一株分离于湘江污染水域的酵母(Candida fermentati)的鉴定及其Cd~(2+)的吸附特性

对湘江湘潭段周边污染水域的微生物群落结构进行调查,筛选出一株能够耐受较高浓度镉的野生型酵母样真菌,命名为XTWJX菌株,并对其进行形态学特征、生理试验以及ITS序列和26S rDNA D1/D2区序列分析。结果表明,该菌株属于假丝酵母属的发酵假丝酵母Candida fermentati。金属抗性试验表明,XTWJX菌株对测试的9种不同金属离子显示出较高的抗性能力,尤其是对毒性较大的Cd2+的抗性能力高达6mmol/L,暗示该菌株可能具有应用前景。研究了XTWJX菌株对Cd2+的吸附特性,结果表明,在Cd2+浓度为10mg/L的水溶液中,该菌株对Cd2+显示出有较强的吸附能力。这一结果暗示XTWJX菌株的分离很可能为Cd2+污染的河流和湖泊等水生环境的生物修复提供了一种新型的生物材料。     

基于阻抗匹配条件的树枝状超材料吸收器

基于树枝状金属结构单元的电磁谐振特性,设计了一种双面大小树枝状结构的超材料吸收器,该结构分别是正面二级树枝及正对的背面三级树枝.通过仿真模拟设计了不同的阻抗匹配方式,调节相应的结构参数,找到了阻抗匹配对吸收特性的影响.在最佳的阻抗匹配条件下,得到最大吸收率.实验测量表明,阻抗匹配条件下双面大小树枝模型可以实现90.01%吸收率.增加样品层数可以有效的增加吸收率,3层样品就可以达到99%以上的吸收率,实现工程意义的完美吸收.     

A spectral response approach for detecting dominant phytoplankton size class from satellite remote sensing

An important goal in ocean colour remote sensing is to accurately detect different phytoplank- ton groups with the potential uses including the validation of multi-phytoplankton carbon cycle models; synoptically monitoring the health of our oceans, and improving our understanding of the bio-geochemical interactions between phytoplankton and their environment. In this paper a new algorithm is developed for detecting three dominant phytoplankton size classes based on distinct differences in their optical signatures. The technique is validated against an independent cou- pled satellite reflectance and in situ pigment dataset and run on the 10-year NASA Sea viewing Wide Field of view Sensor (SeaWiFS) data series. Results indicate that on average 3.6% of the global oceanic surface layer is dominated by microplankton, 18.0% by nanoplankton and 78.4% by picoplankton. Results, however, are seen to vary depending on season and ocean basin.     

基于多波长激光吸收光谱技术的气体浓度与温度二维分布遗传模拟退火重建研究

利用可调谐半导体激光吸收光谱技术实现气体浓度温度二维分布重建.设计了气体浓度温度二维分布重建测量系统,采用四路波分复用技术以减少投影光路布置数量和增加气体吸收测量信息.针对于图像重建过程中建立的非线性投影方程组,将遗传算法与模拟退火算法相结合进行求解,在实现全局最优搜索基础上提高算法搜索效率.建立燃烧环境下H₂O浓度温度二维分布模型,借助于近红外波段1.3—1.5 μm范围内4条H₂O气体吸收谱线,利用数值模拟计算方法进行了气体分布重建,重建结果与模型符合得很好     

Intramolecular photoinduced electron-transfer in azobenzene-perylene diimide

This paper studies the intramolecular photoinduced electron-transfer (PET) of covalent bonded azobenzene-perylene diimide (AZO-PDI) in solvents by using steady-state and time-resolved fluorescence spectroscopy together with ultrafast transient absorption spectroscopic techniques. Fast fluorescence quenching is observed when AZO-PDI is excited at characteristic wavelengths of AZO and perylene moieties. Reductive electron-transfer with transfer rate faster than 10¹¹ s^-1 is found. This PET process is also consolidated by femtosecond transient absorption spectra.     

常见重金属在翅碱蓬(Suaeda heteroptera)根际沉积物系统季节迁移变化

应用原子吸收光谱法(AAS)和电感耦合等离子体原子发射光谱法(ICP-AES)对翅碱蓬-根际沉积物系统常见重金属(Cu、Pb、Zn和Cd)总量和不同化学形态含量进行了季节跟踪测定。结果表明,系统中Cu、Zn、Pb和Cd环境化学行为呈现显著季节变化。从化学形态上看,根际沉积物中Cu和Pb在生理周期内均以残渣态为主,有机结合态在夏季和秋季达较高值。Zn在生理周期内均以交换态为主且随季节变化明显,碳酸结合态和铁锰结合态随季节变化不明显。Cd以残渣态为主,交换态在春季达最高。从总量上看,根际沉积物中的Cu、Zn、Pb的总量在夏季和秋季具有较高值。从系统迁移情况看,植物对Cu和Pb吸收量均为冬季春季秋季夏季,且大部分限制于地下;其体内分布除秋季Pb为根叶茎外,其它时期均为根茎叶。Zn吸收量为秋季夏季冬季春季,且绝大部分被吸收至地上。Zn吸收和分布取决于根际沉积物生物有效含量;总之,春季植物体重金属向根际沉积物迁移。夏季和秋季,Cu、Pb和Cd由根际沉积物向植物体迁移变化并不明显,而Zn正好相反。4种元素在冬季均为根际沉积物向植物体内迁移。     

海洋CDOM光吸收研究中若干问题的探讨

本文结合在厦门湾的现场调查和实验室分析，对目前海洋CDOM研究中的若干问题，从空白扣除、吸收系数和光谱斜率S值的估算方法、不同粒径滤膜对CDOM光学性质的影响等方面进行了探讨，并就河口混合过程中S值理论保守行为的判断进行了分析。结果表明，测定水样时，应以过滤后的纯水作为空白，CDOM的吸收系数应进行校正以消除样品中非CDOM信号的影响。进行CDOM的S值估算时，不论是高浓度的河流端还是低浓度的海端水样，当波长范围相同时，非线性回归所得S值均大于线性回归。当波长范围不同时，对任何一种回归方法，S值随长波区成分增多而降低，线性回归方法其降低程度尤其明显，总之波长范围对非线性回归处理的影响很小，S值通过对校正后的吸收系数进行非线性回归处理，同时波长范围选300—500nm较为适宜。决定河口混合时S值变化的因素不仅仅是河海两个端元CDOM的S值，还有它们CDOM浓度的相对大小，滤膜对近海Ⅱ类水域CDOM光吸收的影响是不可忽略的，以采用0．20μm左右的滤膜过滤水样为宜。     

Phytoplankton community adaptation to changing light levels in the southern Beaufort Sea,Canadian Arctic

The chlorophyll a specific absorption coefficient of phytoplankton, a_φ^∗(λ) is an important parameter to determine for primary production models and for the estimation of phytoplankton physiological condition. Knowledge of this parameter at high latitudes where nutrient rich cold water submitted to low incident light is a common environment is almost nonexistent. To address this issue, we investigated the light absorption properties of phytoplankton as a function of irradiance, temperature, and nutrients using a large data set in the southern Beaufort Sea during the open water to ice cover transition period. The a_φ^∗(λ) tended to increase from autumn when open water still existed to early winter when sea ice cover was formed, resulting from a biological selection of smaller-size phytoplankton more efficient to absorb light. There was no significant correlation between a_φ^∗(λ) and irradiance or temperature for both seasons. However, a_φ^∗(λ) showed a significant positive correlation with NO₃ + NO₂. Implications of the results for phytoplankton community adaptation to changing light levels are discussed.     

Phytoplankton pigments,functional types,and absorption properties in the Delagoa and Natal Bights of the Agulhas ecosystem

An investigation of pigments, phytoplankton types and absorption characteristics was conducted in the Delagoa and Natal Bights during late winter and spring in the southwest Indian Ocean. The study demonstrated that small flagellates dominated the phytoplankton communities in both bights and were ubiquitous across a temperature range of 18–24 °C. Diatoms were dominant in patches of cool water (<22 °C) related to upwelling processes and were associated with elevated levels of phytoplankton biomass, while prokaryotes were observed to increase in warm waters >22 °C. Absorption coefficients varied closely with variations in chlorophyll a and specific coefficients were lower for diatoms compared to flagellates. Chlorophyll-specific coefficients also provided useful information on the level of pigment packaging and were related to the proportion of chlorophylls and carotenoids in the pigment pool.