排序方式: 共有166条查询结果,搜索用时 15 毫秒
1.
动力和盐度影响下长江口近岸沉积物中汞的再悬浮行为 总被引:4,自引:0,他引:4
利用PES(particle entrainment simulator)装置, 实验测定了不同的扰动强度和盐度条件下长江口近岸沉积物中Hg的再悬浮迁移和释放过程. 在盐度再悬浮试验中, 上覆水中HgD(溶解态Hg)和HgP(颗粒态Hg)含量分别在0.06~0.176 μg/L和0.033~0.723 μg/g之间变化, 在盐度×动力耦合再悬浮试验中, 上覆水中HgD和HgP含量分别在0.024~0.112 μg/L和0.05~0.958 μg/g之间变化. 在盐度较低(< 1‰)的水环境中, 动力条件是影响上覆水中Hg行为的重要因子, 动力条件改变后, 沉积物中的部分HgD和HgP存在短期释放行为, 但随扰动时间延长, 被扰动起来的悬浮颗粒对上覆水中的Hg起了较强的吸附作用. 当盐度在1‰以上时, 上覆水中的HgP出现解吸行为, 动力条件的耦合影响促进了Hg的解吸作用, 当动力条件达到250 r/min以上时, Hg的解吸作用增强, 上覆水中的HgD出现正通量, 表现为向上覆水的释放. 此外, 在较强动力条件下, 孔隙水中大量HgD的扩散释放也增加了其释放通量. 相似文献
2.
A new homologous series of isoflavone-based ethers,7-(4-bromoalkyloxy)-3-(4’-decyloxyprienyl)-4H-1-benzopyran-4-ones were synthesized and characterized.The mesomorphic properties of all homologues were investigated by differential scanning calorimetry(DSC) and polarizing optical microscopy(POM).Enantiotropic smectic A(SmA) phase was observed for all homologues.The structure-property study was carried out by comparing the mesomorphic behavior of the homologues with those previously reported analogues.The bromine atom from the alkyloxy side chain of the benzene ring fused to the heterocyclic moiety was found to be capable of changing the mesomorphic properties. 相似文献
3.
Two new diterpenoids,3,4,18β-cyclopropa-ent-abieta-8(14),13(15)-dien-16,12-olide(1) and 3-oxojolkinolide B(2),were isolated from the roots of Suregada glomerulata(Blume) Baill.Their structures were determined by spectroscopic evidences. Compound 2 showed moderate cytotoxicity. 相似文献
4.
CHEN ShengBo & SONG JinHong College of Geoexploration Science Technology Jilin University Changchun China College of Resources Environment Jilin Agricultural University Changchun 《中国科学:物理学 力学 天文学(英文版)》2011,(8)
Atmospheric temperature-humidity profiles and land or sea surface temperature are coupled actions in the earth system process. Based on the numerical perturbation form of the atmospheric radiative transfer equation, a physics-based algorithm is pre- sented to integrate four pairs of MODIS measurements from the Terra and Aqua satellites to retrieve simultaneously atmospheric temperature-humidity profile, land-surface temperature and emissivity. Three pairs of MODIS data at two field sites in China, Luancheng... 相似文献
5.
A new method for preparing (2Z, 4Z, 6Z)-4,5-diethyloxepinodicarboxylate by one-step is described. The synthesis of several oxepines and azepines derivatives was carried out by the reaction of substituted furans or pyrroles with diethyl acetylenedicarbox-ylate in boiling toluene. The effect factors for this reaction were discussed and reaction condition was optimized. 相似文献
6.
Ji Xia Zhang Yong Xue Wanga Zhi An Hea Fu Lin Yana Han Dong Sunb a Pharmaceutical Laboratory Xinxiang Medical University Xinxiang China b State Key Laboratory of Phytochemistry Plant Resources in West China Kunming Institute of Botany Chinese Academy of Sciences Kunming China 《中国化学快报》2009,20(2):201-203
Two new ent-kaurane diterpenoids taihangexcisoidesin A and B(1 and 2),were isolated from the EtOAc extract of the leaves of Isodon excisoides.Their structures were determined on the basis of spectroscopic methods. 相似文献
7.
HUANG HuoQiang PAN XuLin JI ChangJiu ZENG GuangZhi JIANG LiHua FU Xiang LIU JiKai HAO XiaoJiang ZHANG YingJun & TAN NingHua State Key Laboratory of Phytochemistry Plant Resources in West China Kunming Institute of Botany Chinese Academy of Sciences Kunming China Graduate University of the Chinese Academy of Sciences Beijing 《中国科学B辑(英文版)》2009,(3)
Carbonic anhydrase Ⅱ (CAⅡ) is an important enzyme complex with Zn2+,which is involved in many physiological and pathological processes, such as calcification, glaucoma and tumorigenicity. In order to search for novel inhibitors of CAⅡ, inhibition assay of carbonic anhydrase Ⅱ was performed, by which seven natural phenolic compounds, including four phenolics (grifolin, 4-O-methyl-grifolic acid, grifolic acid, and isovanillic acid) and three flavones (eriodictyol, quercetin and puerin A), showed in-hibitory a... 相似文献
8.
JIANG ZhiLiang LI JiShun WEN GuiQing LIU QingYe & LIANG AiHui School of Environment Resources Guangxi Normal University Guilin China College of Chemistry Bioengineering Guilin University of Technology China 《中国科学:化学》2010,(5)
The resonance scattering spectral technique has been established using the synchronous scanning technique on spectrofluorometry.Because of its advantages of simplicity,rapidity and sensitivity,it has been widely applied to analyses of proteins,nucleic acids and inorganic ions.This paper summarizes the application of immunonanogold and aptamer modified nanogold(AptAu) catalytic resonance scattering spectral technique in combination with the work of our group,citing 53 references. 相似文献
9.
CAO Ling-di FANG Yan FANG Chun-hui . Key Laboratory of Salt Resources Chemistry 《高等学校化学研究》2011,(3):490-495
Detailed time-and-space-averaged structure of MgSO4 in the concentrated aqueous solutions was investigated via X-ray diffraction with an X’pert Pro θ-θ diffractometer at 298 K, yielding structural function and radial distribution function(RDF). The developed KURVLR program was employed for the theoretical investigation in consideration of the ionic hydration and ion association. Multi-peaks Gaussian fitting method was applied to deconvolving the overlapping bands of Differential radial distribution function... 相似文献
10.
Hui Fang Pi Peng Zhang Han Li Ruan Yong Hui Zhang Han Dong Sun Ji Zhou Wu 《中国化学快报》2009,20(11):1319-1320
A new alkaloid was isolated from the bulbs of Lycoris aurea(L'Herit.) Herb.Its structure was established as 3-o-ethyltazettinol through chemical and spectroscopic studies including 2D NMR. 相似文献