中国湖泊综合分类原则、级别划分及分类程序之初探

在略述了国内外湖泊分类研究现状的基础上,探讨了开展我国湖泊综合分类的原则、级别划分以及综合分类所应该遵循的程序。主导因素与综合因素相结合,建立分类的主导标志,是湖泊综合分类系统中高层次分类的关键;区域相似性（相对一致性）与差异性的对比分析是低层次分类的重要环节。在此基础上,还应充分考虑到人类经济活动的方式与强度对湖泊诸自然因素的影响,以便使湖泊综合分类工作既具有理论上的意义,同时又具有实用价值。级     

堆积阶地古老滑坡识别方法及其在线状工程地质勘察中的应用

阶地型古老滑坡体形成后,长期受各种营力影响,导致古老滑坡地貌形态破坏严重甚至消失。目前遥感技术和普通工程地质调绘很难发现这些滑坡的存在,给工程建设和后期运营造成较大安全隐患。为准确识别形态特征不明显的古老滑坡体,从阶地物质结构特征演变入手,找到阶地受剪切破坏产生的典型物质结构特征,将地层结构错断、卵砾石异常定向排列、摩擦镜面和泥包粒的眼球构造等作为滑坡准确识别依据。首先采用沿沟谷进行工程地质测绘的纵横交错追踪法确定滑坡体纵向范围和滑面形状,再结合地貌特征推测各级、块滑坡平面范围和分布,最后用点状勘探工程验证和校正推测结论。可将其总结为由"地貌异常、沿沟追踪、面上推断、点状校验"组成的阶地型滑坡识别方法,即物质结构异常推断法。结合线状工程勘察设计各阶段工作特点,提出线状工程前期工作中阶地型滑坡识别步骤,并在临渭高速公路工程建设项目中取得成功应用。     

土壤重金属连续提取方法的优化

重金属在污染土壤中的形态分布决定着重金属的迁移性和危害的程度。土壤重金属形态分析应用最多的是Tessier和BCR连续提取法。Tessier和BCR连续提取法没有考虑土壤样品的特征。美国环保署危险废物浸出毒性鉴别标准法虽然考虑土壤pH值,但没有划分形态。采集不同pH土样,结合Tessier、BCR和毒性浸出鉴别方法的特征,优化出针对不同pH值土壤的连续提取方法,将土壤中重金属划分为活性态、次生碳酸盐结合态、次稳定态和稳定态。用优化的连续提取方法对土样进行连续提取,重金属回收率为85%~115%。优化连续提取方法的结果与Tessier和BCR结果对比显示优化连续提取方法克服了Tessier连续提取法对非石灰质土壤提取过量BCR连续提取法对石灰质土壤提取不足的缺点。优化后的连续提取方法数据稳定可靠,可作为重金属形态分析方法使用。     

Extended consecutive modal pushover procedure for estimating seismic responses of one-way asymmetric plan tall buildings considering soil-structure interaction

Performance based design becomes an effective method for estimating seismic demands of buildings. In asymmetric plan tall building the effects of higher modes and torsion are crucial. The consecutive modal pushover (CMP) procedure is one of the procedures that consider these effects. Also in previous studies the influence of soil-structure interaction (SSI) in pushover analysis is ignored. In this paper the CMP procedure is modified for one-way asymmetric plan mid and high-rise buildings considering SSI. The extended CMP (ECMP) procedure is proposed in order to overcome some limitations of the CMP procedure. In this regard, 10, 15 and 20 story buildings with asymmetric plan are studied considering SSI assuming three different soil conditions. Using nonlinear response history analysis under a set of bidirectional ground motion; the exact responses of these buildings are calculated. Then the ECMP procedure is evaluated by comparing the results of this procedure with nonlinear time history results as an exact solution as well as the modal pushover analysis procedure and FEMA 356 load patterns. The results demonstrate the accuracy of the ECMP procedure.     

Geochemical baseline of trace elements in the sediment in Dexing area,South China

A baseline might be used as a point of reference to monitor change from some specific data without concern for whether the baseline determination is natural or has been changed by human activity. We selected 326 sediment samples from Dexing area, South China, and analyzed for 17 chemical elements. The geochemical baseline was predicted with the method of the normalization procedure combined with the relative cumulative frequency curve. The results indicate Al was the best reference element for the normalization procedure among four potential reference elements (Al, Fe, Ti, and Mn). The baseline value range obtained from the normalization procedure method included both the regional geochemical background of the sediment and the median value of the measured contents. The median value of baselines obtained from relative cumulative frequency method was lower than that obtained from normalization procedure method. In contrast to the geochemical patterns of heavy metals in 1987, the spatial distribution of anomalies sprawled in 2004 in study area, especially for Cu, Pb, Zn, Cd, As, Fe, and Cr.     

基于性能的碳纤维抗震加固设计

本文探讨了基于性能的加固设计的基本思路和设计过程,并给出了一个基于性能的碳纤维加固设计的工程实例,采用pushover静力推覆分析的方法分析对比了结构加固前后的性能,表明原结构的抗震性能不足,经碳纤维加固后的结构抗震性能明显提高,满足8度抗震设防烈度要求。     

大跨预应力混凝土框架结构的静力弹塑性(pushover)分析

基于美国规范ATC-40和N2方法,建立了大跨预应力混凝土框架结构竖向地震反应的静力弹塑性(pushover)分析方法。编制了预应力混凝土构件截面弯矩-曲率的计算程序。这些为评价大跨预应力混凝土框架结构的竖向抗震能力提供了有益的参考。结合具体工程实例进一步说明了该方法的实施步骤。     

A voluntary reduction in the commercial catch of rock lobster (Jasus edwardsii) in a New Zealand fishery

We describe the development and application of a management procedure (decision rule) that resulted in a voluntary reduction in the commercial catch of spiny rock lobster (Jasus edwardsii) in the lower east coast of North Island of New Zealand. The management procedure was developed from an accepted assessment of the CRA 4 (Wellington‐Hawke's Bay) fishery, which used an integrated length‐based assessment model fitted to commercial fishery catch‐per‐unit‐effort (CPUE) biomass indices, commercial length‐frequency data, and tag‐recapture data. The assessment model had been Bayesian, and used the joint posterior distribution of parameters to predict the effect of 384 alternative harvest control rules on the future size of the CRA 4 stock. The harvest control rules all used CPUE as their input, and generated annual changes in catch, which were then simulated by the population dynamics of the operating model. Uncertainty was added to evaluations through observation error, added to the simulated CPUE observations, and stochastic serial auto‐correlation variation in recruitment. We describe how this management procedure was used to effect a voluntary reduction in catch to address the problem of a rapidly declining population.     

Feldspar multi-elevated-temperature post-IR IRSL dating of the Wulanmulun Paleolithic site and its implication

The Wulanmulun site found in 2010 is an important Paleolithic site in Ordos (China), from which lots of stone and bone artifacts and mammalian fossils have been recovered. It was previously dated by radiocarbon and optically stimulated luminescence (OSL) techniques on quartz. To further confirm the reliability of the chronology constructed based on OSL ages and test the applicability of the recently developed pIRIR procedure on sediments from northern China, twenty-four sediment samples (including eolian, lacustrine and fluvio-eolian sands) from the site were determined using the multi-elevated-temperature post-IR IRSL (MET-pIRIR or pIRIR) procedure on potassium feldspar. The results show that the studied samples have two MET-pIRIR D_e preheat plateaus (280–320 and 340–360 °C), and the bleaching rates of the luminescence signals are associated with sample ages and stimulation temperatures. All the pIRIR ages (7–155 ka) corrected for anomalous fading and residual dose obtained after solar bleaching for 15 h are larger than the corresponding quartz OSL ages (4–66 ka) previously determined, even for the young eolian samples (<10 ka). But the corrected IRSL(50 °C) ages (6–85 ka) are broadly consistent with the quartz ages. It appears that the IRSL(50 °C) ages are more reliable, although this contradicts the previously results obtained by other people. On the other hand, we also obtained an extended age plateau between the stimulation temperatures of 50 and 290 °C in the plot of age versus stimulation temperature (A-T plot) by subtracting different residual doses obtained after different bleaching times. The reliability of the plateau ages requires further investigation. For the sediment samples from this site, quartz should be more suitable for dating than K-feldspar, and the quartz OSL ages of 50–65 ka for its cultural layer should be reliable.