Discussion on Network Classroom Teaching of the Meteorology and Climatology in Common Colleges and Universities

Most of the content of the course Meteorology and Climatology in common colleges and universities is what students are interested in,and most students have been exposed to or understood many contents.When studying this part of the content,students often show varying degrees of interest.Of course,each student s own situation is different.In classroom teaching,teachers should comprehensively consider various factors.Especially in the network classroom teaching situation,teachers should combine the learning content to use multi platform teaching in the teaching,students performance to flexibly carry out interaction between teachers and students,and students own situation to pay attention to individualized cultivation.

Some Thoughts on Network Teaching of the Environmental Hydrology in Common Colleges and Universities

In the second term of 2019-2020,colleges and universities have launched a network teaching mode due to"novel coronavirus pneumonia"epidemic.The courses in colleges and universities are diversified due to the difference of majors.For the Environmental Hydrology,students often show different degrees of interest in learning this course.Of course,each student s own situation is different.Teachers should consider a variety of factors in online classroom,pay more attention to students performance,and give appropriate guidance in time.

Asymmetric fireproof gel polymer electrolyte constructed by boron-contained covalent organic framework for dendrite-free sodium metal battery

Gel polymer electrolytes (GPEs) with flexibility, easy processability, and low cost have been regarded as promising alternatives for conventional liquid electrolytes in next-generation sodium metal batteries (SMBs). However, GPEs often suffer from combustion risk and inferior interfacial compatibility toward Na metal anode, which severely limit their wide commercial applications. Here, a rational design of asymmetric fireproof GPE (AFGPE) modified with a boron-contained covalent organic framework (BCOF) on one side is developed through in-situ crosslinking polymerization process. Benefiting from the unique structure and composition, the resulting AFGPE exhibits high Na+ transference number, wide electrochemical window, excellent mechanical properties and high safety. Especially, the nanoscale BCOF layer with uniform nanochannels works as ion sieve that homogenizes Na+ flux during Na plating process, while the abundant Lewis-acid B sites can strongly capture counter anions and decrease space charge layer at anode side, thus promoting the uniform Na deposition to effectively suppress dendrite growth. Consequently, the Na/AFGPE/Na symmetric cells demonstrate remarkable cycling stability for over 1200 h at 0.1 mA·cm^(-2), and the solid-state SMBs exhibit outstanding cycling properties and rate capability, delivering a high capacity retention of 96.4% under current density of 1 C for over 1000 cycles.