HAZ Phase Transformation and Thermal Damage for Laser Remanufacturing a High-Strength Stainless Steel

It briefly introduced laser remanufacturing, which was an advanced repairing method to refabricate damaged components based on laser forming technologies. The possible factors in determining the performance of the laser remanufacturing FV520B were studied by numerical simulation and experimental methods. First, the results of free dilatometry test showed that the volume effect of phase transformations were corresponding to the transformation temperatures and heating rate of the laser process had remarkable effects on the kinetics of phase transformation. In addition, the evolution of temperature fields of the single-pass and multi-layer laser cladding processes were analyzed by numerical simulation method based on deactivate and reactivate element theory. A combined method of dilatometry and metallography was conducted to reveal the effect of cooling condition and phase transformation on the microstructure of HAZ. The maximum temperature of thermal cycle had a dominating effect on the microstructure, microhardness and phase transformation temperature rather than cooling rate. Thermal cycles had a significant effect on the metallographic transformation and consequently decided the mechanical performance. Microhardness and tensile tests were conducted and the results showed that strength and ductility of laser remanufacturing FV520B were equivalent to that of forgings

Can cosmologically-coupled mass growth of black holes solve the mass gap problem?

Observations of elliptical galaxies suggest that black holes (BHs) might serve as dark energy candidates, coupled to the expansion of the Universe. According to this hypothesis, the mass of a BH could increase as the Universe expands. BH low-mass X-ray binaries (LMXBs) in the Galactic disk were born several gigayears ago, making the coupling effect potentially significant. In this work, we calculate the evolution of BH binaries with a binary population synthesis method to examine the possible influence of cosmologically-coupled growth of BHs, if it really exists. The measured masses of the compact objects in LMXBs show a gap around $\sim 2.5-5~{\rm M_\odot}$, separating the most massive neutron stars from the least massive BHs. Our calculated results indicate that, considering the mass growth seem to (partially) account for the mass gap and the formation of compact BH LMXBs, alleviating the challenges in modeling the formation and evolution of BH LMXBs with traditional theory. However, critical observational evidence like the detection of intermediate-mass black hole binaries is required to test this hypothesis.Comment: 10 pages, 4 figures, 3 tables, accepted for publication in ApJ, comments are welcom

Determination of essential oil from Scutellaria baicalensis Georgi (Lamiaceae) by GC-MS, and assessment of its insecticidal properties

Purpose: To isolate essential oil from the aerial parts of Scutellaria baicalensis using GS-MS, and to assess its insect-killing effect against booklice (Liposcelis bostrychophila).Methods: The oil from the aerial parts of S. baicalensis was hydro-distilled and subjected to gas chromatographic and mass spectroscopic (GC-MS) techniques. The components of the oil with insectkilling potentials were fractionated through bioactivity-guided isolation, and the isolated oil and its components were screened for their toxic effects on booklice.Results: A total of 31 components were obtained, with eugenol as the most abundant. When used to fumigate S. baicalensis, the oil and two of its constituents (myristicin and eugenol) exerted appreciable toxic effects. Moreover, the oil and its isolates manifested contact toxicity against booklice.Conclusion: These findings indicate the insecticidal benefits of the essential oil and its components against Liposcelis bostrychophila

The Pseudoscalar Meson and Heavy Vector Meson Scattering Lengths

We have systematically studied the S-wave pseudoscalar meson and heavy vector meson scattering lengths to the third order with the chiral perturbation theory, which will be helpful to reveal their strong interaction. For comparison, we have presented the numerical results of the scattering lengths (1) in the framework of the heavy meson chiral perturbation theory and (2) in the framework of the infrared regularization. The chiral expansion converges well in some channels.Comment: 10 pages, 1 figures, 4 tables. Corrected typos, Improved numerical results, and More dicussions. Accepted for publication by Phys.Rev.

Methyl (1H-pyrrol-2-ylcarbonyl­amino)acetate

In the crystal structure of the title compound, C8H10N2O3, mol­ecules are linked by N—H⋯O hydrogen bonds, forming ribbons of centrosymmetric dimers extending along the c axis