The single machine parallel batch problem with job compatibility is considered to minimize makespan,where the job compatibility constraints are represented by a graph G.This problem is proved to be NP-hard.And when the graph G is limited to be a general bipartite,a complete bipartite and a complete m-partite graph,these problems are solved in polynomial time respectively. 相似文献
A novel gene delivery system, called PoSC, consisting of PEI, PSP, and HA is described. In contrast to the DNA/PEI/HA ternary system whose transfection efficiency decreases significantly with increasing serum concentration, PoSC exhibits a high transfection efficiency of about 51 and 87% for NIH3T3 and HCT116 cells, respectively, at 50% serum concentration. Furthermore, PoSC shows no cytotoxic effect at its working concentration. The overall results suggest that HA adsorption on cationic complexes enhances the transfection efficiency, while PSP is essential for high transfection efficiency at higher serum concentration.
Two types of butadiene-acrylonitrile rubbers (i.e., carboxyl randomized butadiene-acrylonitrile rubber (CRBN) and hydroxyl terminated butadiene-acrylonitrile rubber (HTBN)) have been used for modifying an interpenetrating network of cyanate ester (CE)/epoxy resin (EP) (70/30). The toughness of the matrix can be improved effectively with addition of rubbers. The values of impact strength (11.6 KJ/m2) show a maximum for the CE/EP/HTBN (70/30/8) blend. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) results show that CRBN and HTBN have a different dispersion state in the CE/EP matrix. CRBN aggregates to form regular spheres with a size of about 1 μm. HTBN disperse homogeneously with its size of the nano-level (about 10 nm). Fourier transform infrared spectrum (FTIR) and differential scanning calorimetric (DSC) analysis shows that the CRBN has higher reactivity than HTBN. The thermal gravimetric analysis (TGA) results shows that T10 (temperature of 10% weight loss) of the CE/EP system decreases with the addition of rubbers. For the CE/EP/CRBN system, both T30 (temperature of 30% weight loss) and T50 (temperature of 50% weight loss) are lower than neat CE/EP. However, for the CE/EP/HTBN system, both T30 and T50 are near to neat CE/EP. Different reactivity and compatibility between the rubbers and CE/EP matrix is the main determining factor for the thermal stability of the blends. 相似文献
The preparation of EVM (ethylene‐vinyl acetate copolymer rubber)/TPU (thermoplastic polyurethane) blends with various ratios and their compatibility were investigated. The influence of mixing technology, filler type and content, the VA content in EVM (40 and 70 wt.%) and the addition of compatibilizers on the mechanical properties and the compatibility of the EVM/TPU blends were systematically studied. The test results showed that in preparation of the blend, fillers should be added to the blend to improve the processability and that among the fillers used, silica showed the best reinforcing effect on the blends. The best parameters for blending EVM and TPU in a HAAKE rheometer was: mixing temperature 160°C, rotor speed 45 rpm and mixing time 15 min. The test results also showed that the compatibility of EVM 700 (VA=70%) with TPU was better than that of EVM400 (VA=40%). The addition of a compatibilizer EVM‐g‐MAH and EVM‐g‐FME improved the processability of the blends. The addition of EVM‐g‐MAH also improved the compatibility of EVM 700/TPU blend; both the mechanical properties and hot‐air aging properties of the blends were improved. However, the addition of EVM‐g‐FME did not improve the compatibility of EVM/TPU blends. 相似文献