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661.
金莲小(Ochnaintegerrima(Lour.)Merr.)足金莲术科落叫淞小或小乔小,址潜在的优良Ⅲ林绿化树种.文章从其形态解削特,其光合生理生态特征及播种繁殖技术方面进行了系统的研究。结果表明:金莲小为rft性偏阳性树种,光合速率LI进秤星单峰曲线,尤午休现象;其光饱和点(LSP)和I光补偿点(LCP)分别在800μmol·m^-2.s^-1及52.2μmol·m^-2.s^-1左右、在高于光饱和点的光强下,其叶片的光合速率并未出现叫娃下降趋势,州时还维持了较i舟的蒸腾速率,、金莲小叶绿素荧光参数显水其具有较高的能精利用效率,叶绿素a/b比值(5.677:1)略高于理论价(3:1),表明它能有效吸收比能许传到光反应叭tl山。播种前金莲小种子宵进行浸泡处理,浸泡24h处理后足发芽率高日.发芽较早,播种住泷炭土中的种f较沙土中的种子发芽要甘H荫发周期短,但往沙土中播种的种子最终的发芽率耍相对较高。、㈧此,金莲l术适合生长存水热充沛、土壤十}1对JJ巴沃的热带亚热带地区,栽培时要尽量选择十层肥沃的壤土或砂质壤土。金莲术(Ochnaintegerrima(Lout.)Merr.)是金莲术科落叶灌本或小乔木,是潜在的优良冈林绿化树种。文章从其形态解剖特征、光合生理生态特征及播种繁殖技术方面进行了系统的研究。结果表明:金莲木为中性偏阳性树种,光合速率日进程呈单峰曲线,无午休现象;其光饱和点(LSP)和光补偿点(LCP)分别在800μmol·m^-2.s^-1及52.2μmol·m^-2.s^-1左右。在高于光饱和点的光强下,其叶片的光合速率并未出现明显下降趋势,同时还维持了较高的蒸腾速率。金莲术叶绿素荧光参数显示其具有较高的能量利用效率,叶绿素a/b比值(5.677:1)略高于理论值(3:1),表明它能有效吸收光能并传到光反应中心。播种前金莲木种子宜进行浸泡处理,浸泡24h处理后其发芽率高且发芽较早,播种在泥炭土中的种子较沙土中的种子发芽要早且萌发周期短,但在沙土中播种的种子最终的发芽率要相对较高。因此,金莲木适合生长在水热充沛、土壤相对肥沃的热带亚热带地区,栽培时要尽量选择土层肥沃的壤土或砂质壤土。  相似文献   
662.
液中膜MBR工艺是将膜分离技术与传统生化处理技术相结合的一种新型、高效的污水处理方法,具有出水水质好、设备占地面积小、活性污泥浓度高、剩余污泥量少等特点。采用该工艺对生活污水处理进行了工程应用,对工程设计运行参数和污染物去除机制进行研究,并进行技术经济分析。结果表明:出水COD、氨氮、SS等指标均优于GB/T18920—2002《城市污水再生利用——城市杂用水水质》要求,出水可回用于浇洒道路、绿化、冲厕等,并提出根据出水氨氮浓度的变化作为系统排泥的依据,有效地指导工程的稳定运行。  相似文献   
663.
以丙烯腈生产装置为研究对象,调查分析其存在的主要危险因素以及工艺特性,依据偏差分析原理建立了丙烯腈装置的异常处置原则与标准,设计了具有环境质量浓度监测评估和过程参数偏差预警分析的双重监控预警平台。该平台通过建立的OPC通讯技术,实时获得现场环境质量浓度及关键参数的信息,进行泄漏扩散事故的早期预警和早期干预处置,并通过对监测数据的综合动态分析预测危险气体环境质量浓度的变化趋势以及可能对周边带来的危害。  相似文献   
664.
为探究气象环境条件对消化系统疾病的影响,结合分布滞后非线性模型与广义相加模型,分析了2009~2011年气象环境要素与北京市消化系统疾病急诊人数的暴露-反应关系.结果显示,气温对消化系统疾病的影响主要体现为“高温效应”,高于25℃的气温其危险度RR随气温升高而增加,且滞后效应能达到10d以上.较为极端的湿度(RH<10%或RH>90%)会显著增加消化系统疾病的发病,并有持久的作用,其与高温结合会形成“高温低湿”和“高温高湿”2种让人不适的情况.0~2m/s的风速在短的滞后期(5d)最能增加发病危险性.而3~4m/s的风速对疾病的危险性小,说明适度的风速不影响健康.浓度高于200μg/m3的PM10和浓度高于70μg/m3的 NO2具有即时的危险性(5d内显著);而较高浓度(>55μg/m3)的SO2滞后一定时期后效应更加明显.  相似文献   
665.
Massive developments (blooms) of cyanobacteria represent a major concern in many natural and artificial waterbodies, because of the high levels of toxins that can be released into water. Microcystins, potent hepatotoxins, represent the most frequent toxins produced by cyanobacteria. The determination of the microcystins’ profile in waterbodies is important for determining the real toxic potential. We have investigated the evolution of the microcystins’ profile of Lake Garda (Italy) from both a qualitative and a quantitative point of view over a period of five years. We have also analysed possible correlations between toxin profile and selected environmental parameters. We found that a demethylated microcystin variant (RRdm) was always dominant but showing a cyclic trend, alternating periods in which it represented the only variant, and periods in which other variants were present (LRdm, HtyrRdm, RR, and LR). These changes are probably due to changes in chemotypes composition inside the resident Planktothrix rubescens population and do not seem to be exclusively linked to the considered environmental variables. Total microcystin concentrations were always low (in the ng?L?1 scale), and showed typical peaks in the metalimnetic layer during summer–autumn time of each year.  相似文献   
666.
The role of the peregrine falcon (Falco peregrinus) as a bioindicator for the accumulation of organohalogen compounds and other persistent organic pollutants has been established in field studies. Biometric indices for damage caused by pollutants such as the shell thickness and the shell index were determined and the egg contents were analyzed for various pollutants by gas chromatography/mass spectrometry. A wide range of chemically activated luciferase expression (CALUX®) bioassays were performed on subsamples of the eggs.

The following organohalogen compounds were found in the eggs of 2009: dichlorodiphenyltrichloroethane (DDT) and dichlorodiphenyldichloroethane, heptachlor epoxide, hexachlorobenzene, dieldrin, hexachlorocyclohexane, polychlorobiphenyls and polychlorodibenzodioxins and polychlorodibenzofurans, polybromodiphenyl ethers, hexabromocyclododecane, tetrabromobisphenyl A, perfluoro compounds, and mercury. The DDT metabolite, dichlorodiphenyldichloroethene (DDE) (11,800 ng/g dry matter), was found to be the most highly concentrated egg contaminant followed by 2,2′,4,4′,5,5′-hexachlorobiphenyl (3800 ng/g). After a past general drop in pollution level, most egg contaminants presently plateau at levels that may still exceed limit values in foods of animal origin (DDE) or even toxicological thresholds (polychlorobiphenyls + polychlorodibenzodioxins, polybromodiphenyl ethers, perfluorooctanesulfonate, methylmercury).

Accumulation of DDE could be shown in peregrine falcon eggs from the uplands of Southwest Germany with elevations up to 1500 m, presumably due to its global distribution and its cold condensation in higher altitudes. In contrast, the concentration of polychlorobiphenyls in falcon eggs decreases with elevation, indicating that these pollutants originate mainly from conurbations and local industrial sites.

Significant negative correlations were found between both shell index and thickness and the concentration of Hg. A deleterious effect is also evident from a no-observed-adverse-effect level of 120 ng MeHg per gram egg determined by other authors in chronic feeding studies with ibises, which resulted in decreased egg productivity and male homosexual nesting and courtship behavior. The average Hg concentration in the peregrine falcon eggs from 2009 is almost four times higher than this level. MeHg accounted for 82.5% of the Hg present in the eggs of 2009 and 2010.

The cell test DR CALUX® for screening of dioxin-like activities can be used to detect not only the 29 regulated dioxin-like substances but also many other persistent organic pollutants with dioxin-like potencies, such as mixed halogenated dioxins/biphenyls. In our case, the results of bioanalytical screening methods showed no additional effect of other compounds with dioxin-like activity.

Ninety-three out of 177 analytes sought could be detected in the eggs. Chlorinated paraffins, organotin compounds, some pesticides that are still in use, and phthalic esters with the exception of traces of diethylhexyl phthalate could be excluded. All pollutants found in the eggs belong to substance classes banned by the Stockholm and Minamata Conventions.  相似文献   

667.
Rewalsar Lake, a mid-altitude, shallow and recreational water body located in the north-western Himalayas, Himachal Pradesh (India) was studied through monthly surveys in two consecutive years (March 2008 to February 2010). Forty-seven species belonging to seven groups of phytoplankton were identified from the lake. Microcystis aeruginosa and Synedra ulna exhibited a perennial habit. Ankistrodesmus falcatus, Chlorella vulgaris, Scenedesmus bijugatus, Chlamydomonas reinhardi, Eudorina elegans, Navicula cuspidate, Synedra ulna, Euglena acus, Euglena oxyuris, Spirulina gomontii, Oscillatoria princeps and Arthrospira khannae were abundant, and Oscillatoria limosa and Microcystis aeruginosa were highly abundant. Twenty-one important criteria were studied, for example, temperature, free carbon dioxide, biochemical oxygen demand, total alkalinity, nitrate, silicate and phosphate, which provide an idea of the portability of water for irrigation and drinking purposes as per the permissible limits given in World Health Organization, Indian Council of Medical Research and Indian Standards Institute standards. Pearson's correlation revealed a significant relationship between physicochemical parameters and different algal groups. Both plankton and chlorophyll a showed a bimodal pattern of fluctuation. High annual mean concentrations of chlorophyll a (mg L?1) were recorded as 11.44 in 2008–09, and 11.04 in 2009–10. As per the Palmer pollution index, 13 pollution-tolerant algal species with a pollution score of 37 were observed. The Central Pollution Control Board categorised the water at Rewalsar Lake as ‘D–E’.  相似文献   
668.
一定厚度构造煤的存在是瓦斯突出发生的必要条件;同时,构造煤发育区域也往往是瓦斯富集区。因此,研究构造煤的物性参数具有重要意义。采用灰色关联度和多元回归分析相结合的方法对构造煤的超声波实验测试参数的影响因素进行半定量研究。研究结果表明:影响构造煤纵波波速和品质因子的主要因素是煤体的孔隙率、水分、灰分和挥发分。纵波波速和品质因子随着孔隙率和挥发分的增加而增加,随着水分和灰分的增加而减少,视密度和最大镜质组反射率对两者影响较小。最后,从微观角度定性分析了孔隙率、水分和灰分三个主要影响因素对构造煤超声波参数的影响机理,为超声波探测构造煤技术提供了一定的理论支持。  相似文献   
669.
毒性物质泄漏可能引发严重的环境污染或人员伤亡,分析毒性物质扩散规律及主要影响因素,对环境保护、应急救援和风险评估具有重大意义。选择了氯化氢、氨气、液溴3种有毒物质作为模拟对象,对影响毒性物质扩散的主要参数进行敏感性分析计算,分析了参数值的变化对扩散距离的影响程度。结果表明,参数的影响与泄漏物质自身性质有关,物质的沸点是影响扩散的主要因素之一。  相似文献   
670.
基于OTIS模型的巢湖十五里河源头段氮磷滞留特征   总被引:3,自引:0,他引:3       下载免费PDF全文
为揭示巢湖十五里河源头河段氮磷营养盐滞留特征,选择NH4Cl、KH2PO4及NaCl作为示踪剂,开展野外现场示踪实验.根据获得的氯离子浓度和营养盐浓度穿透曲线数据信息,利用OTIS与OTIS-P计算软件,估算水文参数(D、A、As、a等)和营养盐一阶吸收系数(λ、λs).在此基础上,计算暂态存储指标和营养盐吸收相关参数值,定量评估主河道流动水体与暂态存储对NH4+和SRP的损失贡献.结果表明,主河道与暂态存储区NH4+吸收系数平均值分别为3.88×10-6,8.81×10-4s-1,SRP分别为7.80×10-6,7.98×10-8s-1;综合衰减系数k-NH4平均值为1.64×10-4s-1,k-SRP为7.80×10-6s-1;NH4+和SRP的吸收长度Sw-NH4、Sw-SRP相当大,分别为1632.88,25471.32m,意味着该河段经由物理或生态过程去除N、P的可能性低;该河段Vf-NH4、Vf-SRP 值较营养盐浓度低的溪流或小河流偏小,但U-NH4、U-SRP则明显偏大;暂态存储对于NH4+损失的平均贡献率为93.82%,主河道水流对SRP损失的平均贡献率高达99.70%.  相似文献   
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