从国际治湖经验探讨太湖富营养化的治理   总被引：4，自引：0，他引：4  

虞孝感  Josef Nipper  燕乃玲 《地理学报》2007,62(9):899-906

湖泊富营养化已经成为影响湖泊流域社会经济可持续发展的因素之一,应该充分认识目前我国湖泊富营养化问题的普遍性以及解决问题的迫切性。从国际湖泊富营养化治理的经验看,有效地控制面源和点源污染仍然是湖泊富营养化治理的重要前提;颁布严格的保护水资源的法律,确保饮用水安全是重中之重;应建立全流域统一的水资源保护合作机制,特别是注重把流域综合管理的思想引入湖泊富营养化治理;制定长期的湖泊富营养化治理计划, 细化具体的阶段治理目标。坚持湖泊治理的方向,不能放弃太湖的治理。  相似文献   

Effect of thickness variation on collapse pressure of seamless pipes     

Fuat Kara  Josef Navarro  Robert L. Allwood 《Ocean Engineering》2010,37(11-12):998-1006

The present paper is concerned with determining the effect of thickness variation on collapse pressure of seamless pipes. There exists extensive information on the effects external pressure has on pipelines. A substantial amount of literature deals with results of analysis, numerical modelling and testing of pipes those are gradually subject to external pressure. This knowledge has been incorporated into standards which are intended for designing linepipe operating in deepwater locations. One such example is the DNV-OS-101 (DNV, 2007) Submarine Pipeline Systems standard. This code only addresses pipes with a nominally uniform wall thickness making it inadequate for designing seamless pipe which is prone to thickness variation arising from the manufacturing process. The DNV (2007) code effectively ignores the problem as it simply provides a vague statement regarding a conservative value of wall thickness that should be used in the design calculations.The present paper uses finite element analysis (FAE) modelling to predict the external pressure acting on the pipes. The present paper explains the manner in which FEA models will be used to study the effect wall thickness variation will have on the pressure at which the pipe will collapse. An improvement to the DNV (2007) code is then suggested by interpreting the results of the FEA models. The case study that follows provides insight on the savings the improved method is projected to offer.  相似文献   

The effect of riparian condition on invertebrate drift in mountain streams     

Shelley E. R. Hoover  Leanne G. W. Shannon  Josef Daniel Ackerman 《Aquatic Sciences - Research Across Boundaries》2007,69(4):544-553

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Влияние сколбжения газа на механизм прямого захвата при осаждении частиц аэрозоля на шаре     

Josef Bioh 《Studia Geophysica et Geodaetica》1964,8(4):409-411

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Zum Verhalten von Ankerit im geschlossenen Gefüge und als Einzelkorn.     

Josef Ladurner 《Mineralogy and Petrology》1955,5(3):215-226

Ohne ZusammenfassungMit 14 Gefügediagrammen.  相似文献   

XXIII International Geographical Congress— Moscow 1976: General symposium 3: Geographical aspects of urbanization and urban planning     

Josef Matznetter 《Geoforum》1976,7(4):325-327

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Comparison of Solar and Geomagnetic Activity Effects on the Northern Hemisphere Weather Changes     

Bochníček  Josef  Hejda  Pavel  Pýcha  Josef 《Studia Geophysica et Geodaetica》2001,45(2):133-154

The changes of pressure and temperature fields in the winter lower troposphere observed in association with changes in solar and/or geomagnetic activity are compared. It is shown that the fact whether it was solar or geomagnetic activity was not so important as whether the levels of the two activities were high or low. The differences between the effects of solar/geomagnetic activity, however, are revealed, the pressure and temperature data being stratified according to the QBO phase. The relationship obtained are discussed from the viewpoint of mechanisms resting upon both the planetary wave propagation and the changes of atmospheric air currents in the global electric circuit.  相似文献   

Analysis of State of Stress During The 1997 Earthquake Swarm In Western Bohemia     

Slancová  Alice  Horálek  Josef 《Studia Geophysica et Geodaetica》2000,44(2):272-291

Focal mechanisms of 70 events of the January 1997 earthquake swarm were analysed using the Gephart and Forsyth method to determine the state of stress in the West Bohemia/Vogtland region and to reveal possible stress variations during the swarm activity. The method was applied to the whole set of 70 focal mechanisms and to several subsets distinguishing magnitudes of events and the spatial and temporal distribution of the swarm. The three representative stress models A ( ₁ ,A: 0/45 (az/dip), ₂ A: 134/35, ₃ A: 243/25), B ( ₁ ,B: 162/38, ₂ B: 263/14, ₃ B: 10/49), and C ( ₁ C: 135/30, ₂ C: 1/50, ₃ C: 239/23) which could characterise the state of stress in the region were found. Model C can be considered to be the most probable stress model because of its consistency with the European stress field. The results of the stress analysis applied to the individual subsets of focal mechanisms indicate that the state of stress was more uniform during the first phase of the swarm. To distinguish between the fault plane and the auxiliary plane of fault plane solutions a statistical approach was used. The results showed that the fault planes striking NW-SE and dipping 45° to NE were activated during the swarm.  相似文献   

Comparison of Absolute and Relative Moment Tensor Solutions For The January 1997 West Bohemia Earthquake Swarm   总被引：2，自引：0，他引：2  

Dahm  Torsten  Horálek  Josef  Šílený  Jan 《Studia Geophysica et Geodaetica》2000,44(2):233-250

Moment tensor solutions for 70 clustered events of the 1997 West Bohemia microearthquake swarm, as calculated by two different methods, are given. The first method is a single-event, absolute moment tensor inversion which inverts body-wave peak amplitudes using synthetic Green functions. The second method is a multiple-event, relative method for which Green functions are reduced to 2 geometrical angles of rays at the sources. Both methods yield similar moment tensors, which can be divided into at least two or three different classes of focal solutions, indicating that, during the swarm activity, different planes of weakness were active. The major source component of most events is a double couple. However, the deviations from the double-couple mechanisms seem to be systematic for some classes of solutions. Error analysis was based on transforming the estimate of the standard deviation of amplitudes extracting from the seismograms into confidence regions of the absolute moment tensor. They show that the non-DC components are significant at a fairly high confidence level.  相似文献   

Dr Olivier Coussy,Scientist and Engineer of the Mechanics and Physics of Porous Materials (1953–2010)     

Franz‐Josef Ulm 《国际地质力学数值与分析法杂志》2010,34(6):551-553

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