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B. Buszewski M. Hummel E. Bayer J. Geiger K. Schierbaum W. G?pel 《Fresenius' Journal of Analytical Chemistry》1990,336(5):403-408
Summary Two different types of porous glass (PG) were submitted to a thermal treatment in a temperature range from 620°C–700°C for 2 to 100 h. The materials thereby obtained have been characterized by static Secondary Ion Mass Spectrometry (SIMS). Special attention was paid to the change of the boron surface concentration. In addition we studied the specific surface area (SBET) dependence on the thermal treatment parameters, such as heating time and heating temperature. Selected PG materials have been modified with organosilanes and characterized prior to their use as packings in RP-HPLC.Dedicated to B. B.'s parents on their 60th birthday 相似文献
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Lars Radke Christoph Giese Annika Lubitz Stephan Hinderlich Grit Sandig Michael Hummel Marcus Frohme 《Mikrochimica acta》2014,181(13-14):1733-1742
Quantitative real-time PCR (qPCR) is commonly used for gene expression analyses with defined documentation guidelines to compare published results. To minimize the impact of variances from qPCR performance, sample handling and processing reference genes are used. Their selection process cannot be completely aligned due to variations in experimental conditions. Furthermore, the named sources of error are also present when determining the stability of the reference genes themselves. Even software applications that are used to identify the best reference genes rarely coincide on their rankings and can be misleading under certain conditions. In previous experiments, peripheral blood mononuclear cells (PBMC) were analyzed to identify the most stable reference gene(s). Twelve of the 13 investigated genes showed sample type specific differences in the expression. Direct mRNA measurement was performed in the form of a NanoString analysis, a multiplexed absolute quantification method. The external validation showed a high concordance of the reference gene expression levels. However, it identified the same sample type specific expression pattern for only some of the tested reference genes. By comparing various combinations of reference genes with both methods we are able to suggest a set of well-performing reference genes. Figure
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E.Z. Kurmaev V.R. Galakhov S.N. Shamin V.I. Sokolov R.E. Hummel M.H. Ludwig 《Applied Physics A: Materials Science & Processing》1997,65(2):183-189
2,3 X-ray emission spectra of porous silicon (P-Si) and of spark-processed silicon (sp-Si). Both types of Si-structure display strong photoluminescence in the visible range of the spectrum. Porous
samples were prepared by anodization of n-- and p+-Si-wafers. Whereas for the P-Si processed from p+-Si the presence of some amorphous silicon is detected, the X-ray emission spectra of porous Si prepared from n--Si display a higher content of SiO2. For spark-processed Si the Si L2,3 X-ray emission spectra reveal a much stronger degree of oxidation which extends to depths larger than 10000 Å. Furthermore,
the chemical state of silicon atoms of sp-Si measured at the center of the processed area is close to that of silicon dioxide,
and it has an influence on the photoluminescence energy. Specifically, green photoluminescent sp-Si shows a higher degree
of oxidation than the blue luminescent specimen. However, the depth of oxidation consistently decreases in areas with weak
or no PL. Possible origins of the observed photoluminescence are discussed.
Accepted: 6 March 1997 相似文献
27.
Friedhelm C Hummel Bernhard Voller Pablo Celnik Agnes Floel Pascal Giraux Christian Gerloff Leonardo G Cohen 《BMC neuroscience》2006,7(1):73-10
Background
Previous studies showed that anodal transcranial DC stimulation (tDCS) applied to the primary motor cortex of the affected hemisphere (M1affected hemisphere) after subcortical stroke transiently improves performance of complex tasks that mimic activities of daily living (ADL). It is not known if relatively simpler motor tasks are similarly affected. Here we tested the effects of tDCS on pinch force (PF) and simple reaction time (RT) tasks in patients with chronic stroke in a double-blind cross-over Sham-controlled experimental design. 相似文献28.
Oxidation of the antibiotic kiriothricin with sodium metaperiodate gave several main degredation products (, , ). Interpretation of the spectral data of these compounds will lead to the constitution of kirrothricin (). 相似文献
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W.C. Dijksman W. Verboom D.N. Reinhoudt C.G. Hale S. Harkema G.J. van Hummel 《Tetrahedron letters》1984,25(19):2025-2028
Thermal rearrangerment of 2-vinyl-1-(1-pyrrolidinyl)benzenes varies with the leaving group ability of substituents in the vinyl moiety; compound 3 having an OR group 9-(alkoxy-methyl)pyrrolo[1,2-a]indoles and compounds 6 (X = OAc, OTs or Cl) yield 1-alkylindoles. 相似文献
30.
Nu Xu I. G. Bearden H. Bøggild J. Boissevain J. Dodd B. Erazmus S. Esumi C. W. Fabjan D. Ferenc D. E. Fields A. Franz J. Gaardhøje O. Hansen D. Hardtke H. van Hecke E. B. Holzer T. Humanic P. Hummel B. V. Jacak R. Jayanti M. Kaneta M. Kopytine M. Leltchouk T. Ljubicic B. Lörstad N. Maeda A. Medvedev M. Murray S. Nishimura H. Ohnishi G. Paic S. U. Pandey F. Piuz J. Pluta V. Polychronakos M. Potekhin G. Poulard A. Sakaguchi J. Simon-Gillo J. Schmidt-Sørensen W. Sondheim M. Spegel T. Sugitate J. P. Sullivan Y. Sumi W. J. Willis K. Wolf N. Xu D. S. Zachary 《Acta Physica Hungarica A》1996,4(1-4):263-270
We present recent results on single particle transverse momentum distributions of pions, kaons and protons, measured in CERN Experiment NA44, of 200 AGeV/c S+S and 158 AGeV/c Pb+Pb central collisions. By comparing these data with thermal and transport models, freeze-out parameters like the temperatureT fo and the chemical potentials (μ q ,μ s ) are extracted and discussed. 相似文献