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1.
Frank R. Fronczek Richard D. Gandour Laura M. B. Gehrig Lyman R. Caswell Karen A. McDowell I. Alam 《Journal of inclusion phenomena and macrocyclic chemistry》1987,5(3):379-383
The first crystal structure of a potassium cation complex with dicyclohexano-18-crown-6 is reported. The potassium 2-nitrophenoxide complex ofsyn-cis-syn dicyclohexano-18-crown-6 crystallizes in the triclinic space group P
with cell constantsa=8.604(2),b=10.772(4),C=16.123(5)Å, =73.86(3)°,=77.61(3)°, =82.68(3)° andZ=2 forD
c
=1.31 g cm–3. Least-squares refinement based on 2742 observed reflections led to a final conventionalR value of 0.040. Dicyclohexano-18-crown-6 has the shape of a saddle with the potassium cation sitting at the saddlepoint. The structure of the 2-nitrophenoxide anion is dominanted by the quinoid resonance contributor. Because the complex is devoid of significant intercomplex interactions, it is a prototypical 1:1:1 complex.
Supplementary Data relating to this article are deposited with the British Library as Supplementary Publication No. SUP 82043 (26 pages).Now Mrs. K. M. Balo. 相似文献
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Ursula E. Spichiger Rudolf Eugster E. Haase G. Rumpf Peter Gehrig Angela Schmid Bruno Rusterholz Wilhelm Simon 《Fresenius' Journal of Analytical Chemistry》1991,341(12):727-731
Summary The selectivity of a new magnesium ionophore (ETH 7025) induced in membranes of different compositions is experimentally studied in view of the ion activities in human serum. The required selectivity coefficient against calcium for the application of an ion-selective magnesium electrode to human serum is calculated for the worst case. Other critical parameters for the application of a liquid PVC-based ion-selective membrane to undiluted human serum discussed are: the sensor lifetime which is related to the lipophilicity of the carrier as well as the ruggedness of the membrane against interactions with components of the relatively lipophilic sample. 相似文献
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Christiane Lorenz Harald Hagendorfer Natalie von Goetz Ralf Kaegi Robert Gehrig Andrea Ulrich Martin Scheringer Konrad Hungerbühler 《Journal of nanoparticle research》2011,13(8):3377-3391
Consumer spray products are already on the market in the cosmetics and household sector, which suggest by their label that
they contain engineered nanoparticles (ENP). Sprays are considered critical for human health, because the lungs represent
a major route for the uptake of ENP into the human body. To contribute to the exposure assessment of ENP in consumer spray
products, we analyzed ENP in four commercially available sprays: one antiperspirant, two shoe impregnation sprays, and one
plant-strengthening agent. The spray dispersions were analyzed by inductively coupled plasma mass spectrometry (ICPMS) and
(scanning-) transmission electron microscopy ((S)TEM). Aerosols were generated by using the original vessels, and analyzed
by scanning mobility particle sizer (SMPS) and (S)TEM. On the basis of SMPS results, the nanosized aerosol depositing in the
respiratory tract was modeled for female and male consumers. The derived exposure levels reflect a single spray application.
We identified ENP in the dispersions of two products (shoe impregnation and plant spray). Nanosized aerosols were observed
in three products that contained propellant gas. The aerosol number concentration increased linearly with the sprayed amount,
with the highest concentration resulting from the antiperspirant. Modeled aerosol exposure levels were in the range of 1010 nanosized aerosol components per person and application event for the antiperspirant and the impregnation sprays, with the
largest fraction of nanosized aerosol depositing in the alveolar region. Negligible exposure from the application of the plant
spray (pump spray) was observed. 相似文献
4.
V.N.?StavrouEmail author D.?Preisser E.?Gehrig O.?Hess 《Applied physics. B, Lasers and optics》2004,78(6):765-768
A theory of ultra-fast carrier–light field dynamics of quantum dots is presented. The carrier–light field dynamics is described by Maxwell–Bloch equations. A calculation of the dipole matrix elements requires the determination of the electronic wave functions taking into account their dependence on the degeneracy of the carrier states. The ultra-fast carrier–light field dynamics depends strongly on the external applied electric field. PACS 42.55.Px; 42.60.Rn; 74.78.Fk 相似文献
5.
Peter Max Gehrig Bernd Roschitzki Dorothea Rutishauser Sonja Reiland Ralph Schlapbach 《Rapid communications in mass spectrometry : RCM》2009,23(10):1435-1445
In order to investigate gas‐phase fragmentation reactions of phosphorylated peptide ions, matrix‐assisted laser desorption/ionization (MALDI) and electrospray ionization (ESI) tandem mass (MS/MS) spectra were recorded from synthetic phosphopeptides and from phosphopeptides isolated from natural sources. MALDI‐TOF/TOF (TOF: time‐of‐flight) spectra of synthetic arginine‐containing phosphopeptides revealed a significant increase of y ions resulting from bond cleavages on the C‐terminal side of phosphothreonine or phosphoserine. The same effect was found in ESI‐MS/MS spectra recorded from the singly charged but not from the doubly charged ions of these phosphopeptides. ESI‐MS/MS spectra of doubly charged phosphopeptides containing two arginine residues support the following general fragmentation rule: Increased amide bond cleavage on the C‐terminal side of phosphorylated serines or threonines mainly occurs in peptide ions which do not contain mobile protons. In MALDI‐TOF/TOF spectra of phosphopeptides displaying N‐terminal fragment ions, abundant b–H3PO4 ions resulting from the enhanced dissociation of the pSer/pThr–X bond were detected (X denotes amino acids). Cleavages at phosphoamino acids were found to be particularly predominant in spectra of phosphopeptides containing pSer/pThr–Pro bonds. A quantitative evaluation of a larger set of MALDI‐TOF/TOF spectra recorded from phosphopeptides indicated that phosphoserine residues in arginine‐containing peptides increase the signal intensities of the respective y ions by almost a factor of 3. A less pronounced cleavage‐enhancing effect was observed in some lysine‐containing phosphopeptides without arginine. The proposed peptide fragmentation pathways involve a nucleophilic attack by phosphate oxygen on the carbon center of the peptide backbone amide, which eventually leads to cleavage of the amide bond. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
6.
Structural Design Principle of Small‐Molecule Organic Semiconductors for Metal‐Free,Visible‐Light‐Promoted Photocatalysis 下载免费PDF全文
Lei Wang Wei Huang Run Li Dr. Dominik Gehrig Prof. Paul W. M. Blom Prof. Katharina Landfester Dr. Kai A. I. Zhang 《Angewandte Chemie (International ed. in English)》2016,55(33):9783-9787
Herein, we report on the structural design principle of small‐molecule organic semiconductors as metal‐free, pure organic and visible light‐active photocatalysts. Two series of electron‐donor and acceptor‐type organic semiconductor molecules were synthesized to meet crucial requirements, such as 1) absorption range in the visible region, 2) sufficient photoredox potential, and 3) long lifetime of photogenerated excitons. The photocatalytic activity was demonstrated in the intermolecular C?H functionalization of electron‐rich heteroaromates with malonate derivatives. A mechanistic study of the light‐induced electron transport between the organic photocatalyst, substrate, and the sacrificial agent are described. With their tunable absorption range and defined energy‐band structure, the small‐molecule organic semiconductors could offer a new class of metal‐free and visible light‐active photocatalysts for chemical reactions. 相似文献
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8.
E. Gehrig O. Hess C. Seibert D. Woll R. Wallenstein 《Applied physics. B, Lasers and optics》2003,76(3):285-288
We theoretically describe and experimentally investigate the spatio-spectral wave mixing of induced and spontaneous emission
in large-area InGaAs-semiconductor laser amplifiers. The dynamic light-matter-coupling is described by a spatially resolved
theory based on Maxwell–Bloch–Langevin equations, taking into account many-body-carrier interactions, energy transfer between
the carrier and phonon systems and, in particular, the spatio-temporal interplay of stimulated and amplified spontaneous emission
and the noise caused by spontaneous emission. Our numerical model reveals the fundamental physical processes which are responsible
for the spectral power distribution of the amplified laser light and predicts the emission properties of high-power semiconductor
laser amplifiers, such as emission spectra and input power–output power characteristics.
Received:30October2002/Revisedversion:21November2002 / Published online: 12 February 2003
RID="*"
ID="*"Corresponding author. Fax: +49-711/6862-349, E-mail: Edeltraud.Gehrig@dlr.de
RID="**"
ID="**"Also at: Institute of Physics, Tampere University of Technology, P.O. Box 692, FIN-33101, Tampere, Finland
RID="***"
ID="***"Present address: Heidelberger Druckmaschinen AG, Speyerer Strasse 6, 69115 Heidelberg, Germany
RID="****"
ID="****"Present address: Lightbit Corporation, 411 Clyde Avenue, Mountain View, CA 94043, USA 相似文献
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