Enhancement of quantum correlations between two particles under decoherence in finite temperature environment

Enhancing the quantum correlations in realistic quantum systems interacting with the environment of finite temperature is an important subject in quantum information processing. In this paper, we use weak measurement and measurement reversal to enhance the quantum correlations in a quantum system consisting of two particles. The transitions of the quantum correlations measured by the local quantum uncertainty of qubit-qubit and qutrit-qutrit quantum systems under generalized amplitude damping channels are investigated. We show that, after the weak measurement and measurement reversal, the joint system shows more robustness against decoherence.Comment: 5 pages, 5 figure

The unique rapid variabilities of the iron Kα\alpha line profiles in NGC 4151

We present a detailed analysis of the iron K$\alpha$ line variabilities in NGC 4151 by using long ASCA observation data obtained in May 1995. Despite the relatively small amplitude variations in the continuum flux, the iron K$\alpha$ line flux and profile show dramatic variations. Particularly, the line profile changes from single peak to seeming double peaks and back in time scales of a few 10$^4$ sec. The seemingly double-peaked profiles can be well interpreted as line emission from a Keplerian ring around a massive black hole. An absorption line at around 5.9 keV is also marginnaly detected. We discussed current Fe K line models, but none of them can well explain the observed line and continuum variations.Comment: 18 pages, latex, 3 figures, ApJ accepte

Numerical simulation on the impact dynamics of a novel rotation air hammer and experimental research

Novel rotation air hammer (NRAH) is a rock-breaking tool in the gas drilling. The rock-breaking ability of the NRAH is mainly from the collision between piston and drill bit in it. The collision makes the piston and the drill bit suffer from a high instantaneous impact stress, so that they are prone to failure. Thus, both of them are not only the most crucial parts of the NRAH, but also the easily damaged parts. So it is necessary to analyze the impact stress in them and optimize their structure to improve the security and reliability. First of all, we analyzed the working mechanism of the NRAH to understand motion and structure of the piston and the drill bit. Then we used the LS-DYNA program to analyze impact dynamics problem of the piston and the drill bit to obtain their stress change rule in the impact process. According to the structure optimization, the security coefficient of the piston and the drill bit has been obviously improved. Moreover, their energy conversion regulations were studied in the impact process of the NRAH and the last impacting velocity of the piston was computed, which can provide helpful for effective application of this tool in the field. Finally, based on the experimental study on the NRAH after the optimization, we found that its function had satisfied the design requirements as well as overall performance was improved

10-Ethyl-3-(5-methyl-1,3,4-oxadiazol-2-yl)-10H-phenothia­zine

In the title compound, C17H15N3OS, the phenothia­zine ring system is slightly bent, with a dihedral angle of 13.68 (7)° between the benzene rings. The dihedral angle between the oxadiazole ring and the adjacent benzene ring is 7.72 (7)°. In the crystal, a π–π inter­action with a centroid–centroid distance of 3.752 (2) Å is observed between the benzene rings of neighbouring mol­ecules

Evidence for a population of beamed radio intermediate quasars

Whether radio intermediate quasars possess relativistic jets as radio-loud quasars is an important issue in the understanding of the origin of radio emission in quasars. In this letter, using the two-epoch radio data obtained during Faint Image of Radio Sky at Twenty centimeter sky (FIRST) and NOAO VLA Sky Survey (NVSS), we identify 89 radio variable sources in the Sloan Digital Sky Survey. Among them, more than half are radio intermediate quasars (RL=f2cm/f2500A<250). For all objects with available multiple band radio observations, the radio spectra are either flat or inverted. The brightness temperature inferred from the variability is larger than the synchrotron-self Compton limit for a stationary source in 87 objects, indicating of relativistic beaming. Considering the sample selection and viewing angle effect, we conclude that relativistic jets probably exist in a substantianl fraction of radio intermediate quasars.Comment: 15 pages, 4 figures, 1 table, Accepted to the Astrophysical Journa

Emission Line-Ultraviolet to X-Ray Continuum Correlations: Constraints on the Anisotropy of the Ionizing Continuum in Active Galactic Nuclei

Anisotropic emission of the ionizing continuum is a general prediction of the accretion disk models. In this paper, we present the results of correlation analysis of the UV emission line and UV to X-ray continuum properties for a large sample of broad emission line AGNs observed with ROSAT, IUE and HST. We find strong correlations between the CIV/$Ly\alpha$ ratio, the equivalent width of CIV, and the UV to soft X-ray spectral slope. The results are in good agreement with the photoionization calculation, suggesting that the overall ionizing continuum can well match the observed UV to soft X-ray spectrum. These results are consistent with the assumption of isotropic ionizing continuum shape. Our analysis suggests a small range for the ``big blue bump'' cutoff energy for the objects in this sample, consistent with the similar results of Laor et al. (1997) and Walter & Fink (1993) based on the continuum properties . The mean UV-to-X-ray spectral slope is similar to the soft X-ray spectral slope. This similarity also holds for radio-loud and radio-quiet objects separately. This suggests that the two might be drawn from the same distribution. The two spectral slopes are only weakly correlated. The UV to X-ray spectral index is correlated with absolute optical magnitude. This result confirms the earlier suggestion that the ionizing continua are softer for higher luminosity objects.Comment: Accepted for publication in the Astrophysical Journal. 15 pages AAStex + 5 figures + three table

The broad Fe K line profile in NGC 4151

We present an analysis of the Fe K line profile of NGC 4151 by using long ASCA observation data obtained in May 1995. The unprecedented good data quality, which is much better in the energy band around 6.4 keV than that of the famous 4.2-day ASCA observation of MCG -6-30-15 in July 1994, offers a unique opportunity to study the details of Fe K line profile. Apart from those characteristics already noticed in earlier ASCA observations on this object (Yaqoob et al. 1995): a broad and skewed profile, with a strong peak at about 6.4 keV and a large red wing extending to $\sim$4 - 5 keV, which is remarkably similar to that of MCG -6-30-15, we also find a weak blue wing extending to about 8 keV, thanks to the good quality of the data. When fitted by a relativistic accretion disk line plus a narrow core at 6.4 keV, the data constrain the accretion disk to be nearly face-on, contrary to the edge-on geometry inferred from optical and UV observations. However, the extended blue wing can not be well fitted even after we include corresponding Fe K$\beta$ components. Ni K$\alpha$ line emission by an amount of 12% of Fe K$\alpha$ is statistically required. An alternative explanation is a model consisting of a narrow core and two disk lines with inclinations of 58$^{\rm o}$ and 0$^{\rm o}$, respectively. We suppose that the component with inclination of 58$^{\rm o}$ was observed directly, consistent with its edge-on geometry, and the component with inclination of 0$^{\rm o}$ was scattered into our line of sight by a Compton mirror, which might be the cool accretion disk corona proposed by Poutanen et al. (1996).Comment: 15 pages, including 2 figures, aasms4.sty. To appear in ApJL 52

Methyl 2-[(E)-(4-nitro­phen­yl)hydrazono]-3-oxobutyrate

The mol­ecule of the title compound, C11H11N3O5, exists as the E isomer as it is stabilized by an intra­molecular hydrogen bond. Except for the methyl H atoms, all atoms lie in special positions on a mirror plane and form a large conjugated system; the methyl H atoms are disordered about the mirror plane. In the crystalline state, bifurcated intra- and inter­molecular N—H⋯O hydrogen bonds and four inter­molecular C—H⋯O hydrogen bonds link the mol­ecules into large perfectly planar sheets. Along the c axis, the N—N bond center approaches the phenyl-ring centroids of its neighbouring mol­ecules above and below to give π–π overlap (at a distance of ca 3.57 Å), thus fusing the mol­ecules into a three-dimensional framework