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571.
Dr. Haslina Ahmad Benedict W. Hazel Dr. Anthony J. H. M. Meijer Dr. Jim A. Thomas Dr. Karl A. Wilkinson 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(16):5081-5087
Metal‐ion‐directed self‐assembly has been used to construct kinetically inert, water‐soluble heterometallic Ru2Re2 hosts that are potential sensors for bioanions. A previously reported metallomacrocycle and a new derivative synthesised by this approach are found to be general sensors for bioanions in water, showing an “off–on” luminescent change that is selective for nucleotides over uncharged nucleobases. Through a change in the ancillary ligands coordinated to the ruthenium centres of the host, an “off–on” sensor has been produced. Whilst this host only shows a modest enhancement in binding affinities for nucleotides relative to the other two host systems, its sensing response is much more specific. Although a distinctive “off–on” luminescence response is observed for the addition of adenosine triphosphosphate (ATP), related structures such as adenine and guanosine triphosphate (GTP) do not induce any emission change in the host. Detailed and demanding DFT studies on the ATP‐ and GTP‐bound host–guest complexes reveal subtle differences in their geometries that modulate the stacking interactions between the nucleotide guests and the ancillary ligands of the host. It is suggested that this change in stacking geometries affects solvent accessibility to the binding pocket of the host and thus leads to observed difference in the host luminescence response to the guests. 相似文献
572.
Laser drilling of high aspect ratio holes in copper with femtosecond,picosecond and nanosecond pulses 总被引:1,自引:0,他引:1
A. Weck T.H.R. Crawford D.S. Wilkinson H.K. Haugen J.S. Preston 《Applied Physics A: Materials Science & Processing》2008,90(3):537-543
Deep laser holes were drilled in copper sheets using various pulse lengths and environments. By recording the intensity on
a photodiode placed under the sample while drilling the holes, we obtained the number of pulses to drill through the sheet
as a function of pulse length and energy. The entrance diameter of the holes was successfully predicted using a Gaussian approximation
and a material removal fluence threshold of 0.39 J/cm2 for a pulse length of 150 fs. From cross sections of the holes, the morphology of the inside walls was observed and shows
an increase in the amount of molten material with pulse length. A transition pulse length is defined as the point at which
the laser affected material goes from being mainly vaporized to mainly melted. This transition occurs near ∼10 ps, which corresponds
approximately to the electron–phonon relaxation time for copper.
PACS 62.20.Mk; 62.25.+g; 79.20.Ds 相似文献
573.
Athar SB Patel R Yelton J Rubin P Eisenstein BI Karliner I Mehrabyan S Lowrey N Selen M White EJ Wiss J Mitchell RE Shepherd MR Besson D Pedlar TK Cronin-Hennessy D Gao KY Hietala J Kubota Y Klein T Lang BW Poling R Scott AW Zweber P Dobbs S Metreveli Z Seth KK Tomaradze A Libby J Powell A Wilkinson G Ecklund KM Love W Savinov V Lopez A Mendez H Ramirez J Ge JY Miller DH Shipsey IP Xin B Adams GS Anderson M Cummings JP Danko I Hu D Moziak B Napolitano J He Q Insler J Muramatsu H Park CS 《Physical review letters》2008,100(18):181802
Using e+e--->Ds*-Ds+ data collected near the peak Ds production energy, Ecm=4170 MeV, with the CLEO-c detector, we present the first observation of the decay Ds+-->pn. We measure a branching fraction B(Ds+-->pn)=(1.30+/-0.36(-0.16)+0.12)x10(-3). This is the first observation of a charmed meson decaying into a baryon-antibaryon final state. 相似文献
574.
Dobbs S Metreveli Z Seth KK Tomaradze A Libby J Powell A Wilkinson G Ecklund KM Love W Savinov V Lopez A Mendez H Ramirez J Ge JY Miller DH Shipsey IP Xin B Adams GS Anderson M Cummings JP Danko I Hu D Moziak B Napolitano J He Q Insler J Muramatsu H Park CS Thorndike EH Yang F Artuso M Blusk S Khalil S Li J Mountain R Nisar S Randrianarivony K Sultana N Skwarnicki T Stone S Wang JC Zhang LM Bonvicini G Cinabro D Dubrovin M Lincoln A Naik P Rademacker J Asner DM Edwards KW Reed J Briere RA 《Physical review letters》2008,101(18):182003
A precision measurement of the mass of the h_{c}(1P1) state of charmonium has been made using a sample of 24.5x10;{6} psi(2S) events produced in e;{+}e;{-} annihilation at the Cornell Electron Storage Ring (CESR). The reaction used was psi(2S)-->pi;{0}h_{c}, pi;{0}-->gammagamma, h_{c}-->gammaeta_{c}, and the reaction products were detected in the CLEO-c detector. Data have been analyzed both for the inclusive reaction and for the exclusive reactions in which eta_{c} decays are reconstructed in 15 hadronic decay channels. Consistent results are obtained in the two analyses. The averaged results of the present measurements are M(h_{c})=3525.28+/-0.19(stat.)+/-0.12(syst.) MeV, and B(psi(2S)-->pi;{0}h_{c})xB(h_{c}-->gammaeta_{c})=(4.19+/-0.32+/-0.45)x10;{-4}. Using the ;{3}P_{J} centroid mass, DeltaM_{hf}(1P) identical withM(chi_{cJ})-M(h_{c})=+0.02+/-0.19+/-0.13 MeV. 相似文献