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151.
HYDROLOGIC IMPACTS OF A LARGE-SCALE MOUNTAIN PINE BEETLE (DENDROCTONUS PONDEROSAE HOPKINS) EPIDEMIC1
Donald F. Potts 《Journal of the American Water Resources Association》1984,20(3):373-377
The Jack Creek watershed, a 133 km2 (51.5 mi2) drainage in southwestern Montana, was impacted by a mountain pine beetle (Dendroctonus ponderosae Hopkins) epidemic in 1975–1977 which killed an estimated 35 percent of its total timber. Analyses of USGS streamflow data for four years prior to and five years after mortality suggest a 15 percent post-epidemic increase in annual water yield, a two-to three-week advance in the annual hydrograph, a 10 percent increase in low flows and little increase of peak runoff. 相似文献
152.
植物叶片中氟的测定一般采用离子选择电极法,离子色谱法对其测定还鲜见报道,本文对用离子色谱方法测定植物叶片中的氟进行了探讨。 相似文献
153.
利用厌氧反应器技术+高效絮凝处理造纸法烟草薄片生产废水,CODCr可从6000mg/L降到2000mg/L以下,再用去除率高达90%的SBR序批式反应器技术进行深度处理,废水经处理可达标排放(CODCr≤100mg/L)。 相似文献
154.
155.
豆制品是中国的传统食品,在生产过程中产生高浓度废水,如果对高浓度有机废水进行预处理,采用回收蛋白质以及化学混凝处理方法可以大大降低废水浓度,一定程度上可以减轻后续处理的难度、降低处理成本。针对豆制品生产废水问题,对高浓度豆制品废水的预处理方法作了实验研究。采用调节等电点酸沉降的方法回收蛋白质,然后用聚合硫酸铁化学混凝处理上清液以降低COD的含量。实验证明了方法的可行性并得出了最佳实验条件。 相似文献
156.
Beata Szafranek Elżbieta Synak Danuta Waligóra Janusz Szafranek Jan Nawrot 《Chemoecology》2008,18(4):205-216
Summary. The sampling behavior of the Colorado potato beetle Leptinotarsa decemlineata Say (CPB) involves examination of the surface
of potato leaves. It has been suggested that leaf surface compounds (volatiles and cuticular waxes) may be involved in host-plant
recognition, acceptance or discrimination. Here we report on the effect of leaf surface extracts of six Polish commercial
potato varieties on CPB feeding. We tested the influence of potato leaf surface extracts on CPB adult and larval feeding,
then separated the extracts with HPLC, and finally tested the effect of the HPLC-separated fractions on CPB feeding. The bioassays
were performed using potato leaf discs deprived of their original surface compounds. Applied to test discs at concentrations
ten times higher than natural (10 leaf area equivalent), the extracts deterred CPB adults and larvae from feeding. HPLC-separated
fractions composed of alkanes, sesquiterpene hydrocarbons, wax esters, benzoic acid esters, fatty acid methyl, ethyl, isopropyl
and phenylethyl esters, aldehydes, ketones, methyl ketones, fatty acids, primary alcohols, β-amyrin and sterols did not affect
adult CPB feeding. Similarly, alkanes, sesquiterpene hydrocarbons, wax esters, methyl ketones, sesquiterpene alcohols and
secondary alcohols had no effect on larval CPB feeding. The sterol fraction (cholesterol, β-sitosterol and stigmasterol) acted
as a phagostimulant to CPB larvae. We isolated a fraction demonstrating a phagodeterrent effect on CPB adults and larvae.
The qualitative composition of the deterrent fraction was quite similar in all potato extracts, but there were quantitative
differences between the varieties. Much further work is needed to identify the compounds that can produce the deterrent effect. 相似文献
157.
水生甲虫(昆虫纲,鞘翅目)群落结构受多种环境因素的制约.西苕溪中上游流域38个样点共发现水生甲虫12科36个分类单元.优势属是长角泥甲科的Stenelmis属和扁泥甲科的Psephenoides属,出现频度分别为30和22,但有29属的出现频率不大于5.典范对应分析(CCA)表明,鞘翅目群落组成受荫蔽度、总氮、电导率和栖境质量影响最大.样点环境指标聚类结果与CCA结果一致,样点被分为3组.从第1组至第3组,水体中的总氮(2.80→3.52 mg/L)和化学需氧量(14.5→20.29 mg/L)明显上升,荫蔽度(18→6)明显降低.第1组(18个分类单元)和第3组(16个分类单元)的水生甲虫种类组成差异极显著(P<0.01),第2组水生甲虫多样性最高(26个分类单元).Macronychus,Zaitzevia,Scirtes,Stenocolus,Berosus,Laccobius和Ectopria属可作为清洁水体指示生物,Hydrocassis和Ancyronyx属是重污染水体指示生物.图3表4参16 相似文献
158.
The performance of the building envelope predominantly determines the ultimate energy performance throughout the lifecycle of a building. A sustainable alternative to enhance roof performance while limiting heat flux through a roof is integrating passive techniques such as green roof. Particularly, green roof performance is sensitive to local climate. The main objective of this study was to evaluate the evapotranspiration effect of an extensive green roof on annual energy consumption of an office building in relation to the humid continental climate of Republic of Korea. The dynamic behavior of green roof and building energy performance were investigated through a parametric simulation method using green roof module in EnergyPlus coupled with jEPlus. Structural data of the reference building and ASHARE 90.1-2007 operational schedules were used as inputs for baseline building model while inputs for the green roof module were based on experimental data sets. Due to the influence of the humid conditions and local wind current on the evapotranspiration process, it was generally found that high leaf area index (LAI) reduced cooling energy demand and somewhat reduced heating energy demand as well; corresponding to the highest daily evapotranspiration fluxes of 4.79 mm day?1 in summer and 1.80 mm day?1 in winter. Increasing LAI from 20% to 100% cover increased evapotranspiration flux by 10.4% in summer and 80.2% in winter. Thus to minimize energy losses in winter, foliage cover must be carefully considered. Within limitations specified, the overall annual building energy consumption deceased by 90.9 GJ (3.7%). 相似文献
159.
Marija M. Saric-Krsmanovic Dragana M. Bozic Ljiljana M. Radivojevic Jelena S. Gajic Umiljendic 《Journal of environmental science and health. Part. B》2017,52(11):812-816
The effects of field dodder on physiological and anatomical processes in untreated sugar beet plants and the effects of propyzamide on field dodder were examined under controlled conditions. The experiment included the following variants: N—noninfested sugar beet plants (control); I - infested sugar beet plants (untreated), and infested plants treated with propyzamide (1500 g a.i. ha?1 (T1) and 2000 g a.i. ha?1(T2)). The following parameters were checked: physiological—pigment contents (chlorophyll a, chlorophyll b, total carotenoids); anatomical -leaf parameters: thickness of epidermis, parenchyma and spongy tissue, mesophyll and underside leaf epidermis, and diameter of bundle sheath cells; petiole parameters: diameter of tracheid, petiole hydraulic conductance, xylem surface, phloem cell diameter and phloem area in sugar beet plants. A conventional paraffin wax method was used to prepare the samples for microscopy. Pigment contents were measured spectrophotometrically after methanol extraction. All parameters were measured: prior to herbicide application (0 assessment), then 7, 14, 21, 28 and 35 days after application (DAA). Field dodder was found to affect the pigment contents in untreated sugar beet plants, causing significant reductions. Conversely, reduction in the treated plants decreased 27% to 4% for chlorophyll a, from 21% to 5% for chlorophyll b, and from 28% to 5% for carotenoids (T1). Also, in treatment T2, reduction decreased in infested and treated plants from 19% to 2% for chlorophyll a, from 21% to 2% for chlorophyll b, from 23% to 3% for carotenoids and stimulation of 1% and 2% was observed 28 and 35 DAA, respectively. Plants infested (untreated) by field dodder had lower values of most anatomical parameters, compared to noninfested plants. The measured anatomical parameters of sugar beet leaves and petiole had significantly higher values in noninfested plants and plants treated with propyzamide than in untreated plants. Also, the results showed that propyzamide is an adequate herbicide for control of field dodder at the stage of early infestation. 相似文献
160.
Physicochemical characteristics of ambient particles settling upon leaf surfaces of urban plants in Beijing 总被引:3,自引:0,他引:3
Particulate pollution is a serious health problem throughout the world, exacerbating a wide range of respiratory and vascular illnesses in urban areas. Urban plants play an important role in reducing particulate pollution. Physicochemical characteristics of ambient particles settling upon leaf surfaces of eleven roadside plants at four sites of Beijing were studies. Results showed that density of particles on the leaf surfaces greatly varied with plant species and traffic condition. Fraxinus chiuensis, Sophora japonica Ailanthus altissima, Syringa oblata and Prunus persica, had larger densities of particles among the tall species. Due to resuspension of road dust, the densities of particles of Euonymus japonicns and Parthenocissus quinquefolia with low sampling height were 2-35 times to other taller tree species. For test plant species, micro-roughness of leaf surfaces and density of particles showed a close correlation. In general, the larger micro-roughness of leaf surfaces is, the larger density of particles is. Particles settling upon leaf surfaces were dominantly PM30 (particulate matter less than 10 μm in aerodynamic diameter; 98.4%) and PM2.5 (particulate matter less than 2.5 μm in aerodynamic diameter; 64.2%) which were closely relative to human health. Constant elements of particles were C, O, K, Ca, Si, Al, Mg, Na, Fe, S, Cl and minerals with higher content were SiO2, CaCO3, CaMg(CO3)2, NaCI and 2CASO4. H2O, SiO2. CaCO3 and CaMg(CO3)2 mainly came from resuspension of road dust. 2CaSO4. H2O was produced by the reaction between CaCO3 derived from earth dust or industrial emission and SO2, H2SO4 or sulfate. NaCl was derived from sea salt. 相似文献