We report a new redox initiator couple of ammonium persulfate (APS)/carbon dots (CDs) with high initiation efficiency used in frontal polymerization (FP).

Polypropylene (PP)/microcrystalline cellulose (MCC) composites and PP/MCC composites modified by maleic anhydride grafted PP (PP-g-MA) and methyl acrylic acid glycidyl ester grafted PP (PP-g-GMA) respectively were prepared in a twin-screw extruder. The mechanical properties, morphology, and thermal performance were investigated. The nonisothermal crystallization, melting behavior, and nonisothermal crystallization kinetics were investigated by DSC. The results indicated that the addition of MCC had led to the increase of the tensile strength, impact strength, and flexural strength of PP. PP-g-GMA modification was more conducive to the improvement in tensile strength, impact strength, and flexural strength. The three types of PP/MCC composites have higher thermal decomposition temperatures, Vicat softening temperatures, and dimensional stability. Nonisothermal crystallizations of PP/MCC composites were in accordance with tridimensional growth with heterogeneous nucleation. Meanwhile, MCC was acted as the nucleating agent in PP matrix, which increased the crystallization temperature. PP-g-GMA further increased the crystallization temperature while PP-g-MA weakened the heterogeneous nucleation effect of MCC. Avrami equation and Mo method give a satisfactory description of the crystallization kinetics process. The activation energy of crystallization, nucleation constant, and fold surface free energy of PP were markedly reduced in PP/MCC composites and its compatibilized composites. The value of F( T) systematically increased with increasing relative degree of crystallinity. The addition of microcrystalline cellulose has greatly reduced the spherulitic size of PP.

Abstract-as a new concept, cloud computing has attracted the IT enterprise attention especially the e-commerce enterprise. At present, there is a great problem of environmental costs during the enterprises apply the ecommerce, but with the coming of cloud computing, all of the problem will be solved. Therefore, this article will introduce the concepts, the origins and development trend of cloud computing and on the basis of this issue, analyzing the ecommerce models. On the other hand, from the characteristics of clouds, analyzing the network security problems and solutions.

Nitrogen-doped carbon dots (CDs) were synthesized through a hydrothermal process by using N-riched polyamindoamine (PAMAM) dendrimer as the precursor. The CDs depict bright blue fluorescence with the quantum yield (QY) of 40 %, and show excellent monodispersity and solubility in water. The CDs also demonstrate sensitivity detection of Fe 3+ ions (ppm level). To be more practical applications, the as-prepared CDs could be the ink candidates of nano-printing patterns, which are of high fluorescence. Also, we have found the pH values and solvents used in the ink have great influence on the intensity of their fluorescence. More interestingly, we prepared poly(N-isopropylacrylamide) (PNIPAM) and CDs hybrids, which exhibit temperature switch property. It was reversibly sensitive to external temperatures range from 20 o C to 40 o C, making it possible to develop CDs-based thermo-sensitive devices or sensors.