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To research the static recrystallization behavior of high strength steel 300 M,single/double-pass hot compression tests of 300 M steel were carried out using Gleeble-3800 thermal simulation experiment equipment. The effects of deformation temperature,strain rate,height reduction and initial grain size on the volume fraction of static recrystallization were analyzed by double-pass hot compression tests. It is found that the volume fraction of static recrystallization rapidly increases with increasing deformation temperature,strain rate or height reduction,while it decreases with increasing initial grain size. Initial grain size has less effect than the others. A static recrystallization volume fraction model and a completely static recrystallization grain size model of 300 M steel were established based on the results of double-pass and single-pass hot compression tests,respectively,and the static recrystallization volume fraction model was verified to be correct by single-pass hot compression tests.

An optimization of flow control "devices in a 40-t single strand continuous casting tundish was carried out by water modeling experiments and industrial experiments. Three cases were considered during the experiments, i. e, tundish equipped with a turbulence inhibitor, tundish equipped with a turbulence inhibitor and dams, and tundish equipped with a turbulence inhibitor, dams and weirs. The results show that the dams play a much more important role than the weirs in improving the fluid flow characteristics and decreasing the dead volume fraction in the tundish. The average residence time increases firstly and reduces afterward with increasing distance between the dam and nozzle. The tundish equipped with a turbulence inhibitor and dams is the optimized according to these results, and the dead volume fraction reduces to 13.6% from 25.9%. The results of industrial application shows that the T. O and N contents reduce greatly and the mass fraction of macro inclusions in normal slabs reduced to 3.2×10-7 from 8.4 × 10-7.

The cleanness evolution and inclusion distribution of IF slabs in the thickness direction were studied by original morphology analysis, scanning electron microscopy and energy spectroscopy analysis, and total oxygen (T. O) and nitrogen analysis. The average values of mass fraction of total oxygen and N in the slabs in the thickness direction are within 17 × 10-6. The mass fractions of T. O and N in the area within 1/16 thickness from the slab surface are 5% to 10% higher than the average values, in the area between 1/4 thickness from the inner are and 1/4 thickness from the outer arc are 5% to 10% lower than the average values and in other area are close to the average levels. The average size of inclusions is 5.7 txm based on a total of 963 statistical inclusions. Inclusions with the particle size smaller than 5μm account for 60% and with the particle size smaller than 10 txm account for 90%. Al2O3 mainly exits within 5 mm from the slab surface with the size of 2 to 10μm; TiN-Al2O3 and TiN exist in the area from 5 to 80 mm in the thickness direction, and their particle size grows up as the thickness increasing; TiN-TiS and TiS inclusions mainly exist in the area from 80 to 130 mm in the thickness direction with the size of 1 to 5μm. Inclusions from the slab surface to center are mainly Al2O3, Al2O3-TiN, TiN, TiN-TiS, TiS, and MnS in order.

To investigate the protective effects and the possible mechanisms of garlic oil (GO) against N-nitrosodiethylamine (NDEA)-induced hepatocarcinoma in rats, Wistar rats were gavaged with GO (20 or 40 mg/kg) for 1 week, and then were gavaged with GO and NDEA (10 mg/kg) for the next 20 weeks. The changes of morphology, histology, the biochemical indices of serum, and DNA oxidative damage of liver were examined to assess the protective effects. Lipid peroxidation (LPO), antioxidant defense system, and apoptosis-related proteins were measured to investigate potential mechanisms. At the end of the study (21 weeks), GO administration significantly inhibited the increase of the nodule incidence and average nodule number per nodule-bearing liver induced by NDEA, improved hepatocellular architecture, and dramatically inhibited NDEA-induced elevation of serum biochemical indices (alanine aminotransferase , aspartate aminotransferase, alkaline phosphatase and gamma-glutamyl transpeptidase) and hepatic 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels in a dose-dependent manner. The mechanistic studies demonstrated that GO counteracted NDEA-induced oxidative stress in rats illustrated by the restoration of glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), glutathione peroxidase (GPx), glutathione-S-transferase (GST) levels, and the reduction of the malondialdehyde (MDA) levels in liver. Furthermore, the mRNA and protein levels of Bcl-2, Bcl-xl, andβ-arrestin-2 were significantly decreased whereas those of Bax and caspase-3 were significantly increased. These data suggest that GO exhibited significant protection against NDEA-induced hepatocarcinogenesis, which might be related with the enhancement of the antioxidant activity and the induction of apoptosis.

Two new isoflavones (1 and 2), as well as eight known ones were isolated from the roots of Sophora tonkinensis Gagnep. Compound 1 represents an unprecedented polymerization pattern constructed by isoflavone and cytisine. Their structures were elucidated by comprehensive spectroscopic data analysis, combined with ECD calculations. Compound 1 displayed significant anti-tobacco mosaic virus (TMV) activity compared with the positive control ningnanmycin. Moreover, compound 6 exhibited potent α-glucosidase inhibitory activity with IC50 value of 47.4 mg/L. [ABSTRACT FROM AUTHOR]

Los aceros de fácil mecanizado o corte libre con nitruro de boro agregado han despertado un gran interés. Sin embargo, aún no se han determinado los mecanismos que explican el papel de las inclusiones de BN en la mejora de la maquinabilidad de estos aceros. En este trabajo, se investigan los mecanismos de corte de las inclusiones BN en aceros mediante la combinación de un análisis teórico y una serie de experimentos. En primer lugar, se determina la morfología de las inclusiones BN y se analiza cuantitativamente la cantidad y distribución de las mismas. Posteriormente, el rendimiento de corte del acero se determina mediante ensayos de corte. Por otra parte, las propiedades mecánicas locales y los mecanismos de eliminación de material para el corte de inclusiones BN son investigados por medio de nanoindentación. Los resultados revelaron que las inclusiones son BN con forma hexagonal y se distribuyen de manera uniforme, su contenido promedio es de 23,2 por unidad de superficie y su fracción de volumen es 0,51% en el acero con un contenido de 74 ppm de B y 180 ppm N. Se demuestra que las inclusiones BN pueden mejorar el rendimiento de corte del acero de manera significativa, y se presenta un modelo que describe el mecanismo de corte de las inclusiones de BN. Finalmente, se comprueba que los BN actúan como fuente de concentración de tensiones, la lubricante y de conglomerante de partículas duras.