The study of the formation, characterization, and functionality of isolated surface hydrides on solid materials is a formidable task because of the complexity of solid surfaces and the difficulty of analyzing structures in solids. Herein, we found the formation of indium (In) hydride species supported by CHA zeolites. The In hydrides were formed by treatment of an In-exchanged CHA zeolite (In-CHA) with H 2 at high temperatures (>773 K). In situ Fourier transform infrared (FTIR) spectroscopy and density functional theory (DFT) calculations revealed that an [InH 2 ] + ion on a framework anionic site is a plausible structure. In-CHA exhibited high selectivity and durable catalytic activity for the nonoxidative dehydrogenation of ethane for at least 90 h. Kinetic and in situ spectroscopic studies as well as transition state (TS) calculations suggested that [InH 2 ] + ions serve as catalytically active sites for selective dehydrogenation using In-CHA.

Wearable devices are being intensively investigated in an extensive range of applications, particularly in the field of human motion detection. Herein, a graphene‐modified silk fabric strain sensor is fabricated and its satisfactory performance including high sensibility and comfortable fit to the human body is reported. Graphene oxide is coated on silk fabric by vacuum filtration and is reduced by hot press method, which provides the obtained silk fabric strain sensor with good piezoresistivity and being more environmentally friendly compared with chemical reduction. Meanwhile, compared with the other strain sensors, the silk fabric strain sensor shows a linear and high resistance variation rate with increasing strain. Moreover, the fabric sensor also exhibits other excellent performances, including cycle stability, UV‐blocking, and hydrophobicity to some extent. Owing to the above advantages, the modified silk fabric sensor can be sewed together with fabric and has the potential to detect human motions.

A rhodium-catalyzed annulation between ethyl benzimidates and α- aroyl sulfur ylides was developed, affording a series of pyrano[4,3,2-ij]isoquinoline derivatives in moderate to good yields with good functional group compatibility. The procedure featured dual ortho-C-H functionalization and dual cyclization in one pot. The optoelectronic properties of those fused heteroarenes were tested by UV/vis and fluorescence spectrometers.

No abstract

No abstract

A rhodium-catalyzed annulation between aroyl sulfoxonium ylides and anthranils has been developed to synthesize 10H-indolo­[1,2-a]­indol-10-one derivatives. This reaction started with an unpredented (4 + 1) annulation toward N-(2-formylphenyl) indolones, proceeding with the sequential ortho-amination of the C–H bond in aroyl sulfoxonium ylides by anthranils and the insertion of N–H to carbene. Finally, the Aldol condensation constructed the second indole ring. This procedure features the formation of two C–N bonds and one CC bond in one pot.

The reactivity order of 12 anions toward ethyl chloride has been investigated by using the G2(+) method, and the competitive E2 and SN2 reactions are discussed and compared. The reactions studied are X(-) + CH3CH2Cl → HX + CH2═CH2 + Cl(-) and X(-) + CH3CH2Cl → CH3CH2X + Cl(-), with X = F, Cl, Br, HO, HS, HSe, NH2 PH2, AsH2, CH3, SiH3, and GeH3. Our results indicate that there is no general and straightforward relationship between the overall barriers and the proton affinity (PA) of X(-); instead, discernible linear correlations only exist for the X's within the same group of the periodic table. Similar correlations are also found with the electronegativity of central atoms in X, deformation energy of the E2 transition state (TS), and the overall enthalpy of reaction. It is revealed that the electronegativity will significantly affect the barrier height, and a more electronegative X will stabilize the E2 and SN2 transition states. Multiple linear regression analysis shows that there is a reasonable linear correlation between E2 (or SN2) overall barriers and the linear combination of PA of X(-) and electronegativity of the central atom.

As one of the most influential international large-scale educational assessments, the Program for International Student Assessment (PISA) provides a valuable platform for the horizontal comparisons and references of international education. The cognitive diagnostic model, a newly generated evaluation theory, can integrate measurement goals into the cognitive process model through cognitive analysis, which provides a better understanding of the mastery of students of fine-grained knowledge points. On the basis of the mathematical measurement framework of PISA 2012, 11 attributes have been formed from three dimensions in this study. Twelve test items with item responses from 24,512 students from 10 countries participated in answering were selected, and the analyses were divided into several steps. First, the relationships between the 11 attributes and the 12 test items were classified to form a Q matrix. Second, the cognitive model of the PISA mathematics test was established. The liner logistic model (LLM) with better model fit was selected as the parameter evaluation model through model comparisons. By analyzing the knowledge states of these countries and the prerequisite relations among the attributes, this study explored the different learning trajectories of students in the content field. The result showed that students from Australia, Canada, the United Kingdom, and Russia shared similar main learning trajectories, while Finland and Japan were consistent with their main learning trajectories. The primary learning trajectories of the United States and China were the same. Furthermore, the learning trajectory for Singapore was the most complicated, as it showed a diverse learning process, whereas the trajectory in the United States and Saudi Arabia was relatively simple. This study concluded the differences of the mastery of students of the 11 cognitive attributes from the three dimensions of content, process, and context across the 10 countries, which provided a reference for further understanding of the PISA test results in other countries and shed some evidence for a deeper understanding of the strengths and weaknesses of mathematics education in various countries.