Atomic-Resolution Interfacial Reaction Mechanism between Bi2Te3-Based Alloys and Ni Electrodes.

Interdiffusion and solid-solid phase reaction at the interface between thermoelectric (TE) materials and the electrode critically influence interfacial transport properties and the overall energy conversion efficiency during service. Here, the microstructural evolution and diffusion mechanisms at the interfaces between the most widely used Bi2Te3-based TE materials, n-type Bi2Te2.7Se0.3 (BTS) and p-type Bi0.5Sb1.5Te3 (BST), and Ni electrodes were investigated at atomic resolution using spherical aberration-corrected scanning transmission electron microscopy (STEM). The BTS(0001)/Ni and BST(0001)/Ni interfaces were constructed by depositing Ni nanoparticles on mechanically exfoliated BTS and BST bulk materials and subsequent annealing. The interfacial reaction is initially dominated by Ni diffusion into the TE matrix to form NiAs-type NiM intermetallics, while Ni trans-quintuple-layer diffusion only occurs in Sb-rich BST. The Bi-rich BTS is more influenced by the Ni-Te preferential reaction, resulting in NiM abnormal grain growth and the formation of tilted and rotated interfaces. Bi diffusion into the BTS matrix forms a Bi double layer at the interface or Bi2[Bi2(Te,Se)3] as the annealing temperature increases, while Bi diffusion into the Ni thin film greatly accelerates the interfacial reaction rate, as elucidated by in situ heating STEM. The results provide essential structural details to understand and prevent the degradation of TE device performance.

Direct observation of cation diffusion driven surface reconstruction at van der Waals gaps.

Weak interlayer van der Waals (vdW) bonding has significant impact on the surface/interface structure, electronic properties, and transport properties of vdW layered materials. Unraveling the complex atomistic dynamics and structural evolution at vdW surfaces is therefore critical for the design and synthesis of the next-generation vdW layered materials. Here, we show that Ge/Bi cation diffusion along the vdW gap in layered GeBi2Te4 (GBT) can be directly observed using in situ heating scanning transmission electron microscopy (STEM). The cation concentration variation during diffusion was correlated with the local Te6 octahedron distortion based on a quantitative analysis of the atomic column intensity and position in time-elapsed STEM images. The in-plane cation diffusion leads to out-of-plane surface etching through complex structural evolutions involving the formation and propagation of a non-centrosymmetric GeTe2 triple layer surface reconstruction on fresh vdW surfaces, and GBT subsurface reconstruction from a septuple layer to a quintuple layer. Our results provide atomistic insight into the cation diffusion and surface reconstruction in vdW layered materials.

[Design and application of special solid phase extraction column for three cannabinol compounds in hemp].

Cannabidiol (CBD), cannabinol (CBN), and Δ9-tetrahydrocannabinol (THC) are the most important components of hemp, whose concentrations determine the properties and applications of hemp. Hemp contains a large number of impurities, which must be removed from the extracting solution before determining the cannabinol contents by ultra-high performance liquid chromatography (UHPLC). Neutral alumina, magnesium silicate, and graphitized carbon black have different surface characteristics when used as adsorbents. The removal rates of pigments, total sugar, total fatty acid glyceride, and metal ions as well as the recoveries of the three cannabinols in the extraction solution were evaluated. The amounts of neutral alumina, magnesium silicate, and graphitized carbon black were 1.80 g, 0.15 g, and 0.05 g, respectively. The three adsorbents were mixed well and packed into a polypropylene pipe to prepare a special 2 g/6 mL solid phase extraction (SPE) column for determining the three cannabinol compounds in hemp. The chemical components of the hemp flowers and leaves were extracted with an ethyl acetate/methanol (9∶1, v/v) mixture. After the extracting solution was allowed to pass through the SPE column, the recoveries of CBD, CBN, and Δ9-THC were 98.9%, 95.7%, and 99.2%, respectively. The removal rates of xanthophyll, chlorophyll a, and chlorophyll were 96.3%, 99.2%, and 95.5%, respectively. The removal rates of total sugar, total fatty glyceride, and metal ions were 98.5%, 96.9%, and 85.4%, respectively. In this study, the chromatographic conditions for analyzing the three cannabinol compounds were optimized. The cannabinol compounds were separated within 10 min on an Eclipse Plus C18 column (50 mm×2.1 mm, 1.8 µm) using a mobile phase consisting of 1% (v/v) acetic acid and acetonitrile (30∶70, v/v) at a flow rate of 0.5 mL/min. The detection wavelength was set at 210 nm with a diode array detector, and the sample injection volume was 1 µL. Good linear relationships were observed between the mass peak areas and mass concentrations of CBD, CBN, and Δ9-THC in the range of 0.5-50 mg/L. The corresponding correlation coefficients (R2) were 0.9983, 0.9995, and 0.9981, while the detection limits were 0.45 µg/L, 0.53 µg/L, and 0.38 µg/L. The recoveries of CBD, CBN, and Δ9-THC were 90.3%-96.9%, 93.7%-95.6%, and 90.8%-96.1%, with relative standard deviations (RSDs) of 2.2%-6.1%, 4.1%-8.0%, and 2.4%-4.8%, respectively. The results were satisfactory, demonstrating that the special SPE column made of neutral alumina, magnesium silicate, and graphitized carbon black was well suited for the determination of the three cannabinol compounds in hemp.

Protective Effect of the Traditional Chinese Patent Medicine Qing-Xuan Granule against Bleomycin-Induced Pulmonary Fibrosis in Mice.

Pulmonary fibrosis (PF) is a chronic obstructive pulmonary disease without effective clinical drug treatment. Qing-Xuan Granule (QX) as a traditional Chinese patent medicine is clinically used to cure children's cough. This study was designed to investigate the effects of QX and possible molecular mechanisms for bleomycin-induced PF. The work used Western blotting and Q-PCR to explore the vitro and vivo mechanisms of QX treatment, while using HPLC-TOF/MS to explore the composition of QX. QX was given daily orally for two weeks after bleomycin intratracheal instillation. The protective effects of QX on lung function, inflammation, growth factors, hydroxyproline content and deposition of extracellular matrix were investigated. QX decreased expression of Col I and α-SMA in lung tissues by down-regulating TGF-ß1-Smad2/3 signaling and suppressed epithelial-mesenchymal transition and effectively reversed abnormal mRNA levels of MMP-1and TIMP-1 as well as LOXL-2 in lung tissues. HPLC-TOF/MS indicate that six substances could be the main active components, which were reported to protect against experimental lung disease.

[Preparation of nickel-titanium alloy fiber/organosilicone-polyurethane solid phase microextraction head and its application to the determination of seven substituted benzenes in water].

Toluene-2,4-diisocyanate, polyester polyol, and hydroxy silicone oil were used as raw materials; stannous octoate was used as the catalyst; and cyclohexanone was used as the solvent to synthesize organosilicone-polyurethane (SP). The polymer was coated on the surface of a nickel-titanium alloy fiber treated hydrothermally with potassium hydroxide. It was the prepared for headspace solid phase microextraction (HS-SPME). The polymer structure was analyzed by infrared spectroscopy, the highest temperature of the coating was determined by thermogravimetric analysis, and the surface morphology of the extraction head was observed by scanning electron microscopy. The benzene series of toluene, xylene, m-dichlorobenzene, o-dichlorobenzene, ethyl benzoate, nitrobenzene and benzyl alcohol in water were determined by HS-SPME-gas chromatography (GC) method. There was a good linear relationship between the chromatographic peak area and mass concentration of each measured object. The correlation coefficients (R2) were 0.9926-0.9998. The limits of detection were 0.08-0.24 µg/L. The recoveries of the spiked samples were 95.9%-105.4%, and the relative standard deviations were 1.4%-5.0%. The coating of SPME head adhered more firmly, and had a better adsorption performance for the substituted benzenes in water.

[Determination of patulin in fruits and jam by solid phase extraction-ultra performance liquid chromatography].

With magnesium silicate, silica gel, diatomite and calcium sulfate as raw materials, a new solid phase extraction column was prepared through a series of processes of grinding to ethanol homogenate, drying and packing into polypropylene tube. The sample was hydrolyzed by pectinase, extracted by acetonitrile and purified by solid phase extraction. The target compounds were separated on a C18 column (100 mm×2.1 mm, 1.8 µm), using 0.8% (v/v) tetrahydrofuran solution as mobile phase with a flow rate of 0.5 mL/min. The detection wavelength was 276 nm. The effect of pectinase on extraction yield and purification effect of solid-phase extraction column were investigated. The optimum chromatographic conditions were selected. There was a good linear relationship between the peak heights and the mass concentrations of patulin in the range of 0.1 to 10 mg/L with the correlation coefficient (R2) of 1. The limit of detection for this method was 10.22 µg/kg. The spiked recoveries of samples were 86.58%-94.84% with the relative standard deviations (RSDs) of 1.45%-2.28%. The results indicated that the self-made solid phase extraction column had a good purification efficiency, and the UPLC had a high separation efficiency. The method is simple, accurate and of great significance for the quality and safety control of fruit products.