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目的研究舱室间壁板不同约束条件及不同敷设方式对隔声量的影响。方法用VA One建立两个舱室的统计能量分析(Statistical Energy Analysis,SEA)模型,对约束阻尼结构和自由阻尼结构的隔声性能进行分析。针对约束阻尼结构,讨论其两侧金属层厚度差对整个壁板的隔声性能的影响;对自由阻尼结构,分析金属层与阻尼层之间的相对位置对其隔声性能影响。结果约束阻尼结构隔声量A计权声压级比自由阻尼结构高。结论阻尼层厚度和壁板总厚度一定时,自由阻尼结构金属层与阻尼层之间的相对位置对实际的隔声性能并没有影响;约束阻尼结构,两侧金属层等厚敷设时,其隔声效果最优,且两侧厚度差越大隔声量越小。 相似文献
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Field experiment on 10 ha area of fly ash dump was conducted to restore and revegetate it using biological interventions,
which involves use of organic amendment, selection of suitable plant species along with specialized nitrogen fixing strains
of biofertilizer. The results of the study indicated that amendment with farm yard manure at 50 t/ha improved the physical
properties of fly ash such as maximum water holding capacity from 40.0 to 62.42% while porosity improved from 56.78 to 58.45%.
The nitrogen content was increased by 4.5 times due to addition of nitrogen fixing strains of Bradyrhizobium and Azotobacter species, while phosphate content was increased by 10.0 times due to addition of VAM, which helps in phosphate immobilization.
Due to biofertilizer inoculation different microbial groups such as Rhizobium, Azotobacter and VAM spores, which were practically absent in fly ash improved to 7.1 × 107, 9.2 × 107 CFU/g and 35 VAM spores/10 g of fly ash, respectively. Inoculation of biofertilizer and application of FYM helped in reducing
the toxicity of heavy metals such as cadmium, copper, nickel and lead which were reduced by 25, 46, 48 and 47%, respectively,
due to the increased organic matter content in the fly ash which complexes the heavy metals thereby decreasing the toxicity
of metals. Amendment of fly ash with FYM and biofertilizer helped in profuse root development showing 15 times higher growth
in Dendrocalamus strictus plant as compared to the control. Thus amendment and biofertilizer application provided better supportive material for anchorage
and growth of the plant. 相似文献
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菌种品系及VA对黄孢原毛平革菌降解两种染料的影响 总被引:2,自引:0,他引:2
黄孢原毛平革菌的不同品系与染料亚甲基蓝的比布列希猩红的浅层静培养表明,对于亚甲基蓝而言,ME-446降解能力最强,OGC101和BKM-F-1767相似;以比布列希猩红为底物,则OGC101最好,ME-446其次,最后为BKM-F-1767。虽然外源藜芦醇(VA)的补充在培养初期有利于染料脱色降解率的提高;但一周后,与不添加VA的样品比较,脱色降解率接近或相等。这说明菌的品系存在降解能力的差异,完整菌体自身合成的VA足以维持降解培养体系的正常运作。 相似文献
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以豇豆为供试植物,分别接种泡囊丛枝菌根(VAM)真菌Acaulospora lavis(光壁无梗球囊霉,菌号:34)和Glomus caledonium(苏格兰球囊霉,菌号:90036),研究VA菌根对菌根际(A)、菌丝际(B)和常规土(C)土层中不同浓度DEHP(4、20、100mg/kg)降解的影响。试验持续60d。结果表明:接种VAM真菌促进了DEHP在A、B、C土层中的降解,尤其在B层的降解,说明菌丝在DEHP降解和转移过程中起了重要作用。其中34号菌接种效果较为显著,A、B土层中的DEHP残留浓度分别比不接种最大下降25.1%和10.1%。受VAM直接影响的A、B土层中细菌、真菌、放线菌数量呈下降趋势,而在C层中呈增加趋势,A、B、C土层中土壤中性磷酸酶活性也呈现出同样变化趋势。微生物数量和中性磷酸酶活性的下降可能会影响VA菌根在DEHP降解中的作用。 相似文献
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棉花VA菌根的形成与土壤几丁质酶活相关性的研究 总被引:1,自引:0,他引:1
盆栽条件下,对棉花VA菌根的形成与根区土壤中几丁质酶活的相关性及其动态变化的研究结果表明.接种VA菌根真菌Glomusmosseae形成的菌根可促进解几丁质微生物的增殖,并能诱导出较高的土壤几丁质酶活性.酶活增长与菌很感染率成正相关;接种VA菌根真菌的处理与未接种对照比较,差异显著或极显著. 相似文献
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以贵州花江喀斯特高原生态综合治理试验示范区内草本群落阶段的几种主要植物为材料,对其根际微生态环境进行了研究,包括根际土壤化学性质、土壤酶活性和VA菌根侵染率及AMF孢子密度。结果表明:VA菌根侵染率和根际土壤中AMF孢子密度存在极显著正相关,相关系数达到0.97;不同植物根际土壤的化学指标和土壤酶活性均表现出较强的根际效应,即R/S〉1;VA菌根侵染率与pH值存在显著负相关,与有效磷质量分数存在极显著正相关,与碱性磷酸酶存在显著正相关,说明VA菌根能够促进土壤中难溶态磷往有效磷方向转化;AMF对宿主植物的侵染能够在一定程度上改善根际微生态环境的营养状况。 相似文献
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Michael R. Patsfall Nickolaus R. Feimer Gregory J. Buhyoff J. Douglas Wellman 《Journal of environmental psychology》1984,4(1):7-26
Two studies were conducted to examine distance classes of vegetation (foreground, middleground and background) and scene composition (presence of vegetation in left, center or right section of the image) as predictors of perceived scenic beauty. In study one, 41 students rated 63 landscape scenes with regard to scenic beauty. The Scenic Beauty Estimation Method was used to derive interval scale beauty values (SBEs). For each landscape image, areal measures of vegetation in each distance class and for each vertical section were taken and used as predictors. Presence of haze, clouds and human impacts were also recorded. Among the most important contributors to scenic beauty were amount of center middleground vegetation, and center background vegetation. Left foreground vegetation and right foreground vegetation were found to have significant and opposing regression weight signs—negative for the left and positive for the right. Study two was conducted to determine whether these opposing regression weight signs for foreground vegetation were due to a perceptual right-left bias or to some specific content in the image itself. In the second study, the photographic slides used to present landscape scenes to subjects were reversed so that the content which was previously on the right was now left, and vice versa. Thirty-nine students rated the reversed slides with regard to their scenic beauty. The signs of the regression weights in study two shifted such that left foreground was now positively valued and right foreground was negatively valued. This finding suggests that viewers are sensitive to foreground content and its placement in the image, and not simply to one side of the field of vision. 相似文献
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