主次结构减震特性研究

本文探讨了主次结构的减震特性以及土－结构相互作用对减震效果的影响，在一定条件下，次结构对主结构有减震作用，其减震效果与主次结构的刚度比和质量比、次结构的阻尼和输入地震动的特性有关，对于多层建筑，次结构既可能减小主结构的加速度，也可能减小其相对位移，对于高层建筑、则主要是减小主结构的相对位移，对于中软至弱地基条件，ＳＳＩ效应明显降低高层建筑的加速度反应；对于中等地基条件，ＳＳＩ效应显著降低次结构对高     

南沙群岛海区浮游动物次级生产力及转换效率估算

1999年7月在南沙群岛海区进行了初级生产力和浮游生物调查,对海区27个站的100m水层的次级生产力作了估算,结果表明,85号站的次级生产力最高,为139.9mgC·m-2·d-1,其次是96号站和44号站,分别为128.2和113.8mgC·m-2·d-1。海区次级生产力较低的站为1号站、4号站和8号站,均少于50mgC·m-2·d-1。整个海区100m以上水体的次级生产力平均为72.9mgC·m-2·d-1。同时计算了初级生产力与浮游动物的次级生产力的营养传递的效率,平均转化效率为18%。94和102号站的转化效率较低,仅为6%和9%;最高为17号站为32%;其次6、22和85号站转化率也较高,分别为29%、30%和30%。     

Interpretation of Repulsive Bifurcation of the Kuroshio and Gulf Stream with Classification of Their Branches

Distinctive features of the repulsive bifurcation of Kuroshio and Gulf Stream jets, induced from various observations, have been examined by equations of motion of a 1 1/2 -layer model in natural coordinates, although causes of the bifurcation are discussed little. From the conservation of volume flux through paths above a main thermocline, we have derived the equation M _n K _In + M _s K _Is = 0 for northern (n) and southern (s), steady-state curved jets, just downstream of the bifurcation from a straight jet, where M is momentum flux through the path and K _I, positive for cyclonic deflection of the streamline, is the curvature of a certain intermediate streamline in the laminar path. Assuming concentric streamlines in the curved path, which is narrower than 1–0.5 times the radius of curvature of the center streamline of the path, and symmetric momentum flux through a path element of unit width with respect to the center streamline, we found that K _I approximates to the curvature averaged across the path, relative errors being <0.25−(0.25)². Bifurcation starts with a ‘Big Bang’ and the leading turbulent front of a split jet may be unsteady, but the succeeding laminar part can be regarded as stationary or as translating at a constant velocity, as if frozen. Thus, such features are described by the equation. A provisional classification is given of various warm extrusions along branches of both Streams, all of which exemplify the repulsive bifurcation, except for the mainstreams with very narrow (< 30–40 km) branches, possibly due to misapplication of the model. This revised version was published online in August 2006 with corrections to the Cover Date.     

Response of Nereis diversicolor (Polychaeta, Nereidae) populations to reduced wastewater discharge in the polluted estuary of Oued Souss, Bay of Agadir, Morocco

Field investigations on the population dynamics of Nereis diversicolor were carried out from January 2002 to December 2003 in the estuary of Oued Souss (southwestern Morocco) to determine the changes caused by setting up of a domestic and industrial wastewater purification plant (M'zar) before and after by the end of wastewater discharges in November 2002 on the structure of the ecosystem. Samples of N. diversicolor were collected monthly in the intertidal zone at low tide before (during 2002) and after (during 2003) the end of wastewater discharges.Separation of cohorts using the Algorithm EM method (McLachlan, G.J., Krishnan, T., 1997. The EM algorithm and extensions. Wiley Series in Probability and Statistics. Wiley, New York, 274 pp.) allowed determination of the growth rate (mm day⁻¹) by cohort and the annual production. The data showed significant differences between populations of Nereis diversicolor before and after the end of wastewater discharges. During the wastewater discharge period (2002), the population had a mean annual density of 1992 ind m⁻², a mean annual biomass of 75.52 g DW m⁻² and an annual secondary production of 141.3 g DW m⁻² with a P/B ratio of 1.87. After the end of discharges (2003), density, biomass and secondary production decreased significantly. The annual averages for these parameters were 740 ind m⁻², 14.16 g DW m⁻² and 23.83 g DW m⁻², respectively, with a P/B ratio of 1.68.The important decrease observed in density, biomass and secondary production of Nereis diversicolor may be attributed (a) to the environmental changes observed after the end of wastewater discharges in the estuary of Oued Souss, namely the increase of salinity and the decrease of organic matter content, and (b) to the migration of this species towards other areas.     

Mesozooplankton dynamics in nearshore waters of the Great Barrier Reef

Zooplankton dynamics (community composition, juvenile somatic growth rate, adult egg production, secondary production) were studied in coastal waters of the Great Barrier Reef. Two sectors were compared, one adjacent to a catchment of near-pristine land use patterns, the other to a more intensively farmed catchment. Sampling was conducted in the austral winter (August) and summer (January–March) of two succeeding years. Gradients in zooplankton community composition were weak, with only moderate effects of season and sector. Overall, 37% of zooplankton biomass was in the 73–150 μm size fraction, 26% in the 150–350 μm fraction, and 38% was >350 μm. There was no biomass difference and only small differences in community composition between samples taken during the day and at night; ostracods and large calanoid copepods were occasionally more common at night. Carbon-specific growth rates averaged 0.29 d⁻¹ for cyclopoid copepods and 0.35 d⁻¹ for calanoid copepods, with no difference between sectors. Calanoid copepod growth showed a significant relationship to chlorophyll concentration, but cyclopoid copepods did not. Copepod egg production was low (7.9 ± 5.9 eggs female⁻¹ d⁻¹) and apparently food-limited. Copepod secondary production was lower in August (mean = 2.6, range 1.4–4.0 mg C m⁻² d⁻¹) than in January–March (mean = 8.5, range 2.4–15.5 mg C m⁻² d⁻¹). Secondary production by mesozooplankton in the 73–100 μm size range averaged 0.9% of total phytoplankton production.     

长江三峡大宁河流域3 000年来的沉积环境和风尘堆积

对长江三峡大宁河流域双堰塘剖面的粒度、磁化率和氧化物进行了综合分析，揭示了该区3000a来的沉积环境变化，并对全新世第1寒冷期的风尘堆积作了初步探讨。该区3000a来的风尘堆积是在全新世第1寒冷期（1000－850BC），即是亚北方期又是新冰期时形成的。而此寒冷期又存在次一级的气候波动。风尘堆积下层是在干凉气候下形成的原始风尘堆积，而上层气候趋于冷湿，流水作用增强，原始风尘堆积被流水搬运，在此形成次生黄土。由于所受水动力条件和风化程度的不同，本区风尘堆积与长江下游地区的风尘堆积以及北方黄土之间存在着明显的差异之处。     

地震次生火灾蔓延模型在MapX上的实现

本文根据经典的火灾蔓延模型，完成计算机火灾模型化和模拟技术的研究。首先分析地震次生火灾因素，建立相应的数学模型，其次使用Mapinfo公司的MapX控件开发了软件，最后以鞍山市为例进行了结果展示。     

不同成因原油全扫描定量荧光特征及其影响因素

为揭示不同成因类型原油的三维全扫描荧光特征及其主控因素,对50个不同成因类型的原油的三维荧光特征进行了分析。原油样品代表了未熟—低熟至高成熟度范畴原油、淡水与咸水湖相、沼泽相成因原油、高蜡低硫与低蜡高硫油、常规油与重质油等类型。结果表明,分析原油三维荧光谱图及其定量参数有所差异。原油的荧光强度随芳烃含量增加而增加,沼泽相高蜡油荧光强度总体高于湖相原油;荧光强度随成熟度增加而降低、荧光主峰波长随成熟度增加而变短,反映芳烃总量与相对高分子量芳烃丰度具有降低趋势。稠油的荧光谱图不同于常规油,具有波长分布范围宽、主峰不明显等特征。成熟度、母源岩有机质类型与生源、次生改造等多种因素对原油的三维荧光特征有控制作用。     

应用稀土元素示踪森林沼泽区表生介质不同粒级物质来源

稀土元素广泛地应用于研究不同地质体的同源性判断方面。通过小西林和绰尔水系沉积物和不同层位土壤中稀土元素地球化学特征研究,发现不同粒级( 80目和-80目)的泥炭均具有“Ce亏损型“配分模式,土壤残积层和坡积层的配分模式基本上相同,表明它们来自同一类母体;腐殖层土壤和水系沉积物细粒级(-60目)的配分模式与泥炭基本相同,表明腐殖层土壤是泥炭的重要供给源;水系沉积物细粒级(-60目)部分则主要来自泥炭。     

MapInfo二次开发的若干问题

介绍了MapInfo二次开发中的跨平台集成开发、多幅地图的物理连接，通过MIF格式实现数据的转出与转入、动态生成可视的MapInfo表，并给出河道信息系统的应用实例。