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991.
Krzysztof Tesch Michael W. Collins Tassos G. Karayiannis Mark A. Atherton Paul Edwards 《Flow, Turbulence and Combustion》2011,87(1):55-77
In this paper the modelling of an important industrial problem is addressed, which involves the two-component turbulent flow
with heat transfer that takes place inside protective clothing. The geometry of the flow boundaries is reconstructed in a
CAD system from photogrammetry scan data. The overall model is sufficiently realistic to allow, after validation, design improvements
to be tested. Those presented here allow the reduction of hotspots over the worker’s body surface and increase thermal comfort. 相似文献
992.
Sutherland I Hewitson P Siebers R van den Heuvel R Arbenz L Kinkel J Fisher D 《Journal of chromatography. A》2011,1218(32):5527-5530
Two different laboratory scale liquid-liquid extraction processes using aqueous two-phase systems (ATPS) are compared: centrifugal partition chromatography (CPC) and multilayer toroidal coil chromatography (MTCC). Both use the same phase system, 12.5% (w/w) PEG-1000:12.5% (w/w) K(2)HPO(4), the same flow rate of 10 mL/min and a similar mean acceleration field of between 220 × g and 240 × g. The main performance difference between the two processes is that there is a continuous loss of stationary phase with CPC, while for MTCC there is not - even when sample loading is increased. Comparable separation efficiency is demonstrated using a mixture of lysozyme and myoglobin. A throughput of 0.14 g/h is possible with CPC despite having to refill the system with stationary phase before each injection. A higher throughput of 0.67 g/h is demonstrated with MTCC mainly due to its ability to tolerate serial sample injections which significantly reduces its cycle time. While CPC has already demonstrated that it can be scaled to pilot scale, MTCC has still to achieve this goal. 相似文献
993.
Letitia L. BenadeStephen O. Ojwach Collins ObuahIlia A. Guzei James Darkwa 《Polyhedron》2011,30(17):2878-2883
Complexes of 2-((3,5-dimethyl)-1H-pyrazol-1-ylmethyl)pyridine (L1), 2-((3,5-ditert-butyl-1H-pyrazol-1-yl)methyl)pyridine (L2), 2-((3,5-diphenyl)-1H-pyrazol-1-yl)methyl)pyridine (L3), 2-((3,5-bis(trifluoromethyl)-1H-pyrazol-1-ylmethyl)pyridine (L4) and 2,6-bis(3,5-dimethyl-1H-pyrazol-1-yl)methyl)pyridine (L5) with cobalt(II), iron(II) and nickel(II), Ni(L1)Cl2 (1), Co(L1)Cl2 (2), Fe(L1)Cl2 (3), Ni(L2)Cl2 (4), Ni(L3)Cl2 (5), Co(L3)Cl2 (6), Fe(L3)Cl2 (7), Ni(L4)Cl2 (8) and Ni(L5)Cl2 (9), were used as catalyst precursors to produce vinyl-addition type norbornene polymers. Both the identity of the metal center and nature of ligand affected the polymerization behaviour of the resultant catalysts. Nickel catalysts were generally more active than the corresponding iron and cobalt analogues. The polynorbornene produced have high molecular weights (0.5-2.1 × 106 g/mol) and narrow molecular weight distributions. Analyses of polymer microstructure using NMR and IR spectroscopy confirmed the polymers produced to be vinyl-addition polynorbornene. 相似文献
994.
Foley DA Doecke CW Buser JY Merritt JM Murphy L Kissane M Collins SG Maguire AR Kaerner A 《The Journal of organic chemistry》2011,76(23):9630-9640
On-flow ReactIR and (1)H NMR reaction monitoring, coupled with in situ intermediate characterization, was used to aid in the mechanistic elucidation of the N-chlorosuccinimide mediated transformation of an α-thioamide. Multiple intermediates in this reaction cascade are identified and characterized, and in particular, spectroscopic evidence for the intermediacy of the chlorosulfonium ion in the chlorination of α-thioamides is provided. Further to this, solvent effects on the outcome of the transformation are discussed. This work also demonstrates the utility of using a combination of ReactIR and flow NMR reaction monitoring (ReactNMR) for characterizing complex multicomponent reaction mixtures. 相似文献
995.
We consider a model for gene regulatory networks that is a modification of Kauffmann's J Theor Biol 22 (1969), 437–467 random Boolean networks. There are three parameters: $n = {\rm the}$ number of nodes, $r = {\rm the}$ number of inputs to each node, and $p = {\rm the}$ expected fraction of 1'sin the Boolean functions at each node. Following a standard practice in thephysics literature, we use a threshold contact process on a random graph on n nodes, in which each node has in degree r, to approximate its dynamics. We show that if $r\ge 3$ and $r \cdot 2p(1-p)>1$ , then the threshold contact process persists for a long time, which correspond to chaotic behavior of the Boolean network. Unfortunately, we are only able to prove the persistence time is $\ge \exp(cn^{b(p)})$ with $b(p)>0$ when $r\cdot 2p(1-p)> 1$ , and $b(p)=1$ when $(r-1)\cdot 2p(1-p)>1$ . © 2011 Wiley Periodicals, Inc. Random Struct. Alg., 2011 相似文献
996.
We present a framework for validated numerical computations with real functions. The framework is based on a formalisation
of abstract data types for basic floating-point arithmetic, interval arithmetic and function models based on Banach algebra.
As a concrete instantiation, we develop an elementary smooth function calculus approximated by sparse polynomial models. We
demonstrate formal verification applied to validated calculus by a formalisation of basic arithmetic operations in a theorem
prover. The ultimate aim is to develop a formalism powerful enough for reachability analysis of nonlinear hybrid systems. 相似文献
997.
998.
Feist J Nagele S Ticknor C Schneider BI Collins LA Burgdörfer J 《Physical review letters》2011,107(9):093005
We show that the correlation dynamics in coherently excited doubly excited resonances of helium can be followed in real time by two-photon interferometry. This approach promises to map the evolution of the two-electron wave packet onto experimentally easily accessible noncoincident single-electron spectra. We analyze the interferometric signal in terms of a semianalytical model which is validated by a numerical solution of the time-dependent two-electron Schr?dinger equation in its full dimensionality. 相似文献
999.
Larin I McNulty D Clinton E Ambrozewicz P Lawrence D Nakagawa I Prok Y Teymurazyan A Ahmidouch A Asratyan A Baker K Benton L Bernstein AM Burkert V Cole P Collins P Dale D Danagoulian S Davidenko G Demirchyan R Deur A Dolgolenko A Dzyubenko G Ent R Evdokimov A Feng J Gabrielyan M Gan L Gasparian A Gevorkyan S Glamazdin A Goryachev V Gyurjyan V Hardy K He J Ito M Jiang L Kashy D Khandaker M Kingsberry P Kolarkar A Konchatnyi M Korchin A Korsch W Kowalski S Kubantsev M Kubarovsky V Li X Martel P 《Physical review letters》2011,106(16):162303
High precision measurements of the differential cross sections for π0 photoproduction at forward angles for two nuclei, 12C and 208Pb, have been performed for incident photon energies of 4.9-5.5 GeV to extract the π0→γγ decay width. The experiment was done at Jefferson Lab using the Hall B photon tagger and a high-resolution multichannel calorimeter. The π0→γγ decay width was extracted by fitting the measured cross sections using recently updated theoretical models for the process. The resulting value for the decay width is Γ(π0→γγ)=7.82±0.14(stat)±0.17(syst) eV. With the 2.8% total uncertainty, this result is a factor of 2.5 more precise than the current Particle Data Group average of this fundamental quantity, and it is consistent with current theoretical predictions. 相似文献
1000.
Tom R. Wendland Brian S. Muntean Jaskiran Kaur Jhindan Mukherjee Jie Chen Xinxuan Tan Dinesh Attygalle Robert W. Collins Jon R. Kirchhoff L. M. Viranga Tillekeratne 《Electroanalysis》2011,23(10):2275-2279
Thiolated o‐quinone‐capped electrocatalysts modeled on the naturally occurring o‐quinone cofactor pyrroloquinoline quinone (PQQ) were designed and synthesized for the development of biosensor devices. The o‐quinone‐capped electrocatalysts self assembled on gold electrodes through a thiolated phenyleneethynylene linkage to form a monolayer less than 2 nm in thickness. Cyclic voltammetric measurements demonstrated reversible electrochemical properties between the quinone and hydroquinone forms of the head group. In an amperometric sensing mode, the modified electrodes reproducibly detected ethanethiol at micromolar levels demonstrating their robust electrocatalytic activity toward thiols. Their redox cycling and electrocatalytic properties show promise for detection of biologically important thiols and other nucleophiles. 相似文献