MOSES软件在系泊浮体运动计算中的应用研究

采用MOSES软件计算某起重船迎浪下的水动力性能和运动响应,并对该船进行缩尺比为1:50的模型试验。通过软件计算结果和试验结果的对比,分析计算模型的网格划分、二阶波浪力计算方法和粘性阻尼等关键参数的选取对MOSES计算系泊浮体运动的影响,为MOSES软件在系泊下运动计算方面提出建议。     

Bacterial Community Dynamics in a Seagrass (<Emphasis Type="Italic">Posidonia oceanica</Emphasis>) Meadow Sediment

Some traits of the bacterial community dynamics associated to the rhizosphere of the Mediterranean seagrass Posidonia oceanica, growing in carbonate sediments, were analyzed during a 2-year period in an enclosed bay of the Balearic Islands. The diversity of the bacterial community was studied by the construction of 16S rDNA clone library. For testing temporal and vertical differences in the abundance of total cells and active Bacteria, we used 4′,6-diamidino-2-phenylindole (DAPI) staining and fluorescence in situ hybridization (FISH). Moreover, some relevant groups of sulfate-reducing bacteria (SRB) were occasionally assessed by FISH. Despite the observed decrease in the total DAPI-stained cells, bacterial counts, and sulfate reduction rates throughout the sampling time, we found an increase in both the pore-water sulfide concentration and the proportion of SRB. Overall, the results revealed a very high bacterial diversity and indicated shifts in bacterial dynamics that could not be related to temperature-dependent factors, suggesting a link between the documented regression of the seagrass meadow and the decline of the microbial community, likely due to large organic matter inputs to the bay.     

新一代省级农业气象预报系统通用统计预报模型的设计与实现

统计预报方法是农业气象预报业务中常用的一种方法.在"新一代农业气象预报系统"中,系统设计了一种通用统计预报模型构建方法,可用于作物产量预报、农业气象灾害预报等农气预报业务.本文主要介绍了通用预报模型的设计原理、实现方法及应用试验结果等.     

Models-3/CMAQ模式对郑州市大气污染物的预报分析研究

介绍了美国国家环保局第三代空气质量模式(Models-3)的主要组成部分:气象模式系统、排放模式系统以及公共多尺度模式系统(CMAQ).并对郑州市SO2和NO2观测值与Models-3/CMAQ预报值进行对比分析,结果表明:模式可以模拟出郑州市SO2和NO2的同位相变化规律;预报值存在系统性偏低的现象;随着预报时效的延长,对SO2和NO2的预报效果逐渐变差.     

Sequence stratigraphic evolution of The post-rift MEGASEQUENCE in The northern part of The Nile Delta basin,Egypt

The stratigraphic succession of the subsurface Pliocene-Quaternary post-rift megasequence in the north-central part of the Nile Delta includes the rock units; Kafr El-Sheikh Formation (Early-Middle Pliocene), El- Wastani Formation (Late Pliocene), Mit-Ghamr and Bilqas formations (Quaternary). These rock units were analyzed according to the sequence stratigraphic principles to construct their stratigraphic architecture and discuss the depositional events influencing their evolution. Accordingly, seven 3rd order depositional sequences were encountered, of which six 3rd order seismic depositional sequences (sequences 1–6) are found in the Early–Middle Pliocene Kafr El-Sheikh Formation, whereas sequence-7 includes the Quaternary rock units. Sequences 1 and 7 were further subdivided, on the basis of high-resolution sequence stratigraphy into 8 and 11 4th order subsequences respectively. The results of the sequence stratigraphic analyses suggested that the depositional evolution of the examined Pliocene-Quaternary megasequence represents a complete prograding depositional phase during the Nile Delta history. The lower part of Kafr El-Sheikh Formation (sequences 1, 2, 3 and 4) was deposited as a thick outer marine shelf succession over which the younger rock units were deposited. However, the depositional sequences 5 & 6 of Kafr El-Sheikh Formation and the lower parts of El-Wastani Formations may indicate a deposition within active prograding prodelta sub-aqueous deltaic-subenvironments. The upper parts of El-Wastani Formation were deposited as a constructive delta-front pushing its way northward. The Pleistocene Mit-Ghamr Formation was evolved as a direct result of a huge fluvial input, organized as coalescing laterally extensive sand-rich bars. These were laid-down by active fluvial distributary streams that dominated the delta plain as the final phases of the present deltaic subaqueous environments.     

Higher reactivity of allochthonous vs. autochthonous DOC sources in a shallow lake

Dissolved organic carbon (DOC) reactivity in aquatic systems is essentially dependent on DOC precursor material and on the processes regulating its bioavailability, especially photodegradation and microbial activity. We investigated temporal changes (from hours to weeks) in the reactivity of allochthonous and autochthonous DOC sources in a macrophyte-dominated shallow lake using a set of incubation experiments. Changes in DOC fluorescence and absorbance properties due to biodegradation (BD) and to the combined effect of photo- and biodegradation (UV + BD) were traced. Allochthonous DOC was more reactive than autochthonous DOC (AutoDOC), showing higher DOC losses (between 22 and 36 %) and faster changes in DOC properties than AutoDOC. The effect of UV + BD was larger than BD alone for both sources of DOC. The rates of change of DOC properties were stronger during the first days of incubation and showed no regular pattern for any of the treatments or DOC sources. Our findings highlight the relevance of the timescale when assessing changes in DOC quality under different degradation pathways, as well as the need of discussing the labile character usually attributed to autochthonous DOC in systems dominated by submerged vegetation, as many shallow lakes or lagoons.     

高密度电阻率法在四川高川茶园沟滑坡勘察中的应用

将高密度电阻率法用于四川省高川乡茶园沟滑坡地质勘察中,结合钻孔资料确定了滑坡体主滑动面的位置、基岩的埋深及含水程度,为滑坡治理提供可靠的地球物理依据。     

吉林延边棉田金铜矿床成矿流体特征及矿床成因

棉田金铜矿床是受断裂构造和中性侵入体联合控制的以金、铜为主的多金属矿床。笔者在对该区地质调查的基础上,运用红外光谱分析和显微测温技术对成矿流体进行研究,发现该区围岩蚀变以绢云母化和青磐岩化最为普遍,并将成矿阶段分为4 个阶段: 黄铁绢英岩阶段、石英--黄铁矿阶段、多金属硫化物阶段和石英--碳酸盐阶段; 对应的均一温度为320℃ ～ 360℃、280℃ ～ 320℃、200℃ ～ 280℃和200℃ ～ 240℃; 其中主成矿阶段为第二、三阶段,主成矿温度为200℃ ～ 320℃,这也是热液中水和二氧化碳含量最高的阶段。流体盐度为1. 91 ～ 13. 40 ( wt%,NaCl) ,密度为0. 69 ～ 0. 95 g /cm3,具低盐度和低密度的特点; 成矿深度为0. 8 ～ 1. 5 km,具浅层成矿的特点; 氢氧同位素分析, δ18OH2O的值为－ 4. 7 × 10 － 3 ～ 5. 83 × 10 － 3,δDH2O的值为－ 89 × 10 － 3 ～ － 124 × 10 － 3,说明成矿流体主要为岩浆水,含少量大气水。综合研究表明,棉田金铜矿床属于浅成中温岩浆热液型矿床。     

基于多源信息融合的黄淮海地区植被覆盖变化遥感监测研究

植被是气候及其他环境因子的综合反映,植被变化与气候变化具有密切的关系。基于Holdridge生命地带指标法和非监督分类法,利用研究区1982年、1992年和2002年气候数据、NDVI数据和DEM数据融合后的多源数据,进行非监督分类。经过分类后处理、空间分析、数据挖掘后,得出黄淮海地区1982—2002年植被覆盖变化图。结果表明:20 a间黄淮海地区植被覆盖变化较为和缓,保持了较一致性;变化比较剧烈地区主要分布在二、三地形阶梯交界及400 mm左右年降水量线处、山东低山丘陵以及淮河下游地区。