基于FlowCam影像和YOLOv3深度学习模型的多纹膝沟藻检测

海洋中的有害藻华,包括微藻形成的赤潮和褐潮以及大型藻类形成的绿潮和金潮,已成为一类突出的海洋生态灾害问题。2021年11—12月,山东半岛东北部海域发生多纹膝沟藻(Gonyaulax polygramma)形成的大规模赤潮,导致海带养殖严重受损,亟待构建有针对性的赤潮监测预警体系。本文以多纹膝沟藻为对象,尝试应用流式影像仪(FlowCam)结合卷积神经网络模型YOLOv3,分别对含有多纹膝沟藻的浓缩海水样品、含有多纹膝沟藻和链状亚历山大藻(Alexandrium catenella)的浓缩海水样品,以及含有多纹膝沟藻活细胞及空壳的浓缩海水样品进行了检测实验,探究了基于藻种影像的深度学习模型在赤潮原因种检测方面的应用潜力。结果表明,在以FlowCam获取的影像数据集训练3万次后,YOLOv3对多纹膝沟藻表现出较好的识别能力,对浓缩海水样品中目标藻种识别的平均精度为88.2%;当样品中存在与多纹膝沟藻形态相似的链状亚历山大藻时,模型对多纹膝沟藻识别的平均精度下降为76.6%,对两种微藻同时进行训练和检测,可将对多纹膝沟藻识别的平均精度提高至84.6%。对于低温下出现脱壳现象的多纹膝沟藻,模型对海水中活细胞识别的平均精度为86.7%,对空壳识别的平均精度87.8%,将多纹膝沟藻活细胞与空壳分别识别的平均精度均值(87.3%)高于将两者统一作为多纹膝沟藻进行检测的识别精度(84.2%),整体识别精度提升3.1%。综合相关结果可以看出,FlowCam与深度学习模型相结合在赤潮监测和研究中具有重要应用潜力。     

侏罗系宝塔山砂岩水文地质特征与解危开采研究——以新上海一号煤矿为例

西部矿区是我国重要的能源战略基地,侏罗纪煤田可采煤层多、资源储量丰富,中下组煤受“宝塔山砂岩”含水层严重威胁,但目前国内对该含水层研究较少、资料匮乏。以新上海一号煤矿“11·25 ”突水事故为例,采用延深排水钻孔、水文地质补充勘探、井下放水试验等手段,查明该含水层具有沉积结构复杂、富水性不均、静储量丰富、水头高、水压大、容易疏放等特点;通过安全隔水层厚度计算,说明“ 11·25”事故突水原因。SEM镜下显示砂岩为泥质胶结,块状结构,内生孔隙发育。以砂岩总厚度、砂地比、单位涌水量、渗透系数为主控因素,分析含水层富水性规律;预计正常情况下开采涌水量1 200.7 m³/h,最大涌水量1 860.84 m³/h,超出矿井排水能力。在水文地质单元边界条件分析的基础上,利用Visual MODFLOW建立非稳定渗流场三维数值模型,模拟4个放水阶段的解危效果,结果表明,历时215 d,放水量约487.6万m³,一分区18煤突水危险可以解除。     

东秦岭杨斜金矿区石英闪长玢岩锆石U-Pb年代学、地球化学特征及地质意义

杨斜中型金矿床是东秦岭杨斜-丰北河地区典型的石英脉型金矿床,成矿与区内石英闪长玢岩密切相关,具中高温蚀变特征及矿物组成。LA-ICP-MS锆石U-Pb测年结果表明,石英闪长玢岩锆石²⁰⁶Pb/²³⁸U加权平均年龄为149.5±2.7 Ma,谐和年龄为149.5±2.1 Ma,属晚侏罗世。岩石地球化学研究显示,石英闪长玢岩具有高SiO₂(65.53%~65.76%)、高Al₂O₃(15.65%~15.87%)、富碱(N₂O+K₂O=8.07%~8.30%)及贫MgO(1.37%~1.40%)特征,属于高钾钙碱性准铝质系列岩石;相对富集Rb、Ba、K、Pb、Sr等大离子亲石元素和LREE,亏损Nb、Ta、Ti等高场强元素和HREE;其高Sr、高Sr/Y、低Y和低Yb值及正Eu异常等特征参数,与典型埃达克质岩一致,岩浆应起源于加厚下地壳的部分熔融。综合研究认为,杨斜金矿属岩浆期后热液型金矿床,成岩成矿时代一致,形成于秦岭造山带晚侏罗世-早白垩世陆内俯冲向伸展转换的构造环境。     

Discussion and reassessment of the method used for accepting or rejecting data observed by a Bowen ratio system

The Bowen ratio energy balance method often produces extremely inaccurate magnitudes of the flux due to resolution limits of the instruments. We analysed the criteria used for rejecting inaccurate data observed using a Bowen ratio system and the resolution limit of the sensors to analytically determine the reliable values of the Bowen ratio (β) and the latent and sensible heat fluxes. The formula used to calculate the error limit of the Bowen ratio (β) was corrected based on the theory of error analysis. An example was proposed for the common case with 0.2 °C resolution limit of temperature measurement and 0.08 kP_a resolution limit of water vapour pressure measurement, to show the steps of accepting or rejecting data observed by a Bowen ratio system. The acceptance or rejection of data observed by a Bowen ratio system is a dynamic process, which should be performed based on the excluded interval of the Bowen ratio and the qualitative relationships among the data observed by a Bowen ratio system. The excluded interval of the Bowen ratio can be structured based on the accuracy of the sensors used. Data are excluded first if they do not satisfy the qualitative relationships between the vapour pressure difference, the temperature difference, Bowen ratio, and the available energy, whereas the data in the rejection region range of the Bowen ratio are excluded second. It is necessary to improve the accuracy of the temperature and humidity probes to improve the acceptance rate for data collected using the Bowen ratio system, apart from improving the observed precision of available energy. Copyright © 2013 John Wiley & Sons, Ltd.     

澜沧5.9,6.7级强余震前后的重力变化

1988年11月6日澜沧——耿马地震后,使用2台Worden重力仪在7.6级地震震中附近的大塘乡下扎二进行了定点场地重力测量,本文对这次重力测量的结果进行了初步分析,认为观测期间在竹塘附近发生的二次强余震(11月27日,M=5.9,11月30日,M=6.7),震前引起了约30×10~(-8)ms~(-2)的重力变化,并且认为这二次强余震的孕育过程可以用DD模式来进行解释,据此初步估算这二次强余震之前的最大应力值约4×10~7达因/厘米~2,应变值约4×10~(-5),震源体的隆起约12厘米。     

A coupled high-resolution hydrodynamic and cellular automata-based evacuation route planning model for pedestrians in flooding scenarios

Flooding is now becoming one of the most frequent and widely distributed natural hazards, with significant losses to human lives and property around the world. Evacuation of pedestrians during flooding events is a crucial factor in flood risk management, in addition to saving people’s lives and increasing time for rescue. The key objective of this work is to propose a shortest evacuation path planning algorithm by considering the evacuable areas and human instability during floods. A shortest route optimization algorithm based on cellular automata is established while using diagonal distance calculation methods in heuristic search algorithms. The Morpeth flood event that occurred in 2008 in the UK is used as a case study, and a highly accurate and efficient 2D hydrodynamic model is adopted to discuss the flood characteristics in flood plains. Two flood hazard assessment approaches [i.e., empirical and mechanics-based and experimental calibrated (M&E)] are chosen to study human instability. A comprehensive analysis shows that extreme events are better identified with mechanics-based and experimental calibration methods than with an empirical method. The result of M&E is used as the initial condition for the Morpeth evacuation scenario. Evacuation path planning in Morpeth shows that this algorithm can realize shortest route planning with multiple starting points and ending points at the microscale. These findings are of significance for flood risk management and emergency evacuation research.

     

中国锰矿资源特征及潜力预测

中国的锰矿资源丰富,截止到2016年,保有储量达15.5亿t,位居世界第六位。中国锰矿主要集中分布在南方的泛扬子古陆、北部的燕辽、西部的天山和祁连山等地区。中新元古代、早古生代（寒武纪、奥陶纪）、晚古生代-早中生代是中国锰矿形成的重要时代。在锰矿成矿规律研究的基础上,提出了如下方案：（1）以成矿作用作为一级分类要素,含矿岩系作为二级分类要素的8种成因类型划分方案;（2）根据锰资源潜力评价工作需要,将成因类型和工业类型相结合,以成矿作用和预测要素为一级要素,含矿岩系为二级要素的3种预测类型划分方案。其中,海相沉积型、风化壳型和古天然气渗漏沉积型锰矿是中国具有找矿潜力的主要锰矿床类型。基于此,将全国锰矿划分为11个Ⅲ级锰矿成矿带,对优选出的7个主要锰矿远景区的含锰层位、成矿特征、主攻类型、资源潜力进行了分析。最后,针对目前中国锰矿资源面临的问题,提出了下一步工作部署的建议和意见。     

福建省近海海底麻坑的地貌特征及其与海洋工程的联动效应

为科学开发利用海洋资源、防范海底地质灾害和保护生态环境,文章梳理福建省近海海底麻坑的类型和成因,并分析海洋工程与灾害性地貌的联动效应。研究结果表明:受板块挤压和海平面波动等的影响,福建省近海海底地形和沉积环境复杂多变,流体活动形成的海底麻坑主要包括单元麻坑、圆形麻坑、拉长形麻坑、链状麻坑和复合麻坑5种类型,在北部泥质区、南部砂质区、河口区和海湾区有不同分布,其成因主要包括海相生物气、生物气和海陆生物混合热解气;应高度重视海洋工程与海底麻坑等灾害性地貌的联动效应,避免发生海底地质灾害和破坏海洋生态环境。     

新疆维宝铅锌矿床地质、流体包裹体和同位素地球化学特征

新疆维宝铅锌矿床位于东昆仑祁漫塔格地区西段,铅锌矿体受地层及岩性控制,多呈层状、似层状赋存于蓟县纪狼牙山组中下部条带状绿帘石（透辉石）矽卡岩中,矿石类型主要为绿帘石-透辉石矽卡岩型铅锌（铜）矿石。矿石矿物主要为方铅矿、闪锌矿、黄铜矿等,脉石矿物主要为透辉石、绿帘石、方解石、绿泥石、石榴子石等。金属硫化物电子探针分析表明,闪锌矿中Fe质量分数为2.206%~2.679%,贫Ga、Ge、Cd,Zn/Cd为143~150,方铅矿中Ag质量分数较低（0.163%~0.210%）,具有与岩浆热液有关的金属硫化物特征。流体包裹体以富气相两相包裹体和富液相两相包裹体为主,均一温度平均值分别为268.2和273.1 ℃,含有CO₂、CH₄、N₂、H₂等成分,成矿流体可能来源于岩浆流体,具中温、高盐度、低密度的特征,成矿过程中发生了不混溶作用。金属硫化物的δ³⁴S_V-CDT为0.49‰~2.41‰,主要来源于岩浆;金属硫化物的²⁰⁶Pb/²⁰⁴Pb为18.254~18.336,²⁰⁷Pb/²⁰⁴Pb为15.556~15.664,²⁰⁸Pb/²⁰⁴Pb为38.060~38.367,主要来源于区内深源岩浆活动,有少量地壳铅的混染。综合分析认为维宝铅锌矿床为与印支期岩浆作用有关的层控矽卡岩型矿床。