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31.
W.A. MacFarlane R.F. Kiefl J.E. Fischer S.R. Dunsiger J.E. Sonier J. Chakhalian K.H. Chow 《Hyperfine Interactions》1997,105(1-4):77-82
We report ZF μSR measurements in Cs1C60 at low temperature and LF μSR in the superconductor Rb3C60. In Cs1C60, the internal magnetic field distribution is broad and static, and the relaxation at 1.9 K resembles that of a spin density
wave. In Rb3C60, we observe a strong field dependence to the coherence peak in the LF relaxation rate of endohedral muonium ( Mu@C60) at anomalously low field and a residual low temperature relaxation.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
32.
J.A. Chakhalian S.R. Dunsiger R.F. Kiefl W.A. MacFarlane J.E. Sonier B. Hitti J. Fischer 《Hyperfine Interactions》1997,106(1-4):245-249
We describe a simple method by which time differential μSR spectra are collected on two different samples simultaneously.
One application is to make accurate measurements of the muon precession frequency in a sample relative to a reference. As
an example we report precise measurements of the muon Knight shift on HOPG graphite with H parallel to \hat c as a function
of temperature.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
33.
T.M.S. Johnston K.H. Chow S. Dunsiger T. Duty R.F. Kiefl E. Koster W.A. MacFarlane G.D. Morris J. Sonier D.Ll. Williams 《Hyperfine Interactions》1997,106(1-4):71-76
A detailed study has been undertaken of the muon Knight shift in high purity antimony single crystals. No periodic variations
with magnetic field (de Haas–van Alphen oscillations) are observed. The temperature dependence below 175 K is close to that
expected for a Kondo‐like impurity with an anisotropic muon–electron hyperfine interaction. At higher temperatures the paramagnetic
state becomes unstable and a transition occurs to a second state. The longitudinal relaxation rate rises from an apparently
non‐zero value at T=0 to a maximum at 50 K, followed by a slow decline. This leads to a Korringa product which is strongly
temperature dependent.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
34.
S.R. Dunsiger R.F. Kiefl K.H. Chow B.D. Gaulin M.J.P. Gingras J.E. Greedan A. Keren K. Kojima G.M. Luke W.A. MacFarlane N.P. Raju J.E. Sonier Y.J. Uemura W.D. Wu 《Hyperfine Interactions》1997,104(1-4):275-280
In a system where magnetic ions occupy the vertices of edge or corner sharing triangular units, the natural antiferromagnetic
coupling between ions is geometrically frustrated. A wide variety of interesting magnetic behaviour has been observed in pyrochlores,
where magnetic ions form a network of corner sharing tetrahedra. The low temperature spin dynamics of a number of pyrochlores
A2B2O7 have been investigated using the technique of μ SR. For example, Y2Mo2O7 shows a transition to a disordered magnetic state similar to a spin glass at TF=22 K. However, unlike conventional metallic spin glasses, a non‐zero muon spin depolarization rate is observed to persist
well below 0.1\ TF. These results suggest that there is a finite density of states for magnetic excitations in this system near zero energy.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
35.
36.
Len Roza Kees J. M. van der Wulp Sandra J. MacFarlane Paul H. M.Lohman Robert A. Baan 《Photochemistry and photobiology》1988,48(5):627-633
Abstract— A hybrid cell line (hybridoma) has been isolated after fusion between mouse-plasmacytoma cells and spleen cells from mice immunized with a thymine dimer-containing tetranucleotide coupled to a carrier protein. Monoclonal antibodies produced by this hybridoma were characterized by testing the effect of various inhibitors in a competitive enzyme-linked immunosorbent assay (ELISA). The antibodies have a high specificity for thymine dimers in single-stranded DNA or poly(dT), but do not bind UV-irradiated d(TpC)5 . Less binding is observed with short thymine dimer-containing sequences. In vitro treatment of UV-irradiated DNA with photoreactivating enzyme in the presence of light, or with Micrococcus luteus UV-endonuclease results in disappearance of antigenicity. Antibody-binding to DNA isolated from UV-irradiated human fibroblasts (at 254 nm) is linear with dose. Removal of thymine dimers in these cells during a post-irradiation incubation, as detected with the antibodies, is fast initially but the rate rapidly decreases (about 50% residual dimers at 20 h after 10 J/m2 ). The induction of thymine dimers in human skin irradiated with low doses of UV-B, too, was demonstrated immunochemically, by ELISA as well as by quantitative immunofluorescence microscopy. 相似文献
37.
38.
Rapid,clean, and mild O-acetylation of alcohols and carbohydrates in an ionic liquid 总被引:2,自引:0,他引:2
Forsyth SA MacFarlane DR Thomson RJ von Itzstein M 《Chemical communications (Cambridge, England)》2002,(7):714-715
Archetypal O-acetylation reactions of alcohols and carbohydrates proceed rapidly in high yield under mild conditions in a dicyanamide based ionic liquid, that is not only an effective solvent but also an active base catalyst. 相似文献
39.
Schrödle S Annat G MacFarlane DR Forsyth M Buchner R Hefter G 《Chemical communications (Cambridge, England)》2006,(16):1748-1750
Dielectric relaxation measurements as a function of temperature, and of concentration in a non-coordinating solvent, the first reported for an ionic liquid, indicate a crossover in the relaxation mechanism due to varying levels of ion aggregation and the interplay of formation kinetics and relaxation dynamics of associates. 相似文献
40.
Jaka Sunarso Youssof Shekibi Jim Efthimiadis Liyu Jin Jennifer M. Pringle Anthony F. Hollenkamp Douglas R. MacFarlane Maria Forsyth Patrick C. Howlett 《Journal of Solid State Electrochemistry》2012,16(5):1841-1848
Organic ionic plastic crystal (OIPC) electrolytes are among the key enabling materials for solid-state and higher than ambient
temperature lithium batteries. This work overviews some of the parameter studies on the Li|OIPC interface using lithium symmetrical
cells as well as the optimisation and performance of Li|OIPC|LiFePO4 cells. The effects of temperature and electrolyte thickness on the cycle performance of the lithium symmetrical cell, particularly
with respect to the interfacial and bulk resistances, are demonstrated. Whilst temperature change substantially alters both
the interfacial and bulk resistance, changing the electrolyte thickness predominantly changes the bulk resistance only. In
addition, an upper limit of the current density is demonstrated, above which irreversible processes related to electrolyte
decomposition take place. Here, we demonstrate an excellent discharge capacity attained on LiFePO4|10 mol% LiNTf2-doped [C2mpyr][NTf2]|Li cell, reaching 126 mAh g-1 at 50 °C (when the electrolyte is in its solid form) and 153 mAh g-1 at 80 °C (when the electrolyte is in its liquid form). Most remarkably, at high temperature operation, the capacity retention
at long cycles and high current is excellent with only a slight (3%) drop in discharge capacity upon increasing the current
from 0.2 C to 0.5 C. These results highlight the real prospects for developing a lithium battery with high temperature performance
that easily surpasses that achievable with even the best contemporary lithium-ion technology. 相似文献