Calculation of Kstopped− absorption yields on light nuclei

This paper describes an atomic cascade model which is used to predict the absorption yields for a kaon at low orbits in [Formula: see text]Li,9Be,[Formula: see text]C and [Formula: see text]O nuclei. The calculations show that most of the absorptions occur in [Formula: see text] and [Formula: see text] states so that their contribution adds up to 100% for [Formula: see text]O. However, for all of the targets, absorption in the other states is nearly zero. Also by increasing atomic number of target [Formula: see text], the yield of [Formula: see text] states decreases while it increases for the [Formula: see text] states. The results also display a low sensitivity on the widths of 4[Formula: see text] state (0.1%), in which it is comparable with the natural width of the radiation transition [Formula: see text].

The kHz QPOs as a probe of the X-ray color–color diagram and accretion-disk structure for the atoll source 4U 1728-34

We have taken the kHz QPOs as a tool to probe the correlation between the tracks of X-ray color–color diagram (CCD) and magnetosphere-disk positions for the atoll source 4U 1728-34, based on the assumptions that the upper kHz QPO is ascribed to the Keplerian orbital motion and the neutron star (NS) magnetosphere is defined by the dipole magnetic field. We find that from the island to the banana state, the inner accretion disk gradually approaches the NS surface with the radius decreasing from r ∼ 33.0 km to ∼15.9 km, corresponding to the magnetic field from B(r) ∼ 4.8 × 106 G to ∼4.3 × 107 G. In addition, we note the characteristics of some particular radii of magnetosphere-disk r are: firstly, the whole atoll shape of the CCD links the disk radius range of ∼15.9–33.0 km, which is just located inside the corotation radius of 4U 1728-34 rco (∼34.4 km), implying that the CCD shape is involved in the NS spin-up state. Secondly, the island and banana states of CCD correspond to the two particular boundaries: (I)near the corotation radius at r ∼ 27.2–33.0 km, where the source lies in the island state; (II)near the NS surface at r ∼ 15.9–22.3 km, where the source lies in both the island and banana states. Thirdly, the vertex of the atoll shape in CCD, where the radiation transition from the hard to soft photons occurs, is found to be near the NS surface at r ∼ 16.4 km. The above results suggest that both the magnetic field and accretion environment are related to the CCD structure of atoll track, where the corotation radius and NS hard surface play the significant roles in the radiation distribution of atoll source.

Influence of Polyvinyl Pyrrolidone on Absorption and Radiation Transitions of Mn\(^{2 + }\) ions in Mn-doped ZnS Nanoparticles

ZnS:Mn nanoparticles were synthesized by co-precipitation method from the precursors solutions of 0.1M Zn(CH\(_{3}\)COO)\(_{2}\), Na\(_{2}\)S and Mn(CH\(_{3}\)COO)\(_{2}\) then were capped with polyvinyl pyrrolidone. The XRD patterns showed that the ZnS:Mn nanoparticles possessed the \(T_d^2 - F4\bar {3}m\) cubic structure with the average crystallite size of several nanometers. At 300~K, the obtained photoluminescence spectra showed only a wide yellow-orange band centered at 603 nm, which should be attributed to the radiation transition of [\(^{4}\)T\(_{1}(^{4}\)G)\( \to ^{6}\)A\(_{1}(^{6}\)S)] of Mn\(^{2 + }\)(3d\(^{5})\) cations in the ZnS matrix. The excitation spectra recorded at 300 K on the other hand featured a strong photoluminescence band around 310-334 nm, which were assigned to the near band-edge absorption transition of ZnS host lattice, in addition with three weaker bands relating to the absorption transitions of [\(^{6}\)A\(_{1}(^{6}\)S) \( \to \) \(^{4}\)T\(_{2}(^{4}\)D)]: 430 nm, [\(^{6}\)A\(_{1}(^{6}\)S) \( \to \) \(^{4}\)A\(_{1}(^{4}\)G) -- \(^{4}\)E(\(^{4}\)G)]: 468 nm, and [\(^{6}\)A\(_{1}(^{6}\)S) \( \to ^{4}\)T\(_{2}(^{4}\)G)]: 498 nm of Mn\(^{2 + }\)(3d\(^{5})\) cations. It was shown that the capping affected only the intensities of emissions bands.