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981.
生物滴滤(BTF)净化有机废气是一个复杂的过程,其数学模型往往形式繁琐、参数众多,实际应用比较困难.半经验生物滴滤模型是基于生物酶促反应基本原理(米-门方程),并在含苯废气的生物滴滤净化动态实验和生物膜静态实验等研究的基础上建立和完善的一个应用模型.为了符合生物滴滤器内的实际状况,在建模过程中引入了微生物质量浓度沿床层深度变化的函数等合理假设.模型的检验采用将静态实验所得参数代入模型计算,并与生物滴滤动态实验结果进行对比的方法.检验结果表明:在较宽的负荷、表观过滤气速范围内,该模型对滴滤器的模拟值均较符合实验值.该模型的数学形式简单,参数也较少,且主要参数,如生物膜最大净化速率,K值及微生物质量浓度分布等均可通过生物膜静态实验测得. 相似文献
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984.
PM2.5 chemical source profiles for vehicle exhaust, vegetative burning, geological material, and coal burning in Northwestern Colorado during 1995 总被引:12,自引:0,他引:12
PM2.5 (particles with aerodynamic diameters less than 2.5 μm) chemical source profiles applicable to speciated emissions inventories and receptor model source apportionment are reported for geological material, motor vehicle exhaust, residential coal (RCC) and wood combustion (RWC), forest fires, geothermal hot springs; and coal-fired power generation units from northwestern Colorado during 1995. Fuels and combustion conditions are similar to those of other communities of the inland western US. Coal-fired power station profiles differed substantially between different units using similar coals, with the major difference being lack of selenium in emissions from the only unit that was equipped with a dry limestone sulfur dioxide (SO2) scrubber. SO2 abundances relative to fine particle mass emissions in power plant emissions were seven to nine times higher than hydrogen sulfide (H2S) abundances from geothermal springs, and one to two orders of magnitude higher than SO2 abundances in RCC emissions, implying that the SO2 abundance is an important marker for primary particle contributions of non-aged coal-fired power station contributions. The sum of organic and elemental carbon ranged from 1% to 10% of fine particle mass in coal-fired power plant emissions, from 5% to 10% in geological material, >50% in forest fire emissions, >60% in RWC emissions, and >95% in RCC and vehicle exhaust emissions. Water-soluble potassium (K+) was most abundant in vegetative burning profiles. K+/K ratios ranged from 0.1 in geological material profiles to 0.9 in vegetative burning emissions, confirming previous observations that soluble potassium is a good marker for vegetative burning. 相似文献
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987.
Although assortative mating is widespread among long-lived monogamous birds, the underlying mechanisms still remain unclear
in many species. In this study, we analysed assortative mating by age and body mass in the common tern Sterna hirundo with special regard to mate choice decisions of newly paired birds. To assess whether assortative mating by age is an active
decision involving either homotypic or directional preferences or rather a passive process due to restricted availability
of potential mates, we analysed the influence of age-dependent arrival date and cohort size. Furthermore, we looked for direct
benefits in terms of reproductive success. Common terns mated assortatively by age and arrival date but not by body mass at
arrival. Assortative mating by age was age dependent and was detected mainly in younger birds, whereas birds older than 8 years
rather re-paired with younger ones. The availability of same-aged mates was restricted by cohort size and arrival date. We
found no general evidence for better reproductive performance of same-aged pairs. Instead, relative reproductive success was
related to own age and the relative age of mate: It should be advantageous for any bird to acquire an old mate; hence, assortative
mating by age seems to be beneficial only for old terns but not for young ones. Age-assortative mating in common terns occurred
by both passive and active processes, which are not mutually exclusive. Our results do not indicate a homotypic but a directional
preference and support the theory that high-quality (older/experienced) individuals tend to mate assortatively if same-aged
mates are available, which leaves low-quality (young/inexperienced) individuals to mate among themselves. 相似文献
988.
从单个上升气泡内外流场的完全Navier-Stokes方程数值解出发,用Lagrange轨道跟踪的方法研究了超细颗粒在单个上升气泡内的沉积过程,在气泡的流场中考虑了气泡运动中的变形.在超细颗粒的受力中考虑了粘性阻力和Bromnian运动扩散力.在常温下水.空气体系中,对气泡直径0.1~1mm,超细颗粒直径0.1~2μm的情况进行了数值模拟,并对数值模拟的结果进行了拟合,得出简便易用的经验公式。 相似文献
989.
990.
硝酸锶(钡)降低气溶胶灭火剂腐蚀性研究 总被引:1,自引:0,他引:1
研究了添加硝酸锶(钡)降低气溶胶灭火剂腐蚀性的作用,通过测试气溶胶灭火剂固体产物颗粒的生成量、吸湿性和酸碱性,分析了影响气溶胶灭火剂对金属材料腐蚀性的因素,并考察了改性配方灭火性能的变化。 相似文献