Moiré Physics of One-Dimensional Related Systems and Their Measurement

Currently, the magic-angle graphene has given a tremendous boost to the study of unconventional superconductors. On the other hand, there were still limited experimental studies on superconductivity in one-dimensional (1D) carbon nanotube systems. The study of experimental systems in demonstrating superconductivity was therefore scientifically important. In this review, we have shown strategies toward demonstrating the superconductivity for the single double-wall carbon nanotube (DWCNT). In general, there have been two directions to analyse superconducting properties of one-dimensional materials: (i) strong correlated states (ii) anomalous electron transport operations. We introduced the transmission electron microscope (TEM) and Rayleigh scattering spectroscopy to describe the strong correlation. The theoretical foundations of moiré physics have also been described. Given all the methods, we concluded that the most intuitive way to demonstrate the superconductivity of single double-walled carbon nanotubes is the critical temperature. The sharp drop of the resistance could be directly observed, and the Tc could be obtained from the electrical transport data. In the last section, we also summarized the challenges that need to be addressed in future superconductivity studies of 1D carbon nanotubes.

Assessment of the Toxicity and Carcinogenicity of Double-Walled Carbon Nanotubes in the Rat Lung After Intratracheal Instillation: A Two-Year Study

Background Considering the expanding industrial applications of carbon nanotubes (CNTs), safety assessment of these materials is far less than needed. Very few long-term in vivo studies have been carried out. This is the first 2-year in vivo study to assess the effects of double walled carbon nanotubes (DWCNTs) in the lung and pleura of rats after pulmonary exposure. Methods Rats were divided into six groups: Untreated, Vehicle, 3 DWCNT groups (0.12mg/rat, 0.25mg/rat and 0.5mg/rat), and MWCNT-7 (0.5mg/rat). The test materials were administrated by intratracheal - intrapulmonary spraying (TIPS) every other day for 15 days. Rats were observed without further treatment until sacrifice at weeks 52 and 104. Results DWCNT were biopersistent in the rat lung and induced marked pulmonary inflammation with a significant increase in macrophage count and levels of the chemotactic cytokines CCL2 and CCL3. In addition, the 0.5 mg DWCNT treated rats had significantly higher pulmonary collagen deposition compared to the vehicle controls. The development of carcinomas in the lungs of rats treated with 0.5 mg DWCNT (4/24) was not quite statistically higher (p = 0.0502) than the vehicle control group (0/25), however, the overall incidence of lung tumor development, bronchiolo-alveolar adenoma and bronchiolo-alveolar carcinoma combined, in the lungs of rats treated with 0.5 mg DWCNT (7/24) was statistically higher (p < 0.05) than the vehicle control group (1/25). Notably, two of the rats treated with DWCNT, one in the 0.25 mg group and one in the 0.5mg group, developed pleural mesotheliomas. However, both of these lesions developed in the visceral pleura, and unlike the rats administered MWCNT-7, rats administered DWCNT did not have elevated levels of HMGB1 in their pleural lavage fluids. Conclusions Our results demonstrate that DWCNTs are biopersistent in the rat lung and induce chronic inflammation. Moreover, rats treated with 0.5 mg DWCNT developed pleural fibrosis. While our results do not show that DWCNT is carcinogenic in the rat lung, total tumor incidence was significantly increased in the 0.5 mg DWCNT group. Taken together, these findings demonstrate that the possibility that at least some types of DWCNTs are fibrogenic and carcinogenic cannot be ignored.

The Host-Guest Complexes of Various Carbon Nanotubes (CNTs) and Boron Nitride Nanotubes (BNNTs) with Water at DFT Levels

We have investigated the various nanotube (NT)-water complexes as important host-guest complexes via the DFT method using B3LYP/6-31G* and M06/6-31G* levels of theory. These NTs include single-walled and double-walled carbon nanotubes (SWCNT and DWCNT, respectively). In addition, the boron nitride nanotube (BNNT) and tip-functionalized CNTs are also designed. All geometries turn out as minima on their energy surfaces. Calculated structural and thermodynamic parameters, along with atoms in molecules (AIM) and natural bond orbital (NBO) analyses, indicate that water inside the SWCNTs shows a higher interaction with NT where the nature of interactions is partially electrostatic-partially covalent. Therefore, the SWCNTs turn out as the best candidates for carrying and storage the water molecules.

Applicability and Limitations of Simplified Elastic Shell Theories for Vibration Modelling of Double-Walled Carbon Nanotubes

The applicability and limitations of simplified models of thin elastic circular cylindrical shells for linear vibrations of double-walled carbon nanotubes (DWCNTs) are considered. The simplified models, which are based on the assumptions of membrane and moment approximate thin-shell theories, are compared with the extended Sanders–Koiter shell theory. Actual discrete DWCNTs are modelled by means of couples of concentric equivalent continuous thin, circular cylindrical shells. Van der Waals interaction forces between the layers are taken into account by adopting He’s model. Simply supported and free–free boundary conditions are applied. The Rayleigh–Ritz method is considered to obtain approximate natural frequencies and mode shapes. Different aspect and thickness ratios, and numbers of waves along longitudinal and circumferential directions, are analysed. In the cases of axisymmetric and beam-like modes, it is proven that membrane shell theory, differently from moment shell theory, provides results with excellent agreement with the extended Sanders–Koiter shell theory. On the other hand, in the case of shell-like modes, it is found that both membrane and moment shell theories provide results reporting acceptable agreement with the extended Sanders–Koiter shell theory only for very limited ranges of geometries and wavenumbers. Conversely, for shell-like modes it is found that a newly developed, simplified shell model, based on the combination of membrane and semi-moment theories, provides results in satisfactory agreement with the extended Sanders–Koiter shell theory in all ranges.