Abstract: Nonlocal elastic shell model based on the semi-moment theory is developed and applied to investigate the small scale effect on the bending problem of the cantilever carbon nanotube (CNT) with a vertical concentrated load applied at its tip. The small-scale effect is taken into account and is incorporated in the formulation. Analytical expressions of the stress are derived for the nonlocal elastic bending problem. It is obvious to observe significant small-scale effects on the stress resultants. The smaller the radius is, the more obvious the scale effect appears. The numerical results show that the scale effect cannot be ignored for CNTs of small radius.
Abstract: BiOCl/BiOI nanocomposites were synthesized using a thermal impregnation method for the first time. The intense visible-light absorption and large specific surface area gave 4wt.％BiOCl/BiOI nanocomposites the best visible-light photocatalytic properties among all the catalysts for the photodegradation of methyl orange,about 78％ after 2 h. But decreased activities were obtained with the increase of BiOCl content in the nanocomposites. Considering the light absorption,specific surface area and the quantum efficiency, the high recombination of the photoinduced electron-hole pairs of the catalysts that lowed the quantum efficiency was believed to be the critical factor for their decreased photocatalytic activities.
Abstract: Based on self-assembled combination of graphene with Au nanoparticle-doped copper hexacyanoferrate (CuHCF) multilayers, a electrochemical biosensor for sensitive detection of hydrazine has been reported. Graphene was functionalized by wrapping with poly(diallyldimethylammonium chloride) (PDDA). Such polyelectrolyte modified graphene (PDDA-G) was water-soluble and possessed net positive charge. Based on electrostatic self-assembly, graphene multilayers modified electrode (ITO/G-M) was fabricated. After binding with mercaptopropionic acid stabled Au nanoparticles (MPA-AuNPs), three dimensional graphene-AuNPs electrode was obtained. CuHCF multilayers were then formed on AuNPs center by successive self-assembly and solution epitaxy. Due to the synergistic effect of graphene and AuNPs, the developed biosensor (ITO/G-M/CuHCF-M) exhibited fast and sensitive amperometric response for the determination of hydrazine in near physiological pH. The linear response for the determination of hydrazine ranged from 4.0 × 10-7 to 1.3 × 10-4 M with a detection limit of 7.2 × 10-8 M. The biosensor exhibited high reproducibility and stability resulted from simple and reproducible self-assembly methodology.
Abstract: We investigated unipolar resistance switching in CuxO thin films. We studied on the resistive switching behavior associated with the annealing temperature of CuxO thin films and focused on HRTEM, XPS and AFM analyses. In this paper we investigated the surface and interface structures of CuxO films. Results show that there is a mount of oxygen content in the CuxO thin films which is contained in Cu (Ⅱ) oxides and Cu (Ⅰ) oxides. When annealing temperature increases the qualification of oxygen vacancies increase and more oxygen vacancies is connected with top and bottom electrode.
Abstract: This paper demonstrates the preparation of transparent regenerated membrane from bacterial cellulose (BC) sheets using the lithium chloride（LiCl）/dimethylacetamide (DMAc) as dissolved system. The structure of the membrane was investigated by the scanning electron microscopy (SEM). It showed very smooth, dense and homogeneous surface while the raw BC sheet was poriness. FT-IR spectroposcopic analysis of both bacterial cellulose and the transparent membrane revealed that chemical composition was not changed during the fabrication process but only the peak strength changed. Mechanical property tests presented that after regeneration process, the tensile strength of the regenerated membrane was well improved compared with the raw BC sheets. Its light transmission was also attaining 91.2% due to the nano-scale structure. From the above，these properties make the transparent regenerated BC membrane potentially applied in optical electronic and packaging fields as the commercially available material.
Abstract: Insufficience of osteogenesis and antimicrobial effect have been still impacted the long term clinical success rate of dental implants. A nanostructured titanium surface prepared by hydrothermal treatment with H2O2 was evaluated on its osteoblastic viability and antibacterial effect. Samples were divided into 2 groups: untreated pure titanium surface (Ti) and a nanostructured titanium surface (NT). The antibacterial activities against S.mutans and C.albicans were measured by film applicator coating assay, as well as the live/dead bacteria stain. The osteoblastic viability was investigated by SEM and MTT assay. Results showed that the active microbia on NT was reduced at 24h (P<0.05) significantly according to the live/dead bacteria stain and film applicator coating assay, which could also enhance the osteoblast viability. Therefore, a nanostructured titanium surface exhibits good antibacterial activity on S.mutans and C.albicans, and promoting osteoblast viability, which will be a potential kind of dental implant material.
Abstract: The localized mode and its Photoluminescence Characteristics of one dimensional liquid-crystal-filled photonic crystal with a defect layer (1DNLCFPC) were studied numerically by the transfer matrix method. Nematic liquid crystal (NLC) could be treated as uniaxial media when the external electric field intensity over the threshold. The angle θ was the angle between the direction of the vertical incident light and the direction of the electric field. When θ increased, the results could be found as follow: the 1DNLCFPC’s band gap gets wide and the wavelengths of both band edges get small; the defect mode’s wavelength of 1DNLCFPC gets small. The half-width at the defect modes’ half maximum is less than 0.2nm. The localized phenomenon can be found in the defect modes, meanwhile, light energy is localized nearby the defect layer. The largest relative light intensity in the localized layers has large value when the pump rate is very small.
Abstract: In order to obtain a nanocrystalline and amorphous structure, the Mg20Ni8M2 (M=Cu, Co) hydrogen storage alloys were fabricated by the melt spinning technology. The microstructures of the alloys were characterized by XRD, SEM and HRTEM. The effects of the melt spinning on the hydriding and dehydriding kinetics of the alloys were investigated. The results indicate that the as-spun (M=Cu) alloys hold an entire nanocrystalline structure even if the limited spinning rate is applied, while the as-spun (M=Co) alloys display a nanocrystalline and amorphous structure as the spinning rate grows to 30 m/s, suggesting that the substitution of Co for Ni facilitates the glass formation in the Mg2Ni-type alloy. The melt spinning remarkably improves the gaseous hydriding and dehydriding kinetics of the alloys. As the spinning rate grows from 0 (As-cast was defined as the spinning rate of 0 m/s) to 30 m/s, the hydrogen absorption saturation ratio ( ) is enhanced from 56.72% to 92.74% for the (M=Cu) alloy and from 80.43% to 94.38% for the (M=Co) alloy. The hydrogen desorption ratio ( ) is raised from14.89% to 40.37% for the (M=Cu) alloy and from 24.52% to 51.67% for the (M=Co) alloy.
Abstract: With its simple, easy operation, electrostatic spinning has become the most important and effective way on the preparation of nano-fibers. Through experiments, we identified the optimal conditions for the preparation of PAN nano-fibers composite TiO2 are: the spinning solution concentration is 12%, the angle is 5~8°, the spinning distance is 8cm, and the voltage is 12kV. The pre-oxidation largely determine the structure and properties of carbon fiber in the preparation of carbon nano-fibers. The temperature plays a decisive role on pre-oxidation. Through SEM、TG-DTA and FTIR, we explore the best conditions for the pre-oxidation temperature is 280°C and the pre-oxidation time is 2h. After carbonization and activation, the characteristic peak of TiO2 appeared at 2θ=25.2°, 37.7°in the patterns of XRD.