectrometry. The branching ratio or rate constant has been determined for the photodissociation of the n-butylbenzene, bromobenzene, iodobenzene, and aniline molecular ions generated by MPI at 266 nm. The ion internal energies have been estimated by comparing the measured kinetic data with the previous energy dependence data. The analysis has shown that only those molecular ions generated by two-photon ionization contribute to the photodissociation signals. Around half of the available energy has been found to remain as molecular ion internal energy in the two-photon ionization process. Copyright 1999 John Wiley & Sons, Ltd. 相似文献
26.
Jason T Miller John H Bartley Hereward JC Wimborne Aisha L Walker David C Hess William D Hill James E Carroll 《BMC neuroscience》2005,6(1):63
Background
Stromal cell-derived factor 1 (SDF-1 or CXCL12) is chemotaxic for CXCR4 expressing bone marrow-derived cells. It functions in brain embryonic development and in response to ischemic injury in helping guide neuroblast migration and vasculogenesis. In experimental adult stroke models SDF-1 is expressed perivascularly in the injured region up to 30 days after the injury, suggesting it could be a therapeutic target for tissue repair strategies. We hypothesized that SDF-1 would be expressed in similar temporal and spatial patterns following hypoxic-ischemic (HI) injury in neonatal brain. 相似文献27.
Wolfram Vogelsberger Jochen Schmidt Frank Roelofs 《Colloids and surfaces. A, Physicochemical and engineering aspects》2008,324(1-3):51-57
The solubility of nanoparticles was measured in aqueous solution as a function of time, and oxides of aluminium, silicon, titanium, and zirconium were investigated. Our solubility results show a maximum at the beginning of the dissolution process, whereas over time, the solubility levels are shown to decrease. Depending on the special conditions the solubility maximum may exceed the long-time solubility of the nanoparticles by several orders of magnitude. This behaviour is called as kinetic size effect. The extent of the effect depends on the size, surface tension and mass of the particles exposed to dissolution. It will always be of practical interest if a larger quantity of nanoparticles is brought into contact with a solvent, even when the equilibrium solubility data appears negligible. A rigorous thermodynamic and kinetic analysis of a colloidal system, which includes nucleation, particle growth, Ostwald ripening, and dissolution of particles, shows at least a qualitative agreement between all the experimental results and model calculations. 相似文献
28.
Ferroelectric switching and electrochemistry of pyrrole substituted trialkylbenzene‐1,3,5‐tricarboxamides
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Xiao Meng Andrey V. Gorbunov W. S. Christian Roelofs Stefan C. J. Meskers René A. J. Janssen Martijn Kemerink Rint P. Sijbesma 《Journal of Polymer Science.Polymer Physics》2017,55(8):673-683
We explore a new approach to organic ferroelectric diodes using a benzene‐tricarboxamide (BTA) core connected with C10 alkyl chains to pyrrole groups, which can be polymerized to provide a semiconducting ferroelectric material. The compound possesses a columnar hexagonal liquid crystalline (LC) phase and exhibits ferroelectric switching. At low switching frequencies, an additional process occurs, which leads to a high hysteretic charge density of up to ~1000 mC/m2. Based on its slow rate, the formation of gas bubbles, and the emergence of characteristic polypyrrole absorption bands in the UV–Vis–NIR, the additional process is identified as the oxidative polymerization of pyrrole groups, enabled by the presence of amide groups. Polymerization of the pyrrole groups, which is essential to obtain semiconductivity, is limited to thin layers at the electrodes, amounting to ~17 nm after cycling for 21 h. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017 , 55, 673–683 相似文献
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Mia A. Levy John B. Freymann Justin S. Kirby Andriy Fedorov Fiona M. Fennessy Steven A. Eschrich Anders E. Berglund David A. Fenstermacher Yongqiang Tan Xiaotao Guo Thomas L. Casavant Bartley J. Brown Terry A. Braun Andre Dekker Erik Roelofs James M. Mountz Fernando Boada Charles Laymon Matt Oborski Daniel L. Rubin 《Magnetic resonance imaging》2012
Introduction
The National Cancer Institute Quantitative Research Network (QIN) is a collaborative research network whose goal is to share data, algorithms and research tools to accelerate quantitative imaging research. A challenge is the variability in tools and analysis platforms used in quantitative imaging. Our goal was to understand the extent of this variation and to develop an approach to enable sharing data and to promote reuse of quantitative imaging data in the community.Methods
We performed a survey of the current tools in use by the QIN member sites for representation and storage of their QIN research data including images, image meta-data and clinical data. We identified existing systems and standards for data sharing and their gaps for the QIN use case. We then proposed a system architecture to enable data sharing and collaborative experimentation within the QIN.Results
There are a variety of tools currently used by each QIN institution. We developed a general information system architecture to support the QIN goals. We also describe the remaining architecture gaps we are developing to enable members to share research images and image meta-data across the network.Conclusions
As a research network, the QIN will stimulate quantitative imaging research by pooling data, algorithms and research tools. However, there are gaps in current functional requirements that will need to be met by future informatics development. Special attention must be given to the technical requirements needed to translate these methods into the clinical research workflow to enable validation and qualification of these novel imaging biomarkers. 相似文献30.
α-Haloketones and -dibromides are converted to the corresponding ketones and alkenes respectively with nickel boride generated from sodium borohydride and nickel chloride. 相似文献