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1.
The objective of this study was to develop and evaluate a supported capillary membrane sampling-gas chromatography method for the analysis of trihalomethanes (THMs) in drinking water. The effects of experimental parameters, such as flow rate of carrier gas, water temperature, ionic strengths of solutions and transfer line temperature on the system performance were investigated. The results of method detection limit and accuracy and precision studies are reported. 相似文献
2.
Wilson CM Duty T Sandberg M Persson F Shumeiko V Delsing P 《Physical review letters》2010,105(23):233907
We report the observation of photon generation in a microwave cavity with a time-dependent boundary condition. Our system is a microfabricated quarter-wave coplanar waveguide cavity. The electrical length of the cavity is varied by using the tunable inductance of a superconducting quantum interference device. It is measured at a temperature significantly less than the resonance frequency. When the length is modulated at approximately twice the static resonance frequency, spontaneous parametric oscillations of the cavity field are observed. Time-resolved measurements of the dynamical state of the cavity show multiple stable states. The behavior is well described by theory. Our results may be considered a preliminary step towards demonstrating the dynamical Casimir effect. 相似文献
3.
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
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W. A. Macfarlane R. F. Kiefl K. H. Chow S. Dunsiger T. L. Duty T. M. S. Johnston J. W. Schneider J. Sonier L. Brard R. M. Strongin J. E. Fischer A. B. Smith Jr 《Hyperfine Interactions》1994,86(1):467-472
Muon spin relaxation has been observed in both the normal and superconducting states of Rb3C60 (T
c=29.3K). The field dependence of theT
1 spin relaxation rate is due to muonium undergoing spin-exchange scattering with conduction electrons, making this the first observation of muonium in a metal. The temperature dependence ofT
1
–1
shows a Hebel-Slichter coherence peak just belowT
c which is not seen in13C spin relaxation. The peak can be fit assuming spin relaxation due to interaction with the quasiparticle excitations of a BCS superconductor provided the density of states is broadened relative to that of BCS. Such fits yield a value for the zero temperature energy gap, 0/k
B
, of 53(4)K, consistent with weak-coupling BCS. 相似文献
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T. L. Duty J. H. Brewer K. Chow R. F. Kiefl A. W. MacFarlane G. D. Morris J. W. Schneider B. Hitti R. Lichti L. Brard J. E. Fischer A. B. Smith Jr R. M. Strongin 《Hyperfine Interactions》1994,86(1):789-795
The Co60Mu radical in polycrystalline C60 has been studied in zero magnetic field between 9 K and 200 K, and at room temperature. At low temperatures, we observe three low-frequency oscillations which correspond to the intra-triplet transitions of a completely anisotropic muon-electron hyperfine interaction. These signals exhibit a strongly temperature-dependent T1, attributed to thermally-activated jump rotational diffusion of the C60Mu radical. A fit to an Arhenius law yields an activation energy of 200(20) meV for temperatures below the fcc-sc structural phase transition. At room temperature only the motionally-narrowed 325 MHz singlet-triplet transition is observed. 相似文献
8.
Duty T Johansson G Bladh K Gunnarsson D Wilson C Delsing P 《Physical review letters》2005,95(20):206807
We have fabricated a Cooper-pair transistor (CPT) with parameters such that for appropriate voltage biases, it behaves essentially like a single Cooper-pair box (SCB). The effective capacitance of a SCB can be defined as the derivative of the induced charge with respect to gate voltage and has two parts, the geometric capacitance, C(geom), and the quantum capacitance C(Q). The latter is due to the level anticrossing caused by the Josephson coupling and is dual to the Josephson inductance. It depends parametrically on the gate voltage and its magnitude may be substantially larger than C(geom). We have detected C(Q) in our CPT, by measuring the in phase and quadrature rf signal reflected from a resonant circuit in which the CPT is embedded. C(Q) can be used as the basis of a charge qubit readout by placing a Cooper-pair box in such a resonant circuit. 相似文献
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R.W. Johnson C.E. Duty A.G. Fedorov W.J. Lackey 《Applied Physics A: Materials Science & Processing》2008,90(2):333-345
Laser chemical vapor deposition (LCVD) utilizes a laser to localize a CVD reaction. The process involves complex physical
interactions within a very small spatial region. Experimental investigations into the dynamics of the LCVD process are limited
by spatial and resolution capabilities of instrumentation. Models are developed herein using the computational fluid dynamics
(CFD) code, FLUENT, that incorporate heat transfer, fluid flow, and species transport in a single integrated modeling environment.
The models are used to study the carbon deposition process. Insight is gained into the relationships among the process parameters
and the deposition rates and deposition rate profiles. Phenomena such as thermal diffusion and the relative importance of
mass convection and mass diffusion are explored. A designed set of model cases is executed and the results are used to develop
a simple polynomial expression for relating experiment conditions to deposit attributes.
PACS 81.10.Bk; 81.05.Uw; 81.15.Gh; 47.50.Cd; 81.16.Mk 相似文献