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An Approximate Riemann Solver for Advection-Diffusion Based on the Generalized Riemann Problem

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Communications on Applied Mathematics and Computation 2020年第3期2卷 515-539页

作者： Steven Jöns Claus-dieter Munz Institute of Aerodynamics and Gas Dynamics University of StuttgartPfafenwaldring 2170569 StuttgartGermany

We construct an approximate Riemann solver for scalar advection-diffusion equations with piecewise polynomial initial *** objective is to handle advection and diffusion simultaneously to reduce the inherent numerical diffusion produced by the usual advection flux *** approximate solution is based on the weak formulation of the Riemann problem and is solved within a space-time discontinuous Galerkin approach with two *** novel generalized Riemann solver produces piecewise polynomial solutions of the Riemann *** conjunction with a recovery polynomial,the Riemann solver is then applied to define the numerical flux within a finite volume *** results for a piecewise linear and a piecewise parabolic approximation are *** results indicate a reduction in numerical dissipation compared with the conventional separated flux calculation of advection and ***,it is shown that using the proposed solver only in the vicinity of discontinuities gives way to an accurate and efficient finite volume scheme.

关键词： Generalized Riemann problem Advection-diffusion Discontinuous Galerkin Numerical flux ADER Diffusive generalized Riemann problem Space-time solution Recovery method

Tuning thermal release kinetics of soy oil from organic nanoparticles using variable synthesis conditions

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Particuology 2016年第3期14卷 54-65页

作者： Pieter Samyn dieter Van Nieuwkerke Vibhore Rastogi Dirk Stanssens University of Freiburg Freiburg Research Institute for Advances Studies (FRIAS) Faculty for Environment and Natural Resources Chair of Bio-based Materials Engineering Werthmannstrasse 6 D-79085 Freiburg Germany Ghent University Department of Textiles Technologiepark 907 B-9052 Zwijnaarde Belgium Topehim N.K Nijverheidsstraat 98 B-2160 Wommelgem Belgium

The thermal release properties of soy oil from poly（styrene-co-maleimide） nanoparticles containing 50 wt% encapsulated oil have been quantified as a function of temperature and time. The effects of dif- ferent synthesis conditions on the thermal stability of the nanoparticles and their oil release have been evaluated, i.e., by gradually increasing the amount of ammonium hydroxide used for the imidization of poly（styrene-co-maleic anhydride）. First, the intrinsic thermal properties of the oil-filled nanoparti- cles were analysed by differential scanning calorimetry, which revealed an exothermal reaction related to the oil release and a suppression of the glass transition that may be masked owing to the complex structure of the hybrid nanoparticles. The isothermal scans showed different rates of oil release after a post-imidization reaction. The oil release was better followed by dynamic mechanical analysis, which illustrated changes in visco-elastic properties expressed by the maximum in the loss factor that related to the amount of released oil. Depending on the amount of ammonium hydroxide, the oil started to release below the glass transition temperature at various rates. Thermal release profiles of the oil we re quantified by infrared and Raman spectrocopy after heating for 2 min to 6 h at 125 to 250 ℃, based on variations in oil-related and imide-related absorption bands. The oil release increased below and above the glass transition temperature, following a parabolic trend, and progressively decreased at higher ammonium hydroxide concentrations, in parallel with higher imide content and changes in imide conformation. The kinetics and mechanism of the oil release can be described by the Korsmeyer-Peppas model, suggesting a dominating diffusion mechanism that is influenced by further imidization of the polymer matrix during heating.

关键词： Soy oil Nanoparticle Encapsulation Release

eIF-Three to Tango: emerging functions of translation initiation factor eIF3 in protein synthesis and disease

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Journal of Molecular Cell Biology 2020年第6期12卷 403-409页

作者： dieter AWolf Yingying Lin Haoran Duan Yabin Cheng School of Pharmaceutical Sciences Fujian Provincial Key Laboratory of Innovative Drug Target Research&Innovation Center for Cell Stress SignalingXiamen UniversityXiamen 361102China

Studies over the past three years have substantially expanded the involvements of eukaryotic initiation factor 3 (eIF3) in messenger RNA (mRNA) translation. It now appears that this multi-subunit complex is involved in every possible form of mRNA translation, controlling every step of protein synthesis from initiation to elongation, termination, and quality control in positive as well as negative fashion. Through the study of eIF3, we are beginning to appreciate protein synthesis as a highly integrated process coordinating protein production with protein folding, subcellular targeting, and degradation. At the same time, eIF3 subunits appear to have specific functions that probably vary between different tissues and individual cells. Considering the broad functions of eIF3 in protein homeostasis, it comes as little surprise that eIF3 is increasingly implicated in major human diseases and first attempts at therapeutically targeting eIF3 have been undertaken. Much remains to be learned, however, about subunit- and tissue-specific functions of eIF3 in protein synthesis and disease and their regulation by environmental conditions and post-translational modifications.

关键词： mRNA translation translation initiation factor eIF3 protein homeostasis cancer

Paving small matrices and the Kadison-Singer Extension Problem Ⅱ—computational results

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Science China Mathematics 2011年第11期54卷 2463-2472页

作者： SCHMIDT dieter WEISS Gary ZARIKIAN Vrej Department of Mathematics University of Cincinnati Cincinnati OH 45221 USA Department of Mathematics United States Naval Academy Annapolis MD 21402 USA

This article is part exposition of a recent rather technical paper of the last two authors on matrix pavings related to the 1959 Kadison-Singer Extension Problem and part a report on further computational results providing new bounds on the paving parameters for classes of small matrices investigated there and subsequently. A website maintained by the authors provides to all interested the matrices experimentally discovered that yield these bounds along with the proprietary MATLAB software with simple operational directions to load them, pave them, and perform paving searches. The convergence to 1 or not of the infinite sequences of these paving parameters in most cases is equivalent to the Kadison-Singer Extension Problem, and in all cases convergence to 1 negates the problem. The last two sections describe the search process and an interpretation of the data integrated with the results of the precursor to this paper.

关键词： Kadison-Singer Extension Problem Anderson's Paving Problem

The antiproton annihilation detector system of the ATRAP experiment

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Chinese Science Bulletin 2009年第2期54卷 189-195页

作者： OELERT Walter GRZONKA dieter SEFZICK Thomas Institute of Nuclear Physics Forschungszentrum Jülich D-52425 Jülich Germany

The ATRAP (antihydrogen trap collaboration) at CERN (European organization for nuclear research) has developed a completely new, larger and more robust apparatus in the second experimental zone. The antiproton annihilation detector system consists of 10 layers of scintillating fibers, counts the antihydrogen atoms and determines the annihilation vertex of the atoms. This diagnostic element will allow to optimize the production of cold antihydrogen sufficiently to permit the optical observations and measurements. Using this new apparatus thousands of antihydrogen atoms have been produced within a combined Penning-Ioffe trap. These observed antihydrogen atoms resolve a debate about whether positrons and antiprotons can be brought together to form antihydrogen atoms within the divergent magnetic fields of a quadrupole Ioffe trap.

关键词：反氢原子光纤探测器能量分辨位置分辨粒子 ATRAP

Parameter Survey of Thermally Highly Loaded,Porous and Cooled Multi-Layer Systems for Turbine Blades

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Journal of Thermal Science 2007年第2期16卷 181-185页

作者： Peng Shan dieter Bohn Jing Ren N.Surken Department of Jet Propulsion Beijing University of Aeronautics & AstronauticsBeijing 100083China Institute of Steam and Gas Turbines RWTH Aachen52056 AachenGermany

This study is an advanced investigation for the cooling of high temperature turbine vanes and blades. The efficient heat exchanging near the surface of a blade may be achieved by forcing a cooling air flow emitting out of a thin layer of the porous metal which is pasted on the structural high strength metal. The contents include the consideration on the computational model of heat transfer through a layer of porous material, the concrete modeling and the analysis of the model, the numerical survey of key parameters for both the two-layer porous materials and the heat transfer fluid flow passing through the model channels. The results revealed that the constructed system is reasonable. Proposed an evaluation formula for the porous material heat transfer efficiency.

关键词： heat transfer thermally highly loaded porous multi-layer

Coupled solid-fluid FE-analysis of an embankment dam

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Frontiers of Structural and Civil Engineering 2011年第1期5卷 53-62页

作者： Michael PERTL Matthias hofmann Guenter HOFSTETTER Insitute of Basic Sciences in Civil Engineering University of InnsbruckInnsbruck A-6020Austria

A coupled solid-fluid FE-model for partially saturated soils,characterized by modeling the soil as a three-phase material consisting of a deformable soil skeleton and the fluid phases water and air,is reviewed *** a constitutive model for the soil skeleton,the well-known Barcelona Basic model(BBM)is employed,which is formulated in terms of net stress and matric *** the BBM,a computationally efficient return mapping algorithm is proposed,which only requires the solution of a scalar nonlinear equation at the integration point *** coupled FE-model is applied to the coupled transient numerical simulation of the water flow and the deformations and stresses in an embankment dam.

关键词： multi-phase model unsaturated soil model Barcelona Basic model(BBM) return mapping algorithm embankment dam

Experimental study on the tribo-chemical smoothening process between self-mated silicon carbide in a water-lubricated surfacecontact reciprocating test

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Friction 2019年第2期7卷 181-191页

作者： Le JIN Herbert SCHEERER Georg ANDERSOHN Matthias OECHSNER dieter HELLMANN Center for Structural Materials Technische Universit?t Darmstadt KSB

Silicon carbide(SiC) can be tribo-chemically smoothened during a self-mated sliding procedure in the aqueous environment. As well reported in the point-contact tests, this smoothening process works well due to the abundant water as oxidant. After this smoothening process, the tribo-surface is well polished, a closely mated tribo-gap naturally forms, and an ultra-low friction state is built. However, water in the tribo-gap could be insufficient in industrial applications, e.g., the seal gap in mechanical seals. In this study, the tribo-chemical smoothening behavior in such environment was researched. A surface-contact reciprocating test was used to simulate the aqueous environment where water was insufficient. After tests, compared to the published results from the point-contact tests, the same ultra-low friction state was achieved. A part of the tribo-surface was tribo-chemically smoothened. The obtained smoothened surface microstructure was consistent with the published information. Meanwhile, severe abrasive wear occurred. A porous oxygen-rich layer was found existing beneath the abrasion-induced grooves, in which numerous smashed wear debris adhered on the worn surfaces. We concluded that the shortage of water initiated the severe abrasion, meanwhile the generated wear debris aggravated the wear condition. This understanding is instructive for developing new methods to avoid the severe abrasion in the same water insufficient environment.

关键词： silicon carbide surface-contact sliding friction tribo-chemical smoothening abrasion ultra-low friction mechanical seal

Vitamin C and Vitamin D—friends or foes in modulating γδ T-cell differentiation?

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Cellular & Molecular Immunology 2022年第10期19卷 1198-1200页

作者： Christian Peters Katharina Klein dieter Kabelitz Institute of Immunology Christian-Albrechts UniversityKielGermany

The differentiation and functional plasticity of T cells are transcriptionally and epigenetically regulated by signals imposed by the local cytokine milieu and a variety of additional factors,including *** C has pleiotropic functions in the immune *** exerts antioxidant activity,can directly kill selected tumor targets,promotes early T-cell differentiation,and enhances Th1 cytokine production in mature T cells[1,2].

关键词： vitamin cytokine Vitamin