Search

Highlights: A strategy based on metal-organic decomposition is proposed to enhance the tube-tube interactions of carbon nanotubes (CNTs). The robust tube-tube interactions of CNTs enhance both EMI shielding performance and mechanical properties of CNT film. This innovative approach provides an effective way to obtain high-performance CNT film. The remarkable properties of carbon nanotubes (CNTs) have led to promising applications in the field of electromagnetic interference (EMI) shielding. However, for macroscopic CNT assemblies, such as CNT film, achieving high electrical and mechanical properties remains challenging, which heavily depends on the tube–tube interactions of CNTs. Herein, we develop a novel strategy based on metal–organic decomposition (MOD) to fabricate a flexible silver–carbon nanotube (Ag–CNT) film. The Ag particles are introduced in situ into the CNT film through annealing of MOD, leading to enhanced tube–tube interactions. As a result, the electrical conductivity of Ag–CNT film is up to 6.82 × 105 S m−1, and the EMI shielding effectiveness of Ag–CNT film with a thickness of ~ 7.8 μm exceeds 66 dB in the ultra-broad frequency range (3–40 GHz). The tensile strength and Young's modulus of Ag–CNT film increase from 30.09 ± 3.14 to 76.06 ± 6.20 MPa (~ 253%) and from 1.12 ± 0.33 to 8.90 ± 0.97 GPa (~ 795%), respectively. Moreover, the Ag–CNT film exhibits excellent near-field shielding performance, which can effectively block wireless transmission. This innovative approach provides an effective route to further apply macroscopic CNT assemblies to future portable and wearable electronic devices. [ABSTRACT FROM AUTHOR]

In the field of data mining, the performance of clustering is largely affected by the number of samples. However, obtaining enough data samples in some applications is difficult and expensive. To solve this problem, data augmentation like the oversampling methods have been adopted, but these methods mainly focus more on the local information of the data, without considering its potential distribution. In this paper, a new data augmentation method is proposed, which is the Wasserstein Generation Adversarial Network based on the Gaussian Mixture Model (GMM_WGAN) to generate datasets for small samples, to solve the problem of insufficient dataset size in clustering. It includes two steps, in the first step we use the Gaussian Mixture Model to capture the potential distribution of the real dataset, and in the second step, we use Wasserstein generative adversarial network to generate data samples to expand the small size dataset. We utilize five clustering algorithms to evaluate GMM_WGAN performance and compare it with the other seven data enhancement methods. Experiments on 10 small size datasets demonstrate that the proposed approach achieves greater result than others based on five evaluation metrics. [ABSTRACT FROM AUTHOR]

MXenes with unique physicochemical properties have shown substantial potential in electromagnetic interference (EMI) shielding. However, the chemical instability and mechanical fragility of MXenes has become a major hurdle for their application. Abundant strategies have been dedicated to improving the oxidation stability of colloidal solution or mechanical properties of films, which always come at the expense of electrical conductivity and chemical compatibility. Here, hydrogen bond (H‐bond) and coordination bond are employed to achieve chemical and colloidal stability of MXenes (0.1 mg mL−1) by occupying the reaction sites of Ti3C2Tx attacking of water and oxygen molecules. Compared to the Ti3C2Tx, the Ti3C2Tx modified with alanine via H‐bond shows significantly improved oxidation stability (at room temperature over 35 days), while the Ti3C2Tx modified with cysteine by synergy of H‐bond and coordination bond can be maintained even after 120 days. Simulation and experimental results verify the formation of H‐bond and Ti‐S bond by a Lewis acid‐base interaction between Ti3C2Tx and cysteine. Furthermore, the synergy strategy significantly improves the mechanical strength of the assembled film (up to 78.1 ± 7.9 MPa), corresponding the increment of 203% compared to untreated one, almost without compromising the electrical conductivity and EMI shielding performance. [ABSTRACT FROM AUTHOR]

A sensitive and efficient mixed cloud point extraction combined with high-performance liquid chromatography was developed for the simultaneous separation and determination of four alkaloids (strychnine, strychnine N-oxide, brucine, and brucine N-oxide) in plasma after the oral administration of processed semen strychni extract. Tergitol TMN-6 and cetyltrimethyl ammonium bromide were chosen as the mixed surfactants, and ultrasound was employed to enhance the extraction efficiency. Some important parameters affecting the mixed cloud point extraction efficiency, such as the content of Tergitol TMN-6 and cetyltrimethyl ammonium bromide, pH, salt effect, extraction temperature, and ultrasound time were studied and optimized. Under optimum conditions, the linear range of four alkaloids was from 1.0 to 1000 ng/mL. All correlation coefficients of the calibration curves were higher than 0.9993. The intraday and interday precision were below 8.65% and the limits of detection for the four alkaloids were less than 1.0 ng/mL (S/N = 3). [ABSTRACT FROM AUTHOR]

The article presents the author's views on 9-Amino-9-deoxyepicinchona alkaloids which is the newest generation of the family of cinchona alkaloids. She mentions that they are capable of promoting many asymmetric reactions and further discusses the preparartion of 9-Amino-9-deoxyepicinchona from inexpensive alkaloid starting materials.