Relatively high purity of nitrogen atom encapsulated fullerene (N@C60) has been synthesized by an electron beam superimposed radio frequency (RF) discharge plasma method. Nitrogen species are characterized by an optical emission spectroscopy (OES); and a relationship between optical emission spectra and the purity of N@C60 has been examined. It is observed that the increased amount of nitrogen molecule ions impinging on the sublimated fullerenes enhance the synthesis of N@C60. Here, it is cleared that the efficient synthesis of N@C60 is possible by controlling the parameters of electron beam superimposed RF plasma. As a consequence, comparatively high purity of about 0.08% of N@C60 has been obtained. 相似文献
Gold nanoparticles (AuNPs) of about 5 nm in diameter were biosynthesized at room temperature (300 K). The PVA/2.5 wt% KH2PO4 or KDP composite film and PVA/2.5 wt% KDP/AuNPs nanocomposite films with different concentrations of AuNPs were prepared. Interestingly, addition of 0.05 wt% of AuNPs to the PVA/2.5 wt% KDP percolative composite film destroys percolative behavior of this composite film. Furthermore, the PVA/2.5 wt% KDP/0.05 wt% AuNPs nanocomposite film exhibited high room temperature dielectric permittivity (ε′ ∼ 590 at 1 kHz). The behavior of AC conductivity (σac) of the nanocomposite films indicated correlated barrier hopping type of conduction mechanism. The Cole–Davidson dielectric response becomes evident as the interfacial polarization process acquires a more symmetric form, tending to Debye relaxation. High value of ε′ promises direct application in capacitors. Moreover, the novel feature of destroying the percolative behavior by AuNPs may be applied even in other systems. 相似文献
Non-coding RNAs, particularly lncRNAs and miRNAs, have recently been shown to regulate different steps in viral infections and induction of immune responses against viruses. Expressions of several host and viral lncRNAs have been found to be altered during viral infection. These lncRNAs can exert antiviral function via inhibition of viral infection or stimulation of antiviral immune response. Some other lncRNAs can promote viral replication or suppress antiviral responses. The current review summarizes the interaction between ncRNAs and herpes simplex virus, cytomegalovirus, and Epstein–Barr infections. The data presented in this review helps identify viral-related regulators and proposes novel strategies for the prevention and treatment of viral infection. 相似文献
Composite materials exhibit various and complex failure behavior. Different formalisms have been used to predict failure. Improvement of old theories and new ones continue to be published. In this paper, the most recent and widely used models are presented. Failure criteria such as Tsai-Wu, parametric formulations, maximal stress and strain, Hashin criterion, Hart-Smith criterion, and the method based on kriging are presented. These failure theories may be classified in two categories, depending whether they integrate failure modes or not. The formalism of each theory is briefly described and their application to model failure of composite laminates is discussed by comparing the advantages and limitations of each method. The diversity of experimental failure envelopes, as reported in the literature on composites, is outlined and it is shown that most criteria permit modeling only particular failure properties of composite laminates. 相似文献
Halloysite as an impressive natural eco-friendly nanotube with aluminosilicate structure has been investigated recently due to its unique features such as specific morphology and excellent bio-adaptability. In this research, Fe3O4 nanoparticles have been loaded on the tubular halloysite by co-precipitation method in order to synthesis magnetic halloysite (Hal-Fe3O4). To characterize this recoverable nanocatalyst, applicable analyses such as Fourier-transform infrared (FT-IR) spectroscopy, energy-dispersive X-ray (EDX) analysis, field-emission scanning electron microscopy (FE-SEM) images, X-ray diffraction (XRD) pattern, Thermogravimetric analysis (TGA) and vibrating sample magnetometer (VSM) curves have been carried out. The results confirmed that Fe3O4 nanoparticles with cubic structure, and uniform distribution, were located at halloysite nanotubes (HNTs). This aluminosilicate nanocomposite with high thermal stability, crystalline structure, and stable morphology was evaluated as a heterogeneous catalyst in the symmetrical Hantzsch reaction for the first time. Easy synthesis process, green media, high performance, recoverable catalyst and reusing of the Hal-Fe3O4 as a nanocatalyst for 8 times are the main features of this protocol.