The electrocatalytic conversion of nitrogen gas at ambient conditions represents a novel approach for ammonia synthesis to the sustainable society. It is critical to understand the detailed pathways and mechanisms of this promising process to develop a highly efficient catalyst. Herein, the N, P co-doping carbon (NP-C-MOF-5) catalyst was prepared for electrocatalytic N2 reduction in acid electrolytes under ambient temperatures and pressures. Experimental results showed that there are two products including NH3 and N2H4·H2O on the NP-C-MOF-5 cathode at −0.1 V versus RHE with the yield of 1.08 and 5.77 × 10–4 μg h–1 mgcat. –1, respectively. Moreover, an electrocatalytic pathway on NP-C-MOF-5 was investigated by the electrochemical in situ Fourier transform infrared technique. The results confirmed the formation of N2H y (1 ≤ y ≤ 4) intermediates on NP-C-MOF-5 cathode surfaces, suggesting an associative pathway for the N2 reduction reaction.

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The lack of effective faculty-student interaction has been identified as a main contributor to the high dropout rate in online education. For this paper, the authors conducted an empirical study using a social networking tool, specifically Facebook, to improve student-instructor communication and student performance in an online learning environment. They recruited three sections of an introductory IT course at a public university and divided them into two groups: (1) a treatment group where Facebook was used as an additional communication tool and (2) a control group where the course setting wasn't changed. The authors surveyed the participants' opinions on the use of Facebook in the treatment group, and collected participants' academic performance data for both the treatment and control groups. Their research findings show that the use of Facebook as a supplemental communication method can help an instructor better reach out to students, reduce a course's failure rate, and improve student course performance.

Water is a key and limiting factor for ecosystem processes (carbon dioxide fixation, vegetation growth, respiration, etc.) and functions (NPP, Net Primary Productivity) in arid and semi-arid areas. As the main regulator, knowledge of plant water use patterns is essential in understanding the SPAC (Soil-Plant-Atmosphere-Continuum) cycle. The tree-planting project in the southern and northern mountains of Lanzhou city aims to improve the ecological environment and promote urban construction. In this study, we analyzed the water use strategies of the dominant plants C. korshinskii and R. soongorica in natural shrubs of southern and northern mountains of Lanzhou city using oxygen stable isotope techniques. The result showed that the flexible water uptake pattern of C. korshinskii and its faster response to precipitation pulse, compared with R. soongorica, might help it to make full use of water and nutrients and adapt to the dry environment. However, R. soongorica progressively switched to suck up deeper soil water and increased the water use proportion from 0.5% to 84.4% as the seasons changed, indicating a greater degree of ecological plasticity. The flexible water use strategies of C. korshinskii and R. soongorica in the same habitat reduced competition for water and nutrients and enhanced adaptability to arid environments. The work presented here provides insights into vegetation restoration and ecological management for the southern and northern mountains of Lanzhou city.

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Hydrological processes produce effects on water resources in inland mountainous regions. To perform a comprehensive investigation of the important segments of the water cycle, using the Qilian Mountains as a case study, precipitation, soil, plant, river, and groundwater were collected during the plant growing season of 2016. All samples were collected on a monthly basis, except precipitation, which was collected on a per event basis. The results showed that: the “temperature effect” was apparent, which suggested a drier climate background; there were differences in the slope and intercept of the local meteoric water line, using different regression methods; and the δ18O of soil water varied greatly in the topsoil, tended to be similar in the deep soil, and became increasingly depleted as the soil depth increased. The responses of the soil water isotopes to precipitation pulses had different boundaries. The major water source for Caragana Fabr. in no-precipitation month was located in the 0–30 cm soil layer, but was different in months when precipitation occurred. Overall, the findings from the stable isotopes provide insights into hydrological processes and offer a platform to understand mountainous water cycle in arid areas.

Although stable isotopes of hydrogen and oxygen in surface waters (especially in river waters) are useful tools to understand regional hydrological processes, relevant information at some upper reaches of large rivers in western China is still limited. During 2016–2017, we focused on the Liujiaxia Reservoir along the upper Yellow River, where we collected surface water samples at two locations, above and below the dam (identified as “lake water” and “river water”). The results show that the heavy isotopes in lake and river waters are enriched during the warm months, when the river discharge is large, and depleted during the cold months. The slopes of the water line (δ2H versus δ18O) for both the lake and river waters were lower than that of the global mean, due to evaporation. The different d values of the lake and river water reflect the regional evaporation and water sources.