Given a non-negative integer n and a complete hereditary cotorsion triple , the notion of subcategories in an abelian category is introduced. It is proved that a virtually Gorenstein ring R is n-Gorenstein if and only if the subcategory of Gorenstein injective R-modules is with respect to the cotorsion triple , where stands for the subcategory of Gorenstein projectives. In the case when a subcategory of is closed under direct summands such that each object in admits a right -approximation, a Bazzoni characterization is given for to be . Finally, an Auslander–Reiten correspondence is established between the class of subcategories and that of certain subcategories of which are -coresolving covariantly finite and closed under direct summands.

A 100-J-level Nd:glass laser system in nanosecond-scale pulse width has been constructed to perform as a standard source of high-fluence-laser science experiments. The laser system, operating with typical pulse durations of 3–5 ns and beam diameter 60 mm, employs a sequence of successive rod amplifiers to achieve 100-J-level energy at 1053 nm at 3 ns. The frequency conversion can provide energy of 50-J level at 351 nm. In addition to the high stability of the energy output, the most valuable of the laser system is the high spatiotemporal beam quality of the output, which contains the uniform square pulse waveform, the uniform flat-top spatial fluence distribution and the uniform flat-top wavefront.

The impact of lubricants on pole-tip recession and surface morphology of hard disk drive heads in the precision lapping process was investigated with atomic force microscopy, scanning electron microscopy, and auger electron spectroscopy. In particular, the effects of deionized water, hydrocarbon oil, ethanediol, isopropanol, and ethanol lubricants were evaluated. The results reveal that proper selection of lubricant is critical for achieving optimal performance in the lapping process. A mixture of 68% hydrocarbon oil, 30% isopropanol, and 2% octadecenoic acid was found to yield the most favorable results, displaying a writer shield recession, first shield of reader recession, and surface roughness of 0.423, 0.581, and 0.242 nm, respectively.

A facile one-pot synthetic approach, using oleic acid and oleylamine as composite stabilizers combined with high-temperature treatment in 1-octadecene, has been developed for the preparation of monodisperse and uniform lanthanum phosphate and europium-doped lanthanum phosphate nanocrystals. In particular, with the present synthetic approach, the size of the resulting nanocrystals could be tuned precisely and continuously from 3.5 to 6.5 nm by seed-mediated epitaxial growth. The as-obtained uniform nanocrystals with hydrophobic surfaces, which show efficient photoluminescence, could be easily dispersed in nonpolar solvents. More importantly, these nanocrystals can also be easily modified to water-dispersed ones with hydrophilic surfaces for potential use in in vitro imaging in bioanalysis. In addition, a synthetic mechanism for these monodisperse nanocrystals is presented and discussed.

In regards to the spatial associations of flares to velocity fields, Martres and Soru-Escaut (1977) found that flares occurred in the vicinity of the site where the magnetic neutral lines B∥=0 and the velocity neutral lines V∥=0 lines were crossing in the photosphere; Harvey and Harvey (1976) revealed that flares were related to velocity patterns different from Evershed flows. Recently Ai et al. (1991) discovered that flares occurred on the red-shift side of the velocity inversion lines (V∥=0) of the Hβ Dopplergrams observed half to two hours before flares. In this paper we further examined the associations with high resolution data obtained by Solar Magnetic Field Telescope at Huairou. A reconnection model applied to the magnetosphere is adopted here to tentatively interpret some of the observational results.