国内外初中化学教材编写的比较研究

选取国内外有代表性的初中化学教材作为范例,从教材设计的背景中对教材编写理念、教材内容选取、教材内容组织方式、教材栏目和版面设计以及化学实验和习题设计等方面进行比较,并从5个维度得出现行国内外初中化学教材编写的共同特点。     

Replacing alkyl side chain of non-fullerene acceptor with siloxane-terminated side chain enables lower surface energy towards optimizing bulk-heterojunction morphology and high photovoltaic performance

Towards a good control of the morphology of bulk-heterojunction(BHJ) active layers for polymer solar cells(PSCs), selecting an appropriate side chain for a polymer donor and a nonfullerene acceptor(NFA) is very crucial. In this work, two novel NFAs i-IE-4F and i-IESi-4 F comprising alkyl and siloxane-terminated side chains on the central indacenodithiophene(IDT) core,respectively, were synthesized. Attaching the siloxane-terminated side chain to i-IESi-4 F affords surface energy(γ) of33.32 mN/m, much lower than that of 39.83 mN/m for i-IE-4F, supplying a big chance to tune miscibility with a polymer donor.Two fluorobenzotriazole-based polymer donors J52 and PBZ-2Si bearing alkyl and siloxane-terminated side chains, respectively, show γ values of 36.08 and 33.10 mN/m, respectively. The estimated Flory-Huggins interaction parameters(χD,A) indicate that the i-IESi-4 F is more miscible than i-IE-4F in pairing with J52 or PBZ-2Si. The resulting i-IESi-4 F-based blend film exhibits low film roughness and accompanies obviously improved BHJ uniformity. In PSCs, the J52:i-IESi-4F and PBZ-2Si:i-IESi-4 F active layers display power conversion efficiencies(PCEs) of 12.67% and 14.54%, respectively, all remarkably higher than PCEs≤ 7.34% of the i-IE-4F-based active layers. Interestingly, the PBZ-2Si:i-IESi-4 F active layer, a donor:acceptor blend system comprising siloxane-terminated side chains(DSi:ASimatching) with the highest BHJ miscibility due to the combinatory effect of the side chains, shows the highest efficiency, as supported by efficient exciton dissociation, the lowest bimolecular recombination, and the optimal charge transport. Our results demonstrate that attaching siloxane-terminated side chains to NFAs,as a side chain engineering, has big potential in lowering their surface energy towards fine control of BHJ morphology and leading to a better donor:acceptor blend system.     

Degradation of pyrazinamide in aqueous solution by electron beam irradiation: kinetics,influence factors and mechanism study

The degradation of pyrazinamide (PZA) by electron beam irradiation (EBI) was studied. It was found that the degradation of PZA was efficient with the removal rate of 99% for 0.2 mM PZA under 5 kGy, and the degradation kinetics followed pseudo-first-order kinetics. The presence of CO₃^2?, HCO₃^?, NO₃^?, and fulvic acid inhibited the degradation of PZA. The addition of H₂O₂ or K₂S₂O₈ effectively enhanced the degradation and mineralization of PZA. The scavenger experiments and quantum chemical calculations showed that ^·OH was the primary reactive species in the degradation. The identification of intermediates and quantum chemical calculations illustrated the mechanism of degradation.