微细水雾除尘技术的实验研究

分析了煤矿并下呼吸性粉尘防治技术现状，并对水的超声雾化技术进行了实验研究，应用回归分析建立了超声雾化性能的数学模型。在分析微细水雾捕尘机理及捕尘水雾凝并沉降技术的基础上，设计了一集微细水雾捕尘-凝聚、凝并降尘-惯性沉降分离为一体的含尘气流净化系统，并对该系统的除尘效率进行了实验研究，建立了相应的数学模型。     

玉米自交系氮效率基因型差异的比较研究

采用溶液培养的方法。选用经田间，土壤试验对N反应有典型差异的玉米自交系478，H21，Wu312,Zong31,Baici，在4个供氮水平下（0.04,0.4,2和4nmol/L)，研究了不同基因型玉米苗期氮素吸收，利用的差异及其原因，结果表明：极低N胁迫条件下（０.04mmol/L),总干重的基因型差异是由根系，地上部的共同作用的结果，高N下，总干重是由地上部的差异所决定的（表1），极低供N条件下，4578的总干重最大，且有较高的氮效率，Wu312,Zong31相对较低，478相对较高的氮效率主要来源于吸收效率的差异。该基因型在低N下总吸氮量最高，H21居中，Baici,Zong31相对较低，478相对较高的氮效率主要来源于吸收效率的差异。该基因型在低N下总吸氮量最高，H21居中，Baici,Zong31,Wu312相对较低（图1），吸收效率的差异主要是由于根系全N量的不同所致（图3），而根系全N量的差异主要是由于根系大小不同（表1），在极低氮水平下，不同基因型玉米根系全氮量的变幅比地上部高出28.1%，高N下（4mmol/L)，全N量的变幅比地上部高出15.4%(图2，图3），在0.04mmol/L下，478与Wu312,Zong31的利用效率不存在显著差异（表2）。     

低磷胁迫下木豆利用磷的基因型差异及其机制

以木豆[Cajanus Cajan(L.)Millsp]MD2、MD5、MD7为材料,采用水培试验方法研究了木豆对磷的吸收、利用的基因型差异及其机理。结果表明:低磷(P1 μmol·L-1)胁迫下,木豆对磷素的吸收和利用效率存在明显的基因型差异,其中MD2、MD7属于磷素吸收、利用效率较强的基因型,而MD5为磷素效率较低的基因型。低磷培养16d后,磷高效的基因型的根/冠比显著增加,根分泌的酸性磷酸酶(APA)活性较高,说明木豆对磷素的吸收效率与植株的根冠比及根分泌的酸性磷酸酶活性有关。在低磷胁迫下,虽然MD7、MD2的含磷量较低,但是磷素利用效率和根尖中APA活性较高,说明根中高APA活性是磷利用效率高的重要原因之一。     

Using Niche-Based Models to Improve the Sampling of Rare Species

Abstract:  Because data on rare species usually are sparse, it is important to have efficient ways to sample additional data. Traditional sampling approaches are of limited value for rare species because a very large proportion of randomly chosen sampling sites are unlikely to shelter the species. For these species, spatial predictions from niche-based distribution models can be used to stratify the sampling and increase sampling efficiency. New data sampled are then used to improve the initial model. Applying this approach repeatedly is an adaptive process that may allow increasing the number of new occurrences found. We illustrate the approach with a case study of a rare and endangered plant species in Switzerland and a simulation experiment. Our field survey confirmed that the method helps in the discovery of new populations of the target species in remote areas where the predicted habitat suitability is high. In our simulations the model-based approach provided a significant improvement (by a factor of 1.8 to 4 times, depending on the measure) over simple random sampling. In terms of cost this approach may save up to 70% of the time spent in the field.     

Efficiency of composite sampling for estimating a lognormal distribution

In many environmental studies measuring the amount of a contaminant in a sampling unit is expensive. In such cases, composite sampling is often used to reduce data collection cost. However, composite sampling is known to be beneficial for estimating the mean of a population, but not necessarily for estimating the variance or other parameters. As some applications, for example, Monte Carlo risk assessment, require an estimate of the entire distribution, and as the lognormal model is commonly used in environmental risk assessment, in this paper we investigate efficiency of composite sampling for estimating a lognormal distribution. In particular, we examine the magnitude of savings in the number of measurements over simple random sampling, and the nature of its dependence on composite size and the parameters of the distribution utilizing simulation and asymptotic calculations.     

Designing an efficient adaptive cluster sample

The choice of neighborhood definition and critical value in adaptive cluster sampling is critical for designing an efficient survey. In designing an efficient adaptive cluster sample one should aim for a small difference between the initial and final sample size, and a small difference between the within-network and population variances. However, the two aims can be at odds with each other because small differences between initial and final sample size usually means small within-network variance. One way to help in designing an efficient survey is to think in terms of small network sizes since the network size is a function of both critical value and neighborhood definition. One should aim for networks that are small enough to ensure the final sample size is not excessively large compared with the initial sample size but large enough to ensure the within-network variance is a reasonable fraction of the population variance. In this study surveys that had networks that were two to four units in size were the most efficient.     

青岛市生态足迹动态研究

利用生态足迹和生态承载力度量和评价1995—2004年间的青岛市可持续发展程度。结果发现,随着经济的发展和社会的进步青岛市的生态足迹显著上升,各类用地都呈现增加趋势,耕地增加程度最大,而水域则表现出不稳定;承载力明显下降,其中主要是耕地承载力下降,林地、水域等其他用地则有相对的提高。生态足迹和承载力的变化造成生态赤字进一步加大。将单位生态足迹内产生的GDP作为生态效率,可以发现青岛市的生态效率呈现增加趋势,表明青岛市的资源利用效率明显增加。按照1995到2004年的发展趋势,青岛在未来十年的生态赤字将进一步加大,通过科学技术提高生态效率是青岛降低生态赤字的主要途径。文章首次分析了青岛市的生态足迹动态,提出了降低生态赤字的途径,为青岛市的可持续发展提供了理论参考。     

模拟控制性分根交替滴灌对玉米的节水效应

以盆栽玉米为试材，模拟田间控制性分根交替滴灌(Controlled Root-divided alternative Drip Irrigation，简称CRDADI)供水方式对夏玉米净光合速率、气孔导度、蒸腾速率、水分利用效率及其根冠比的影响。结果表明，控制1／2根区交替滴灌(ADL)比常规滴灌(CK)节水25％而生物量仅下降9％，水分利用效率和根冠比均明显增加，气孔导度和蒸腾速率下降明显而净光合速率变化很小，蒸腾效率明显提高；控制：1／2根区固定滴灌(FDI2)水分利用效率虽然是CK的1．2倍，但生物量仅为CK的60．1％，ADI1的66．0％，严重影响了玉米的正常生长；控制1／2根区交替滴灌(ADI)比控制1／2根区固定滴灌(FDI)的根冠比、根干质量和根条数增加且根系分布均匀，地上部分生物量增加。表明控制性分根交替滴灌(ADI)能在不牺牲作物光合产物积累的前提下提高玉米的水分利用效率。     

气态有机物组成对生物过滤及菌体密度的影响

以堆肥-火山灰为填料的生物过滤器连续处理含甲苯、乙酸乙酯和异丙醇的气体,观测生物过滤效果和填料的菌系状态变化.结果表明:在甲苯和乙酸乙酯共存的条件下,生物过滤器优先去除乙酸乙酯;当进气中同时存在甲苯、乙酸乙酯和异丙醇时,优先去除乙酸乙酯和异丙醇.填料中各种微生物的菌体密度与过滤去除的有机物组成和浓度有关.霉菌和酵母菌竞争利用乙酸乙酯和异丙醇的能力较强,放线菌和细菌对甲苯的竞争利用能力较强.进气中高浓度的有机物会使填料中的菌体密度增大.在处理甲苯、乙酸乙酯和异丙醇的生物过滤器的各段填料中,菌体密度按细菌、霉菌、酵母菌、放线菌的顺序而降低. 图 1表 3参 17     

污水生物处理单元平衡分析方法研究(Ⅰ)

依据热力学第二定律建立了污水处理单元平衡分析的灰箱模型,提出了进行处理单元过程评价的指标体系.在热力学意义上,污水生物处理是通过微生物内部的耗散来消耗污水污染物能量的过程,推动该过程加速进行需要耗费外部的.因此,节能的主要目的是节,即应防止推动力过剩造成反应器单元的外部损失.这一方法体系将为合理科学评判处理过程能耗机制奠定重要的理论基础.