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51.
古田山国家自然保护区黄山松林主要种群生态位研究 总被引:11,自引:0,他引:11
采用样方法进行调查,每个样地面积为20m×20m。测度主要种群的生态位宽度、生态位相似比例、生态位重叠值。结果表明,黄山松、木荷、野漆树、甜槠等有较大的生态位宽度,其Levins生态位宽度(Bi值)和Hurlbert生态位宽度(Ba值)分别为0.7619、0.6517、0.5886、0.5384和0.9175、0.6278、0.5571、0.4377;野鸭椿的生态位宽度最小,其Bi值和Ba值分别为0.3655和0.2343。黄山松、木荷、野漆树、甜槠等生态位宽度较大的树种,生态位相似性比例高;而生态位宽度较小的物种,生态位相似性比例较小。黄山松、木荷、野漆树、甜槠等生态位宽度较大种群之间具有较大的生态位重叠。 相似文献
52.
高架复合道路噪声声场分布研究 总被引:5,自引:2,他引:5
高架复合道路有效地缓解了交通拥挤的问题,但随之也带来了严重的噪声污染,以几何声学和衍射声学为理论基础,利用声级叠加原理,建立了高架复合道路噪声对临街建筑立面影响的预测模式。预测值与实测值基本相符,可直接应用于城市噪声预测。为城市发展规划尤其是城市高架复合道路的发展提供了科学依据。 相似文献
53.
Synergistic solubilization of polycyclic aromatic hydrocarbons by mixed anionic-nonionic surfactants 总被引:21,自引:0,他引:21
Water solubility enhancements of naphthalene (Naph), acenaphthylene (Acen), anthracene (An), phenanthrene (Phen) and pyrene (Py) by micellar solutions of single and mixed anionic-nonionic surfactants were measured and compared. Effects of typical inorganic ions, such as NH(4)(+), Na(+) and Mg(2+) coexisted with the organic pollutants (in soils) on water solubilities of polycyclic aromatic hydrocarbons (PAHs) in the presence of single and mixed surfactants were also investigated. Solubilities of PAHs in water are greatly enhanced in a linear fashion by each of Triton X-100 (TX100), Triton X-305 (TX305), Brij 35, and sodium dodecyl sulfate (SDS). Solubility enhancement efficiencies of surfactants above the critical micelle concentration (CMC) follow the order of TX100>Brij 35>TX305>SDS. PAHs are solubilized synergistically in mixed anionic-nonionic surfactant solutions, especially at low surfactant concentrations. The synergistic power of the mixed surfactants is SDS-TX305>SDS-Brij 35>SDS-TX100. Synergistic effect of a given mixed-surfactant solution on different PAHs also appears to be linearly related to the solute logK(ow). The noted synergism for the mixed surfactants is attributed to the formation of mixed micelles, the lower CMC of the mixed-surfactant solutions, and the increase of the solute's molar solubilization ratio or micellar partition coefficients (K(mc)) because of the lower polarity of the mixed micelles. Suitable quantity of inorganic cations can enhance the solubilization capacities of anionic-nonionic mixed surfactants, the effect being Mg(2+)>NH(4)(+)>Na(+). The water solubility of pyrene was slightly increased by anthracene and significantly increased by 1,2,3-TCB in the presence of SDS-Brij 35. Mixed surfactants may improve the performance of surfactant-enhanced remediation of soils and sediments by decreasing the applied surfactant level and thus the remediation cost. 相似文献
54.
空气中挥发性有机物监测技术的研究进展 总被引:13,自引:0,他引:13
讨论了空气中挥发性有机化合物(VOCs)的监测分析方法研究进展。重点介绍了空气中VOCs的采集、分析和测定;简要叙述了样品前处理的新方法--固相微萃取法(SPME)与其它前处理方法的研究概况。 相似文献
55.
蓖麻油衍生微乳液对菲的增溶和洗脱作用及其对菲污染土壤的修复机理 总被引:2,自引:0,他引:2
比较研究了蓖麻油硫酸盐(SCOS)与普通表面活性剂Triton X-100(TX100)、Tween 80(TW80)、Brij35、十二烷基苯磺酸钠(SDBS)和十二烷基硫酸钠(SDS)等对菲的增溶和洗脱作用.结果表明,菲表观溶解度与SCOS的浓度呈单一线性关系,SCOS微乳液对菲的增溶比SR=0.0314为最大,菲在微乳相和水相之间的分配系数logKem=4.44,大于菲在胶束相和水相之间的分配系数(logKmc).1:10土-水体系下,SCOS微乳液对菲污染土壤的清洗速率最快,清洗效率最高.SCOS有望成为土壤有机污染淋洗修复的增效试剂. 相似文献
56.
分别用溴化十六烷基三甲铵(CTMAB)和氯化十六烷基吡啶(CPC)改性膨润土,研究了制备有机膨润土的适宜条件及其对吸附对对硝基苯酚性能的影响。25℃时,CTMB-膨润土和CPC-膨润土对对硝基苯酚的饱和吸附量分别为475mg/g,远大于原土的饱和吸附量(125mg/g)。pH〉7时,有机膨润土吸附处理对硝基苯酚的去除率都在85%以上,比原土的去除率(8.6%)大9倍,通过X-衍射、红外光谱分析、比 相似文献
57.
58.
Levels and source of organochlorine pesticides in surface waters of Qiantang River, China 总被引:3,自引:0,他引:3
Qiantang River is a typical river used for drinking water source, flowing through agricultural area in east China. Surface
water samples at 45 sampling sites from the river were collected and analyzed for 13 organochlorine pesticides (OCPs) during
six surveys in 2 years of 2005–2006. Sediments, soils, farmland runoff water and dry/wet deposition of this region were also
measured for their OCPs residue in order to know possible source of OCPs contamination. The total OCPs concentrations in surface
water were 7.68–615.2 ng/l. β-HCH, δ-HCH, Aldrin, Heptachlor, Heptachlor epoxide are the major OCPs in water. The maximum
levels of OCPs in water were found in July, while significantly lower OCP concentrations were measured in January. Significant
linear correlation was found between the concentration of HCH and that of total 13 OCPs in water. The measured OCP concentrations
in sediments, soils, farmland runoff water and dry/wet deposition are discussed in relation to concentrations and patterns
found in the surface water. Comparison of OCP levels in sediments and soils led to conclusion that erosion of soil contribute
significantly to the contamination of water. The OCPs dry and wet deposition to water body was estimated to 0.49 and 0.86 ton/year,
respectively. The ratio of α/γ-HCH and (DDE+DDD)/∑DDT in environmental matrix indicated there probably existed new OCPs input
of lindane and dicofol into the river. 相似文献
59.
Mili Weng Lizhong Zhu Kun Yang Shuguang Chen 《Environmental monitoring and assessment》2010,163(1-4):573-581
Concentrations of formaldehyde, acetaldehyde, acetone, propionaldehyde, i-pentanal, and butyraldehyde in residential indoor air in Hangzhou were determined. The mean concentration of the total carbonyl compounds in summer was 222.6 μg/m3, higher than that in winter (68.5 μg/m3). The concentration of a specific carbonyl in indoor air was higher than the outdoor air measurement, indicating the release of carbonyls from the indoor sources. Formaldehyde and acetone were the most abundant carbonyls detected in summer and winter, respectively. Multiple regression analysis indicated that carbonyl concentrations in residential indoor air depended on the age of decoration and furniture, as well as their concentrations in outdoor air. In addition, a primary estimation showed that the health risks of carbonyls in summer were higher than those in winter. 相似文献
60.
A study was conducted to investigate the effect of organic acids on Cd and Cu desorption from natural contaminated soils (NCS) with permanent contamination by metal smelters and from artificial contaminated soils (ACS) derived from an artificial amendment of Cd to three representative zonal soils in Central China. Results showed that the desorption of Cd in either NCS or ACS, with the increment of tartrate or citrate concentration in desorption solution, can be characterized as a valley-like curve. The presence of tartrate or citrate at a low concentration (< or =0.5 mmol/l) inhibited Cd desorption from these two types of soils, whereas the presence of organic acids at high concentrations (> or =2 mmol/l for citrate and about > or =15 mmol/l for tartrate) apparently promoted Cd desorption. The desorption curve of Cu by tartrate solution with different tartrate concentrations can also be characterized as a valley-like curve, while the desorption of Cu in the presence of citrate was directly enhanced with the increment of citrate concentration. With the enhancement of initial pH value from 2 to 8 in the presence of citrate, Cu desorption ratio decreased at the first stage, then increased, and then decreased again. A valley and a peak sequentially appeared in the Cd or Cu desorption curve with initial pH value increment. Compared with citrate, the desorption ratio of Cd or Cu from NCS or ACS was directly decreased in the presence of tartrate, with the enhancement of the pH value from 2 to 8. Cd or Cu desorption was clearly enhanced when the electrolyte concentration of KNO3 or KCl increased in the presence of 2 mmol/l tartrate. Moreover, a higher desorption ratio of Cd or Cu was shown with KCl electrolyte than with KNO3 electrolyte with the same concentration. Based on these observations, we suggest that bioavailabilities of heavy metal can be promoted with selected suitable types and concentrations of organic acid amendment and reasonable field condition. 相似文献