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81.
N Li F Yang HA Stock DV Dearden JD Lamb RG Harrison 《Organic & biomolecular chemistry》2012,10(36):7392-7401
Resorcinarene-based deep cavitands alanine methyl resorcinarene acid (), alanine undecyl resorcinarene acid () and glycine undecyl resorcinarene acid (), which contain chiral amino acids, have been synthesized. The upper rim of the resorcinarene host is elongated with four identical substituents topped with alanine and glycine groups. The structures of the new resorcinarenes were elucidated by nuclear magnetic resonance (NMR), mass spectrometry (MS) and the sustained off-resonance irradiation collision induced dissociation (SORI-CID) technique in FTICR-MS. These studies revealed that eight water molecules associate to the cavitand, two for each alanine group. The alanine substituent groups are proposed to form a kite-like structure around the resorcinarene scaffold. The binding of , , and with chiral R- and S-methyl benzyl amines was studied by (1)H NMR titration, and compared to that of a binary l-tartaric acid and the monoacid phthalyl alanine (). The results show that these compounds interact with amine guests; however, with four carboxylic acid groups, they bind several amine molecules strongly while the binary l-tartaric acid only binds one amine guest strongly. The simple compound , which contains one carboxylic group, shows weak binding to the amines. The (1)H NMR titration of with primary, secondary, and tertiary chiral amines showed that it can discriminate between these three types of amines and showed chiral discrimination for chiral secondary amines. 相似文献
82.
Harry Podlesak Uta Faust Bernhard Wielage Michael Quast Peter Mayr Heinz-Rolf Stock 《Mikrochimica acta》2000,133(1-4):285-288
Detailed examinations were made by AES depth profiling, SEM, TEM and electron diffraction to get information about the relation
between treatment conditions and the state of plasma-nitrided aluminium. The chemical composition and the elemental depth
distribution were proofed to be depending on gas phase mixture, pressure and temperature during plasma treatment. The admixture
of hydrogen during presputtering for surface cleaning and during nitriding results both in an improved nitriding behaviour
and in a reduction of the formation of conical-shaped particles at the surface. The microstructure of the nitride layer isn’t
depending on tested process conditions significantly. Surface and interface between layer and substrate are roughly in a scale
of a few ten nanometers owing to sputtering effects. The main phase inside the layer is nanocrystalline AlN of the known hexagonal
modification. In addition, some crystallites of remaining aluminium are present as a second phase. In contrast to nitrogen-implanted
aluminium no preferred lattice orientation of the AlN phase was evident. 相似文献
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87.
A. Stock und Nelly Neuenschwander-Lemmer 《Fresenius' Journal of Analytical Chemistry》1941,122(7-8):294-298
Ohne Zusammenfassung 相似文献
88.
Elise Miller-Hooks Sarah Stock Patterson 《Journal of Mathematical Modelling and Algorithms》2004,3(1):39-71
In this paper, a pseudopolynomial time algorithm is presented for solving the integral time-dependent quickest flow problem
(TDQFP) and its multiple source and sink counterparts: the time-dependent evacuation and quickest transshipment problems.
A more widely known, though less general version, is the quickest flow problem (QFP). The QFP has historically been defined
on a dynamic network, where time is divided into discrete units, flow moves through the network over time, travel times determine how
long each unit of flow spends traversing an arc, and capacities restrict the rate of flow on an arc. The goal of the QFP is
to determine the paths along which to send a given supply from a single source to a single sink such that the last unit of
flow arrives at the sink in the minimum time. The main contribution of this paper is the time-dependent quickest flow (TDQFP) algorithm which solves the TDQFP, i.e. it solves the integral QFP, as defined above, on a time-dependent dynamic network, where the arc travel times, arc and node capacities, and supply at the source vary with time. Furthermore,
this algorithm solves the time-dependent minimum time dynamic flow problem, whose objective is to determine the paths that
lead to the minimum total time spent completing all shipments from source to sink. An optimal solution to the latter problem
is guaranteed to be optimal for the TDQFP. By adding a small number of nodes and arcs to the existing network, we show how
the algorithm can be used to solve both the time-dependent evacuation and the time-dependent quickest transshipment problems.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
89.
D. Brill P. Beckerle C. Bormann E. Schwab Y. Shin R. Stock H. Ströbele P. Baltes C. Müntz H. Oeschler C. Sturm A. Wagner R. Barth M. Cieślak M. Dębowski E. Grosse P. Koczoń M. Mang D. Miśkowiec R. Schicker P. Senger B. Kohlmeyer F. Pühlhofer J. Speer K. Völkel W. Waluś 《Zeitschrift für Physik A Hadrons and Nuclei》1996,355(1):61-68
Midrapidity protons from209Bi+209Bi collisions were measured with the Kaon Spectrometer at SIS at incident energies of E Lab /A=400, 700 and 1000 MeV. Additionally, light fragments were analysed at 400 MeV. We have investigated the azimuthal emission pattern of the particles relative to the reaction plane as function of transverse momentum, bombarding energy and impact parameter. We observe an enhanced emission of particles perpendicular to the reaction plane at all bombarding energies. The ratio of the number of particles emitted out-of-plane/in-plane increases strongly with the particles transverse momentum. The anisotropy decreases with increasing beam energy. Composite particles show a much stronger effect than protons. 相似文献
90.