山东龙口北皂煤矿软岩力学特性实验研究

根据室内实验结果, 本文讨论了北皂煤矿的岩石力学性质, 物化特性。泥质岩类的力学性质和水理性质、物化特性有关。泥质岩类具有显著的流动变形和各向异性。     

Succession of phytoplankton functional groups from spring to early summer in the central Bohai Sea using HPLC–CHEMTAX approaches

Phytoplankton is a key component in the functioning of marine ecosystems, phytoplankton community structures are very sensitive to their environment. This study was conducted in the central Bohai Sea in the spring and early summer of 2015. Spatial variations in phytoplankton functional groups were examined through high-performance liquid chromatography pigment–CHEMTAX analysis. Results suggested that the phytoplankton biomass (chlorophyll a [Chl a]) in spring was mainly derived from the diatom community and was 3.5-fold higher than that in the summer. Meanwhile, the phytoplankton in the early summer sustained more diverse marker pigments than that in the spring. Despite the overwhelming predominance of microsized phytoplankton in the spring, some smaller phytoplankton (pico- or nanosized), including flagellates, such as prasinophytes, chlorophytes, and cryptophytes, highly contributed to the total Chl a in the summer. Various physico-chemical variables were recorded, and their correlations with phytoplankton density were established by redundancy analysis. Temperature, water stratification, nutrient availability, and even nutritive proportion influenced the succession of phytoplankton functional groups from diatom dominance in the spring to flagellate (mainly haptophytes and prasinophytes) dominance in the early summer. In conclusion, our work comprehensively evaluated the phytoplankton diversity and dynamics in the central Bohai Sea and suggests the need for long-term monitoring for further investigation.     

扬州港客运大楼地基加固与边坡围护

位于长江下游北岸某凹岸区的扬州港,因受局部塌岸的危害,多处建构物被毁,新落成的客运大楼产生不均匀沉降与裂缝,直接危及大楼的安全与使用,迫使该港长航客运中断。后在大楼西南侧岸边构筑了一道防护帷幕墙,并对大楼地基土进行了压密注浆加固,保住了大楼,控制了沉降,并使大楼处于稳定状态,恢复了长航客运。简述了该建筑物病害的成因,治理加固方案的设计与施工,效果验证等问题。     

太湖长孢藻属(Dolichospermum)生物量长期动态变化及驱动因子

针对近年来太湖水体中长孢藻（Dolichospermum,曾用名鱼腥藻Anabaena）比例增加的趋势,本文研究了2005—2019年太湖春季不同湖区长孢藻生物量的长期变化趋势和空间差异,探究了冬、春季气象条件（气温、日照时长、风速、降雨量）和营养盐（总氮、总磷）水平对其的影响.结果表明,2005—2019年太湖监测数据显示春季长孢藻生物量有比较明显的升高现象,主要发生在竺山湖富营养程度较高的区域,其次是湖心区、梅梁湾和南部湖区.偏最小二乘路径建模（PLS-PM）结果表明,不同湖区长孢藻生物量变化的主要驱动因素存在差异.在湖心区,春季长孢藻的生物量主要受冬季气候条件（气温、风速、日照时长）的影响,其次受春季营养盐和春季气候条件的影响.在梅梁湾、竺山湖和南部湖区,春季长孢藻的生物量主要受春季气候条件的影响.在梅梁湾和竺山湖,春季风速、日照时长是春季长孢藻生物量的显著影响因子;在南部湖区,春季长孢藻生物量的主要驱动因素是春季的日照时长和春季气温.本研究从长时间序列角度,对太湖固氮蓝藻的时空分布特征和影响因素开展了研究,为太湖不同湖区开展针对性的藻类水华防控和富营养化治理提供理论基础.     

基于浮标观测的南海西沙群岛潟湖区潮流特征研究

本文利用南海西沙群岛潟湖区29 d的全水深浮标观测资料研究了潟湖区内正压潮和内潮的基本特征,采用深度平均方法分析海流的适用性,并讨论潟湖区内潮的主要来源。深度平均流的动能谱显示全日潮流占主导,其动能占整体海流动能的41%。对比分析深度平均流和Tpxo7.2模式预测的全日、半日潮流的调和常数,两者均表明全日正压潮流受地形调制,主轴方向为西北−东南向,而半日正压潮流主轴方向为东−西向。两种方法得到的全日正压潮流大−小潮存在半个相位（6～7 d）的差异,进一步分析发现全日正压潮和全日内潮潮龄不同,存在部分相互抵消,且全日内潮大潮发生时间在深度上存在差异,推测由于缺少海表和海底的测量数据,导致深度平均方法得到的全日正压潮仍然包含全日内潮信号。调和分析结果表明,全日内潮的动能中相干部分占比高达91%,说明潟湖区的全日内潮是正压潮与局地岛礁地形相互作用产生,而从远场传播而来的可能性很小。     

爆破、塌陷识别研究进展综述

简要介绍当前国内外关于天然地震与爆破、塌陷等非天然地震特征研究及事件类型识别的进展.对各类事件的定义及主要波形特征进行简要综述,重点介绍了事件类型判定的各类识别方法.与自然界天然地震不同,非天然地震由人工干预或人类活动间接引发.爆破是炸药在爆炸瞬间能量迅速释放,部分能量以地震波形式向外传播,引起地表振动而产生破坏效应的...     

山西河东煤田石楼北区块NSL05井煤层气钻井施工工艺

石楼北区块位于鄂尔多斯盆地东缘。该区域表土层松散易坍塌,在以往的钻探施工中,地层中不同程度的存在涌水或者漏失情况。太原组第三层灰岩可钻性较差,取心作业中频繁发生钻头被堵死的情况。为了解决以上问题,缩短施工工期,对钻具组合和钻井参数进行了调整,采用四翼PDC钻头、直螺杆的钻具结构;取心作业主要采用绳索取心,采用①215．9mm的取心钻头代替该区以往的016．9mm钻头,利用Φ127mm钻杆作为绳索取心工具的运行通道,并采用自行研制的内外管总成和内管取心工具．保证了取心效果;将钻头水眼更改为12mm×2＋14mm＋16ram的组合方式,有效保持了钻孔内的清洁,避免岩屑重复破碎,进一步提高钻进效率。同时介绍了钻探施工程中设备的配套、钻井液的配制、钻井技术参数的选择等。结果表明：该井取心岩心总收获率为92．15％,其中8#煤心质量总采取率为93．50％;井斜3°10′,全井水平位移44．17m,最大全角变化率耋1．1。／30m。对该区煤层气井钻探施工有很好的借鉴作用。     

Topographic elastic least-squares reverse time migration based on vector P- and S-wave equations in the curvilinear coordinates

Elastic least-squares reverse time migration has been applied to multi-component seismic data to obtain high-quality images. However, the final images may suffer from artefacts caused by P- and S-wave crosstalk and severe spurious diffractions caused by complex topographic surface conditions. To suppress these crosstalk artefacts and spurious diffractions, we have developed a topographic separated-wavefield elastic least-squares reverse time migration algorithm. In this method, we apply P- and S-wave separated elastic velocity–stress wave equations in the curvilinear coordinates to derive demigration equations and gradient formulas with respect to P- and S-velocity. For the implementation of topographic separated-wavefield elastic least-squares reverse time migration, the wavefields, gradient directions and step lengths are all calculated in the curvilinear coordinates. Numerical experiments conducted with the two-component data synthetized by a three-topographic-layer with anomalies model and the Canadian Foothills model are considered to verify our method. The results reveal that compared with the conventional method, our method promises imaging results with higher resolution and has a faster residual convergence speed. Finally, we carry out numerical examples on noisy data, imperfect migration velocity and inaccurate surface elevation to analyse its sensitivity to noise, migration velocity and surface elevation error. The results prove that our method is less sensitive to noise compared with the conventional elastic least-squares reverse time migration and needs good migration velocities as other least-squares reverse time migration methods. In addition, when implementing the proposed method, an accurate surface elevation should be obtained by global positioning system to yield high-quality images.     

近百年来大亚湾沉积物有机质的沉积记录及对人为活动的响应

通过对沉积物中粒度组成、总有机碳（TOC）、总氮（TN）、碳氮比（TOC/TN）和碳、氮稳定同位素丰度（δ13C、δ15N）等的分析,结合沉积年代学信息与端元混合模型结果,解析了百年尺度下大亚湾沉积物中不同来源有机质的演变过程及控制因素。结果表明,大亚湾沉积物特性在20世纪70年代末至80年代初发生了显著改变:在此之前,TOC、TN、δ13C和δ15N表现稳定,陆源与海源有机碳的比例维持在3∶7,而自此之后,TOC与TN含量显著升高,TOC/TN持续下降,在1980—2000年和2010年至今都出现了陆源有机碳比例升高,海源有机碳比例降低的现象。上述显著变化表明大亚湾海洋环境自20世纪70年代末至80年代初已经发生了重大变化。近20年来GDP与沉积柱中TN和δ15N呈现出的显著正相关,与TOC/TN呈现出的显著负相关,表明沿岸经济的迅猛增长,水产养殖业的快速发展,周边人口的急速增加等人为活动,是造成大亚湾生态环境变化的重要原因。未来的研究应更密切关注人为活动对海湾生态环境的影响,通过法律法规约束行为,加强海湾生态环境保护与修复治理工作。     

Spike in phytoplankton biomass in Greenland Sea during 2009 and the correlations among chlorophyll-a,aerosol optical depth and ice cover

The distributions and correlations of chlorophyll-a(Chl-a),aerosol optical depth(AOD)and ice cover in the southeast Arctic Ocean-Greenland Sea(10°W–10°E,70°–80°N)between 2003 and 2009 were studied using satellite data and statistical analyses.Regression analysis showed correlations between Chl-a and AOD,Chl-a and ice cover,and AOD and ice cover with different time lags.The time lag of Chl-a and AOD indicated their long-term equilibrium relationship.Peaks in AOD and Chl-a and generally occurred in May and July,respectively.Despite the time lag,the correlation between Chl-a and AOD in the study region was as high as 0.7.The peak gap between Chl-a and AOD shifted for about 6 weeks during 2003–2009.In the summer and autumn of 2009,Chl-a and AOD levels were much higher than during the other years,especially in the northern band of the study region(75°–80°N).The driving forces for this localized increase in phytoplankton biomass could be mainly attributed to the very high rate of ice melting in spring and early summer and the high wind speed in autumn,together with the increased deposition of aerosol throughout the year.The unusually high AOD in the spring of 2003 was mainly due to a massive fi re in Russia,which occurred in the fi rst half of the year.Over the 7 years of the study,the sea surface temperature generally decreased.This may have been due to the release of dimethylsulfi de into the air,excreted in large amounts from abundant phytoplankton biomass,and its subsequent reaction,form large amounts of aerosol,and resulting in regional cooling.