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81.
为探究海州露天矿东邦废弃采空区自然发火状态,基于采空区遗煤自燃特性和气体扩散理论,采用智能土壤气体通量监测系统,以月为单位,对东邦自燃采空区上覆地表CO2通量开展长周期、多测点连续性监测试验;根据试验区域内地表CO2通量和土壤温度分布特征,探究地下火区释放CO2的地表涌出范围和变化情况;同时,着眼于温室气体排放的评估,计算试验区域内的CO2涌出量,并分析其随时间的变化特征。结果表明:地表CO2通量与土壤温度有明显正相关性;试验区域地表CO2高通量区域呈逐月扩大和递增的趋势;CO2涌出量随月份逐渐递增,试验区域年CO2涌出量约为3.6×106 m3。 相似文献
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84.
从传质和生化反应基本过程出发,经合理简化,将复杂的生物填料塔中三相传质生化反应过程综合为一个有效生化反应过程并得到其数学模型。模型中综合参数——总传质有效因数η可通过容易测定的本征反应和实际反应速率来确定;实验研究了不同入塔污水CODCr和入塔水量对η的影响。结果表明:入塔污水CODCr较高时,有较大的孕;当入塔水量增大,传质效果增加η增大。 相似文献
85.
Surface modification by physical adsorption of Tween 20 was accomplished on polypropylene microporous membranes (PPMMs). Attenuated total reflection-Fourier transform infrared spectroscopy (ATR/FT-IR) and scanning electron microscope (SEM) were used to characterize the chemical and morphological changes on the membrane surfaces. Water contact angles and relative pure water fluxes were measured. The data showed that the hydrophilic performance for the modified membranes increased with the increase in the adsorption amount of Tween 20 onto the surface or into the pores of polypropylene microporous membranes. To test the antifouling property of the membranes by the adsorption of Tween 20 in a membrane bioreactor (MBR), filtration for active sludge was performed using synthetic wastewater. With the help of the data of water fluxes and the FE-SEM photos of the modified PPMMs before or after operating in a MBR for about 12 d, the PPMMs with monolayer adsorption of Tween 20 showed higher remained flux and stronger antifouling ability than unmodified membrane and other modification membranes studied. 相似文献
86.
Diffusive fluxes of elements (NO-2, NO-3, NH+4, SiO2, PO3-4, Cl-, SO2-4, Fe, Mn) have been measured by applying the Fick's first law in two stations of the Tigullio Gulf: the first one characterized by sandy sediments rich in vegetal detritus and the second one, located to within the tourist harbour, characterized by a silty-clay sediments.
Benthic fluxes were measured only in the second station by means of benthic chamber experiments. Although the significant presence of dissolved oxygen in the surface sediments, and the evidence of processes usually occurring in oxidised sediments such as nitrification, both stations also presented characteristics of anoxic sediments such as high oxygen consumption rate and high pore water concentrations of ion, manganese and N-ammonia and reactive orthophosphate.
In both stations, sediments seemed to represent a potential source for most of the chemical species studied, although fluxes were not confirmed for ion, manganese and reactive orthophosphate in benthic chamber experiments.
Diffusive fluxes presented a general agreement for both stations, with higher fluxes of N-nitrate and N-nitrite at the first station were oxidative processes of N-ammonia in the upper layer of the sediments seemed to be more active. the comparison between diffusive and benthic fluxes showed a possible contribution of bioturbation. 相似文献
Benthic fluxes were measured only in the second station by means of benthic chamber experiments. Although the significant presence of dissolved oxygen in the surface sediments, and the evidence of processes usually occurring in oxidised sediments such as nitrification, both stations also presented characteristics of anoxic sediments such as high oxygen consumption rate and high pore water concentrations of ion, manganese and N-ammonia and reactive orthophosphate.
In both stations, sediments seemed to represent a potential source for most of the chemical species studied, although fluxes were not confirmed for ion, manganese and reactive orthophosphate in benthic chamber experiments.
Diffusive fluxes presented a general agreement for both stations, with higher fluxes of N-nitrate and N-nitrite at the first station were oxidative processes of N-ammonia in the upper layer of the sediments seemed to be more active. the comparison between diffusive and benthic fluxes showed a possible contribution of bioturbation. 相似文献
87.
D. G. Zamolodchikov A. I. Utkin G. N. Korovin O. V. Chestnykh 《Russian Journal of Ecology》2005,36(5):291-301
The state and results of studies on the carbon cycle of forests on lands of the Russian forest fund (total area 1172 × 106 ha) are analyzed at the federal level. Consideration is given to changes in the areas of different categories of forest lands, the age structure of stands, the pool and deposition of carbon in the phytomass, and the organic carbon pool of soils over the period from 1966 to 1998; the dynamics of activity in the forest industry by years and the extent of pyrogenic transformation of the forest cover between 1990 and 2001; and carbon fluxes associated with forest exploitation, including carbon emission resulting from fires. 相似文献
88.
89.
潮滩沉积物-水界面营养盐N、P分布及交换特征 总被引:4,自引:0,他引:4
通过2月枯季和8月洪季样品的采集、室内分析和测试,对滨岸带潮滩沉积物孔隙水中营养盐含量的分布、迁移和扩散通量进行了初步研究。结果表明,NH_4~--N和N0_3~--N的平均含量8月洪季比2月枯季低,但是NO_2-N含量在8月份却达到最高,为0.04 mg/L;TP在季节分布上变化不大,8月洪季时含量较高。在空间分布上发现,排污口及大面积围垦对营养盐局部分布的影响较大。营养盐剖面分布总体趋势为NH_4~--N含量随深度增加而增加,NO_3~--N随深度增加而减少,但同时受到沉积速率和污水排放的影响。潮滩沉积物—水界面间无机氮磷的平均扩散通量分别为7.15、-0.53μg/(cm~2·d),因此沉积物是N的输入源,P的汇。同时还发现,污染物的排放能极大地改变该地区的N、P迁移量甚至迁移方向。 相似文献
90.
Offspring should be selected to influence maternal effort to maximize their own fitness, whereas mothers are selected to limit
investment in present progeny. In mammals, this leads to a conflict over the amount of milk provided and the timing of weaning.
The intensity and time course of such conflict has so far mostly been investigated experimentally in altricial rodents. However,
it is expected that offspring options for conflict will depend on developmental state. We therefore investigated in the highly
precocial domestic guinea pig (Cavia aperea f. porcellus) who decides over nursing performance and weaning and how pup state influences these decisions. Specifically, we tested whether
a threshold mass of pups predicts weaning time. By exchanging older litters against neonates and vice versa, we produced a
situation in which females differed in lactational stage from the cross-fostered pups. Our results indicate that females decide
about the timing of weaning, as cross-fostered younger pups were weaned at a much younger age than controls and older pups
benefited from continuing lactation of foster mothers. Growth rates did not differ in the treatment groups, and different
weaning ages resulted in differing weaning mass refuting the hypothesis that weaning is based on a threshold mass of offspring.
This constitutes clear evidence that in a precocial rodent, the guinea pig, decisions about maternal care are primarily determined
by maternal state and little influenced by pup state despite the extreme precociality of offspring. We suggest that precocial
pups show little resistance to early weaning when food is abundant, as they reach sufficient nutritional independence by the
middle of lactation to enable independent survival. 相似文献