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221.
Abouzaid E Arenton M Barker AR Bellantoni L Blucher E Bock GJ Cheu E Coleman R Corcoran MD Cox B Erwin AR Escobar CO Glazov A Golossanov A Gomes RA Gouffon P Hsiung YB Jensen DA Kessler R Kotera K Ledovskoy A McBride PL Monnier E Nguyen H Niclasen R Phillips DG Ping H Ramberg EJ Ray RE Ronquest M Santos E Slater W Smith D Solomey N Swallow EC Toale PA Tschirhart R Velissaris C Wah YW Wang J White HB Whitmore J Wilking MJ Winston R Worcester ET Worcester M Yamanaka T Zimmerman ED 《Physical review letters》2011,107(20):201803
The KTeV E799 experiment has conducted a search for the rare decays, K(L)→π(0)π(0)μ(+)μ(-) and K(L)→π(0)π(0)X(0)→π(0)π(0)μ(+)μ(-), where the X(0) is a possible new neutral boson that was reported by the HyperCP experiment with a mass of (214.3 ± 0.5) MeV/c(2). We find no evidence for either decay. We obtain upper limits of Br(K(L)→π(0)π(0)X(0)→π(0)π(0)μ(+)μ(-)) < 1.0 × 10(-10) and Br(K(L)→π(0)π(0)μ(+)μ(-)) < 9.2 × 10(-11) at the 90% confidence level. This result rules out the pseudoscalar X(0) as an explanation of the HyperCP result under the scenario that the dsX(0) coupling is completely real. 相似文献
222.
A general algorithm is presented that computes the stress-field parameters for opening-mode crack problems in a least-squares
sense from full-field moiré or speckle-displacement fringe patterns. The algorithm can be used in the presence of rigid-body
rotation and does not require absolute fringe numbering. Extensive numerical experiments were conducted with the algorithm
to determine the sensitivity of the method to experimental errors. Small random position errors in locating the fringe maxima
were found to have a negligible influence on the stress-intensity-factor calculation when the number of data points was about
ten times greater than the number of unknown stress-field parameters. It was also found that systematic position errors due
to an incorrectly specified crack-tip location could be minimized by assuming various crack-tip locations in the vicinity
of the actual crack tip and selecting the best fit results. Bothu andv fields were found to be equally suitable for determination of the stress-intensity factor.
Paper was presented at 1983 SESA Spring Meeting held in Cleveland, OH on May 15–19, 1983. 相似文献
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Lasse Murtomki Michael H. Barker Jos A. Manzanares Kysti Kontturi 《Journal of Electroanalytical Chemistry》2003,560(2):95-103
The rate of ion transfer across the supported liquid membrane (SLM) is studied in the rotating diffusion cell (RDC), varying the chemical composition of the SLM from net-cloth supported gel membranes to radiation-grafted polymer membranes. Steady-state current–voltage curves are measured as a function of the rotation rate, and values for the standard rate constant, k0, are determined for a series of tetraalkylammonium cations from the analysis of the initial slopes and the diffusion limiting currents. The analysis gives values for k0 of the order of 10−2–10−4 cm s−1, which is in rather good agreement with the values found in the literature for this type of the system. As controlled delivery of ionic drugs can be achieved by control of the electric current, whereby the SLM acts as a drug reservoir, the study is extended to the release of the anti-Alzheimer drug Tacrine, where ion-exchange fibers are embedded in the membrane as the drug carrier. Our previous transient experiments are also discussed, and it is suggested that their interpretation is seriously hampered by the non-uniform potential distribution, which brings about high capacitive currents. 相似文献
225.
Two species of Hawaiian crustaceans, Portunis sanguinolentus and Podophthalmis vigil, are shown to be effective for the construction of antennular receptrodes. The resulting chemoreceptor-based biosensors respond to stimulant compounds at levels below 10?15 M with very short response times. Experimental studies focused on trimethylamine oxide as a novel test compound, combined with chemometric techniques for data analysis, yield quantitative dose-response data over a wide concentration range. 相似文献
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Summary A semi-continuous chromatographic refiner, the SCCR5, has been used for dextran fractionation. Several operating parameters, such as eluent, feed and purge rate, feed concentration, temperature, switch time, batch of feed, feed column and packing, were varied in order to evaluate the effect they have on the fractionating performance of the chromatographic system. The effects on the separation achieved due to the change in the operating conditions of the SCCR5 unit are discussed. 相似文献
230.
The contribution, ΔC, to the specific heat arising from the spin-phonon interaction is calculated for general spin values. For a given set of spin-phonon coupling constants and cubic symmetry the ratio ΔCmax/ C(Schottky)max for ions having S = 2 or is one or two orders of magnitude greater than that for ions having S = 1 or . The relative low values of ΔC in the latter cases is traced to two distinct reasons, and the differences that the inclusion of a lower symmetry crystals field makes to the ratio is discussed. 相似文献