“PBL”模式下有机化学实验的教与学

结合化学实践教学特点,分析有机化学实验教学中存在的问题,讨论如何将"PBL"教学模式应用到"有机化学实验"教学中,形成"学生为主,教师为辅"的新型教学模式;同时探索思政教育融入有机化学实验课程的实践途径,提出在实践教学过程中,通过典型案例融入思政元素的具体方法,以"立德树人"为理念形成融会贯通、持续创新的新工科教育体系,加强学生的思想教育建设,系统推进大学组织模式、学科专业结构、人才培养机制和教师评价机制等方面的综合改革,构建一流卓越人才培养体系。

Impacts of Aerosol−Radiation Interactions on the Wintertime Particulate Pollution under Different Synoptic Patterns in the Guanzhong Basin,China

The effects of aerosol-radiation interactions(ARI)are not only important for regional and global climate,but they can also drive particulate matter(PM)pollution.In this study,the ARI contribution to the near-surface fine PM(PM_(2.5))concentrations in the Guanzhong Basin(GZB)is evaluated under four unfavorable synoptic patterns,including“northlow”,“transition”,“southeast-trough”,and“inland-high”,based on WRF-Chem model simulations of a persistent heavy PM pollution episode in January 2019.Simulations show that ARI consistently decreases both solar radiation reaching down to the surface(SWDOWN)and surface temperature(TSFC),which then reduces wind speed,induces sinking motion,and influences cloud formation in the GZB.However,large differences under the four synoptic patterns still exist.The average reductions of SWDOWN and daytime TSFC in the GZB range from 15.2%and 1.04°C in the case of the“transition”pattern to 26.7%and 1.69°C in the case of the“north-low”pattern,respectively.Furthermore,ARI suppresses the development of the planetary boundary layer(PBL),with the decrease of PBL height(PBLH)varying from 18.7%in the case of the“transition”pattern to 32.0%in the case of the“north-low”pattern.The increase of daytime near-surface PM_(2.5)in the GZB due to ARI is 12.0%,8.1%,9.5%,and 9.7%under the four synoptic patterns,respectively.Ensemble analyses also reveal that when near-surface PM_(2.5)concentrations are low,ARI tends to lower PM_(2.5)concentrations with decreased PBLH,which is caused by enhanced divergence or a transition from divergence to convergence in an area.ARI contributes 15%-25%toward the near-surface PM_(2.5)concentrations during the severe PM pollution period under the four synoptic patterns.

A molecular brake hoop for the motion of metal atoms inside fullerene cage

Molecular machines have attracted extensive attention due to their fancy concept and their potential to influence the science and technology.The dynamic motion of encapsulated metallic clusters is a distinctive character for endohedral metallofullerenes.For the development of molecular rotors based on metallofullerenes,the most challenging issue is how to control the motion of untouchable metallic cluster inside fullerene cage.In this work,we report a molecular brake hoop for the motion of metal atoms inside fullerene cage.A cycloparaphenylene of[12]CPP was employed to hoop the metallofullerene and produce two supramolecular complexes of Sc_(3)N@C_(80)⊂[12]CPP and Sc_(2)C_(2)@C_(82)⊂[12]CPP.Moreover,the temperature-dependent ^(45)Sc nuclear magnetic resonance spectroscopy(NMR)was employed to detect the motion of internal Sc_(3)N and Sc_(2)C_(2) clusters.^(45)Sc NMR results reveal that the[12]CPP can slow down the rotation of internal metallic cluster through host-guest interaction,and thus the[12]CPP can be considered as a molecular brake hoop for the internal metal motion of metallofullerenes.Furthermore,by means of this molecular brake hoop,the motion of metal atoms inside fullerene cage have expanded range of velocity.In addition,theoretical calculations on Sc_(3)N@C_(80)⊂[12]CPP were executed to illustrate the molecular orientation as well as internal Sc_(3)N rotation.This study would promote the research of endohedral metallofullerene as a molecular rotor.

Studies on the Luminescence Property of Yttrium-Based Metallofullerenes

Endohedral metallofullerenes(EMFs) exhibit various properties due to their multiple combinations between internal metals and outer carbon cages. Among them, yttrium-based metallofullerenes have attracted much attention due to their luminescence properties. For example,YN@Cis distinguished by its photoluminescence(PL) properties with a small energy gap between the lowest singlet states(S) and the triplet excited states(T) in YN@C, allowing reverse intersystem crossing(RISC) of T→Sand resulting in thermally activated delayed fluorescence(TADF). In addition, the PL intensity, lifetime, and quantum yield(QY) of YN@Call depend on the molecular structure and surrounding environment. Typically, modulation of the PL properties can be achieved by replacing the yttrium metal inside the carbon cage as well as by modifying the carbon cage externally.Here, we focus on the luminescence properties of yttrium-based metallofullerenes, summarize recent research advances, and predict their future development.