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91.
John M. T. Thompson Giles W. Hunt 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》1971,22(6):1001-1015
Zusammenfassung Eine allgemeine Theorie zur numerischen Berechnung eines konservativen Systems mitn Freiheitsgraden undm überlagerten Verzweigungspunkten wird dargestellt. Im Unterschied zu früheren Arbeiten wird kein Diagonalisierungsschema der totalen potentiellen Energie benötigt. Ein Störungsschema wird angegeben, umn–m verallgemeinerte Koordinaten mit Hilfe vonn–m Gleichgewichtsbedingungen zu eliminieren. Anschließend wird ein zweites Störungsschema angegeben, um die Ableitungen der 2
m
–1 möglichen Äste der Last-Verformungskurven, die im kritischen Punkt entspringen, zu bestimmen. Anschließend wird die Theorie auf zweifache kritische Punkte angewendet, die beim Ausbeulen der durch gleichmäßigen Außendruck belasteten vollständigen Kugelschale auftreten. 相似文献
92.
William B Giles 《Journal of Combinatorial Theory, Series B》1976,20(2):103-116
Let G be a graph. If v is a vertex of G then the (? 1, v)-subgraphs of G are defined to be the point deletions of G, except for G ~ {v}, with v labeled on each. This paper first classifies all outerplanar blocks which have a pair of v-isomorphic (? 1, v)-subgraphs and next classifies all outerplanar blocks which have a pair of isomorphic point deletions. Finally, this classification is used to prove the Harary conjecture for outerplanar blocks, namely that an outerplanar block can be reconstructed from the isomorphism classes of its point deletions. 相似文献
93.
Riba Garcia I Giles K Bateman RH Gaskell SJ 《Journal of the American Society for Mass Spectrometry》2008,19(12):1781-1787
The structures of peptide a- and b-type fragment ions were studied using synthetic peptides including a set of isomeric peptides,
differing in the sequence location of an alanine residue labeled with 15N and uniformly with 13C. The pattern of isotope labeling of second-generation fragment ions derived via a
n
and b
n
ions (where n=4 or 5) suggested that these intermediates existed in part as macrocyclic structures, where alternative sites of ring opening
gave rise to different linear forms whose simple cleavage might give rise to the observed final products. Similar conclusions
were derived from combined ion mobility/tandem MS analyses where different fragmentation patterns were observed for isomeric
a- or b-type ions that display different ion mobilities. These analyses were facilitated by a new approach to the processing
of ion mobility/tandem MS data, from which distinct and separate product ion spectra are derived from ions that are incompletely
separated by ion mobility. Finally, an example is provided of evidence for a macrocyclic structure for b
n
ions where n=8 or 9. 相似文献
94.
Paul J. J. Colbon Alison C. Foster Melvyn E. Giles Zakariya Patel John T. Singleton 《Journal of heterocyclic chemistry》2008,45(5):1451-1456
We have developed a convenient two‐stage process for the synthesis of 6‐methylpyrazine‐2‐yl‐amines from commercially available materials. The procedure involves the synthesis of (6‐chloro‐pyrazin‐2‐yl)‐acetic acid via arylation of diethyl malonate and in situ hydrolysis/decarboxylation. A second decarboxylation takes place under the subsequent amination conditions allowing simple and efficient access to the intended pyrazines. 相似文献
95.
A new device that we refer to as the spherical superconducting torsion balance has been used to search for a new force coupling mass to intrinsic spin. Our experimental approach also employs a novel spin-source geometry that allows unprecedented sensitivity in the range 100 mum10 mm at 1sigma confidence. At a range of 1 mm our most relaxed limit is g_{p};{e}g_{s}<1.5x10;{-24}. 相似文献
96.
Dosso SE Morley MG Giles PM Brooke GH McCammon DF Pecknold S Hines PC 《The Journal of the Acoustical Society of America》2007,122(5):2560-2570
This article examines the effects of spatial field shifts in ocean acoustic environmental sensitivity analysis. Acoustic sensitivity studies are typically based on comparing acoustic fields computed for a reference environmental model and for a perturbed model in which one or more parameters have been changed. The perturbation to the acoustic field due to the perturbed environment generally includes a component representing a spatial shift of the field (i.e., local field structure remains coherent, but shifts in range and/or depth) and a component representing a change to the shifted field. Standard sensitivity measures based on acoustic perturbations at a fixed point can indicate high sensitivity in cases where the field structure changes very little, but is simply shifted by a small spatial offset; this can conflict with an intuitive understanding of sensitivity. This article defines and compares fixed-point and field-shift corrected sensitivity measures. The approaches are illustrated with examples of deterministic sensitivity (i.e., sensitivity to a specific environmental change) and stochastic sensitivity (sensitivity to environmental uncertainty) in range-independent and range-dependent environments. 相似文献
97.
The LaIn(3-x)Sn(x) alloy system is composed of superconducting Pauli paramagnets. For LaIn3 the superconducting critical temperature T(c) is approximately 0.7 K and it shows an oscillatory dependence as a function of Sn substitution, presenting its highest value T(c) ≈ 6.4 K for the LaSn3 end member. The superconducting state of these materials was characterized as being of the conventional type. We report our results for Gd3+ electron spin resonance measurements in the LaIn(3-x)Sn(x) compounds as a function of x. We show that the effective exchange interaction parameter J(fs) between the Gd3+ 4f local moment and the s-like conduction electrons is almost unchanged by Sn substitution and observe microscopically that LaSn3 is a conventional superconductor. 相似文献
98.
Giles K Williams JP Campuzano I 《Rapid communications in mass spectrometry : RCM》2011,25(11):1559-1566
The use of ion mobility separation to determine the collision cross-section of a gas-phase ion can provide valuable structural information. The introduction of travelling-wave ion mobility within a quadrupole/time-of-flight mass spectrometer has afforded routine collision cross-section measurements to be performed on a range of ionic species differing in gas-phase size/structure and molecular weight at physiologically relevant concentrations. Herein we discuss the technical advances in the second-generation travelling-wave ion mobility separator, which result in up to a four-fold increase in mobility resolution. This improvement is demonstrated using two reverse peptides (mw 490 Da), small ruthenium-containing anticancer drugs (mw 427 Da), a cisplatin-modified protein (mw 8776 Da) and the noncovalent tetradecameric chaperone complex GroEL (mw 802 kDa). What is also shown are that the collision cross-sections determined using the second-generation mobility separator correlate well with the previous generation and theoretically derived values. 相似文献
99.
Michael D. Hargreaves Andrew D. Burnett Tasnim Munshi John E. Cunningham Edmund H. Linfield A. Giles Davies Howell G. M. Edwards 《Journal of Raman spectroscopy : JRS》2009,40(12):1974-1983
The laser excitation wavelength is an important parameter in obtaining Raman spectra from drugs‐of‐abuse. This article compares the effect of near infrared wavelengths, 785 nm, using both benchtop and portable instrumentation and benchtop 1064 nm on the Raman spectra of seized drugs‐of‐abuse, including cocaine hydrochloride, cocaine freebase (crack), methylenedioxymethamphetamine (‘ecstasy’), amphetamine, diamorphine (heroin) and cannabis. The significant benefit of using 1064 nm for the interrogation of this type of sample is highlighted. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
100.
Data encoding on terahertz signals for communication and sensing 总被引:1,自引:0,他引:1
We demonstrate and analyze data modulation of terahertz (THz) signals in the 1 Mbit/s range. THz pulse trains are phase and amplitude encoded with pseudorandom binary data, transmitted over a short distance, and detected. Different modulation formats are generated. Bit error measurements characterize the communication channel. We estimate from experimental results the maximum data rates for an optimized system. 相似文献