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121.
T. A. Armstrong M. Benayoun I. J. Bloodworth J. N. Carney C. Evangelista B. R. French B. Ghidini M. Girone A. Jacholkowski J. Kahane J. B. Kinson A. Kirk K. Knudson V. Lenti Ph. Leruste A. Malamant J. L. Narjoux F. Navach A. Palano N. Redaelli L. Rossi M. Sené R. Sené M. Stassinaki G. Vassiliadis O. Villalobos Baillie M. F. Votruba G. Zito 《Zeitschrift fur Physik C Particles and Fields》1993,58(2):257-265
We have performed a search for vector-vector final states centrally produced in proton proton interactions at 300 GeV/c using the CERN Ω spectrometer. Evidence is found for ωρ0 production in the reactionpp→p f (2π+2π?2π0)p s and for ωω production in the reactionpp→p f (2π+2π?2π0)p s . However no evidence is found for ωø production in the reactionpp→p f (K + K ?π+π?π0)p s . 相似文献
122.
In many cell types, oscillations in the concentration of free intracellular calcium ions are used to control a variety of cellular functions. It has been suggested [J. Sneyd et al., "A method for determining the dependence of calcium oscillations on inositol trisphosphate oscillations," Proc. Natl. Acad. Sci. U.S.A. 103, 1675-1680 (2006)] that the mechanisms underlying the generation and control of such oscillations can be determined by means of a simple experiment, whereby a single exogenous pulse of inositol trisphosphate (IP(3)) is applied to the cell. However, more detailed mathematical investigations [M. Domijan et al., "Dynamical probing of the mechanisms underlying calcium oscillations," J. Nonlinear Sci. 16, 483-506 (2006)] have shown that this is not necessarily always true, and that the experimental data are more difficult to interpret than first thought. Here, we use geometric singular perturbation techniques to study the dynamics of models that make different assumptions about the mechanisms underlying the calcium oscillations. In particular, we show how recently developed canard theory for singularly perturbed systems with three or more slow variables [M. Wechselberger, "A propos de canards (Apropos canards)," Preprint, 2010] applies to these calcium models and how the presence of a curve of folded singularities and corresponding canards can result in anomalous delays in the response of these models to a pulse of IP(3). 相似文献
123.
It has been speculated that the application of nanofluids in real systems could lead to smaller, more compact heat exchangers
and reductions in material cost. However, few studies have been conducted which have carefully measured the thermo-physical
properties and thermal performance of these fluids as well as examine the system-level effects of using these fluids in traditional
cooling systems. In this study, dilute suspensions of 10 nm aluminum oxide nanoparticles in propanol (0.5, 1, and 3 wt%) were
investigated. Changes in density, specific heat, and thermal conductivity with particle concentration were measured and found
to be linear, whereas changes in viscosity were nonlinear and increased sharply with particle loading. Nanofluid heat transfer
performance data were generally commensurate with that measured for the baseline. For the 1 wt% concentration, a small but
significant enhancement in the heat transfer coefficient was recorded for 1800 < Re < 2800, which is attributed to an earlier
transition to turbulent flow. In the case of high particle loading (i.e. 3 wt%), the thermal performance was observed to deteriorate
with respect to the baseline case. Discoloration of the fluid was also observed after being cycled at high flow rates and
increased temperature. 相似文献
124.
Feng S Liang Q Kinser RD Newland K Guilbaud R 《Analytical and bioanalytical chemistry》2006,385(5):975-981
A modified interval hypothesis testing procedure based on paired-sample analysis is described, as well as its application in testing equivalence between two bioanalytical laboratories or two methods. This testing procedure has the advantage of reducing the risk of wrongly concluding equivalence when in fact two laboratories or two methods are not equivalent. The advantage of using paired-sample analysis is that the test is less confounded by the intersample variability than unpaired-sample analysis when incurred biological samples with a wide range of concentrations are included in the experiments. Practical aspects including experimental design, sample size calculation and power estimation are also discussed through examples. 相似文献
125.
Platinum-acetylide polymer based solar cells: involvement of the triplet state for energy conversion
Guo F Kim YG Reynolds JR Schanze KS 《Chemical communications (Cambridge, England)》2006,(17):1887-1889
Relatively efficient photovoltaic devices were fabricated using blends of a phosphorescent platinum-acetylide polymer and a fullerene (PCBM); involvement of the triplet excited state of the platinum-acetylide polymer in photoinduced charge transfer is believed to contribute to the device efficiency. 相似文献
126.
127.
Imaging of cell nuclei plays a critical role in cancer diagnosis and prognosis. To image noninvasively cell nuclei in vivo without staining, we developed UV photoacoustic microscopy (UV-PAM), in which 266 nm wavelength UV light excites unlabeled DNA and RNA in cell nuclei to produce photoacoustic waves. We applied UV-PAM to ex vivo imaging of cell nuclei in a mouse lip and a mouse small intestine and to in vivo imaging of the cell nuclei in the mouse skin. The UV-PAM images of unstained cell nuclei match the optical micrographs of the histologically stained cell nuclei. Given intrinsic optical contrast and high spatial resolution, in vivo label-free UV-PAM has potential for unique biological and clinical application. 相似文献
128.
Kirk A Koch B Scannell R Wilson HR Counsell G Dowling J Herrmann A Martin R Walsh M;MAST team 《Physical review letters》2006,96(18):185001
Edge-localized modes (ELMs) are repetitive instabilities that occur in the outer region of tokamak plasmas. This Letter provides new information on and the implications of the evolution of the filament structures observed during ELMs in the MAST tokamak. The filaments exist for the time over which particles are being released into the scrape off layer. They start off at the plasma edge rotating at the velocity of the pedestal, and then decelerate toroidally and accelerate radially outwards. As the filaments propagate radially they remain aligned with the local magnetic field line. 相似文献
129.
The paper describes a novel transmission electron microscopy (TEM) experiment with in situ ion irradiation designed to improve and validate a computer model. TEM thin foils of molybdenum were irradiated in situ by 1?MeV Kr ions up to ~0.045 displacements per atom (dpa) at 80°C at three dose rates ?5?×?10?6, 5?×?10?5, and 5?×?10?4?dpa/s – at the Argonne IVEM-Tandem Facility. The low-dose experiments produced visible defect structure in dislocation loops, allowing accurate, quantitative measurements of defect number density and size distribution. Weak beam dark-field plane-view images were used to obtain defect density and size distribution as functions of foil thickness, dose, and dose rate. Diffraction contrast electron tomography was performed to image defect clusters through the foil thickness and measure their depth distribution. A spatially dependent cluster dynamic model was developed explicitly to model the damage by 1?MeV Kr ion irradiation in an Mo thin foil with temporal and spatial dependence of defect distribution. The set of quantitative data of visible defects was used to improve and validate the computer model. It was shown that the thin foil thickness is an important variable in determining the defect distribution. This additional spatial dimension allowed direct comparison between the model and experiments of defect structures. The defect loss to the surfaces in an irradiated thin foil was modeled successfully. TEM with in situ ion irradiation of Mo thin foils was also explicitly designed to compare with neutron irradiation data of the identical material that will be used to validate the model developed for thin foils. 相似文献
130.
In situ self-ion irradiations (150?keV?W+) have been carried out on W and W–5Re at 500?°C, with doses ranging from 1016 to 1018 W+m?2 (~1.0?dpa). Early damage formation (1016W+m?2) was observed in both materials. Black–white contrast experiments and image simulations using the TEMACI software suggested that vacancy loops were formed within individual cascades, and thus, the loop nucleation mechanism is likely to be ‘cascade collapse’. Dynamic observations showed the nucleation and growth of interstitial loops at higher doses, and that elastic loop interactions may involve changes in loop Burgers vector. Elastic interactions may also promote loop reactions such as absorption or coalescence or loop string formation. Loops in both W and W–5Re remained stable after annealing at 500?°C. One-dimensional hopping of loops (b?=?1/2 ?111>) was only seen in W. At the final dose (1018W+m?2), a slightly denser damage microstructure was seen in W–5Re. Both materials had about 3–4?×?1015 loops m?2. Detailed post-irradiation analyses were carried out for loops of size???4?nm. Both b?=?1/2 ?111? (~75%) and b?= ?100> (~25%) loops were present. Inside–outside contrast experiments were performed under safe orientations to determine the nature of loops. The interstitial-to-vacancy loop ratio turned out close to unity for 1/2 ?111? loops in W, and for both 1/2 ?111? and ?100? loops in W–5Re. However, interstitial loops were dominant for ?100? loops in W. Re seemed to restrict loop mobility, leading to a smaller average loop size and a higher number density in the W-Re alloy. 相似文献