[en] A ratiometric luminescence sensing method is developed and makes the chemically stable Eu metal–organic framework to be the first bifunctional chemical sensor for Cd²⁺ and F⁻ ions with naked-eye observation in the field of sensing applications utilizing luminescent Ln-MOFs. This is the first example of luminescent colorimetric sensor caused by the direct dual emissions of a single Ln-MOF. A recyclable vapoluminescent sensor for HCl and NH₃ by the naked eye has also been realized. - Graphical abstract: A luminescent Eu-MOF is successfully designed to be a novel bifunctional chemical sensor and a vapoluminescent sensor. - Highlights: • A ratiometric luminescence sensing method is developed. • This is the first chemical sensor for Cd²⁺ and F⁻ via Ln-MOF. • A recyclable vaporluminescent sensor has been realized.

[en] There mainly are three methods which can be used to measure crater parameters after burst of Earth-penetrating Nuclear Weapons now. They are direct measure method, geophysical imagery among wells method and remote sensing measure method. In this article, the basic principles of these measure methods are explained briefly, their characteristics are analyzed and the comparison in many aspects of these methods is accomplished according to the sizes of crater after burst of Earth-penetrating Nuclear Weapons from the angle of military demands. At last, a viewpoint that the InSAR method is the best measure method which can meet military demands is pointed out. (authors)

[en] In this article, a summary of CdZnTe detector for astrophysics applications is provided. The main properties of CdZnTe crystal and the principle of CdZnTe detector are introduced. The applications of CdZnTe detector in the astrophysics are summarized. The characters of applications and the development trend are discussed at four aspects. (authors)

[en] As organic dyes are a major group of water pollutants, the development of materials for the removal of dyes is of great significance for the environment. Here, a novel flower-like Fe₃O₄@ZIF-67 photocatalyst was synthesized using a simple method at room temperature. It was found that the Fe₃O₄@ZIF-67 exhibited the ability of degrading Congo red (CR) quickly under visible light irradiation in a short time after adsorption equilibrium. Free radical trapping experiments revealed that the photo-induced active species superoxide radical (• O²⁻) and holes (h⁺) were the predominant active species in the photocatalytic system. In addition, results demonstrated that the Fe₃O₄@ZIF-67 can be magnetically recycled, and maintain high photocatalytic activity after reuse over five cycles with no obvious decrease in the removal efficiency. It suggested that the synthesized material had a potentially promising application for CR removal from waste water. - Graphical abstract: A flower-like structure of ZIF-67 loaded with Fe₃O₄ was synthesized by a facile method. It showed high photocatalysis activity that can degradate congo red (CR) completely in a short time. Display Omitted - Highlights: • A flower-like structure of ZIF-67 was synthesized. • It presents high photocatalytic activity to CR. • The product could be collected conveniently by magnets.

[en] In this study, Bi₁₂O₁₇Cl₂ nanosheets preferentially oriented growth along [200] were successfully synthesized through a facile hydrothermal method in the presence of various surfactants, including PVP, CTAB and CTAC. The crystallization behavior, band gap structure and morphology of Bi₁₂O₁₇Cl₂ could be modulated by the addition of surfactants. Bi₁₂O₁₇Cl₂ with surfactants displays superior visible light photocatalytic performance than pristine sample for photodegrading RhB and 2-chlorophenol. Moreover, Bi₁₂O₁₇Cl₂ preferentially oriented growth along [200] maintained stable and recyclable in the photocatalytic process, demonstrating their promising application in environment remediation.

[en] Estimation of remaining useful life (RUL) is helpful to manage life cycles of machines and to reduce maintenance cost. Support vector machine (SVM) is a promising algorithm for estimation of RUL because it can easily process small training sets and multi-dimensional data. Many SVM based methods have been proposed to predict RUL of some key components. We did a literature review related to SVM based RUL estimation within a decade. The references reviewed are classified into two categories: improved SVM algorithms and their applications to RUL estimation. The latter category can be further divided into two types: one, to predict the condition state in the future and then build a relationship between state and RUL; two, to establish a direct relationship between current state and RUL. However, SVM is seldom used to track the degradation process and build an accurate relationship between the current health condition state and RUL. Based on the above review and summary, this paper points out that the ability to continually improve SVM, and obtain a novel idea for RUL prediction using SVM will be future works.

[en] Ultrathin structures have gained more and more attention due to their large surface area and abundant reactive sites, which are beneficial for the improvement of performances. Herein, we report an ultrathin Bi₂MoO₆ synthesized by a simple mannitol-assisted hydrothermal method for the first time. The as-synthesized ultrathin Bi₂MoO₆ exhibits highly selective adsorption efficiency toward various positively charged organic dyes. Moreover, the ultrathin Bi₂MoO₆ displays enhanced photocatalytic activity in comparison with pristine Bi₂MoO₆. Systematic photoelectrochemical measurements reveal that the higher separation efficiency of photogenerated carriers takes responsibility for the improved photocatalytic performance. This work provides a simple path for designing ultrathin nanoarchitectures and widening application for these ultrathin materials.

[en] A sequence of isostructural lanthanide metal-organic frameworks (MOFs) [Tb_xEu_1-xNa(HL²)₂(H₃L²)_0.5].EtOH [H₃L² = 5-hydroxy-isophthalic acid] (x = 0.1-0.9) are successfully obtained by doping Tb^III and Eu^III into the same framework. A fluent change in their photoluminescence is achieved by varying the ratio of Tb^III/Eu^III from 1:9 to 9:1. Among the obtained lanthanide MOFs, [Tb_0.5Eu_0.5Na(HL²)₂(H₃L²)_0.5].EtOH displays remarkable dual emission, with macroscopic bright red-orange luminescence in ethyl alcohol that is easily quenched, even with a low water content, thus presenting an innovative approach for an ideal chemical sensor for the detection of trace amounts of water in ethyl alcohol. As the water content increases, the probe exhibits a distinguishable change in its luminescence. To the best of our knowledge, it is quite rare for a self-referencing luminescent sensor to be able to quantify the amount of water in ethyl alcohol over a wide range (0.01-3.2 %). The detection limit of the codoped Ln MOFs is 0.01 %, which is ahead of other reported MOF-based sensors. (copyright 2018 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

[en] In this work, uniform BiOCl microspheres were used as self-sacrificed template to construct Bi₂O₃/BiOCl heterojunctions by a simple alkaline treatment method. Details of structure and chemical properties were carefully characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy (TEM), high-resolution TEM, X-ray photoelectron spectroscopy, UV–vis diffuse reflectance spectroscopy, and Brunauer–Emmett–Teller techniques. The results indicated that BiOCl microspheres composed of numerous nanosheets transformed to rod-like Bi₂O₃ nanostructures during the alkaline treatment, which resulted in strong visible-light absorption. The as-obtained Bi₂O₃/BiOCl heterojunctions exhibited remarkably enhanced photocatalytic performance for the degradation of methyl orange (MO) under visible-light irradiation, which was ~1.2 and 2.5 times as that of pure BiOCl and Bi₂O₃, respectively. The formation of Bi₂O₃/BiOCl heterojunctions facilitated the transfer and separation of photogenerated charge carriers which was further confirmed by the photocurrent measurement and photoluminescence spectra results. The finding reported here offers a valid in situ route for constructing heterojunction photocatalysts to effectively decompose the organic pollutants in aqueous solution.

[en] Highlights: • In₂O₃/HNTs adsorbents were firstly synthesized for tetracycline (TC) removal. • In₂O₃/HNTs displayed dramatically enhanced adsorption efficiency. • The electrostatic attraction was primarily responsible for the enhanced adsorption efficiency. • The hydroxyl groups and interfacial interaction contributed to more negative surface charges. Indium oxide/halloysite nanotubes (In₂O₃/HNTs) composites used as adsorbents for tetracycline (TC) removal were synthesized through a simple hydrothermal method. The influences of adsorbent dosage, pH value, temperature and TC concentration on adsorption efficiency were investigated. The adsorption behavior of In₂O₃/HNTs toward TC could be described by Langmuir isotherm and pseudo second–order kinetic models. The adsorption results indicated that the adsorption efficiency and capacity of 20% In₂O₃/HNTs were 7 times and 10 times as those of In₂O₃ as well as both 4 times as those of HNTs, respectively. Adsorption mechanism studies suggested that the electrostatic attraction was primarily responsible for the improvement of adsorption performance. The abundant hydroxyl groups of HNTs and the interfacial interaction between In₂O₃ and HNTs contributed to more negative surface charges of In₂O₃/HNTs, which was favorable for enhancing the adsorption efficiency. This work provides an efficient adsorbent for pollutant removal and contributes a feasible idea for constructing the potential adsorbents using natural minerals with abundant hydroxyl groups.