杭州湾滩涂湿地植被主要植物的光能利用率和光化学指数的相关性研究

利用LCPro‐SD便携式光合仪和FieldSpec Pro光谱仪观测了3种典型湿地植被旱柳（Salix matsu‐dana）、柽柳（Tamarix chinensis）和芦苇（Phragm itescommunis）的光合作用日变化及同步光谱,分析了影响光能利用率（LUE）变化的环境和生理因子,探讨了 LUE和光化学指数（PRI）的相关性．研究结果表明：影响芦苇、柽柳和旱柳光合作用变化的生理因子不同,芦苇的 LUE与Pn、PAR和Gs呈负相关;旱柳和柽柳的 LUE与 Pn 和Gs 呈正相关,与 PAR无关．3种植被的 PRI和LUE的相关性为：旱柳（R2＝0．9565）＞柽柳（R2＝0．9515）＞芦苇（R2＝0．6425）,湿地旱柳的相关性为最大,LUE和 PRI相关性受叶面积指数影响较大．     

光动力学法测定食品中的亚硫酸盐

以亚硫酸盐与光化学反应产生碘的反应, 用于某些食品中痕量亚硫酸盐的测定． 标准加入回收率在 ９８％ ～１０５％ 之间, 相对标准偏差低于 ４％     

‘Waldsterben’, part IV (continuing series)

Summary Peroxidase and superoxide dismutase activities, and ascorbic acid content, were measured in both intercellular fluid and cell material of current and 1-year-old needles of Norway spruce saplings treated with ozone, ambient air and activated carbon-filtered air in outdoor fumigation chambers. Ethylene evolution was also compared. Plants from carbon-filtered air treatments had significantly lower enzyme activities and higher ascorbic acid content. These changes were more marked in intercellular fluid than in cell material. Significant changes were noted at ozone levels typical of ambient air quality in a typical urban area. These results suggest the need for simultaneous screening of several biochemical markers as a way of overcoming the lack of specificity of any single marker for the identification of a perturbation by a particular stress, such as ozone.Acknowledgments. This work was supported in part by Grant Number 4849-0.85 (NFP 14) from the Swiss National Fund of Scientific Research. We thank Dr. F. Cupelin and Dr. J. Cl. Landry from the Service d'Ecotoxicologie, Genève, who provided the facilities for the monitoring of ozone levels. We also thank A. Mesrobian, A. Rossier and D. Voluntaru for technical assistance. Du Pont de Nemours International is gratefully acknowledged for the gift of TEDLAR (polyvinyl fluoride film) to build up the fumigation chambers.     

关于人工影响消减雾霾的思考

 借助人工影响天气开展消减雾霾影响不失为一种有效的尝试。本文介绍消减雾霾可能采用的人工影响天气方法、原理、应用, 并分析其优缺点和关键问题。人工影响天气消减雾霾的主要方式包括人工增雨、人工消雾及消减干霾的物理化学方法。人工增雨和人工消过冷雾技术相对成熟, 但人工增雨作业依赖地理背景和天气条件, 不适用于消减处于发展阶段的雾霾。人工消暖雾尚未成熟, 有待研制更高效的暖云催化剂或开发新型消暖雾技术。喷水地球工程法需要进行更深入的理论分析, 结合实验寻找高效清除PM_2.5的方法。城市风道法因受地理环境和气象条件限制, 并不适用于所有城市。当然, 治理雾霾还要从社会经济发展方式、能源结构组成、节能减排和降低能耗等方面综合入手, 从根源上解决问题。     

Enhanced calcification ameliorates the negative effects of UV radiation on photosynthesis in the calcifying phytoplankter <Emphasis Type="Italic">Emiliania huxleyi</Emphasis>

The calcifying phytoplankton species,coccolithophores,have their calcified coccoliths around the cells,however,their physio-logical roles are still unknown.Here,we hypothesized that the coccoliths may play a certain role in reducing solar UV radiation(UVR,280-400 nm) and protect the cells from being harmed.Cells of Emiliania huxleyi with different thicknesses of the cocco-liths were obtained by culturing them at different levels of dissolved inorganic carbon and their photophysiological responses to UVR wer...     

光化学原位制备PDEA-磁性纳米凝胶用于DNA 固定及缓释研究

应用光化学原位聚合法合成了聚(甲基丙烯酸二乙氨基乙酯)包覆的磁性纳米凝胶 (PDEA-磁性纳米凝胶). 应用傅里叶变换红外光谱(FTIR)、热重分析仪(TGA)、振动样品磁强计 (VSM)、光子相关光谱(PCS)等对PDEA-磁性纳米凝胶的结构、形貌、磁学性质、粒径及表面 ζ-电位等进行了表征. 结果表明, PDEA-磁性纳米凝胶形状较规则, 为“核-壳”结构, 表面PDEA高分子层约为26%, 平均水合粒径为43 nm, 具有超顺磁性. 该磁性纳米凝胶具有明显的pH敏感性, 在室温、 pH 5.0时可结合DNA分子, 最大结合量为51 μg/mg, 在pH 7.4条件下能够将DNA高效释放出来, 且呈现出明显的缓释效应, 加之良好的磁响应性能, 使其可作为一种新型磁靶向转基因载体应用于生物医学研究.     

SO3光解反应的热力学机制

SO3光解反应的反应式为2SO3＋hν（λ1）2SO2＋O2＋hν（λ2）,因而SO3的转化率α与温度T,波长λ1和λ2有关.利用公式△rG0m＋RTInK0p=0.1196λ1-0.1196λ2计算了当T=318K,λ1=211nm,α=35%时,λ2=277.8nm,这一波长正好位于SO2的吸收峰,从而解释了为什么在318K时SO3的转化率为35%.     

Long-day photoperiod induced unhealthy development of chloroplasts in the photoperiod-sensitive genie male-sterile rice

By measurement of photochemical activities of chloroplasts and observation on supramolecular archi tecture of thylakoids in chloroplasts, it was found that compared with the effects of short-day photoperiod, long-day pho toperiod could induce normal development of chloroplasts in seedlings of NK58S (photoperiod-sensitive genie male-sterile rice) and NK58 (original line) which do not enter the photoperiod sensitive phase and in seedlings of NK58 just enter the photoperiod-sensitive phase. However, it could induce unhealthy development of chloroplasts in seedlings of NK58S which also just enter the photoperiod sensitive phase. This special effect of long-day photoperiod on the development of chloroplasts in NK58S is probably one of main reasons why long-day photoperiod induces rale-sterility in NK58S and normal fertility in NK58.     

吡啶光氯化反应机理的量子化学研究(II)——PM3计算吡啶光氯化反应体系能量与反应动力学分析

用量子化学方法 PM3结构参数全优化方法对吡啶光氯化反应所涉及的分子、自由基进行了能量计算 ,得到键解离能 ,并对反应活化能与动力学进行分析 .对吡啶光氯化反应 ,提出了氯自由基直接进攻吡啶环的碳原子和氯自由基首先夺取与吡啶环键链的氢原子两种不同的反应机理 .量化计算结果表明 :吡啶光氯化反应中夺氢反应机理所需的反应活化能较低 ,不同产物以生成2 -氯吡啶的活化能最低 ,为 1 74.0 8k J/mol,总反应级数为 1 .5级 ,对吡啶的分级数为 1级 .对氯气的分级数为 0 .5级 .     

城市大气中甲醛来源分析的示踪技术

甲醛是城市大气中浓度水平最高的含氧挥发性有机物。甲醛在城市地区主要来自机动车尾气排放等一次来源及大气光化学反应二次来源。然而,目前识别甲醛一次和二次来源的研究开展得较少。基于大气一次污染和二次污染示踪物的统计分析方法,是大气甲醛来源分析的新进展。作者介绍了采用示踪物估算城市大气甲醛来源贡献的技术方法和初步结果,并针对示踪物的特点讨论了该方法的适用性。