Search

Heavy metal contamination in soil, which is harmful to both ecosystem and mankind, has attracted worldwide attention from the academic and industrial communities. However, the most-widely used remediation technologies such as electrochemistry, elution, and phytoremediation. suffer from either secondary pollution, long cycle time or high cost. In contrast, in situ mineralization technology shows great potential due to its universality, durability and economical efficiency. As such, the development of mineralizers with both high efficiency and low-cost is the core of in situmineralization. In 2021, the concept of ‘Super-Stable Mineralization’ was proposed for the first time by Kong et al.[1] The layered double hydroxides (denoted as LDHs), with the unique host–guest intercalated structure and multiple interactions between the host laminate and the guest anions, are considered as an ideal class of materials for super-stable mineralization. In this review, we systematically summarize the application of LDHs in the treatment of heavy metal contaminated soil from the view of: 1) the structure–activity relationship of LDHs in in situ mineralization, 2) the advantages of LDHs in mineralizing heavy metals, 3) the scale-up preparation of LDHs-based mineralizers and 4) the practical application of LDHs in treating contaminated soil. At last, we highlight the challenges and opportunities for the rational design of LDH-based mineralizer in the future.

With modern information technology widely applied to school teaching in all aspects, blended teaching based on SPOC is increasingly popular with colleges and universities. However, it’s still rare to see the applied research into it for English teaching in primary schools. In order to explore the application of SPOC in English teaching of primary schools, this paper analyzed the current situation of English teaching in primary schools in China in detail, and then proposed a blended teaching model based on the SPOC platforms of Cloud Class and 17zuoye.com. We also conducted an experiment that lasts about one year by tracking and recording the performance of two groups of classes in Zhongwu Primary School with an experimental class and a control class in each group. After analyzing the experimental data, we found that the SPOC-based teaching model proposed in this paper can achieve good practical results, and can be applied and promoted for future teaching in other schools.

Metal-organic framework material [Cd(tib)(dnbpdc) (H2O)]·2DMF·2H2O (1) [tib = 1, 3, 5-tris(1-imidazolyl)benzene, H2dnbpdc = 2, 2′-dinitro-4, 4′-biphenyldicarboxylic acid] was synthesized and characterized by Thermogravimetric analyses (TGA), Powder X-ray diffraction (PXRD) analyses and Bruker D8 Advance X-ray diffractometer. The results showed that 1 was a 1D chain structure to be joined together by hydrogen bonds to generate a 3D supramolecular structure. CO2 and N2 adsorption behavior of the material was studied. It is significative that 1 can selective sorption of CO2.

Zn metal-organic framework material [Zn2(tib)(HBTB)2(H2O)]·2H2O (1) [tib = 1,3,5-tris(1- imidazolyl)benzene, H3BTB = 4,4′,4″-benzene-1,3,5-triyl-tribenzoic acid] was synthesized and characterized by Thermogravimetric analyses (TGA), Powder X-ray diffraction (PXRD) analyses and Bruker D8 Advance X-ray diffractometer. The results showed that 1 was a 2D network to be joined together by hydrogen bonds to generate a 3D supramolecular structure. Gas, vapor adsorption behavior of the material was studied. It is meaningful that 1 can selective sorption of CO2 and MeOH.

Multi-phase electric machines such as five-phase permanent magnet synchronous motor (PMSM) play an important role in the ships electrical propulsion because of the advantages of high performance and high reliability. The decoupled mathematic models of five-phase PMSM in dq coordinate frame are established, and the reason caused to high stator harmonic current in the multi-phase motor is analyzed based on the mathematic models. To suppress the harmonic current, a novel vector control (VC) method based on SVPWM and harmonic current closed loop control is proposed. Based on the proposed algorithm, a five-phase PMSM vector control system is established with MATLAB, the performance is simulated and analyzed. The results show that, the stator harmonic current is much little than that of the traditional control method.