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Solidification behavior in the mold region plays an important role in production efficiency and steel quality. To investigate shell growth within a mold, the sulfur prints of the entire shell thickness profile from the meniscus to 100 mm below the mold were obtained by adding FeS tracer into molten steel during bloom continuous casting of hypo-peritectic steel. The law of shell thickness evolution along mold height and circumference was analyzed. The results show that there are three weak regions of solidification, which are in the mold upper part, in the mold lower part, and just below mold exit, possibly resulting from periodic fluctuation of air gap between the shell and the mold, the impingement of melt jets on the solidification front, and the decreasing cooling intensity, respectively. Initial solidification point along casting direction appears at approximately 35 mm below the meniscus. Overall, the solidified shell thickness in the inner side of the mold is a little larger than that in the outer side, and the former and the latter reach 25.5 and 24.3 mm at the mold exit, respectively. The non-uniform shell growth in the inner side of the bloom is provided, while shell thicknesses in the narrow face and the outer side follow relatively regular growth. Out of the mold, the thinnest shells on the transverse section exist in the regions of 60–90 mm and 40–70 mm from the corners of the inner and outer sides, respectively, i.e., the off-corners.

Nanomaterials have received increasing attentions owing to their potential hazards to the environment and human health; however, the multi-generational toxicity of graphene oxide under consecutive multi-generational exposure scenario still remains unclear. In the present study, Caenorhabditis elegans as an in vivo model organism was employed to explore the multi-generational toxicity effects of graphene oxide and the underlying mechanisms. Endpoints including development and lifespan, locomotion behaviors, defecation cycle, brood sizes, and oxidative response were evaluated in the parental generation and subsequent five filial generations. After continuous exposure for several generations, worms grew smaller and lived shorter. The locomotion behaviors were reduced across the filial generations and these reduced trends were following the impairments of locomotion-related neurons. In addition, the extended defecation cycles from the third filial generation were in consistency with the relative size reduction of the defecation related neuron. Simultaneously, the fertility function of the nematode was impaired under consecutive exposure as reduced brood sizes and oocytes numbers, increased apoptosis of germline, and aberrant expression of reproductive related genes ced-3, ced-4, ced-9, egl-1 and ced-13 were detected in exposed worms. Furthermore, the antioxidant enzyme, SOD-3 was significantly increased in the parent and filial generations. Thus, continuous multi-generational exposure to graphene oxide caused damage to the neuron development and the reproductive system in nematodes. These toxic effects could be reflected by indicators such as growth inhibition, shortened lifespan, and locomotion behavior impairment and induced oxidative response.

J.W. Robbin and D.A. Salamon [Linear Algebra Appl. 317 (2000) 225] generalized the classical Vandermonde determinant to the signed or unsigned exponential Vandermonde determinant and proved that both of them are positive. In this paper we shall generalize their results to more extensive matrices.

To investigate the antibacterial mechanism of sulforaphaneon (SFN) on Escherichia coli.To determine membrane penetrability, changes of SDS-PAGE protein spectra, soluble protein and alkaline phosphatase and reducing sugar were determined. Cellular nucleic acid synthesis was detected by 4, 6- diamidino-2-phenylindole (DAPI) staining assay.SFN affected the membrane permeability of Escherichia coli. Ions and small molecules could leak out of the cells. But it did not destroy the membrane integrity directly. After 16 hours of treatment with SFN, the total contents of intracellular and extracellular proteins decreased by 42.5% and 17.6%, respectively, while the quantity of DNA and RNA reduced by 34.8% and 48.5% respectively.SFN can affect cell membrane permeability, material and energy metabolism and inhibit the synthesis of nucleic acid and protein.