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Active participation in project-based learning (PBL) could develop students` knowledge and crucial learning skills across various disciplines. However, the implementation of PBL in the K-12 classroom is usually impeded by the stepby-step PBL cycle. Micro project-based learning (MPBL), which advocates and adheres to the learning principles and mechanisms of PBL with constraining the learning cycle in shorter periods, has been considered as a lightweight alternative to PBL process. As an exploration, this study explored the impact of MPBL on the conceptual understanding of sodium bicarbonate and the crucial learning skills in chemistry class at upper-secondary schools. The quasi-experimental research was implemented for 125 students, with an experimental group receiving MPBL teaching and a control group receiving conventional teaching. In the study, data including knowledge tests, crucial learning skills survey, and student interview were collected and analysed. The results indicated that MPBL was effective in the development of students' conceptual understanding and crucial learning skills (i.e., communication and collaboration, information integration, independent learning, and problem-solving). The study will inform the pedagogical innovation in chemistry education and teaching practices in chemistry class.

Entity relationship extraction aims to detect the relationship between entities and entity pairs from unstruc-tured text. It is an important step in constructing domain knowledge map. In view of the poor semantic expression ability of the existing extraction models and the low accuracy of overlapping triples extraction, this paper studies the joint extraction of entity relationships by integrating pre-trained model and attention, and divides the entity relation-ship extraction task into two tag modules. The head entity tagging module uses a pre-trained model to encode sen-tences. In order to further learn the internal characteristics of sentences, bi-directional long-short term memory and self-attention mechanism are used to form a feature enhancement layer. The binary classifier is used as the decoder of the model to mark the start and end positions of the head entity in the sentence. In order to deepen the relationship between the two marking modules, a feature fusion layer is set up before the tail entity marking task. The head entity features and sentence vectors are fused through convolutional neural networks (CNN) and attention mechanism. The relationship between entities is determined and the tail entity is marked through multiple identical and independent binary classifiers. A joint model based on pre-trained encoder and attention mechanism (JPEA) is constructed. Experimental results show that this method can significantly improve the extraction effect, and the performance of extraction tasks under different pre-trained models is compared, which further illustrates the superio-rity of the model.

Mo–30Cu alloy billets were prepared by powder metallurgy infiltration method, the rolled Mo–30Cu billets and oxygen-free copper plates were hot-pressed at 970 ℃ with a pressure of 30 MPa to obtain 5-layer Cu/MoCu/Cu (CPC) composites. The effects of the Mo–30Cu surface treatments on the interface bonding strength of the multi-layer CPC composites were studied by the microstructure observation, ultrasonic scanning analysis, high-temperature thermal examination, and air leakage rate testing. The results show that, the multi-layer CPC composites prepared by Mo–30Cu interlayer materials treated by wiredrawing have no cavity defects after being heated at 830 ℃ for 10 min, and the leakage rate is less than 5×10−3 Pa·cm3·s−1. The multi-layer CPC composites prepared by Mo–30Cu interlayer materials treated by grinding show the bulging phenomenon after the thermal examination, have the obvious cavity defects in the interior, and the leakage rate is greater than 5×10−3 Pa·cm3·s−1.

CuWO4 is a medium bandgap (2.3 eV) n-type semiconductor capable of photoelectrochemical water oxidation under applied electrical bias. Here, we show for the first time that suspended microcrystals CuWO4 evolve oxygen photocatalytically under visible illumination from solutions of 0.05 M AgNO3 (10.8 μmol/hour; AQE of 0.56% at 400 nm) and 0.0002 M FeCl3 (1.5 μmol/hour). No oxygen is detected with 0.002 M [Fe(CN)6]3- as sacrificial agent. The activity dependence on the redox potential of the acceptors is due to the presence of Cu2+ based electron trap states in CuWO4. According to surface photovoltage spectroscopy and electrochemistry, these states are located on the particle surface, 1.8 eV above the valence band edge of the material. Controlling the chemistry of these states will be key to uses of CuWO4 particles in tandem catalysts for overall water splitting. [ABSTRACT FROM AUTHOR]

The S-doped mesoporous nanocomposite (S-TNT) of HTiNbO5 nanosheets (NSs) and anatase TiO2 nanoparticles (NPs) with exposed {101} facets has been successfully synthesized by first mixing freeze-dried HTiNbO5 NSs with titanium isopropoxide and then calcination with thiourea in air. The exposed anatase {101} facets can act as a possible reservoir of the photogenerated electrons, yielding a highly reactive surface for the reduction of O2 to O2Ṗ−. The partial substitution of Ti4+ by S6+ in the lattice of TiO2 NPs leads to a charge imbalance in S-TNT and the formation of Ti–O–S bonds. As a result, the formed cationic S-TNT favours adsorption of hydroxide ions (OH−ads) and thus captures the photo-induced holes to form hydroxyl radicals (ṖOH). Moreover, with the formation of Ti–O–S bonds, partial electrons can be transferred from S to O atoms and hence the electron-deficient S atoms might capture photo-induced electrons. The surface-adsorbed SO42− could also act as an efficient electron trapping center to promote the separation of charge carriers. In addition, the Ti3+ species due to the removal of oxygen atoms during calcination and the associated oxygen vacancy defects on the surface of S-TNT could act as hole and electron scavengers, respectively. Besides, the closely contacted interface is formed between HTiNbO5 NSs and anatase TiO2 NPs due to the common features of TiO6 octahedra in two components, resulting in a nanoscale heterojunction structure to speed up the separation rate of photogenerated charge carriers. The formation of a nano-heterojunction and the incorporation of Ti3+ and S dopants give rise to the visible and near-infrared light response of S-TNT. The combined effects greatly retard the charge recombination and improve the photocatalytic activity for the degradation of rhodamine B (RhB) and phenol solution under visible light irradiation. The corresponding photocatalytic mechanism was investigated via the active species capture experiments. The present work may provide an insight into the fabrication of delicate composite photocatalysts with excellent performance. [ABSTRACT FROM AUTHOR]

It is important to realize good consistency among different device units on a big wafer. The bad product consistency results from the processing deviation which is hard to control. A novel simulation method to control and reduce the influence of processing deviation on the sensitivity of a piezoresistive pressure sensor is provided in this paper. Based on finite element analysis (FEA) and mathematical integration, the performance of the pressure sensors is simulated. The pressure sensors are designed and fabricated according to the simulation results. The test results confirm that this simulation method can help to design the pressure sensor very precisely. From the simulation and test results, we find that properly enlarging the size of the square silicon membrane can improve the devices consistency. [ABSTRACT FROM AUTHOR]

Abstract: A convenient synthesis of bisamide from aldehyde and amide with BF3 etherate as catalyst was reported. Both aryl and aliphatic bisamides could be prepared with this procedure in high yield at room temperature and the catalyst loading as low as 0.5 mol % was achieved. Fine-tuned solvent was utilized for both rapid conversion and simple isolation. Two CB2 receptor inverse agonists were synthesized with this protocol in high yield. [Copyright &y& Elsevier]

A series of rice husk biochar (RHBC) modified bimetallic oxides were prepared using a simple pyrolysis method to activate peroxymonosulfate (PMS) for the degradation of acid orange G (OG). The results demonstrated that 50 mg L -1 OG was completely decomposed by 1 mM PMS activated with 100 mg L -1 RHBC-CuCo 2 O 4 within 15 min at initial pH 3.4. The OG degradation rate constant k of RHBC-CuCo 2 O 4 /PMS (0.95 × 10 -1 min -1 ) was five times greater than that of CuCo 2 O 4 /PMS (0.19 × 10 -1 min -1 ), suggesting that the introduction of RHBC significantly improved the activity of bimetallic oxides. The effects of the initial pH, catalyst dosage, PMS concentration and reaction temperature on OG removal were also studied. The degradation products of OG were analysed using a gas chromatography-mass spectrometer (GC-MS). Electron paramagnetic resonance (EPR) and quenching experiments showed that singlet oxygen ( 1 O 2 ) was the main active species. The RHBC-CuCo 2 O 4 /PMS oxidation system is not only unaffected by inorganic anions (Cl - , NO 3 - , HCO 3 - ) and humic acid (HA), but also could remove other typical pollutants of acetaminophen (ACT), sulfathiazole (STZ), rhodamine B (RhB), and bisphenol A (BPA). These findings show that RHBC-CuCo 2 O 4 has great potential for practical applications in the removal of typical organic pollutants., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

In this study, a bimetallic oxide catalyst of cobalt-manganese (CoMn 2 O 4 ) was synthesized using the sol-gel method, and it was then characterized using a variety of techniques such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) spectroscopy, X-ray photoelectron spectroscopy (XPS), and nitrogen adsorption-desorption isotherms. The obtained novel catalyst, i.e., CoMn 2 O 4 , was then used as an activator of peroxymonosulfate (PMS) for the catalytic degradation of a commonly-used UV filter, 2-phenylbenzimidazole-5-sulfonic acid (PBSA) in water. The effects of various factors (e.g., catalyst dosage, PMS concentration, reaction temperature, and pH) in the process were also evaluated. Chemical scavengers and electron paramagnetic resonance (EPR) tests showed that the • OH and SO 4 •- were the main reactive oxygen species. Furthermore, this study showed that CoMn 2 O 4 is a promising catalyst for activating PMS to degrade the UV filters.