Precursory phenomena associated with large avalanches in the long-range connective sandpile (LRCS) model

Reduction in b-values before a large earthquake is a very popular topic for discussion. This study proposes an alternative sandpile model being able to demonstrate reduction in scaling exponents before large events through adaptable long-range connections. The distant connection between two separated cells was introduced in the sandpile model. We found that our modified long-range connective sandpile (LRCS) system repeatedly approaches and retreats from a critical state. When a large avalanche occurs in the LRCS model, accumulated energy dramatically dissipates and the system simultaneously retreats from criticality. The system quickly approaches the critical state accompanied by the increase in the slopes of the power-law frequency-size distributions of events. Afterwards, and most interestingly, the power-law slope declines before the next large event. The precursory b-value reduction before large earthquakes observed from earthquake catalogues closely mimics the evolution in power-law slopes for the frequency-size distributions of events derived in the LRCS models. Our paper, thus, provides a new explanation for declined b-values before large earthquakes.     

Study of the Evolution of Carbon Dioxide from Active Carbon by a Threshold Temperature-Programmed Desorption Method

A particular Temperature-Programmed Desorption (TPD) method, called ‘Intermittent TPD’, has been applied to the decomposition of oxygen groups naturally present at the surface of a microporous active carbon. It is shown that this method provides more information on the kinetics of the thermal decomposition of these species than the classical TPD technique. The main result is that the decomposition of these oxygen groups occurs in at least 7 distinct stages which have been characterized by their apparent activation energy and the corresponding frequency factor. The present study underlines the usefulness of ITPD for studying the rate of desorption of gases from powdered samples with a strongly heterogeneous surface. This revised version was published online in July 2006 with corrections to the Cover Date.     

高能诱导核反应中的核碰撞几何与末态粒子的间歇行为

考虑到核碰撞几何,我们推导出高能诱发核反应中二阶阶乘矩与参加反应核子数涨落之间的关系.分析表明,在高能碰撞的射弹碎裂区,强子-核反应末态粒子的间歇性质决定于其强子-强子子过程的间歇特征;而在靶碎裂区,它却主要依赖于参加反应核子数的涨落.推广到核-核反应(B<相似文献   

重有机污染河道曝气试验的工程性研究

根据上海地区中小河流重有机污染的特点,选择上澳塘进行了河道曝气的工程性试验,结果表明河道曝气是改善重有机污染型中小河流水质的一种经济、有效的方法。     

内置蜂窝陶瓷的气升式内循环生物反应器II.固定化Achromobacter sp.降解氯酚和苯酚

蜂窝陶瓷固定化细胞气升式内循环生物反应器(IAL-CHS)降解氯酚和苯酚.对该反应器进行了批式和连续流降解实验,固定于陶瓷载体上的微生物经过短时间适应后,能有效地降解氯酚和苯酚,表现出较好的稳定性和抵抗冲击负荷性能,在350h的连续流处理过程中,氯酚的降解率越来越高,达到98%以上.     

Measurement of turbulence production in the cylinder separated shear-layer using event-triggered Laser-Doppler anemometry

In the transitional cylinder wake as well as the primary vortex street, the separated shear layer becomes unstable and sequences of small-scale vortex structures are produced intermittently. This paper describes how LDA data can be collected exclusively for these intermittent events. A real-time digital signal processing algorithm is developed in order to detect the instability of the shear layer from the characteristic hot-wire signal. Simultaneously, LDA data is selected so that the turbulence production in the unstable separated shear-layer can be derived. This trigger technique can be used for any kind of intermittent signal and measurement process.     

通过好氧选择池防止污泥膨胀

在污水处理厂中 ,经常发生由于丝状菌 0 2lN引发的活性污泥膨胀 .污水中的有机污染物约含 70 %的易于降解的溶解性物质 .当液相中易于降解的有机物质在选择池中去除的不完全 ,丝状细菌就会快速增长 .易生物降解的物质在选择池中主要通过生物相的吸附和贮存而得以去除 .选择池中用于生物贮存的需氧取决于有机物的类型 .为保持选择池的吸附能力 ,污泥必须在曝气池中进行再生 .一旦发生超负荷或供氧量及营养物质不足 ,贮存能力不能得到恢复 ,好氧选择池也就失去了效果 .通过研究对选择池中去除易生化降解物质的影响因素 ,发现了好氧选择池设计的简单计算方法 ,并得出了一个模型 .     

包气带土层中重质油的生物可降解性

通过投加高效微生物和半腐熟堆肥材料 ,改善微生物生态环境 ,促进重质油的生物降解。利用 Soxhlet抽提重量法评价重质油污染土层生物修复的进程 ,并探讨了微生物活性与石油污染物生物降解之间的关系。结果表明 ,重质油生物降解的半衰期长 ,经过 90 d,生物降解量仅占总量的2 0 %。微生物计数和脱氢酶活性与石油污染物生物降解之间存在良好的相关性 ,表明了微生物量和脱氢酶活性是油污土层生物可修复性的良好评价指标     

氧化沟动力配置的讨论

氧化沟系统动力配置主要考虑曝气、推动水流和水流混合的需要。该文从理论上对曝气、推动水流和水流混合的动力需要作了探讨,并认为进行氧化沟动力设备的配置时,还应考虑供氧、推动水流、水流混合的过程和对动力设备的要求之间的差别。     

改进曝气生物滤池技术研究

提出化学混凝与曝气生物滤池结合,通过混凝处理和生物膜过滤的双重作用,对城市二级处理出水进行深度处理,以实现污水的回用.结果表明:在原水水质CODcr=672 mg/L、SS=200 mg/L、BOD5=576mg/L、pH=6.1时,出水CODcr=52 mg/L、SS=10 mg/L、BOD5=24 mg/L、pH=8.6.相对于单独使用BAF,组合工艺对CODcr,SS,BOD5,pH值的去除率均有所提高.系统、综合地给出了混凝-曝气生物滤池工艺流程和最佳工艺条件,为混凝-曝气生物滤池应用提供了技术参数.