Narrow double-peaked emission lines of SDSS J131642.90+175332.5: signature of a single or a binary AGN in a merger, jet-cloud interaction, or unusual narrow-line region geometry

We present an analysis of the active galaxy SDSS J131642.90+175332.5, which is remarkable because all of its narrow emission lines are double-peaked, and because it additionally shows an extra broad component (FHWM ~ 1400 km/s) in most of its forbidden lines, peaking in between the two narrow systems. The peaks of the two narrow systems are separated by 400--500 km/s in velocity space. The spectral characteristics of double-peaked [O III] emission have previously been interpreted as a signature of dual or binary active galactic nuclei (AGNs), among other models. In the context of the binary scenario, SDSS J131642.90+175332.5 is a particularly good candidate because not just one line but all of its emission lines are double-peaked. However, we also discuss a number of other scenarios which can potentially account for double-peaked narrow emission lines, including projection effects, a two-sided outflow, jet-cloud interactions, special narrow-line region (NLR) geometries (disks, bars, or inner spirals), and a galaxy merger with only one AGN illuminating two NLRs. We argue that the similarity of the emission-line ratios in both systems, and the presence of the very unusual broad component at intermediate velocity, makes a close pair of unrelated AGNs unlikely, and rather argues for processes in a single galaxy or merger. We describe future observations which can distinguish between these remaining possibilities.Comment: ApJ Letters, 705, L20-L24, 2009 (November 1 issue); incl. 2 colour figure

Review and data analysis of low salinity water effect through induced fine migration

Low salinity water flooding (LSWF) is well proved to be an effective EOR technology both in laboratory and field tests, however, the conditions for LSWF to work and EOR mechanism is still debatable. Up till now, many mechanisms have been proposed to explain the incremental oil recovery in sandstone by LSWF, for instance, fine migration, ionic exchange, wettability alteration and pH increase. In this study, we only focus on low salinity water flooding effect through induced fine migration mechanism. The objective of this study is to conduct a comprehensive analysis using statistical analysis methods and explaining the mechanism of fine migration and its impact during low salinity water flooding in sandstone reservoirs. First, we extracted data from a large number of LSWF flooding tests using sandstone core samples that have been published to date (by January 2019), and analyzed the permeability and injected pressure difference change during the flooding process results collectively. In most of the sandstone flooding experiments, the permeability will decrease because of the migration of fine particles except some cores with extremely high initial permeability. Secondly, according to the particles detachment model six rock/fluid system properties are pointed out to be the reason of particles detachment in porous media, including clay minerals concentration, injection brine velocity, brine salinity, brine pH, divalent ion concentration and oil viscosity. Experimental results are collected, organized and analyzed, from different papers, different authors and comprehensive analysis were made to reveal the impact of high relative rock/fluid system properties on permeability change and oil recovery --Abstract, page iii

Thermo-Mechanical Coupling Analysis of a Diesel Engine Piston

As the research object to a certain type of diesel engine pistons, a three-dimensional finite element analysis model is established. Piston stress is calculated under the conditions of thermal load, mechanical load and coupled load. Results show that, the main cause of the piston safety, the piston deformation and the great stress is the temperature, so it is feasible to further decrease the piston temperature with structure optimization

Electric dipole sheets in BaTiO3_{3}/BaZrO3_{3} superlattices

We investigate two-dimensional electric dipole sheets in the superlattice made of BaTiO$_{3}$ and BaZrO$_{3}$ using first-principles-based Monte-Carlo simulations and density functional calculations. Electric dipole domains and complex patterns are observed and the complex dipole structures with various symmetries (e.g. Pma2, Cmcm and Pmc2_{1}) are further confirmed by density functional calculations, which are found to be almost degenerate in energy with the ferroelectric ground state of the Amm2 symmetry, therefore strongly resembling magnetic sheets. More complex dipole patterns, including vortices and anti-vortices, are also observed, which may constitute the intermediate states that overcome the high energy barrier of different polarization orientations previously predicted by Lebedev\onlinecite{Lebedev2013}. We also show that such system possesses large electrostrictive effects that may be technologically important