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The profile of sound speed and dissolved oxygen in the polymetallic nodules depositional area in the Western Pacific

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Journal of Oceanology and Limnology 2023年第6期41卷 2090-2100页

作者： Bowen LI yonggang jia Zhihan FAN Kai LI College of Oceanography and Space Information China University of PetroleumQingdao 266580China Laboratory for Marine Geology Qingdao National Laboratory for Marine Science and TechnologyQingdao 266100China Shandong Provincial Key Laboratory of Marine Environment and Geological Engineering Ocean University of ChinaQingdao 266100China

With the consumption of terrestrial metal resources,the exploitation of deep-sea polymetallic nodule minerals has been widely concerned around the world.Therefore,the environmental impact of deep-sea polymetallic nodule mining cannot be ignored.However,duo to the lacks in stable and safe deep-sea(the depth>1000 m)vertical profile observation systems and consequently in long-term in-situ observation data,the sound speed and dissolved oxygen and the other water environment factors in the deposition areas of polymetallic nodules remains poorly understood.In this study,a deep-sea in-situ observation system was designed and deployed,and the water environment data of the polymetallic nodule deposition area were collected and analyzed.Result shows that the dissolved oxygen in the depth of 0–600 m was mainly affected by biological factors,while that in the area deeper than 600 m was affected by physical factors.The sound speed in the water body was mainly affected by temperature and pressure.At depths below 840 m,the sound speed is mainly controlled by temperature,and at depths between 840 m and 5700 m,the sound speed is mainly controlled by pressure.The correlations of sound speed vs.pressure and vs.temperature were regressed into equation.The resuspension of sediments rich in various metals may result in the reduction of dissolved oxygen and the improvement of redox potential.This environmental impact caused by a single sediment resuspension could last for 24 h or more.These findings enrich the understanding of the background value of the water environment in the polymetallic nodule deposition area.

关键词： deep sea dissolved oxygen redox potential sound speed conductivity

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Centrifuge experiment on the penetration test for evaluating undrained strength of deep-sea surface soils

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International Journal of Mining Science and Technology 2022年第2期32卷 363-373页

作者： Xingsen Guo Tingkai Nian Wei Zhao Zhongde Gu Chunpeng Liu Xiaolei Liu yonggang jia Shandong Provincial Key Laboratory of Marine Environment and Geological Engineering Ocean University of ChinaQingdao 266100China State Key Laboratory of Coastal and Offshore Engineering Dalian University of TechnologyDalian 116024China Department of Civil Environmental and Geomatic EngineeringUniversity College LondonLondon WC1E 6BTUnited Kingdom

Rapid advances in deep-sea mining engineering have created an urgent need for the accurate evaluation of the undrained strength of marine soils,especially surface soils.Significant achievements have been made using full-flow penetration penetrometers to evaluate marine soil strength in the deep penetration;however,a method considering the effect of ambient water on the surface penetration needs to be established urgently.In this study,penetrometers with multiple probes were developed and used to conduct centrifuge experiments on South China Sea soil and kaolin clay.First,the forces on the probes throughout the penetration process were systematically analyzed and quantified.Second,the spatial influence zone was determined by capturing the resistance changes and sample crack development,and the penetration depth for a sample to reach a stable failure mode was given.Third,the vane shear strength was used to invert the penetration resistance factor of the ball and determine the range of the penetration resistance factor values.Furthermore,a methodology to determine the penetration resistance factors for surface marine soils was established.Finally,the effect of the water cavity above various probes in the surface penetration was used to formulate an internal mechanism for variations in the penetration resistance factor.

关键词： Static penetrometer Centrifuge experiment Deep-sea surface soil Undrained shear strength Penetration resistance factor Water cavity

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Deep seabed mining:Frontiers in engineering geology and environment

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International Journal of Coal Science & Technology 2023年第2期10卷 1-31页

作者： Xingsen Guo Ning Fan Yihan Liu Xiaolei Liu Zekun Wang Xiaotian Xie yonggang jia Shandong Provincial Key Laboratory of Marine Environment and Geological Engineering Ocean University of ChinaQingdao 266100China Department of Civil Environmentaland Geomatic EngineeringUniversity College LondonLondon WC1E 6BTUK College of Civil Engineering and Architecture Wenzhou UniversityWenzhou 325035China Key Laboratory of Engineering and Technology for Soft Soil Foundation and Tideland Reclamation of Zhejiang Province Wenzhou UniversityWenzhou 325035China Laboratory for Marine Geology Qingdao National Laboratory for Marine Science and TechnologyQingdao 266061China

Ocean mining activities have been ongoing for nearly 70 years,making great contributions to industrialization.Given the increasing demand for energy,along with the restructuring of the energy supply catalyzed by efforts to achieve a low-carbon economy,deep seabed mining will play an important role in addressing energy-and resource-related problems in the future.However,deep seabed mining remains in the exploratory stage,with many challenges presented by the high-pressure,low-temperature,and complex geologic and hydrodynamic environments in deep-sea mining areas,which are inaccessible to human activities.Thus,considerable efforts are required to ensure sustainable,economic,reliable,and safe deep seabed mining.This study reviews the latest advances in marine engineering geology and the environment related to deep-sea min-ing activities,presents a bibliometric analysis of the development of ocean mineral resources since the 1950s,summarizes the development,theory,and issues related to techniques for the three stages of ocean mining(i.e.,exploration,extraction,and closure),and discusses the engineering geology environment,geological disasters,in-situ monitoring techniques,envi-ronmental protection requirements,and environmental effects in detail.Finally,this paper gives some key conclusions and future perspectives to provide insights for subsequent studies and commercial mining operations.

关键词： Deep seabed mining Marine engineering geology Geological disasters Environment Techniques

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Impact of seepage flow on sediment resuspension by internal solitary waves:parameterization and mechanism

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Journal of Oceanology and Limnology 2023年第2期41卷 444-457页

作者： Zhuangcai TIAN Chao LIU Ziyin REN Xiujun GUO Mingwei ZHANG Xiuhai WANG Lei SONG yonggang jia State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and TechnologyXuzhou 221116China Key Laboratory of Coastal Science and Integrated Management Ministry of Natural ResourcesQingdao 266061China Shandong Provincial Key Laboratory of Marine Environment and Geological Engineering Ocean University of ChinaQingdao 266100China

Sediment incipient motion is the first step in sediment resuspension.Previous studies ignored the effect of seepage flow on the mobility of sediment particles and simplified the seabed surface as a rigid boundary.A flume experiment was designed to innovatively divide the seabed into two parts to control the dynamic response of the seabed and control the seepage conditions.In the experiment,the seabed sediments and the amplitude of internal solitary waves(ISWs)were changed to compare and analyze the impact of seepage flow on the sediment resuspension by shoaling ISWs.Moreover,parametric research and verification were carried out.Results indicate that seepage flow can greatly influence fine sand,promote sediment resuspension,and increase the amount of suspension by two times on average.However,seepage flow had a little effect on the suspension of clayey silt and sandy silt.Besides,seepage force was added to the traditional gravity,drag force,and uplift force,and the parameterization of threshold starting shear stress of coarse-grained sediments was developed.The results of this parameterization were verified,and seepage force was critical to parameterization.The threshold starting shear stress was reduced by 54.6%after increasing the seepage force.The physical mechanism of this process corresponded to the vertical reciprocating transient seepage in and out the seabed interface caused by the wave-induced transient excess pore water pressure.This quantitative study on seepage flow for shear stress of coarse-grained sediments induced by ISWs is critical to geohazard assessment.

关键词： internal waves seepage flow sediment resuspension parameterization mechanism

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Nepheloid layer generation by gas eruption:unexpected experimental results

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Journal of Oceanology and Limnology 2023年第2期41卷 769-777页

作者： Chaoqi ZHU Sanzhong LI jiangxin CHEN Dawei WANG Xiaoshuai SONG Zhenghui LI Bo CHEN Hongxian SHAN yonggang jia Shandong Provincial Key Laboratory of Marine Environment and Geological Engineering Key Lab of Submarine Geosciences and Prospecting TechniquesMinistry of Education(MOE)Ocean University of ChinaQingdao 266100China Laboratory for Marine Geology Qingdao National Laboratory for Marine Science and TechnologyQingdao 266061China Frontiers Science Center for Deep Ocean Multispheres and Earth System and College of Marine GeosciencesOcean University of ChinaQingdao 266100China Hainan Key Laboratory of Marine Geological Resources and Environment Haikou 570206China Laboratory for Marine Mineral Resources Qingdao National Laboratory for Marine Science and TechnologyQingdao 266061China Key Laboratory of Gas Hydrate Ministry of Natural ResourcesQingdao Institute of Marine GeologyQingdao 266061China Laboratory of Marine Geophysics and Georeource Institute of Deep-Sea Science and EngineeringChinese Academy of SciencesSanya 572000China

Knowledge of nepheloid layers is important to improve the understanding of physical,geological,and sedimentary processes from continental shelf to abyssal environments.We had not tried to study the nepheloid layers in a hydrate-associated tank until unexpected results occurred.Tank experimental results show that gas eruptions triggered intermediate nepheloid layers.Thus,we proposed a new mechanism of intermediate nepheloid layer generation by eruptions.The intermediate nepheloid layers were generated in uniform-density fluid,which indicated that stratified fluid is not a necessary condition for intermediate nepheloid layers.Sufficient space for advection and an oblique slope for detachment are the key ingredients for intermediate nepheloid layer generation by eruptions.Our experiments also offer a new experimental evidence for bottom nepheloid layer generation by earthquakes.Given the scale effects of laboratory experiment,it is important to determine whether submarine volcanic eruption or hydrate-associated venting causes intermediate nepheloid layer in the nature.

关键词： intermediate nepheloid layer gas eruption bottom nepheloid layer gas hydrate tank experiment seafloor instability

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Amelioration of habitat since the early Holocene contributed to the origin of agriculture in the farming-pastoral zone of northern China

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Science China Earth Sciences 2024年第8期67卷 2535-2546页

作者： Xin jia Zhiping ZHANG yonggang SUN Runqi jiaNG Shuangwen YI Wei CHEN Jue SUN Guoqiang LI Shuzhi WANG Enrui LI Xiaonong HU Qingchun BAO Harry F.LEE Huayu LU Ulanqab Museum The Institute of Cultural Relics and Archaeology Department of Geography and Resource Management The Chinese University of Hong Kong jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application School of Geography and Ocean Science Nanjing University Key Laboratory of Virtual Geographic Environment (Ministry of Education of PRC) Nanjing Normal University School of Geography Nanjing Normal University Institute of Environmental Archaeology Nanjing Normal University Schlool of History and Culture Chifeng University State Key Laboratory of Palaeobiology and Stratigraphy Nanjing Institute of Geology and Palaeontology Chinese Academy of Sciences Key Laboratory of Western China's Environmental Systems (Ministry of Education) College of Earth and Environmental SciencesLanzhou University Institute of Archaeology Chinese Academy of Social Sciences

The origin of agriculture in the farming-pastoral zone of northern China remains in dispute. The central region of the Inner Mongolia Plateau is located in the core area of the farming-pastoral zone; thus, it is a critical region for exploring the origin of the dryland farming system in northern China. This study selected the Yumin Site and Banan Site, which belong to the Yumin Culture-the beginning of Neolithic culture in Inner Mongolia-as the research objects. Based on the quartz optically stimulated luminescence(OSL) dating on the sedimentary sections from the Yumin site(YM) and Banan site(BN1 and BN2), the Holocene chronology framework of each section was established. After that, by identifying carbonized grains in the Yumin site and the multi-proxy analysis of each section, we investigated the relationship between the origin of agriculture and climate change in this region. The results revealed that the timing of the origin of agriculture recorded in the Yumin site lagged behind the timing of a significant increase of precipitation during the early Holocene but coincided with the timing of a significant increase of vegetation around 8.4 ka. This phenomenon was further confirmed by the published high-resolution paleoenvironmental records from the surrounding area of the Yumin Culture. We propose that with the gradual amelioration of hydrothermal conditions since the beginning of the Holocene, the regional ecosystem had been improved, resulting in the gradual conversion of the land surface from infertile sand to organic-rich soil, providing an appropriate environmental foundation for the origin of dryland farming in northern China around 8.4 ka. This study highlighted that the “accumulative environmental effects” during the early Holocene played a vital role in the origin of agriculture in northern China and provided a reference for agricultural management in the context of future climate change.

关键词： Origin of agriculture Accumulative environmental effects Yumin Culture Northern China Holocene

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Wave flume experiments on dynamics of the bottom boundary layer in silty seabed

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Acta Oceanologica Sinica 2020年第5期39卷 96-104页

作者： Mingzheng Wen yonggang jia Zhenhao Wang Shaotong Zhang Hongxian Shan Shandong Provincial Key Laboratory of Marine Environment and Geological Engineering Ocean University of ChinaQingdao 266100China Tianjin Center China Geological SurveyTianjin 300170China Laboratory for Marine Geology Pilot National Laboratory for Marine Science and Technology(Qingdao)Qingdao 266061China First Institute of Oceanography Ministry of Natural ResourcesQingdao 266061China

The objectives of this study are carried out a series of controlled large wave flume experiments using fine-grained sediment from the Huanghe River Delta,exploring the complete sequence of sediment behavior in the bottom boundary layer(BBL)during wave-induced liquefaction.The results show that:(1)The BBL in silty seabed is exposed to a progressive wave,goes through a number of different stages including compaction before liquefaction,sediment liquefaction,and compaction after liquefaction,which determines the range and thickness of BBL.(2)With the introduction of waves,first,the sediment surface has settled by an amount S(S=1–2 cm)in the course of wave loadings with an insufficient accumulation of pore water pressure.And a thin high concentration layer formed the near-bed bottom.(3)Once the liquefaction sets in,the liquefied sediment with an‘orbital motion’and the sub-liquefied sediment form a two-layer-sediment region.The range of BBL extends downwards and stopped at a certain depth,subsequently,develops upwards with the compaction process.Meanwhile,resuspended sediments diffuse to the upper water column.(4)During the dynamics process of the BBL beneath progressive waves,the re-suspended sediment increment ranked as sediment liquefaction>erosion before liquefaction>compaction after liquefaction.

关键词： bottom boundary layer suspended sediment concentration liquefaction compaction Yellow River Delta

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抽水蓄能机组励磁绕组匝间短路漏磁检测研究

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电机与控制学报 2024年第2期28卷 32-43页

作者：齐鹏李永刚马明晗武玉才黄嘉华北电力大学新能源电力系统国家重点实验室河北保定071003 河北张河湾蓄能发电有限责任公司河北石家庄050300

抽水蓄能机组定子铁心背部漏磁场可有效反应励磁绕组的运行状态,通过对励磁绕组匝间短路前后的漏磁特征进行研究,以实现对其匝间绝缘健康水平的在线监测。首先,推导励磁绕组健康状态与匝间短路状态下的漏磁表达式,得到不同状态所对应的... 详细信息

抽水蓄能机组定子铁心背部漏磁场可有效反应励磁绕组的运行状态,通过对励磁绕组匝间短路前后的漏磁特征进行研究,以实现对其匝间绝缘健康水平的在线监测。首先,推导励磁绕组健康状态与匝间短路状态下的漏磁表达式,得到不同状态所对应的磁密特征谐波;其次,搭建发电容量为278 MVA的抽水蓄能机组二维有限元仿真模型,据此分析匝间短路故障前后径向漏磁及切向漏磁时/频域特征的演变规律,并得到空载工况的径向、切向漏磁峰值分别为111、102μT,负载工况的径向、切向漏磁峰值分别为115、112.5μT,可为漏磁传感器选型提供参考;最后,通过在同步发电机定子铁心背部加装磁通门传感器,采集不同匝间短路程度下的径向、切向及轴向漏磁信号,获其空载工况峰值分别为51.9、40.4、28.2μT,负载工况峰值分别为56.5、47.3、38.4μT,动模机组监测结果证明了,漏磁信号时域特征波形及频谱特征谐波变化可有效表征励磁绕组匝间绝缘健康水平,为励磁绕组匝间短路状态监测拓展了新的技术路径。

关键词：抽水蓄能机组励磁绕组匝间短路漏磁特性在线监测

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The controlling factors of high suspended sediment concentration in the intertidal flat off the Huanghe River Estuary

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Acta Oceanologica Sinica 2020年第10期39卷 96-106页

作者： Bowen Li yonggang jia J.Paul Liu jianfeng Su Xiaolei Liu Mingzheng Wen Shandong Provincial Key Laboratory of Marine Environment and Geological Engineering Ocean University of ChinaQingdao 266100China Laboratory for Marine Geology Pilot National Laboratory for Marine Science and Technology(Qingdao)Qingdao 266237China Department of Marine Earth and Atmospheric SciencesNorth Carolina State UniversityRaleighNC 27695USA State Key Laboratory of Marine Geology Tongji UniversityShanghai 200092China Tianjin Center China Geological SurveyTianjin 300170China

The Huanghe River(Yellow River)is known by its high suspended sediment concentration(SSC)in its river mouth tidal flat.However,the factors controlling the high SSC over there are not well understood.Therefore,we conducted 7-d hydrodynamic observations(water depth,wave height,and current velocity)and SSC measurements on the tidal flat off the Huanghe River Mouth.The data shows that in most of time,under the calm sea condition,the SSC ranges 0.1–3.5 g/L,and sediment discharge from the river is the main source.However,when hydrodynamics are enhanced in a tidal cycle and large-scale erosion occurs on the seafloor,resuspended sediment becomes the main source,and the SSC in the water column reaches 17.3 g/L.We find the suspended sediment flux is mainly controlled by the tidal current and Stokes drift,while the wave-induced shear stress could also affect the variation of suspended sediment flux.During the observation period,when sea under calm-rippled conditions,the current-induced resuspended sediment concentration(RSC)was greater than the wave-induced RSC.In contrast,in smooth-wavelet sea conditions,the wave-induced RSC was greater than the current-induced RSC,for instance,a single wave event was found to cause 11.8 cm seabed erosion within 6 h.This study reveals different controlling factors for the high SSC near a river-influenced tidal flat,and helps us get a better understanding of a delta's depositional and erosional mechanisms.

关键词： Huanghe River(Yellow River) sediment re-suspension sediment transport wave current in-situ observation

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执行器幅值与速率约束下线性系统的事件触发控制

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河南师范大学学报（自然科学版） 2024年第3期52卷 106-112页

作者：贾金泽陈永刚白圆圆河南工学院管理学院河南新乡453003 河南科技学院数学科学学院河南新乡453003 河南科技学院河南省数字农业工程技术研究中心河南新乡453003

传统的网络化控制系统中,控制任务通常以周期的方式执行.为了节约网络通信资源,一些学者提出了事件触发控制.另一方面,由于物理限制或出于安全考虑,几乎所有反馈控制系统都会受到饱和约束.饱和的存在是系统性能退化甚至不稳定的主要因素... 详细信息

传统的网络化控制系统中,控制任务通常以周期的方式执行.为了节约网络通信资源,一些学者提出了事件触发控制.另一方面,由于物理限制或出于安全考虑,几乎所有反馈控制系统都会受到饱和约束.饱和的存在是系统性能退化甚至不稳定的主要因素.研究了受到执行器幅值与速率饱和约束的线性系统的事件触发控制问题.首先,一阶系统用来表示执行器的幅值和速率限制.然后,引入了两个推广的扇区条件来处理由饱和引起的死区非线性.接下来,通过利用Lyapunov稳定性理论,获得了确保闭环系统区域渐近稳定的充分条件.通过限制稳定域的最小范围,提出了事件触发率的最优化问题.所获得的结果用线性矩阵不等式表示,能够方便地利用MATLAB中的LMI工具箱进行求解.最后,数值例子和仿真验证了所得结果的有效性.

关键词：线性系统事件触发控制幅值约束速率约束

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