神农架成冰系“南沱组”宏观藻应属大塘坡组的新证据

<正>1研究目的(Objective)Ye et al.(2015)在Geology上报道,华南神农架"Marinoan南坨组下部冰碛岩中黑色页岩夹层内"保存大量复杂形态的同冰期海洋底栖宏观藻炭质印模化石,引起国际同行强烈反响。然而笔者研究团队近期研究查明,Ye et al.(2015)报道的宏观藻炭     

The Firstly Discovered Cosmic Spherules in Carbonaceous Siltstone from the Taizi Formation of the Mesoproterozoic Shennongjia Group, Central China

<正>Objective Spherical micro-particles are often preserved in Precambrian sedimentary rocks.Finnish and Chinese scholars have previously discovered carbonaceous,siliceous or ferruginous spherules of out-space origin in the 1.6 Ga and 1.4 Ga sequence,respectively.The presence of spherules can record possible cosmic impact events.Also,cosmic spherules provide important information on the evolution of planets from outer space.This work firstly discovered cosmic spherules in thin layer of carbonaceous siltstone from the Taizi Fm.(1.2-1.3 Ga)of the Shennongjia group in the Shennongjia area,Hubei     

中西非裂谷盆地白垩系两类优质烃源岩发育模式

中西非裂谷系位于非洲中部,主要为沿中非剪切断裂带分布的被动裂谷盆地,进一步划分为中非裂谷系和西非裂谷系。针对国内外对勘探程度极低的中西非裂谷盆地白垩系优质烃源岩展布、发育机理及油气成藏模式认识薄弱的现状,笔者在开展大量中西非裂谷盆地上、下白垩统两类烃源岩样品的主微量元素等地球化学分析的基础上,从含油气盆地构造、烃源岩发育古环境、古气候、古生产力和有机质保存条件等分析出发,剖析了不同类型含油气盆地优质烃源岩发育主控因素,分别建立了中、西非裂谷系低勘探程度含油气盆地下白垩统、上白垩统优质烃源岩的发育模式:中非裂谷盆地(Bongor、Muglad、Melut盆地)下白垩统裂陷期快速沉降、温暖湿润气候条件下,勃发的水生有机质(藻类)控制的深水湖相优质烃源岩"生产力"单因素发育模式;西非裂谷盆地(Termit盆地)上白垩统拗陷期海侵、炎热潮湿气候条件下,陆源有机质输入为主,优越的保存条件(偏咸水体)优质海相烃源岩"生产力+保存条件"双因素控制的发育模式。从而进一步锁定富油气凹陷和主力成藏组合,有效指导含油气盆地内选区选带,助推油气规模储量发现。     

Variations in paleoproductivity and the environmental implications over the past six decades in the Changjiang Estuary

Total organic carbon and organic carbon stable isotope, biogenic silica, chlorin were measured from a high resolution sediment core to indicate the variation in paleoproductivity and the environmental implications over the past decades (1942 to 1997) in the Changjiang Estuary. Based on these biomarkers, the shift in the phytoplankton community structure in the past decades was discussed in response to the long-term variations in nutrient concentrations and nutrient ratios. The results showed that the δ 13 C values varied from –26.15‰ to –19.5‰, suggesting the combined organic carbon sources of riverine and marine organisms. Based on the biogenic proxies, paleoproductivity changes were categorized into three stages: low production before 1950; an increase in production with the dominance of diatoms during 1950 to 1980, consistent with increasing of nutrient concentrations; a decrease in production after 1980 when the diatom production decreased while the production of non-silicious phytoplankton increased due to high nutrient inputs, and high N/P and P/Si ratios in the Changjiang Estuary. The sedimentation records also indicated that the riverine organic carbon increased since 1980.     

诸暨枫桥高岭土合成4A沸石的研究

本文记述了由高岭土合成4A沸石的原理与工艺，分析了诸暨枫桥的高岭土物理、化学性质，经过人工合成试验，证明产自诸暨枫桥的高岭土是合成4A沸石较为理想的材料。     

中丹水平子午环DCMT光栏的自动控制

本文指出了子午环光栏自动控制系统研制的必要性，并简要介绍了控制原理．结果表明，该控制部分设计合理大大简便了操作．     

基于模型库的城市应急疏散GIS设计与实现

应急疏散是减少突发事件情况下人员伤亡和生命财产损失的重要手段,疏散决策的科学性至关重要,实现应急疏散应用模型与GIS的集成是提高应急疏散决策效率和水平的关键。本文根据城市应急疏散决策需求,设计了突发事件模型库,基于模型库对城市应急疏散GIS进行了设计。以有毒气体泄漏和爆炸为例进行了实验模拟,实验表明在模型库支持下的城市应急疏散GIS的辅助决策功能显著提高。     

Biotic and Abiotic Conditions Can Change the Reproductive Allocation of Zostera marina Inhabiting the Coastal Areas of North China

The relationships between reproductive allocation and different factors have been widely recognized for terrestrial plants, but scarcely for marine angiosperms. Focusing on the seagrass Zostera marina, we examined the change in biomass when it was partitioned to growth, vegetative propagation and reproductive allocation of Z. marina. We also evaluated the relationships between reproductive allocation and biotic and abiotic conditions in the coastal areas of north China. The results indicated that the reproductive allocation of Z. marina at the levels of genet, shoot and spathe was positively correlated with shoot characteristics such as height and biomass(P < 0.01), but was negatively correlated with branch number and leaf number per genet(P < 0.01). In addition, the allocation was also affected by other abiotic factors such as water column phosphate concentration(P < 0.05) and sediment total petroleum(P < 0.01). These findings indicated that both biotic and abiotic conditions significantly influenced the reproductive allocation of Z. marina, which may affect further the population dynamics.     

一种从彩色扫描图像上提取等高线的方法

针对基于滑动窗口分割及序贯跟踪的彩色地图矢量化存在的不足,通过试验改进由灰度较低的像索导致跟踪出现失败或错误的情况.实践表明,改进后的算法可以避免误追踪、追踪死循环等情况.     

Distribution and sources of phosphorus in tidal river sediments in the Washington, DC, Area

 Sediments in the rivers and basins around Washington, DC, have high concentrations of phosphorus, which, based on geographic distributions, is largely derived from urban runoff and municipal sewage. Dissolved-particulate phosphate exchange reactions and biological uptake of dissolved phosphorus from the water column may be an added source of phosphorus to the sediments. Concentrations of total sedimentary phosphorus ranged from 24 to 56 μm P/g-dw, and were highest in areas near combined sewer outfalls. As a part of this study, sedimentary phosphorus was fractionated into Fe-P, Ca-P, Al-P, and organic phases using a selective-sequential leaching procedure. The distribution of the phases in all sediments analyzed follow the order , Fe-P>Ca-P>Al-P. Spatial variations in the amounts of phosphorus in the different phases is related to the sources of phosphorus to the area. The proportions of occluded Al-P and organic P are 10–20% of the total P, respectively. This suggests that phosphorus from natural sources is small compared to anthropogenic inputs in this area. The high leachable Fe-P and Ca-P in these sediments might contribute a substantial amount of P to the water column under conditions of remobilization. Received: 20 February 1996 · Accepted: 2 April 1996