太湖蓝藻水华期间水体和底泥中产毒微囊藻与非产毒微囊藻种群丰度研究

运用实时荧光定量PCR(Quantitative real-time PCR,QPCR)技术研究了太湖蓝藻水华期间不同湖区水体和底泥中产毒微囊藻与总微囊藻种群丰度.结果表明,湖区间产毒微囊藻种群和总微囊藻种群丰度明显不同:在水体中,竺山湾(N5)和梅梁湾(N2)产毒微囊藻和总微囊藻种群丰度高于贡湖湾(N4)和湖心(S4...     

生态补偿的管理与调控模式研究

生态补偿目前是国内外研究的热点,政府和社会各界一直呼吁建立生态补偿机制。文章在理论分析的基础上,提出生态补偿过程中"政府管制、公众参与、市场调节"的管理与调控模式,并对三者之间的关系进行了分析。     

膨胀石墨除油机理及影响因素研究

针对水面浮油的去除问题,通过对新型吸附材料-膨胀石墨的扫描电镜观察,从其结构特征的角度揭示了膨胀石墨的吸油机理,首次系统地研究了温度、时间、pH等操作条件对吸附油性能的影响。扫描电镜的结果显示膨胀石墨的鳞片厚度都在100 nm以上,而且以大孔、超大孔为主,这种结构赋予了膨胀石墨独特的吸附特性。操作条件对膨胀石墨的吸附性能有重要的影响,在本实验条件下即在酸（中）性条件下,吸附时间1 min-2 min左右,转速为660 r/min膨胀石墨可达到饱和吸附量。     

中亚五国气溶胶光学厚度时空分布特征研究

气溶胶时空变化是影响气溶胶气候效应不确定性的主要因素之一.在生态环境脆弱的中亚五国(哈萨克斯坦、乌兹别克斯坦、土库曼斯坦、吉尔吉斯斯坦和塔吉克斯坦)研究气溶胶光学厚度(Aerosol Optical Depth,AOD)的时空变化对中亚地区及全球生态环境和气候变化具有重要意义.基于2002-2019年MODIS 04_...     

Spatial heterogeneity of greenhouse gas emissions from cereal crop production in China

Environmental Chemistry Letters - China is a major producer of wheat, maize and rice, which generates massive greenhouse gas emissions due to the consumption of elevated amounts of energy, land,...     

Spectroscopic characterization and photochemistry of the Criegee intermediate CF3C(H)OO

Criegee intermediates (CIs), also known as carbonyl oxide, are reactive intermediates that play an important role in the atmospheric chemistry. Investigation on the structures and reactivity of CIs is of fundamental importance in understanding the underlying mechanism of their atmospheric reactions. In sharp contrast to the intensively studied parent molecule (CH₂OO) and the alkyl-substituted derivatives, the knowledge about the fluorinated analogue CF₃C(H)OO is scarce. By carefully heating the triplet carbene CF₃CH in an O₂-doped Ar-matrix to 35 K, the elusive carbonyl oxide CF₃C(H)OO in syn- and anti-conformations has been generated and characterized with infrared (IR) and ultraviolet-visible (UV-vis) spectroscopy. The spectroscopic identification is supported by ¹⁸O-labeling experiments and quantum chemical calculations at the B3LYP/6-311++G(3df,3pd) and MP2/6-311++G(2d,2p) levels. Upon the long-wavelength irradiation (λ > 680 nm), both conformers of CF₃C(H)OO decompose to give trifluoroacetaldehyde CF₃C(H)O and simultaneously rearrange to the isomeric dioxirane, cyclic-CF₃CH(OO), which undergoes isomerization to the lowest-energy carboxylic acid CF₃C(O)OH upon UV-light excitation at 365 nm. The O₂-oxidation of CF₃CH via the intermediacy of CF₃C(H)OO and cyclic-CF₃CH(OO) might provide new insight into the mechanism for the degradation of hydro-chlorofluorocarbon CF₃CHCl₂ (HCFC-123) in the atmosphere.