4种水生植物根际磷素耗竭效应的比较

利用短期盆栽试验和抖根法研究了喜旱莲子草(Alternanthera philoxeroides)、香蒲(Typha latifolia)、慈姑(Sagittaria sagittifolia)和芦苇(Phragmites communis)4种水牛植物的根际磷素耗竭效应,分析了植物根冠比、根系形态、磷素吸收有效性和磷素利用有妓性等差异,探讨了植物根际磷素耗竭效应的吸收利用调控机制.结果表明,与非根际土壤(有效磷含量为167.53ìg穏-1)相比,喜旱莲子草、香蒲、慈姑和芦苇根际土壤的有效磷含量分别减少至80.17、124.37、155.38和161.75ìg穏-1,水溶性磷含量分别减少了81%、42%、18%和16%.喜旱莲子草根系较小,但磷素吸收有效性高(1.32 mg·m-1),其磷素利用有效件不高(0.34 g·mg-1);香蒲的磷素吸收有效性虽然比喜旱莲子草低许多(0.52 mg·m-1),但其有强大的根系,且磷素利用有效性高(0.64 g·mg-1)、根冠比大(0.35).喜旱莲子草和香蒲耗竭根际磷素的能力高于慈姑和芦苇.     

巢湖水体氮磷营养盐时空分布特征

在不同汛期对巢湖水体进行了网格化样品采集,研究了巢湖水体中氮磷营养盐的含量与时空分布规律,确定了巢湖水体的主要污染因子.结果表明,巢湖入湖河流中TP、TN和NO-3-N指标均超过了Ⅴ类水标准,南淝河和十五里河中TP、TN、NH+4-N和NO-3-N表现出丰水期低于平水期、枯水期的季节性变化特征,在其他河流则呈现出丰水期高于枯水期、平水期的特征;巢湖湖体氮磷营养盐浓度的分布存在时空差异,西部湖区中氮磷营养盐含量远高于东部湖区;TP、TN和NH+4-N表现出在枯水期高于平水期和丰水期的变化特征,而NO-3-N在丰水期的含量较高;巢湖水体的主要污染因子为TN和NH+4-N,这些污染物从西往东质量浓度不断减少.     

A simple and cheap method for preparation of coupled ZrO2/ZnO with high photocatalytic activities

The objective of this study was to prepare a new photocatalyst with high activities for degradation of organic pollutants. Coupled ZrO₂/ZnO photocatalyst was prepared with a simple precipitation method with cheap raw materials zinc acetate and zirconium oxychloride, and was characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Reactive brilliant red X-3B was used as a model compound to investigate the photocatalytic activity of synthesized catalysts in water under 254 nm UV irradiation. Results show that the optimal calcination temperature and coupling molar ratio of Zr were 350°C And 2.5%, respectively. At the calcination temperature of 350°C, ZrO₂ was dispersed on the surface of hexagonal ZnO in the form of amorphous clusters. The particle size of ZrO₂/ZnO decreased with the decrease of calcination temperature and the increase of Zr coupling amount. ZrO₂/ZnO has better photocatalytic activity for degradation of reactive brilliant red (RBR) X-3B than pure ZnO and P25-TiO₂.     

新型后置反硝化工艺处理低C/N(C/P)比污水脱氮除磷性能研究

从内碳源有效利用角度出发,开发了新型连续流后置反硝化AOA工艺,将厌氧段混合液按一定比例分流至缺氧段,从而强化缺氧段反硝化除磷作用.进水NH₄⁺-N和PO₄^3--P浓度保持在(38.31±2.03) mg·L^-1和(5.74±0.13) mg·L^-1,在不同运行阶段进水COD分别控制在300 mg·L^-1和250 mg·L^-1,考察了AOA工艺处理低C/N(C/P)比污水过程影响因素.当进水C/N比和C/P比分别为7.41±0.26和52.36±1.25时,通过将SRT由10 d延长到16 d,系统TN和PO₄^3--P去除率分别稳定在65.86%±2.06%和90.00%±3.97%;当进水C/N比、C/P比降至6.14±0.32和43.40±1.37时,在SRT为16 d条件下,将A/O/A体积比由1/3/1调整为1/2/2,TN和PO₄^3--P去除率分别升至69.76%±3.36%和98.73%±1.82%.结果表明,采用控制SRT、调整好氧/缺氧HRT等策略,可保证处理低C/N(C/P)比污水AOA工艺高效稳定运行.     

连云港市农业非点源污染对水环境的影响

通过2002年对连云港市农药化肥使用量以及水体中N、P等污染研究的结果显示：化肥的使用强度在381kg/hm^2，农药使用强度在8.12kg/hm^2；市区河流水体中N、P的含量严重超标，郊县河流的污染主要是N；水库污染相对较轻，近海海域的污染较为严重，地下水中，亚硝酸酸盐的含量超标较为严重。     

应用~(32)P-后标记技术对苯醌和氢醌处理人血淋巴细胞形成DNA加合物的研究

应用核酸酶Ｐ１促进的３２Ｐ－后标记技术对苯醌和氢醌处理人血淋巴细胞后形成的ＤＮＡ加合物进行了研究。结果表明，人血淋巴细胞被苯醌和氢醌处理２４ｈ之后，均形成了同一种ＤＮＡ加合物。两种化合物在不同浓度下处理人血淋巴细胞每１０７核苷酸中有０．０１～１０个核苷酸形成加合物。为了达到同等ＤＮＡ加合物水平，氢醌比苯醌需要更高的浓度。小牛胸腺ＤＮＡ与苯醌、氢醌反应可生成５种ＤＮＡ加合物。用苯醌或氢醌处理淋巴细胞所形成的加合物种类与上述纯ＤＮＡ与苯醌，氢醌形成的５种加合物在双向薄层层折图谱上完全不相符合。这些结果意味着苯醌、氢醌与ＤＮＡ的加合作用在细胞内存在着修饰机制。     

聚合氯化铝的27Al NMR研究

聚合氯化铝(PAC)是一种水处理混凝剂,七十年代以来已在我国、日本及其它一些画家得到应用。这种混凝剂是铝离子的水解聚合产物,有较高的铝含量及较大的羟铝比。我们用~(27)Al NMR(核磁共振)法对PAC及其水稀释物中铝的形态进行初步研究,以了解稀释对PAC组成变化的影响。     

砷超富集植物的热解特征及其与砷含量的关系

不同热解气氛和升温速率的比较研究表明,在空气气氛条件和25℃·min-1的升温速率下,砷超富集植物的热解曲线特征明显且实验速度适中,因此,是适用于砷超富集植物的热解实验条件.在该实验条件下,不同含砷浓度的蜈蚣草(Pteris vittata L.)和大叶井口边草(P.cretica L.)的热解温度主要集中在200～500℃之间.与低砷蜈蚣草相比,高砷蜈蚣草在300℃附近热解减弱,而在450℃附近热解加剧,蜈蚣草体内的砷有促使其热解过程向高温方向偏移的趋势;而大叶井口边草体内的砷则促使其在300℃附近热分解程度加剧,而对450℃附近的热解程度影响不明显.     

High resolution proton NMR spectroscopy of human amniotic fluid

Human amniotic fluid (HAF) is a dynamic system whose characteristics depend on continuous interchanges between fetal and maternal circulations. HAF reflects not only the environment of the fetus but may also provide information about fetal development or pathology. The concentration of HAF constituents varies with gestational age and pathological states. The number of the compounds currently implicated in fetal developmental pathology are relatively few. Currently used assay methods are not adequate to totally explain or predict the complex biochemistry of the fetus. The purpose of this work was to investigate HAF with NMR spectroscopy. In the present study HAF was obtained from 47 women undergoing routine amniocentesis. Cells were separated for karyological analysis and the supernatant was acid-extracted, lyophilized and re-suspended in D₂0 resulting in a concentration increase over native fluid. ¹H NMR spectra were obtained at 360 MHz and 60 MHz. Eighteen compounds including several amino acids, were identified using parallel reference and standard addition protocols. NMR spectroscopy detected compounds of known clinical importance including glucose, leucine, isoleucine, lactate and creatinine. In conclusion, we have demonstrated that a number of physiologically relevant compounds are readily observable in HAF using ¹H NMR spectroscopy. This technique can currently provide valuable information regarding HAF composition and has the potential of being used in vivo in the future.     

克山病病区低硒粮喂养的豚鼠红细胞内Na+浓度变化的研究

豚鼠分别喂以克山病病区粮（低硒）和非病区粮（硒含量正常）,借助合成的D_Y（PPP）₂^-7位移试剂用XL-400NMR谱仪直接测试完整红细胞内Na⁺的NMR谱,并定量计算细胞内Na⁺浓度,发现低硒的病区粮饲养的豚鼠红细胞内Na⁺浓度显著高于正常组;病区粮喂养的豚鼠红细胞在老化条件下细胞溶血比非病区严重。