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91.
92.
K.E. Gray 《Solid State Communications》1973,13(11):1787-1789
We propose a model to explain the exponential dependence of the electron transmission coefficient through ultra-thin (4–12 Å average thickness) evaporated films of Al2O3. The mechanism involves molecular pinholes in the Al2O3 rather than tunneling. 相似文献
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95.
S.F. Biagi M. Bourquin A.J. Britten R.M. Brown H. Burchhart A.A. Carter J.R. Carter Ch. Doré P. Extermann M. Gailloud C.N.P. Gee W.M. Gibson J.C. Gordon R.J. Gray P. Igo-Kemenes W.C. Louis T. Modis P. Mühlemann R. Weill 《Physics letters. [Part B]》1982,112(3):265-270
The α parameter for Ξ? → Λπ? decay has been determined to be αΞ?=?0.462 ± 0.015, from a sample of 1.5 × 105 events recorded in the CERN SPS hyperon beam. This value is 2.5 standard deviations higher than the current world average. 相似文献
96.
Reductions in MRI-induced heating at 1.5 T resulting from a simple design change to coiled wires were investigated. MRI-induced heating was assessed for two different coiled wire forms (length, 26 cm): (1) multi-filar coiled wire form and (2) multi-filar coiled wire form having a different coiled pitch, providing an air gap spacing between adjacent five-filar coil loops. Each wire had an electrode and was insulated to create a lead, similar to that which would be used for a medical implant. The wire forms were placed in a gelled-saline-filled head/torso phantom and imaged at 1.5 T [whole-body average specific absorption rate (SAR), 1.79 W/kg]. Fluoroptic thermometry probes were used to measure temperatures at the distal ends of the wires. The experiments demonstrated a substantial reduction in MRI-induced heating for the modified wire compared to the unmodified wire (i.e., 10.5 degrees C difference observed in one experiment and 26 degrees C difference in another). These findings have important implications for MRI-induced heating of leads used for medical implants. 相似文献
97.
Wallace KJ Gray M Zhong Z Lynch VM Anslyn EV 《Dalton transactions (Cambridge, England : 2003)》2005,(14):2436-2441
An artificial siderophore in the form of a squaraine dye (1) has been synthesized. The bidentate ligand chelates to Fe(III) between the deprotonated hydroxyl group on the ortho position of the ring adjacent to the carbonyl group of the cyclobutadiene ring. The optical response is due to a subtle geometry change of 1 on chelation to Fe(III). This artificial siderophore forms a 2 ratio 1 ligand ratio metal complex, as indicated by a sigmoidal isotherm (K(a)= 10(7) M(-1)). The optical response on the addition of Fe(III) is observed at low concentrations in comparison to other metal salts. The X-ray crystal structure and calculated structures of dye (1) are also included, and will be discussed. 相似文献
98.
Adam NE Alexander JP Berkelman K Cassel DG Crede V Duboscq JE Ecklund KM Ehrlich R Fields L Galik RS Gibbons L Gittelman B Gray R Gray SW Hartill DL Heltsley BK Hertz D Hsu L Jones CD Kandaswamy J Kreinick DL Kuznetsov VE Mahlke-Krüger H Meyer TO Onyisi PU Patterson JR Peterson D Phillips EA Pivarski J Riley D Ryd A Sadoff AJ Schwarthoff H Shepherd MR Stroiney S Sun WM Urner D Wilksen T Weinberger M Athar SB Avery P Breva-Newell L Patel R Potlia V Stoeck H Yelton J Rubin P Cawlfield C 《Physical review letters》2005,94(23):232002
We describe new measurements of the inclusive and exclusive branching fractions for psi(2S) transitions to J/psi using e(+)e(-) collision data collected with the CLEO detector operating at CESR. All branching fractions and ratios of branching fractions reported here represent either the most precise measurements to date or the first direct measurements. Indirectly and in combination with other CLEO measurements, we determine B(chi(cJ) --> gamma(J/psi)) and B[psi(2S) --> light hadrons]. 相似文献
99.
Allison IF Davies CT Gray A Kronfeld AS Mackenzie PB Simone JN;HPQCD;Fermilab Lattice;UKQCD 《Physical review letters》2005,94(17):172001
We use lattice QCD to predict the mass of the Bc meson. We use the MILC Collaboration's ensembles of lattice gauge fields, which have a quark sea with two flavors much lighter than a third. Our final result is mBc = 6304+/-12(+18)(-0) MeV. The first error bar is a sum in quadrature of statistical and systematic uncertainties, and the second is an estimate of heavy-quark discretization effects. 相似文献
100.
Adams GS Chasse M Cravey M Cummings JP Danko I Napolitano J Cronin-Hennessy D Park CS Park W Thayer JB Thorndike EH Coan TE Gao YS Liu F Stroynowski R Artuso M Boulahouache C Blusk S Butt J Dambasuren E Dorjkhaidav O Menaa N Mountain R Muramatsu H Nandakumar R Redjimi R Sia R Skwarnicki T Stone S Wang JC Zhang K Csorna SE Bonvicini G Cinabro D Dubrovin M Bornheim A Pappas SP Weinstein AJ Briere RA Chen GP Ferguson T Tatishvili G Vogel H Watkins ME Adam NE Alexander JP Berkelman K Cassel DG 《Physical review letters》2005,94(1):012001
The decay branching fractions of the three narrow Upsilon resonances to mu(+)mu(-) have been measured by analyzing about 4.3 fb(-1) e(+)e(-) data collected with the CLEO III detector. The branching fraction B(Upsilon(1S)-->mu(+)mu(-))=(2.49+/-0.02+/-0.07)% is consistent with the current world average, but B(Upsilon(2S)-->mu(+)mu(-))=(2.03+/-0.03+/-0.08)% and B(Upsilon(3S)-->mu(+)mu(-))=(2.39+/-0.07+/-0.10)% are significantly larger than prior results. These new muonic branching fractions imply a narrower total decay width for the Upsilon(2S) and Upsilon(3S) resonances and lower other branching fractions that rely on these decays in their determination. 相似文献