土与结构相互作用体系振动台模型试验数值模拟研究(英文)

运用土与结构动力相互作用 (SSI)有限元三维分析软件 SASSI2 0 0 0对一个土与结构动力相互作用体系振动台模型试验进行了模拟计算。对振动台模型试验作了简单的介绍 ,并详细叙述了试验的建模方法。对于试验中的刚性地基和柔性地基条件 ,El- centro波、Taft波和 5 0年超越概率为 10 %的南京人工波等三种地震波输入 ,三个加速度峰值水平 0 .1g、0 .2 g、0 .3g及两个水平向地震波输入的各种组合工况均进行了计算。在数值计算中 ,假设地基土为覆盖于基岩上的半无限粘弹性水平成层土 ,采用等效线性模型考虑土的动力非线性的影响 ;上部结构用三维杆系有限元单元模拟 ,楼板用四结点壳单元模拟 ,每个结点有三个平动自由度和三个转动自由度 ,模型试验中所施加的人工质量均匀分布于壳单元上 ;基础视为平板基础 ,用八结点块体单元模拟 ,每个结点有三个平动自由度。将试验结果与计算结果进行对比较 ,结果表明 :计算所建立的模型较好地模拟了相互作用体系在地震荷载下的反应性状 ,计算结果与试验结果吻合较好 ,SSI效应对结构地震反应有很大影响     

TRANSIENT RESPONSE FUNCTIONS FOR CONJUNCTIVE WATER MANAGEMENT IN THE SNAKE RIVER PLAIN,IDAHO1

ABSTRACT: Increasing demands on western water are causing a mounting need for the conjunctive management of surface water and ground water resources. Under western water law, the senior water rights holder has priority over the junior water rights holder in times of water shortage. Water managers have been reluctant to conjunctively manage surface water and ground water resources because of the difficulty of quantification of the impacts to surface water resources from ground water stresses. Impacts from ground water use can take years to propagate through an aquifer system. Prediction of the degree of impact to surface water resources over time and the spatial distribution of impacts is very difficult. Response functions mathematically describe the relationship between a unit ground water stress applied at a specific location and stream depletion or aquifer water level change elsewhere in the system. Response functions can be used to help quantify the spatial and temporal impacts to surface water resources caused by ground water pumping. This paper describes the theory of response functions and presents an application of transient response functions in the Snake River Plain, Idaho. Transient response functions can be used to facilitate the conjunctive management of surface and ground water not only in the eastern Snake River Plain basin, but also in similar basins throughout the western United States.     

化学合成硫化亚铁(FeS)对三价锑的吸附作用研究

厌氧环境中硫化亚铁(FeS)在重金属元素的地球化学循环中扮演极其重要的角色。然而,厌氧条件下FeS与锑(Sb)之间的相互作用尚未有较为清晰的认识。为了探究厌氧条件下FeS对三价锑(Sb(Ⅲ))的吸附动力学、吸附等温线以及吸附的影响因素,本研究以沉淀法制备的FeS为研究对象,测试了其溶解性以及表面形貌。并通过条件实验,考察不同pH、初始FeS、反应时间等因素对FeS吸附Sb(Ⅲ)的影响。结果表明:吸附过程符合准二级动力学模型的描述;中性条件下Langmuir吸附模型对吸附过程具有较高的拟合度,饱和吸附量为380. 3 mg/g; Sb(Ⅲ)在酸性条件下的吸附可能与硫化矿物Sb2S3的析出密切相关,这可能是与FeS溶解产生H_2S反应的结果;而在中性及碱性条件下,FeS与Sb(Ⅲ)的反应主要与表面吸附反应有关。     

Cr3+掺杂对TiO2薄膜光催化活性的影响

采用溶胶-凝胶法制备了TiO2粉末和以釉面瓷砖为载体的TiO2薄膜,讨论了不同Cr3+掺杂浓度对TiO2光催化活性的影响,并采用UVVIS对其光学性能进行了检测.结果表明,Cr3+掺杂和釉面瓷砖的交互作用能够显著提高TiO2薄膜的光催化活性,最佳掺杂浓度为6.04×1017个·cm-3,且随着TiO2光催化活性的提高,薄膜的吸收带边发生了明显的红移,提高了可见光的利用率.     

土壤钙的生物有效性及与其它元素的相互作用

根据国内有关土壤钙素的研究文献、总结了土壤钙的生物有效性.土壤钙与其它元素的相互作用,以及钙在土壤中的固定、移动的研究进展,提出了钙肥的施用原则.其施用原则应该是平衡且适量。     

The Value of Using Feasibility Models in Systematic Conservation Planning to Predict Landholder Management Uptake

Understanding the social dimensions of conservation opportunity is crucial for conservation planning in multiple‐use landscapes. However, factors that influence the feasibility of implementing conservation actions, such as the history of landscape management, and landholders’ willingness to engage are often difficult or time consuming to quantify and rarely incorporated into planning. We examined how conservation agencies could reduce costs of acquiring such data by developing predictive models of management feasibility parameterized with social and biophysical factors likely to influence landholders’ decisions to engage in management. To test the utility of our best‐supported model, we developed 4 alternative investment scenarios based on different input data for conservation planning: social data only; biological data only; potential conservation opportunity derived from modeled feasibility that incurs no social data collection costs; and existing conservation opportunity derived from feasibility data that incurred collection costs. Using spatially explicit information on biodiversity values, feasibility, and management costs, we prioritized locations in southwest Australia to control an invasive predator that is detrimental to both agriculture and natural ecosystems: the red fox (Vulpes vulpes). When social data collection costs were moderate to high, the most cost‐effective investment scenario resulted from a predictive model of feasibility. Combining empirical feasibility data with biological data was more cost‐effective for prioritizing management when social data collection costs were low (<4% of the total budget). Calls for more data to inform conservation planning should take into account the costs and benefits of collecting and using social data to ensure that limited funding for conservation is spent in the most cost‐efficient and effective manner.     

基于兵棋推演理论的城市危机应急管理体系设计

随着经济的发展、城市化进程的加快,城市危机的危害程度日益加剧。基于我国城市危机应急管理总存在的不足,提出将兵棋推演运用到城市危机应急管理中,结合兵棋推演技术、地理信息系统、现代计算机技术和信息技术。提出了一套城市危机应急管理体系框架,并讨论了该系统与城市公共安全体制的融合机制问题。该系统汇集中外危机处置案例,实现动态推演,弥补以往剧本式的应急演练的缺欠,为提高城市危机应急调度指挥的快速性、准确性和科学性,有效整合现有应急救援力量和资源提供了有效的辅助手段,为提升城市危机应急管理决策水平和综合能力提供参考。     

掺杂聚乙烯醇的壳聚糖小球对铜离子-腐殖酸的单一和连续吸附行为

以三聚磷酸钠作为离子交联剂,合成了一种掺杂聚乙烯醇的壳聚糖小球,采用SEM和FTIR表征了小球的表面性能及官能团分布情况,进一步研究了这种小球对腐殖酸和铜离子的单独吸附行为、连续吸附行为及两者共存状态下的吸附行为,并通过XPS能谱分析了吸附过程的机理.结果表明:在单独吸附过程中,壳聚糖小球与腐殖酸和铜的作用方式主要是通过静电引力和络合作用;在连续吸附过程中,先吸附了腐殖酸的小球,后续对铜离子的吸附效果变弱;而先吸附了铜离子的小球,后续对腐殖酸的吸附能力变强,说明这种小球在吸附过程中可以被连续使用.而在腐殖酸和铜离子共存的吸附实验中发现,壳聚糖小球除了会吸附溶液中的铜离子和腐殖酸外,还导致它们的聚集沉降.     

Poisoned plusiines: toxicity of milkweed latex and cardenolides to some generalist caterpillars

Summary. Larvae of Trichoplusia ni Hübner (Lepidoptera: Noctuidae) that ingested latex from Asclepias curassavica L. (Asclepiadaceae) often regurgitated and convulsed with spasms before becoming immobile and unresponsive. Some larvae required over a day to recover sufficiently to feed. Latices from four other plant species in three families were all deterrent, but none caused detectable poisoning. The toxicity of A. curassavica latex was evidently due to cardenolides because pure cardenolides had similar effects when ingested by T. ni. Other species of noctuid caterpillars (Rachiplusia ou Guenée, Anagrapha falcifera Kirby, and Autographa precationis Guenée) sometimes also suffered spasms and temporary immobility when fed A. curassavica latex. A more distantly related noctuid, Spodoptera ornithogalli, was deterred by the latex, but showed no overt physiological responses at the dosage tested. T. ni larvae failed to develop on intact leaves of A. curassavica, on leaves with latex canals deactivated by midrib severance, and on excised leaves. Similarly, larvae reared on excised A. syriaca L. leaves to the final instar died when transferred to A. curassavica leaves with either intact or severed midribs. The final instar larvae sometimes suffered from spasms and immobility even when confined on leaves with depressurized canal systems. Evidently, cardenolides stored outside the latex system suffice to poison larvae. We conclude that cardenolides in A. curassavica have potent physiological effects on some generalist caterpillars and that the presence of these compounds both inside and outside laticifers effectively protects the plant. Received 30 June 1999; accepted 18 October 1999     

A new approach to spatial source apportionment of haze pollution in large scale and its application in China

Long-lasting expansion of haze pollution in China has already presented a stern challenge to regional joint prevention and control. There is an urgent need to enlarge and reconstruct the coverage of joint prevention and control of air pollution in key area. Air quality models can identify and quantify the regional contribution of haze pollution and its key components with the help of numerical simulation, but it is difficult to be applied to larger spatial scale due to the complexity of model parameters. The time series analysis can recognize the existence of spatial interaction of haze pollution between cities, but it has not yet been used to further identify the spatial sources of haze pollution in large scale. Using econometric framework of time series analysis, this paper developed a new approach to perform spatial source apportionment. We applied this approach to calculate the contribution from spatial sources of haze pollution in China, using the monitoring data of particulate matter (PM_2.5) across 161 Chinese cities. This approach overcame the limitation of numerical simulation that the model complexity increases at excess with the expansion of sample range, and could effectively deal with severe large-scale haze episodes.