Sunlight-driven activation of molecular oxygen (O 2 ) for organic oxidation reactions offers an appealing strategy to cut down the reliance on fossil fuels in chemical industry, yet it remains a great challenge to simultaneously tailor the charge kinetics and promote reactant chemisorption on semiconductor catalysts for enhanced photocatalytic performance. Herein, we report iron sites immobilized on defective BiOBr nanosheets as an efficient and selective photocatalyst for activation of O 2 to singlet oxygen ( 1 O 2 ). These Fe 3+ species anchored by oxygen vacancies can not only facilitate the separation and migration of photogenerated charge carrier, but also serve as active sites for effective adsorption of O 2 . Moreover, low-temperature phosphorescence spectra combined with X-ray photoelectron spectroscopy (XPS) and electronic paramagnetic resonance (EPR) spectra under illumination reveal that the Fe species can boost the quantum yield of excited triplet state and accelerate the energy transfer from excited triplet state to adsorbed O 2 via a chemical loop of Fe 3+ /Fe 2+ , thereby achieving highly efficient and selective generation of 1 O 2 . As a result, the versatile iron sites on defective BiOBr nanosheets contributes to near-unity conversion rate and selectivity in both aerobic oxidative coupling of amines to imines and sulfoxidation of organic sulfides. This work highlights the significant role of metal sites anchored on semiconductors in regulating the charge/energy transfer during the heterogeneous photocatalytic process, and provides a new angle for designing high-performance photocatalysts.
With advances in information and communication technology and the rapid development of the mobile Internet, mobile health (m-health) management applications (apps) play a key role in modern health assistance programs. However, m-health management apps still face major dilemmas in ensuring user satisfaction and continuous use. Based on resolving the contradiction between the multiple complex and ambiguous demands of users and the limited development resources of companies, this study explores ways to improve user satisfaction and the willingness to sustain m-health management app usage to build efficient and clear m-health management app demand insights and development strategies. This study integrates the advantages of the Kano model and the decision-making trial and evaluation laboratory (DEMATEL) method. From the systematic level, an attribute acquisition-classification-key attribute extraction and influence relationship quantification-hierarchy analytic hierarchy model was built. The research results provide implications for further improvement efforts to consider not only technological capabilities but also effective insights into the attributes that are highly expected by users, thus improving the accuracy of app function positioning and, in turn, enhancing user satisfaction and continuous usage intention. Additionally, the results provide decision-makers in enterprises and relevant research and development (R&D) departments with clear and efficient app requirement relationships and development strategies.
Published by Canadian author Margaret Atwood in 1985, The Handmaid's Tale, her first dystopian novel, depicts a near-future patriarchal society practicing the legal and sacred form of reproductive surrogacy, the so-called "handmaid" system. The whole system is centered on the male Commanders-male founders of Gilead: they rape the handmaids every month, on the Ceremony, in front of their wives and servants; they dispatch the handmaids to another Commander's family once the newborn infants wean; they push this inhumane torture and autocratic trading of handmaids' wombs to the extreme edge of ethics.
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