Influencing factors and evaluation application of regional crustal stability in the Bohai Strait

Due to the extremely complex geological conditions in the Bohai Strait, active faults is very developed and earthquake activity occurs frequently. It is of great importance to evaluate the regional crustal stability for the planning and construction of the Trans-straits Passage. In this study, the authors carry out the evaluation by means of buffer analysis, topology analysis and overlay analysis based on ArcGIS software. The evaluation mainly analyzed six assessment factors of Bohai Strait including neotectonic activity, active faults distribution, seismicity, tectonic stress fields, Bouguer gravity anomaly and geological disasters. In brief, the crustal stability of the eastern North Yellow Sea Basin is best, while that of the Bohai Basin and southwest Bohai Strait is poor. Meanwhile, small and frequent earthquakes in the southern Strait and geological disasters developed in the northern and central Strait such as tidal ridge and shallow gas which may adversely impact on the Trans-straits Passage construction.

Mesoporous Fe-Doped Carbon Electrocatalysts with Highly Exposed Active Sites for Efficient Synthesis of Hydrogen Peroxide and Tandem Epoxidation of Propene

Catalytic tandem synthesis of fine chemicals using the in situ-formed intermediates by electrocatalytic reactions has increasingly attracted attention in recent years.The difficulty lies in the low local concentration of intermediates because of the slow formation rates in the catalytically electrochemical process.We showcase an efficient tandem epoxidation of propene,which is accelerated by the in situ-generated hydrogen peroxide(H_(2)O_(2)).The catalysts of iron-doped tubular mesoporous carbons feature ultrathin carbon walls and record-high exposed external surface areas,which enable a H_(2)O_(2) formation rate of 747.7 mmol gcat^(-1) h^(-1) at 0.4 V versus reversible hydrogen electrode,together with a H_(2)O_(2) Faradaic efficiency of nearly 100%.A positive correlation between the exposed external surface area and the oxygen reduction activity is experimentally observed.By utilizing the in situ-generated H_(2)O_(2),the tandem epoxidation of propylene displays a yield rate of 80.3μmol gTS-1^(-1) h^(-1) for propylene oxide.The high performance originates from the high local concentration of H_(2)O_(2) surrounding the titanium silicalite-1 catalysts for propylene epoxidation.The results may inspire other tandem electrochemical reactions by using the mesoporous catalysts for synthesis of building block chemicals.