نتایج جستجو برای: 2s
تعداد نتایج: 6212 فیلتر نتایج به سال:
For the excitation of n = 2 states hydrogen atoms due to electron impact, we compared experimental and theoretical ratios cross-sections ?2s/?2p. We found this ratio be systematically higher than corresponding by about 20%—far beyond error margins. suggest that discrepancy can explained presence Second Flavor Hydrogen Atoms (SFHA) in gas. The explanation is based on fact that, experiments, cros...
Following the observation of fully heavy tetraquark candidates $X(6900)$ and possible $X(6300)$ in di-$J/\ensuremath{\psi}$ spectrum by LHCb Collaboration, we investigate near-threshold dynamics pseudoscalar quarkonium pairs a coupled-channel approach di-${\ensuremath{\eta}}_{c}$ channel. We show that Pomeron exchange mechanism should be general pair interactions. In channel, system involving d...
abstract three pear genotypes (nazkeh, lasoreh and qevilah), grown in 2l containers, were studied under four irrigation regimes in order to evaluate the leaf relative water content (rwc), photosynthesis, leaf gas exchanges and plant dry weight induced by water stress. control treatment everyday was irrigation. irrigation was practiced when soil water potential reached at -0.4, -0.8, and -1.2 mp...
We report the observations of the decays B+ → ψ(2S)K+ and B0 → ψ(2S)K∗(892)0 in pp̄ collisions at a center-of-mass energy of 1.8 TeV using a 110 pb−1 data sample recorded by the Collider Detector at Fermilab. We also reconstruct the decays B+ → J/ψK+ and B0 → J/ψK∗(892)0 and measure the six ratios of branching fractions of these four decays. The relative branching-fraction results are shown to b...
The rates for magnetic dipole (M1) transitions Υ(nS) → ηb(n S) + γ, n ≤ n, are compared. The photon energies for allowed (n = n) M1 transitions are very small, so hindered (n < n) transitions could be more favorable for discovering the ηb(1S, 2S). The question then arises whether Υ(2S) or Υ(3S) is a better source of ηb(1S). Whereas one nonrelativistic model favors ηb(1S) production from Υ(2S), ...
Although the growth and proliferation of most tumors is fueled by glucose, some tumors are more likely to metabolize glutamine. In particular, tumor cells with the upregulated c-Myc gene are generally reprogrammed to utilize glutamine. We have developed new 3-fluoropropyl analogs of glutamine, namely [(18)F](2S,4R)- and [(18)F](2S,4S)-4-(3-fluoropropyl)glutamine, 3 and 4, to be used as probes f...
We report the results of a high-statistics search for H dibaryon production in inclusive Υ(1S) and Υ(2S) decays. No indication of an H dibaryon with a mass near the M(H)=2m(Λ) threshold is seen in either the H→Λpπ(-) or ΛΛ decay channels and 90% confidence level branching-fraction upper limits are set that are between one and two orders of magnitude below the measured branching fractions for in...
An optical spectropolarimetric study has shown that the detectability of polarised broad Hα in Seyfert 2 galaxies is correlated to the IRAS f 60 /f 25 flux ratio where only those Seyfert 2s with " warm " IRAS colours show polarised broad line emission. It was suggested that those Seyfert 2s with " cool " IRAS colours have highly inclined tori which obscure the broad line scattering screen. I pr...
The terminal enzyme of heme biosynthesis, ferrochelatase (EC 4.99.1.1), catalyzes the insertion of ferrous iron into protoporphyrin IX to form protoheme. Prior to the present work, [2Fe-2S] clusters have been identified and characterized in animal ferrochelatases but not in plant or prokaryotic ferrochelatases. Herein we present evidence that ferrochelatases from the bacteria Caulobacter cresce...
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