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51.
Esa Haapaniemi 《Magnetic resonance in chemistry : MRC》2017,55(9):804-812
The 1H, 13C{1H}, and 31P NMR spectral parameters of some pyrophosphates were determined in CDCl3. The most complicated 1H spectrum can be solved fully only as (A3MN)R6XX′R6′(MNA3)′, where R6 (= ―N(CH3)2) is coupled only to phosphorus (X). Second‐order coupling between phosphorus was found and solved with iterative analysis. A signal shape of one of the carbon resonance cannot be explained only with couplings. Explanation for exceptional shape was searched from molecular modeling results. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
52.
The local strain range is considered to be the main factor controlling the fatigue damage process. An energetic approach is applied to correlate the elastic-plastic stress and strain near a notch with the remotely applied stress. Fatigue crack initiation lives of LYI2CZ aluminum and 16 Mn steel are predicted from a knowledge of the uniaxial data involving parameters such as the elastic modulus, strain hardening strength and strain hardening exponent. These quantities are contained and identified with the fatigue strength coefficient C* which together with the equivalent stress range provide an estimate for the fatigue life of metals. The results agree well with the test data available in the open literature. 相似文献
53.
Juha Merta Per Stenius Esa Pirttinen 《Journal of Dispersion Science and Technology》2013,34(1-2):677-697
This paper reports on studies of the rheological properties of cationic starch (CS)/ surfactant systems. The degree of substitution of the CS was 0.1 - 0.8. Surfactants investigated were sodium dodecyl sulfate (SDS), potassium octanoate (KOct), sodium decanoate (NaDe)potassium dodecanoate (KDod), sodium oleate (NaOl) and sodium erucate (NaEr). Aggregation of surfactant micelles with the polymer produces a hydrophobic and pseudoplastic gel-like complex phase with low water content and high viscosity. The rheological behavior of the gels is described by the Herschel-Bulkley model. In dilute aqueous solution the CS/surfactant aggregate structure resembles a randomly coiled polymer network, in which polymer molecules are linked by micelles. The rheological data for the gel are compatible with the assumption that the surfactants form liquid crystalline structures with the polymer anchored to the surfactant aggregates, as recently suggested for analogous systems. However, this conjecture needs to be corroborated by more direct determinations of the structure. 相似文献
54.
Joshua A. Carroll Emad L. Izake Biju Cletus Esa Jaatinen 《Journal of Raman spectroscopy : JRS》2015,46(3):333-338
Increasing worldwide terrorist attacks involving explosives presents a growing need for a rapid and ranged explosive detection method that can safely be deployed in the field. Stand‐off Raman spectroscopy shows great promise; however, the radiant exposures of lasers required for adequate signal generation are often much greater than what is safe for the eye or the skin, restricting use of the technique to unpopulated areas. Here, by determining the safe exposure levels for lasers typically used in Raman spectroscopy, optimal parameter values are identified, which produce the largest possible detection range using power densities that do not exceed the eye‐safe limit. It is shown that safe ultraviolet pulse energies can be more than three orders of magnitude greater than equivalent safe visible pulse energies. Coupling this to the 16‐fold increase in Raman signal obtained in the ultraviolet at 266 nm over that at 532 nm results in a 131 times larger detection range for the eye‐safe 266‐nm system over an equivalent eye‐safe 532‐nm laser system. For the Raman system described here, this translates to a maximum range of 42 m for detecting Teflon with a 266‐nm laser emitting a 100‐mm diameter beam of 23.5‐mJ nanosecond pulses. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
55.
We introduce a novel generalization of the discrete nonlinear Schr?dinger equation. It supports solitons that we utilize to model chiral polymers in the collapsed phase and, in particular, proteins in their native state. As an example we consider the villin headpiece HP35, an archetypal protein for testing both experimental and theoretical approaches to protein folding. We use its backbone as a template to explicitly construct a two-soliton configuration. Each of the two solitons describe well over 7.000 supersecondary structures of folded proteins in the Protein Data Bank with sub-angstrom accuracy suggesting that these solitons are common in nature. 相似文献
56.
A study of 1-hexene polymerization with ethylene-bis(9-fluorenyl) hafnium dichloride has been carried out using two different cocatalyst systems, methyl-aluminoxane/trimethylaluminum (MAO/TMA) and tris-isobutyl-aluminum/N,N-dimethylanilinium tetrakis(pentafluorophenyl) borate (TIBA/borate). When MAO/TMA was used, 1-hexene polymerized into a low molar mass poly(1-hexene) with low catalytic activity. Activation with TIBA/borate increased polymerization activity drastically as well as the molar mass of the polymers. In order to analyze differences in the activity profiles, UV-Vis spectroscopy was employed to investigate ligand to metal charge transitions (LMCT) of the hafnocene dichloride during the activation process. The low catalytic activity and the fast chain transfer to the cocatalyst with MAO/TMA may originate from strong bonding between the metallocene cation and the MAO/TMA species thus obstructing monomer coordination and insertion. 相似文献
57.
Esa Nummelin 《Probability Theory and Related Fields》1990,86(3):387-401
Summary Let (S
n
) be a sequence ofR
d
-valued random variables adapted to the internal history of a stationary sequence of random elements (X
n
). We formulate conditions under which the principle of large deviations holds true for the sequence (S
n
). 相似文献
58.
The first synthetic route to amaminol A with use of an organocatalytic intramolecular Diels-Alder reaction is reported. The absolute stereochemistry is proven with a crystallographic image of a cyclic carbamate of amaminol A. 相似文献
59.
Esa?R?s?nenEmail author Eric?J.?Heller 《The European Physical Journal B - Condensed Matter and Complex Systems》2013,86(1):17
Increasing fidelity is the ultimate challenge of quantum information technology. In addition to decoherence and dissipation, fidelity is affected by internal imperfections such as impurities in the system. Here we show that the quality of quantum revival, i.e., periodic recurrence in the time evolution, can be restored almost completely by coupling the distorted system to an external field obtained from quantum optimal control theory. We demonstrate the procedure with wave-packet calculations in both one- and two-dimensional quantum wells, and analyze the required physical characteristics of the control field. Our results generally show that the inherent dynamics of a quantum system can be idealized at an extremely low cost. 相似文献
60.
B. Twomey A. Nindrayog K. Niemi W. G. Graham D. P. Dowling 《Plasma Chemistry and Plasma Processing》2011,31(1):139-156
The effect of varying process parameters on atmospheric plasma characteristics and properties of nanometre thick siloxane
coatings is investigated in a reel-to-reel deposition process. Varying plasma operation modes were observed with increasing
applied power for helium and helium/oxygen plasmas. The electrical and optical behaviour of the dielectric barrier discharge
were determined from current/voltage, emission spectroscopy and time resolved light emission measurements. As applied power
increased, multiple discharge events occurred, producing a uniform multi-peak pseudoglow discharge, resulting in an increase
in the discharge gas temperature. The effects of different operating modes on coating oxidation and growth rates were examined
by injecting hexamethyldisiloxane liquid precursor into the chamber under varying operating conditions. A quenching effect
on the plasma was observed, causing a decrease in plasma input power and emission intensity. Siloxane coatings deposited in
helium plasmas had a higher organic component and higher growth rates than those deposited in helium/oxygen plasmas. 相似文献