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21.
Udo Ziegler 《Computer Physics Communications》2004,157(3):207-216
I describe a Poisson solver for the adaptive mesh magnetohydrodynamics (MHD) code NIRVANA using ADI techniques (ADI: Alternative Direction Implicit). The solver is fit to the mesh refinement framework of the code and utilizes its special block-structured design. The key part of the method is an algorithm for the intelligent clustering of subgrids which permits the application of numerical methods based on dimensional operator splitting like ADI. Test problems show the convergence of this ansatz. 相似文献
22.
C Daumas-Duport ML Tucker H Kolles P Cervera F Beuvon P Varlet N Udo M Koziak JP Chodkiewicz 《Canadian Metallurgical Quarterly》1997,34(1):61-78
Myocardial perfusion scintigraphy is a noninvasive diagnostic method for the evaluation of patients with suspected or proven coronary artery disease (CAD). We utilized case-based reasoning (CBR) methods to develop the computer-based image interpretation system SCINA which automatically derives from a scintigraphic image data set an assessment concerning the presence of CAD. We compiled a case library of 100 patients who underwent both perfusion scintigraphy and coronary angiography to document or exclude the presence of CAD. The angiographic diagnosis of the retrieved nearest neighbor match of a scintigraphic input case was selected as the CBR diagnosis. We examined the effects of input data granularity, case indexing, similarity metric, and adaptation on the diagnostic accuracy of the CBR application SCINA. For the final prototype, sensitivity and specificity for detection of coronary heart disease were 98% and 70% suggesting that CBR systems may achieve a diagnostic accuracy that appears feasible for clinical use. 相似文献
23.
Scott R Boss Laurie J Kirsch Ingo Angermeier Raymond A Shingler R Wayne Boss 《欧洲信息系统杂志》2009,18(2):151-164
Information security has become increasingly important to organizations. Despite the prevalence of technical security measures, individual employees remain the key link – and frequently the weakest link – in corporate defenses. When individuals choose to disregard security policies and procedures, the organization is at risk. How, then, can organizations motivate their employees to follow security guidelines? Using an organizational control lens, we build a model to explain individual information security precaution-taking behavior. Specific hypotheses are developed and tested using a field survey. We examine elements of control and introduce the concept of ‘mandatoriness,’ which we define as the degree to which individuals perceive that compliance with existing security policies and procedures is compulsory or expected by organizational management. We find that the acts of specifying policies and evaluating behaviors are effective in convincing individuals that security policies are mandatory. The perception of mandatoriness is effective in motivating individuals to take security precautions, thus if individuals believe that management watches, they will comply. 相似文献
24.
Erkan Aydin Michele De Bastiani Xinbo Yang Muhammad Sajjad Faisal Aljamaan Yury Smirnov Mohamed Nejib Hedhili Wenzhu Liu Thomas G. Allen Lujia Xu Emmanuel Van Kerschaver Monica Morales‐Masis Udo Schwingenschlgl Stefaan De Wolf 《Advanced functional materials》2019,29(25)
Parasitic absorption in transparent electrodes is one of the main roadblocks to enabling power conversion efficiencies (PCEs) for perovskite‐based tandem solar cells beyond 30%. To reduce such losses and maximize light coupling, the broadband transparency of such electrodes should be improved, especially at the front of the device. Here, the excellent properties of Zr‐doped indium oxide (IZRO) transparent electrodes for such applications, with improved near‐infrared (NIR) response, compared to conventional tin‐doped indium oxide (ITO) electrodes, are shown. Optimized IZRO films feature a very high electron mobility (up to ≈77 cm2 V?1 s?1), enabling highly infrared transparent films with a very low sheet resistance (≈18 Ω □?1 for annealed 100 nm films). For devices, this translates in a parasitic absorption of only ≈5% for IZRO within the solar spectrum (250–2500 nm range), to be compared with ≈10% for commercial ITO. Fundamentally, it is found that the high conductivity of annealed IZRO films is directly linked to promoted crystallinity of the indium oxide (In2O3) films due to Zr‐doping. Overall, on a four‐terminal perovskite/silicon tandem device level, an absolute 3.5 mA cm?2 short‐circuit current improvement in silicon bottom cells is obtained by replacing commercial ITO electrodes with IZRO, resulting in improving the PCE from 23.3% to 26.2%. 相似文献
25.
Manuel Lasch Kritika Sudan Corinna Paul Christian Schulz Thomas Kolben Julia van Dorp Sibel Eren Susanne Beyer Lorenzo Siniscalchi Sven Mahner Udo Jeschke Sarah Meister 《International journal of molecular sciences》2022,23(11)
(1) Background: Placental immune cells are playing a very important role in a successful placentation and the prevention of pregnancy complications. Macrophages dominate in number and relevance in the maternal and the fetal part of the placenta. The evidence on the polarization state of fetal and maternal macrophages involved in both, healthy and pregnancy-associated diseases, is limited. There is no representative isolation method for the direct comparison of maternal and fetal macrophages so far. (2) Material and Methods: For the isolation of decidual macrophages and Hofbauer cells from term placenta, fresh tissue was mechanically dissected and digested with trypsin and collagenase A. Afterwards cell enrichment was increased by a Percoll gradient. CD68 is represented as pan-macrophage marker, the surface markers CD80 and CD163 were further investigated. (3) Results: The established method revealed a high cell yield and purity of the isolated macrophages and enabled the comparison between decidual macrophages and Hofbauer cells. No significant difference was observed in the percentage of single CD163+ cells in the distinct macrophage populations, by using FACS and immunofluorescence staining. A slight increase of CD80+ cells could be found in the decidual macrophages. Considering the percentage of CD80+CD163− and CD80−CD163+ cells we could not find differences. Interestingly we found an increased number of double positive cells (CD80+CD163+) in the decidual macrophage population in comparison to Hofbauer cells. (4) Conclusion: In this study we demonstrate that our established isolation method enables the investigation of decidual macrophages and Hofbauer cells in the placenta. It represents a promising method for direct cell comparison, enzyme independently, and unaffected by magnetic beads, to understand the functional subsets of placental macrophages and to identify therapeutic targets of pregnancy associated diseases. 相似文献
26.
Laura Unverdorben Thomas Haufe Laura Santoso Simone Hofmann Udo Jeschke Stefan Hutter 《International journal of molecular sciences》2016,17(5)
Galectins are galactose binding proteins and, in addition, factors for a wide range of pathologies in pregnancy. We have analyzed the expression of prototype (gal-1, -2, -7, -10) and chimera-type (gal-3) galectins in the placenta in cases of spontaneous abortions (SPA) and recurrent abortions (RA) in the first trimester. Fifteen placental samples from healthy pregnancies were used as a control group. Nine placentas were examined for spontaneous abortions, and 12 placentas for recurrent abortions. For differentiation and evaluation of different cell types of galectin-expression in the decidua, immunofluorescence was used. For all investigated prototype galectins (gal-1, -2, -7, -10) in SPA and RA placenta trophoblast cells the expression is significantly decreased. In the decidua/extravillous trophoblast only gal-2 expression was significantly lowered, which could be connected to its role in angiogenesis. In trophoblasts in first-trimester placentas and in cases of SPA and RA, prototype galectins are altered in the same way. We suspect prototype galectins have a similar function in placental tissue because of their common biochemical structure. Expression of galectin 3 as a chimera type galectin was not found to be significantly altered in abortive placentas. 相似文献
27.
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29.
Florian Meierhofer Lutz Mädler Udo Fritsching 《American Institute of Chemical Engineers》2020,66(2):e16885
In flame spray pyrolysis (FSP), the evolution of metal oxide nanoparticles relies on quite a number of droplet (liquid) and vapor phase related physical mechanism as for instance precursor evaporation, oxidation, nucleation via gas-to-particle conversion mechanism, and subsequent particle (solid) growth mechanisms based on coagulation, sintering/coalescence, and agglomeration. The liquid precursor and dispersion oxygen feed rates are relevant control parameters of the FSP process for tailoring the nanoparticle size (diameter) and structure as well as the atomizer nozzle configuration. Sophisticated nonintrusive, laser-based in situ and ex situ diagnostics with multiscale spatial resolution (micrometer to meter range) are applied for analyzing droplet formation and size, gas velocity, temperature, species concentration, as well as primary and agglomerate diameters along the flow direction. Computational fluid dynamics (CFD) are coupled with population balance modeling (PBM) to elucidate the nanoparticle dynamics within the reactive spray. It is found that the CFD-PBM approach allows estimations of primary and agglomerate nanoparticle diameters within 80 and 75% accuracy compared to experimental data, suggesting that the methods presented could pave the way for designing next-generations of flame reactors. 相似文献
30.
F. Tiarks T. Frechen S. Kirsch J. Leuninger M. Melan A. Pfau F. Richter B. Schuler C. -L. Zhao 《Progress in Organic Coatings》2003,48(2-4):140-152
Modern water-borne paints are widely used in different areas of applications ranging from high-gloss lacquers to flat, scrub-resistant interior paints. From this point of view, the pigment volume concentration (PVC) is one key-parameter adjusting the desired application properties. In high-gloss paints, for example, a low PVC is required to accommodate the proper surface roughness to achieve a high gloss. Consequently, a high concentration of TiO2 is needed to obtain a good hiding power at the same time. Flat paints nonetheless are highly filled due to cost reasons preferentially by CaCO3 and the pigment binding capacity of the binder is crucial. In this work, paint formulations differing in PVC, and the type of binder or dispersing agent were investigated by various techniques concerning the distribution and aggregation of pigment particles, e.g. TiO2. To get a detailed insight into the structure of the liquid paints and the corresponding dried paint films, suitable analytical tools were applied for characterization. The structure of the liquid paints was analyzed by remission light spectroscopy (RLS), disc centrifugation, cryogenic-replication transmission electron microscopy (Cryo-replica TEM) and cryogenic-scanning electron microscopy (Cryo-SEM). The pigment distribution in the corresponding dried paint films was examined by means of atomic force microscopy (AFM), TEM and RLS. The tendency of the TiO2-pigments to form aggregates was found to depend on both: first on the type of binder used in the formulation and second on the employed dispersing agent. It is shown that only by adjusting the properties of the binder in combination with common dispersants, it is possible to get well-distributed TiO2 particles within the paint. Correlation of application properties, e.g. gloss and blocking to the microscopic structure is presented. 相似文献