Heterostructure based interface engineering has been proved an effective method for finding new superconducting systems and raising superconductivity transition temperature (T C ) 1-7 . In previous work on one unit-cell (UC) thick FeSe films on SrTiO 3 (STO) substrate, a superconducting-like energy gap as large as 20 meV 8 , was revealed by in situ scanning tunneling microscopy/spectroscopy (STM/STS). Angle resolved photoemission spectroscopy (ARPES) further revealed a nearly isotropic gap of above 15 meV, which closes at a temperature of 65 ± 5 K 9-11 . If this transition is indeed the superconducting transition, then the 1-UC FeSe represents the thinnest high T C superconductor discovered so far. However, up to date direct transport measurement of the 1-UC FeSe films has not been reported, mainly because growth of large scale 1-UC FeSe films ischallenging and the 1-UC FeSe films are too thin to survive in atmosphere. In this work, we successfully prepared 1-UC FeSe films on insulating STO substrates with non-superconducting FeTe protection layers. By direct transport and magnetic measurements, we provide definitive evidence for high temperature superconductivity in the 1-UC FeSe films with an onset T C above 40 K and a extremely large critical current density J C ~ 1.7×10 6 A/cm 2 at 2 K. Our work may pave the way to enhancing and tailoring superconductivity by interface engineering.The FeSe films and FeTe protection layer are grown by molecular beam epitaxy (MBE) (see Methods).

Novel iron-tungsten catalysts were first developed for the selective catalytic reduction of NO by NH in diesel exhaust, achieving an excellent performance with a wide operating temperature window above 90% NO conversion from 225 or 250 to 450 °C (GHSVs of 30 000 or 50 000 h). It also exhibited a pronounced stability and relatively high NO conversion in the presence of HO, SO and CO. The introduction of W resulted in the formation of α-FeO and FeWO species obtained by HRTEM directly. The synergic effect of two species contributed to the high SCR activity, because of the increased surface acidity and electronic property. The FeWO with octahedral [FeO]/[WO] structure acted as the Brønsted acid sites to form highly active NH species. Combining DFT calculations with XPS and UV-vis results, it was found that the fine electron interaction between α-FeO and FeWO made the electron more easily transfer from W sites to Fe sites, which promoted the formation of NO. Judging by the kinetics and SCR activity studies, the FeWO with an appropriate W amount showed the strongest interaction, and thereby the lowest activation energy of 39 kJ•mol and optimal catalytic activity. These findings would be conducive to the reasonable design of NH-SCR catalysts by adjusting the fabrication.

Inspired by the widely antiphytopathogenic application of diversified derivatives from natural sources, cryptolepine and its derivatives were subsequently designed, synthesized, and evaluated for their antifungal activities against four agriculturally important fungi Rhizoctonia solani, Botrytis cinerea, Fusarium graminearum, and Sclerotinia sclerotiorum. The results obtained from in vitro assay indicated that compounds a1–a24 showed great fungicidal property against B. cinerea (EC50 < 4 μg/mL); especially, a3 presented significantly prominent inhibitory activity with an EC50 of 0.027 μg/mL. In the pursuit of further expanding the antifungal spectrum of cryptolepine, ring-opened compound f1 produced better activity with an EC50 of 3.632 μg/mL against R. solani and an EC50 of 5.599 μg/mL against F. graminearum. Furthermore, a3 was selected to be a candidate to investigate its preliminary antifungal mechanism to B. cinerea, revealing that not only spore germination was effectively inhibited and the normal physiological structure of mycelium was severely undermined but also detrimental reactive oxygen was obviously accumulated and the normal function of the nucleus was fairly disordered. Besides, in vivo curative experiment against B. cinerea found that the therapeutic action of a3 was comparable to that of the positive control azoxystrobin. These results suggested that compound a3 could be regarded as a novel and promising agent against B. cinerea for its valuable potency.

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