Flexural Behavior of RC Beams Under Combined Effects of Acid–Salt Mist and Carbon Dioxide

The coupling effects of hydrochloric acid mist, carbon dioxide, and salt mist rich in Cl– and SO42– on the degradation of reinforcement concrete (RC) beams were researched with the simulation of colliery ground environment (CGE) and experimental investigation. The results indicated that carbonation of concrete and corrosion of rebar increased slowly as the maximum width of crack became \u3c0.5 mm. Meanwhile, the flexural carrying capacity of the deteriorated beam decreased slightly, while the concrete strength got a small increase first and a large decrease of more than 20% quickly. As the width of crack exceeded 0.5 mm, each target changed rapidly except the carbonation depth. Because of the interaction of deteriorated concrete and corroded rebar, the crack width, and flexural behavior of the beams have discrete correlation with the corrosion of rebar. The failure mode of beams changed from the crushing of compression concrete to the yielding of rebar

Experimental and theoretical investigations of Cs+ adsorption on crown ethers modified magnetic adsorbent

This work was financially supported by the NSFC (No: U1607105 and No: 51574286). The Scientific and Technological Funding in Qinghai Province (No: 2018-GX-101, No: 2018-ZJ-722 and No: 2019-HZ-808). “Light of West China” Program and Youth Innovation Promotion Association of CAS (No: 2015141 and 2016377).Carboxyl Fe3O4 nanoparticles (Fe3O4@R-COOH) modified with 18-Crown-6 ether functional groups have been prepared via an amidation reaction and used as bifunctional adsorbent for Cs+. The adsorbent has a superparamagnetic property, allowing an easy recycling, and a high capacity of Cs+ adsorption on the crown ether. The adsorption isotherms and kinetic behaviors agree well with the Langmuir and the pseudo-second-order models. The material exhibits a high selectivity for Cs+ in the solution with co-existing cations (NH4+, Rb+, K+, Na+ and Li+). A theoretical calculation according to density functional theory (DFT) is used to estimate the structure of Cs+ adsorption on crown ether, demonstrating an exothermic process and showing a good agreement with the experimental observations. The adsorption behavior is affected not only by the size of macrocyclic crown ethers, but also by the chelating symmetry and the binding energy. The newly developed adsorbent has a potential application for removing cesium out of wastewater and salt lakes.PostprintPeer reviewe

Hybrid CuCoO-GO enables ultrasensitive detection of antibiotics with enhanced laser desorption/ionization at nano-interfaces

The soaring concerns globally on antibiotic overuse have made calls for the development of rapid and sensitive detection methods urgent. Here we report that the hybrid CuCoO-GO matrix allows for sensitive detection of various antibiotics in combination with MALDI TOF MS. The new matrix is composed of few-layered GO nanosheets decorated with CuCoO nanoparticles with an average size of 10 nm, and exhibits excellent aqueous suspensibility. Accurate quantitation of the sulfonamide antibiotics in milk samples have been demonstrated using a CuCoO-GO matrix and a stable isotope (C13)-labeled analyte as the internal standard. Our experiments have achieved lower limits of detection (LOD) by several hundred fold for the detection of a panel of representative antibiotics, in comparison with the literature reports. Both intrabacterial and extrabacterial residual antibiotics can be sensitively detected with our method. We have further investigated the molecular mechanism of the enhanced desorption/ionization efficiency by the CuCoO-GO matrix with synchrotron radiation techniques for the first time. This work provides a sensitive matrix enabling MALDI-TOF MS to be applied in small molecular analysis, but also presents a distinct perspective on the mechanism behind the material functions

Study on the Anti-inflammatory mechanism of volatile components of hebei Aster tataricus before and after honey-fried based on gas chromatography-mass spectrometry and network pharmacology

Aster tataricus (AT) and honey-fried Aster tataricus (HAT) have a significant effect on relieving cough and reducing sputum, both of which contain many volatile components. Studies have shown that the volatile components of AT and HAT may have an anti-inflammatory effect, but the mechanism is unclear. This study aimed to analyze the daodi herb of Hebei AT and HAT qualitatively and quantitatively using gas chromatography-mass spectrometry and systematically explored the similarities and differences of anti-inflammatory molecular mechanisms of volatile components Hebei AT and HAT by using network pharmacology. These results indicate that there are significant differences in volatile compositions and percentage contents between AT and HAT. Moreover, the anti-inflammatory mechanism of volatile components of Hebei AT and HAT have more prominent similarities and fewer differences. AT and HAT’s similar potential active components such as humulene,γ-muurolene, α-phellandrene, and acetic acid were nine. The similar key gene targets were forty-seven, such as CAT, GAPDH, HMOX1, and CTH. The potential active ingredients peculiar to HAT were furfural, β-elemene, methyleugenol, and unique targets of EIF6 and PKIA. It suggests that HAT had its characteristics in clinical anti-inflammatory. Their active anti-inflammatory components and percentage contents were different, and HAT was higher than that of AT. The anti-inflammatory effect of volatile components of HAT may be better than that of AT. These results provide a theoretical basis for the study of the anti-inflammatory molecular mechanism of AT and HAT

1,1′-[(Hexane-1,6-diyldi­oxy)bis­(nitrilo­methyl­idyne)]dinaphthalene

The title compound, C28H28N2O2, was synthesized by condensation of 1-naphthaldehyde with 1,6-bis­(amino­oxy)hexane in ethanol. The mol­ecule is disposed about a crystallographic centre of symmetry. In the crystal structure, mol­ecules are linked through strong inter­molecular π–π stacking inter­actions [interplana distance = 2.986 (2) Å], forming a three-dimensional network

Graphene-Based Nanostructures in Electrocatalytic Oxygen Reduction

Application of graphene-type materials in electrocatalysis is a topic of growing scientific and technological interest. A tremendous amount of research has been carried out in the field of oxygen electroreduction, particularly with respect to potential applications in the fuel cell research also with use of graphene-type catalytic components. This work addresses fundamental aspects and potential applications of graphene structures in the oxygen reduction electrocatalysis. Special attention will be paid to creation of catalytically active sites by using non-metallic heteroatoms as dopants, formation of hierarchical nanostructured electrocatalysts, their long-term stability, and application as supports for dispersed metals (activating interactions)

2,2′-{1,1′-[Pentane-1,5-diyl­bis(oxy­nitrilo)]­diethyl­idyne}diphenol

In the title compound, C21H26N2O4, there is half a mol­ecule in the asymmetric unit with a crystallographic twofold rotation axis passing through the central C atom of the –CH=N—O—(CH2)5—O—N=CH– bridge. The dihedral angle formed by the two benzene rings is 80.85 (2)°. Strong intra­molecular O—H⋯N and C—H⋯O hydrogen bonds help to establish the molecular conformation. There are also weak inter­molecular π–π stacking inter­actions between neighbouring benzene rings [centroid–centroid separation = 3.502 (3) Å]

3,3′-Dibromo-1,1′-[(propane-1,3-diyl­dioxy)­bis(nitrilo­methyl­idyne)]dibenzene

The mol­ecule of the title compound, C17H16Br2N2O2, lies on a twofold axis that passes through the middle atom of the three-atom trimethyl­ene unit. The two aromatic rings are aligned at an angle of 76.02 (4)°

Formation of coupled three-dimensional GeSi quantum dot crystals

Coupled three-dimensional GeSi quantum dot crystals (QDCs) are realized by multilayer growth of quantum dots (QDs) on patterned SOI (001) substrates. Photoluminescence spectra of these QDCs show non-phonon (NP) recombination and its transverse-optical (TO) phonon replica of excitons in QDs. With increasing excitation power, peak energies of both the NP and TO peaks remain nearly constant and the width of the TO peak decreases. These anomalous features of the PL peaks are attributed to miniband formation due to strong coupling of the holes and the emergence of quasioptical phonon modes due to periodic scatters in ordered GeSi QDs