大型钢筋混凝土结构相似性准则及试验方案研究

目前对于大型钢筋混凝土结构的动力分析研究中,结构动力模型试验与破坏试验仍然是了解结构非线形动力响应与地震破坏形态的一种重要手段。原型结构与模型结构之间各种力学和物理量的相似关系至关重要。本文结合三峡升船机抗震试验,首先介绍了原型基本概况,基于原型对模型进行了设计,给出相似性关系。根据需要研究的内容,给出了可实施的具体方案,包括准备阶段、弹性小震阶段、设计地震阶段和超设计地震阶段,并对加载的地震时程进行了设计。期望研究成果对今后开展大型钢筋混凝土结构的破坏试验工作有一定的指导和借鉴作用。     

Degradation of L- and DL-lactic acid oligomers in the presence ofFusarium moniliforme andPseudomonas putida

Poly(-alkanoates) derived from lactic acid enantiomers are known to degrade easily hydrolytically in aqueous media. The ability of two microorganisms, a filamentous fungus,Fusarium moniliforme, and a bacterium,Pseudomonas putida, to assimilate the degradation by-products of poly(lactic acid) (PLA), namely, lactic acid, lactyllactic acid dimers, and higher oligomers, was investigated in liquid culture. To distinguish the influence of chirality on bioassimilation, two series of substrates were considered which derived from the racemic and the L-form of lactic acid, respectively. The fate of these compounds was monitored by HPLC. Under the selected conditions,DL- andL-lactic acids were totally used by the two microorganisms regardless of the enantiomeric composition. Both microorganisms degraded the LL-dimer rather rapidly. However,F. moniliforme acted more rapidly thanP. putida. It is likely that the DD-dimer also biodegraded but at a slower rate, especially in the case of the fungi. Higher racemic oligomers were slowly assimilated by the two microorganisms, whereas higher L-oligomers appeared biostable probably because of their crystallinity. A synergistic effect was observed when both microorganisms were present in the same culture medium containing racemic oligomers.Presented at the 4th International Workshop on Biodegradable Plastics and Polymers, October 11–14, 1995. Durham, New Hampshire.     

“Pheromones and Animal Behaviour” - Communication by Smell and Taste”

Summary.  ((no summary.))A corrected version of the appendix is available for free download from     

脉冲喷吹2000mm长滤筒的清灰性能

为探究2 000 mm长滤筒滤筒在脉冲清灰时,不同喷吹条件(喷吹孔径、喷吹距离)对滤筒清灰性能的影响及沿长滤筒长度方向上侧壁压力峰值分布规律,设计脉冲喷吹实验,测定Φ147 mm×2 000 mm(覆PTFE膜)长滤筒在不同喷吹条件下的侧壁压力峰值.实验结果表明,2 000 mm长滤筒的最佳喷吹孔径为15 mm,最佳喷吹距离为240 mm,在0.5 MPa条件下,沿滤筒长度方向上各测点的侧壁压力峰值分别为P0 1 084、P1 1 898、P2 1 276、P3 1 556、P4 1 302和P5 3 258.并得出最佳喷吹距离随着喷吹孔径的减小而逐渐增大,以及沿长滤筒长度方向上侧壁压力峰值分布呈现先增加再减小再增加的分布规律.研究成果旨在为长滤筒过滤系统优化设计及滤筒除尘器代替滤袋除尘器的应用上提供指导.     

上部开口诱导引流装置对卧式长滤筒清灰性能的影响

采用仿真模拟及喷吹实验,研究采用卧式长滤筒的脉冲滤筒除尘器的清灰性能。由于卧式长滤筒在截面形状、放置方式和筒身长度上与传统滤筒有明显区别,使得其清灰方式需要进一步优化。探究诱导引流装置的上部开口尺寸对卧式长滤筒清灰性能的影响发现,随着上部开口口径增大,压力均值逐渐增大,压力分布均匀性有所降低。综合清灰性能指标评价得出,D₁₆型上部开口引流装置在0.4 MPa,175 mm的喷吹参数下可实现卧式长滤筒的高效清灰。本研究结果可为卧式长滤筒清灰性能的优化提供参考。     

C?sium-137 in B?den saarl?ndischer Wald?kosysteme

Zusammenfassung Ziel und Schwerpunkte  Um das Verhalten des künstlichen Radionuklids¹³⁷Cs im Landschaftshaushalt der Saar-Lor-Lux Region zu klaren, wurdend die r?umliche Verteilung sowie das deszendente Migrationsverhalten und die Tiefenfunktionen des Radioisotops in den wichtigsten Bodensubstraten saarl?ndischer Wald?kosysteme untersucht. Ergebnisse  Demnach finden sich die h?chsten¹³⁷Cs-Aktivit?ten im Norden des Landes, w?hrend die Gebiete im Süden und Südosten deutlich geringere Konzentrationen aufweisen. Es konnten deszendente Migrationsraten zwischen 0,25 cm/a und 1,0 cm/a festgestellt werden. Durchschnittlich treten die h?chsten Migrationsraten in den tonig-schluffigen Substraten des Muschelkalks auf (0,66 cm/a), gefolgt von den lehmig ausgepr?gten Substraten des Unterrotliegenden (0,53 cm/a) und den sandigen Substraten des Buntsandsteins (0,41 cm/a). In den tonarmen Bodensubstraten des Unterrotliegenden und des Buntsandsteins lassen sich 90–95% der Aktivit?ten in den oberen 10 cm der humusreichen Oberb?den nachweisen, wohingegen in den tonreichen Substraten des Muschelkalks bis zur gleichen Tiefe nur etwa 70–76% zu finden sind. Schlussfolgerungen  Mit einem Abnehmen der als Leitbahnen fungierenden Prim?r-und Sekund?rporen in zunehmender Tiefe ist künftig mit einer deutlichen Reduzierung der Verlagerungsgeschwindigkeit von¹³⁷Cs in den Substraten des Muschelkalks zu rechnen. Insbesondere bei geringm?chtigen B?den auf kluftreichem Ausgangsgestein impliziert die maximale Eindringtiefe des Isorops von 40 cm in den Unterboden jedoch eine m?gliche Kontamination des oberfl?chennahen Grundwassers, ebenso wie an Standorten mit hohem Grundwasserstand. Ausblick  Aufgrund der hier vorgestellten Ergebnisse wurde ein¹³⁷Cs-Monitoring in das Boden-Dauerbeobachtungsprogramm des Landesamts für Umweltschutz des Saarlandes aufgenommen Online-First: 25. April 2000     

PACIFIC NORTHWEST REGIONAL ASSESSMENT: THE IMPACTS OF CLIMATE VARIABILITY AND CLIMATE CHANGE ON THE WATER RESOURCES OF THE COLUMBIA RIVER BASIN1

ABSTRACT: The Pacific Northwest (PNW) regional assessment is an integrated examination of the consequences of natural climate variability and projected future climate change for the natural and human systems of the region. The assessment currently focuses on four sectors: hydrology/water resources, forests and forestry, aquatic ecosystems, and coastal activities. The assessment begins by identifying and elucidating the natural patterns of climate vanability in the PNW on interannual to decadal timescales. The pathways through which these climate variations are manifested and the resultant impacts on the natural and human systems of the region are investigated. Knowledge of these pathways allows an analysis of the potential impacts of future climate change, as defined by IPCC climate change scenarios. In this paper, we examine the sensitivity, adaptability and vulnerability of hydrology and water resources to climate variability and change. We focus on the Columbia River Basin, which covers approximately 75 percent of the PNW and is the basis for the dominant water resources system of the PNW. The water resources system of the Columbia River is sensitive to climate variability, especially with respect to drought. Management inertia and the lack of a centralized authority coordinating all uses of the resource impede adaptability to drought and optimization of water distribution. Climate change projections suggest exacerbated conditions of conflict between users as a result of low summertime streamfiow conditions. An understanding of the patterns and consequences of regional climate variability is crucial to developing an adequate response to future changes in climate.     

Structural marsh management effects on coastal fishes and crustaceans

Structural marsh management, using levees and water-control structures, is used in the coastal zone for many objectives, for example, to reduce marsh loss, to enhance waterfowl habitat, to revegetate open-water areas, and to reduce saltwater intrusion. The literature was evaluated to categorize structural marsh management and to determine some of its effects on fishes and crustaceans. Structural marsh management had positive effects on standing stock of most resident organisms and negative effects on marine-transient organisms. Emigration was negatively affected for both resident and marine-transient organisms. Techniques such as opening structures at critical migration times, designing structures that offer the greatest management flexibility, and using structures to create a flow-through system could reduce these impacts. More effort should be put into monitoring managed areas to determine if the objectives are being met and to evaluate the effects on fishes and crustaceans. Although frequent manipulation could reduce these impacts, the costs and problems incurred may outweigh the anticipated benefits.     

用数模表述分析远距离污染源对土壤环境的影响

在以哈密红星皮革厂铬鞣废水中的重金属污染物（铬）对土壤污染影响的调查分析中,就远距离污染源对环境影响的关系用试验公式作了研究表述就,选出了较为适宜的数学模型,就污染物含量与污染源距离的关系进行了分析。     

SAMPLE UNCERTAINTY IN FLOOD LEVEE DESIGN: BAYESIAN VERSUS NON-BAYESIAN METHODS1

ABSTRACT: Bayesian and non-Bayesian flood levee design methods that account for the uncertainty due to limited record length are compared using a case study. The first method, Bayesian decision theory (BDT), imbeds the uncertainty in the parameters of the yearly peak stage into a loss function. The optimum design of the flood levee, called Bayes design, corresponds to the minimum expected loss, called Bayes risk. The second method, induced safety algorithm (ISA), computes a margin of safety to be added to either an existing levee or a levee designed by classical benefit-cost analysis. The design decision is shown to fluctuate as different record lengths are considered. For short record lengths, BDT, which takes small sample bias into account, appears to yield a more conservative design than ISA. On the other hand, ISA, which is simple to implement, seems to be preferable to BDT for longer record lengths.