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61.
O. Bartholomy R. Bogendörfer V. Credé I. Fabry A. V. Anisovich G. Anton R. Bantes Y. A. Beloglazov R. Castelijns A. Ehmanns J. Ernst H. Flemming A. Fösel M. Fuchs Ch. Funke R. Gothe A. B. Gridnev E. Gutz S. Höffgen I. Horn J. Hößl J. Junkersfeld H. Kalinowsky F. Klein E. Klempt H. Koch M. Konrad B. Kopf B. Krusche J. Langheinrich H. Löhner I. V. Lopatin J. Lotz H. Matthäy D. Menze J. Messchendorp V. A. Nikonov D. V. Novinski M. Ostrick H. van Pee A. K. Radkov A. V. Sarantsev S. Schadmand C. Schmidt H. Schmieden B. Schoch G. Suft V. V. Sumachev T. Szczepanek U. Thoma D. Walther Ch. Weinheimer 《The European Physical Journal A - Hadrons and Nuclei》2007,33(2):133-146
Photoproduction of η -mesons was studied with the Crystal-Barrel detector at ELSA for photon energies in the range from 0.75
to 3GeV. Total and differential cross-sections are presented. The η mesons are detected in two decay modes, in η → 2γ and
in η → 3π0 → 6γ . The cross-sections vary slowly as functions of energy and η production angle suggesting that only few resonances make
significant contributions to the cross-section. For photon energies above 1.5GeV, the differential cross-sections show a strong
forward peak due to meson exchanges in the t channel. A comparison of the η -photoproduction cross-sections with SAID and MAID as well as with a partial-wave analysis
performed on our data in combination with other data sets shows good agreement. The Bonn-Gatchina partial-wave analysis suggests
that the largest contribution to η photoproduction for energies below 3GeV proceeds via three resonances, the well-known N(1535)S
11 , via N(1720)P
13 , and a newly suggested N(2070)D
15 . 相似文献
62.
Elsa Alvarez Nathalie Guillou Charlotte Martineau Bart Bueken Ben Van de Voorde Clément Le Guillouzer Paul Fabry Farid Nouar Francis Taulelle Dirk de Vos Jong‐San Chang Kyoung Ho Cho Naseem Ramsahye Thomas Devic Marco Daturi Guillaume Maurin Christian Serre 《Angewandte Chemie (International ed. in English)》2015,54(12):3664-3668
The synthesis of the commercially available aluminum fumarate sample A520 has been optimized and its structure analyzed through a combination of powder diffraction, solid‐state NMR spectroscopy, molecular simulation, IR spectroscopy, and thermal analysis. A520 is an analogue of the MIL‐53(Al)‐BDC solid, but with a more rigid behavior. The differences between the commercial and the optimized samples in terms of defects have been investigated by in situ IR spectroscopy and correlated to their catalytic activity for ethanol dehydration. 相似文献
63.
Jrg Lahann Wilhelm Plüster Teresa Rodon Marlies Fabry Doris Klee Hans‐Gregor Gattner Hartwig Hcker 《Macromolecular bioscience》2002,2(2):82-87
Chemical modification of recombinant hirudin (r‐hirudin) is necessary whenever surface‐confinement to a biomaterial or biotinylation for subsequent conjugation with carriers is intended. Here, we report a modification strategy that permits chemical discrimination between r‐hirudin's amino groups and preserves its thrombin inhibitor activity. By reaction with Msc‐ONSu, protective groups were successively introduced in r‐hirudin yielding four derivatives (Msc)x‐hirudin (1 ≤ x ≤ 4) and pure fractions were isolated by ion exchange chromatography. Structure–function relationships were studied for all derivatives and revealed a decrease in activity of more than 90% as compared to unprotected r‐hirudin. MALDI‐TOF MS was used to determine the locations of the Msc groups. Furthermore, evidence was provided that r‐hirudin's N‐terminal amino group is highly important for its anti‐thrombin activity. Selective modification of the lysine residues which maintained the free N‐terminal amino group preserved the anti‐thrombin activity of r‐hirudin even after biotinylation and subsequent linkage to streptavidin or confinement to a polymer surface. 相似文献
64.
The chemical analysis with inductively coupled plasma-mass spectrometry (ICP-MS) can help to examine the purity of ultra
pure water (UPW) down to 10 part per trillion (ng/L) and lower. For a proper determination of a high number of samples per
week the analysis must be divided into two parts: the routine analysis and the reference water analysis. The routine analysis
is done by direct measurement of the ultra pure water samples. Applying a standard addition method under particular clean
conditions, the reference water analysis leads to the definition of the accurate zero. A quick evaluation scheme is also presented
for the reference water analysis. The method is tested for its fitness for application by examining LOD (for relevant element
< 2 ng/L), reproducibility and linearity of calibration. The ICP-MS was optimized according to the methodology of G. Taguchi
to improve reproducibility and LOD.
Received: 16 June 1999 / Revised: 2 August 1999 / Accepted: 6 August 1999 相似文献
65.
66.
67.
Rueping M Vila C Koenigs RM Poscharny K Fabry DC 《Chemical communications (Cambridge, England)》2011,47(8):2360-2362
A dual catalytic system combining photoredox and Lewis base catalysis has been developed. By the appropriate choice of light source and catalyst, the photoredox cycle can be optimally modulated to match the base catalyzed reaction cycle to provide the corresponding products under mild reaction conditions. 相似文献
68.
CH Functionalization of Phenols Using Combined Ruthenium and Photoredox Catalysis: In Situ Generation of the Oxidant
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M. Sc. David C. Fabry B. Sc. Meria A. Ronge Dipl.‐Chem. Jochen Zoller Prof. Dr. Magnus Rueping 《Angewandte Chemie (International ed. in English)》2015,54(9):2801-2805
A combination of ruthenium and photoredox catalysis allowed the ortho olefination of phenols. Using visible light, the direct C? H functionalization of o‐(2‐pyridyl)phenols occurred, and diverse phenol ethers were obtained in good yields. The regeneration of the ruthenium catalyst was accomplished by a photoredox‐catalyzed oxidative process. 相似文献
69.
70.
R. Hölzl L. Fabry K.-J. Range R. Pech 《Applied Physics A: Materials Science & Processing》2002,74(4):545-551
We have measured the gettering efficiencies for Cu and Ni of various silicon wafers, such as MeV-boron-implanted p- polished
wafers treated with two different implantation doses of 3×1013 atoms/cm2 B and 1×1015 atoms/cm2 B, respectively. A third kind of wafer was covered with a poly-silicon back side and thermally pretreated before the gettering
test to form oxygen precipitates in the bulk. The gettering test started with a reproducible spin-on spiking on the front
side of the wafers in the range around 1012 atoms/cm2, followed by a thermal treatment to redistribute the metallic impurities in the wafer. Then the gettering efficiencies were
measured by a novel wet chemical layer-by-layer etching technique in combination with inductively coupled plasma mass spectrometry.
This led to “stratigraphical concentration profiles” of the metallic impurities in the wafer with typical detection limits
of (5–10)×1012 atoms/cm3. The concentration profiles were compared with concentration profiles found after testing the gettering efficiency of p/p+
epitaxial wafers. Almost 100% of the total intentional Cu spiking was recovered in the boron buried layer for both implantation
doses. On the front surface and in the region between the front surface and the buried layer a Cu concentration ∼20 times
higher than on/in p/p+ epitaxial wafers/layers was measured for the implanted specimen. The lower implantation dose led to
higher Cu-concentration levels on the front surface compared to the higher implantation dose. The wafer containing a MeV-boron-implanted
layer as well as oxygen precipitates and a poly-silicon back side exhibited a Cu distribution of 30/∼0/70%, respectively.
Thus, the gettering by poly-silicon exceeded both the gettering effects by the buried layer and by the oxygen precipitates.
Ni gettering in MeV-boron-implanted wafers exhibited other characteristics. The gettering efficiency of the buried layer was
65%, while the remaining Ni contamination was equally distributed between the front-side region and the wafer back side. A
wafer containing a buried layer obtained by a 1×1015 atoms/cm3 B dose and oxygen precipitates exhibited 17% of the total Ni contamination in the boron layer, while ∼80% of the total Ni
contamination was gettered by oxygen precipitates. In the case of buried layer/oxygen precipitates/poly-silicon back side
the distribution was found to be 13/37/45%, thus exhibiting equal gettering strengths for oxygen precipitates and the poly-silicon
back side for Ni contamination. The results were discussed in terms of segregation and relaxation-induced gettering mechanisms
including different reaction rates.
Received: 30 May 2001 / Accepted: 16 June 2001 / Published online: 30 August 2001 相似文献