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基于注意力机制U-Net的复杂地表地震初至拾取方法

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地球物理学报 2024年第10期67卷 3891-3903页

作者：李闻达刘洪吴天麒中国科学院地质与地球物理研究所北京100029 中国科学院地球科学研究院北京100029 中国科学院油气资源研究院重点实验室北京100029 中国科学院大学北京100049 中国地质大学(北京) 北京100083

地震数据的初至拾取是近地表初至波反演、静校正等工作的基础,是后续地震数据处理中不可或缺的一部分.随着地震数据量的不断增加,近地表条件更为复杂,信噪比越来越低,传统的自动拾取方法逐渐无法满足海量的拾取任务,需要大量的人工校正... 详细信息

地震数据的初至拾取是近地表初至波反演、静校正等工作的基础,是后续地震数据处理中不可或缺的一部分.随着地震数据量的不断增加,近地表条件更为复杂,信噪比越来越低,传统的自动拾取方法逐渐无法满足海量的拾取任务,需要大量的人工校正工作.因此需要一种更为精确的地震数据自动初至拾取方法.本文的贡献主要有以下几点.本文提出将一个注意力机制的U-Net网络应用于信噪比低、强近地表干扰的地区的初至拾取方法.首先将注意力门结构加入到一个标准的U-Net模型中,逐步抑制不相关的背景部分特征,提升拾取的准确性.其次本文提出使用地震波形数据与能量表象(Energy Semblance,ES)作为双通道数据体,可以使U-Net不仅关注相位信息,而且关注到初至的能量属性.此外,我们使用单通道的"0-1"标签作为网络的输出,可以大大缓解标签值分布不均衡的问题,提升预测精度.最后我们提出构建复杂近地表特征的合成数据集,包含复杂初至特征及复杂非均匀噪声的样本,验证方法的鲁棒性,并证明Dice-loss函数可以提升拾取精度.本文提出的方法对于强噪声干扰、缺道坏道及复杂近地表情况均有良好的适应性.

关键词：初至拾取注意力机制复杂近地表

琼州海峡商渔船安全航行风险分析及碰撞应对措施

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航海技术 2024年第5期 19-22页

作者：黄剑李文达海南海峡航运股份有限公司琼州海峡(海南)轮渡运输有限公司

琼州海峡是交通运输部“六区一线”重点监控水域,具有商渔船流量大及通航条件复杂等特点,商渔船碰撞事故在水上交通事故中的占比较大。为有效防范此类事故,基于多年在琼州海峡的航海经验,结合近年在琼州海峡发生的相关事故案例,从琼州... 详细信息

琼州海峡是交通运输部“六区一线”重点监控水域,具有商渔船流量大及通航条件复杂等特点,商渔船碰撞事故在水上交通事故中的占比较大。为有效防范此类事故,基于多年在琼州海峡的航海经验,结合近年在琼州海峡发生的相关事故案例,从琼州海峡水域和渔船捕捞作业的特点出发,分析商船在琼州海峡航行的风险点,提出避免商渔船碰撞的应对措施。

关键词：琼州海峡水域捕捞作业商渔船风险分析应对措施

Transient tribo-dynamic analysis of crosshead slipper in lowspeed marine diesel engines during engine startup

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Friction 2021年第6期9卷 1504-1527页

作者： Rui li Xianghui MENG Jingjin DONG wenda li State Key Laboratory of Mechanical System and Vibration Shanghai Jiaotong UniversityShanghai 200240China School of Mechanical Engineering Shanghai Jiaotong UniversityShanghai 200240China China Shipbuilding Power Engineering Institute Company limited Shanghai 201206China

A crosshead slipper-guide system,which bears a significant thrust force,is an essential friction pair in low-speed marine diesel *** to the low moving speed of the crosshead slipper during engine startup,it is difficult to form good hydrodynamic lubrication between the crosshead slipper and ***,a detailed analysis of the crosshead slipper during engine startup is *** this study,a new transient tribo-dynamic model for a crosshead slipper during the engine startup process is *** model consists of a mixed lubrication model of the crosshead slipper-guide and dynamic models of the piston assembly,crosshead assembly,connecting rod,and *** tribo-dynamic performances of the crosshead slipper during startup and under the rated conditions were simulated and *** results show that the tribo-dynamics of the crosshead slipper during the startup process are significantly different from those under the rated *** measures beneficial for the low friction of a crosshead slipper-guide under the rated conditions may significantly increase the friction loss of the crosshead slipper-guide system during the startup process.

关键词： low-speed marine diesel engine crosshead slipper engine start-up mixed lubrication friction loss tribo-dynamic model

嘉陵江流域旱涝急转演变规律及其对径流影响研究

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人民长江 2024年第9期55卷 128-140页

作者：李文晖曹辉任玉峰刘新波马一鸣李文达中国长江电力股份有限公司智慧长江与水电科学湖北省重点实验室湖北宜昌443000 中国长江电力股份有限公司三峡水利枢纽梯级调度通信中心湖北宜昌443000

针对气象旱涝转换对流域径流影响的问题,基于嘉陵江流域逐日降水量和流量数据,采用长、短周期旱涝急转指数方法,揭示了旱涝急转时空分布特征与演变规律,定量评估了径流变化对不同旱涝急转类型的响应程度。结果表明:1977~2022年,嘉陵江... 详细信息

针对气象旱涝转换对流域径流影响的问题,基于嘉陵江流域逐日降水量和流量数据,采用长、短周期旱涝急转指数方法,揭示了旱涝急转时空分布特征与演变规律,定量评估了径流变化对不同旱涝急转类型的响应程度。结果表明:1977~2022年,嘉陵江流域共发生了8次汛期旱涝急转事件,其中6次发生在2004年及之后;空间上,南部、中部以及西北部地区发生旱涝急转的频率较大,在17%以上;在月尺度上,6~7月发生旱涝急转的频率最大,超过了20%。当汛期发生涝转旱时,北碚、罗渡溪、武胜以及小河坝等站的前半汛期流量相比常年平均增长了57.52%,38.74%,85.50%和99.73%,后半汛期流量相对常年平均偏低了20.82%,49.83%,22.64%和14.53%;而在旱转涝影响下,上述站点前半汛期流量较常年平均减少了31.17%,45.77%,28.83%和26.16%,后半汛期流量较常年分别增长了31.45%,47.17%,24.31%和3.27%;月尺度上也表现出相似规律,表明旱涝急转对嘉陵江径流有着显著影响。研究成果可为梯级水库科学调度、流域水安全保障提供参考。

关键词：旱涝急转径流变化时空分布嘉陵江流域

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Terminal sulfur atoms formation via defect engineering strategy to promote the conversion of lithium polysulfides

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Journal of Materials Science & Technology 2022年第8期103卷 221-231页

作者： Yuanchang li wenda li Xiujuan Yan Zhenfang Zhou Xiaosong Guo Jing liu Changming Mao Zhonghua Zhang Guicun li College of Materials Science and Engineering Qingdao University of Science and TechnologyQingdao 266042China

The defect engineering shows great potential in boosting the conversion of lithium polysulfides intermediates for high energy density lithium-sulfur batteries(LSBs),yet the catalytic mechanisms remain ***,the oxygen-defective li_(4)Ti_(5)O_(12)-xhollow microspheres uniformly encapsulated by N-doped carbon layer(OD-LTO@NC)is delicately designed as an intrinsically polar inorganic sulfur host for the research on the catalytic *** simulations have demonstrated that the existence of oxygen deficiencies enhances the adsorption capability of spinel li_(4)Ti_(5)O_(12)towards soluble lithium ***-S-S-bonds of the li2S6on the defective li_(4)Ti_(5)O_(12)surface are fractured by the strong adsorption force,which allows the inert bridging sulfur atoms to be converted into the susceptible terminal sulfur atoms,and reduces the activation energy of the polysulfide conversion in some *** addition,with the N-doped carbon layer,secondary hollow microspheres architecture built with primary ultrathin nanosheets provide a large amount of void space and active sites for sulfur storage,adsorption and *** as-designed sulfur host exhibits a remarkable rate capability of 547 m Ah g^(-1)at 4C(1 C=1675 m A g^(-1))and an outstanding long-term cyclability(519 m Ah g^(-1)after 1000 cycles at 3 C).Besides,a high specific capacity of 832 m Ah g^(-1)is delivered even after 100 cycles under a high sulfur mass loading of 3.2 mg cm^(-2),indicating its superior electrochemical *** work not only provides a strong proof for the application of oxygen defect in the adsorption and catalytic conversion of lithium polysulfides,but offers a promising avenue to achieve high performance LSBs with the material design concept of incorporating oxygen-deficient spinel structure with hierarchical hollow frameworks.

关键词： lithium-sulfur batteries Oxygen deficiency lithium titanate Hierarchical hollow microsphere Conversion kinetics

Carbon confinement synthesis of interlayer-expanded and sulfur-enriched MoS2+x nanocoating on hollow carbon spheres for advanced li-S batteries

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Nano Research 2019年第11期12卷 2908-2917页

作者： wenda li Dezhu Wang Zihao Song Zhijiang Gong Xiaosong Guo Jing liu Zhonghua Zhang Guicun li College of Materials Science and Engineering Qingdao University of Science and TechnologyQingdao266042China

High energy density and low-cost lithium-sulfur batteries have been considered as one of the most promising candidates for next-generation energy storage ***,the intrinsic problems of the sulfur cathode severely restrict their further practical ***,a unique double-shell architecture composed of hollow carbon spheres@interlayer-expanded and sulfur-enriched MoS2+x nanocoating composite has been developed as an efficient sulfur host.A uniform precursor coating derived from heteropolyanions-induced polymerization of pyrrole leads to space confinement effect during the in-situ sulfurization process,which generates the interlayer-expanded and sulfur-enriched MoS2+x nanosheets on amorphous carbon hollow *** new sulfur host possesses multifarious merits including sufficient voids for loading sulfur active materials,high electronic conductivity,and fast lithium-ion diffusive *** addition,additional active edge sites of MoS2+x accompanied by the nitrogen-doped carbon species endow the sulfur host with immobilizing and catalyzing effects on the soluble polysulfide species,dramatically accelerating their conversion kinetics and *** detailed defect-induced interface catalytic reaction mechanism is firstly *** expected,the delicately-designed sulfur host exhibits an outstanding initial discharge capacity of 1,249 mAh·g^−1 at 0.2 C and a desirable rate performance(593 mAh·g^−1 at 5.0 C),implying its great prospects in achieving superior electrochemical performances for advanced lithium sulfur batteries.

关键词： few-layered M0S2+X double-shell architecture sulfur enriched MoS2+x nanocoating lithium-sulfur batteries

Forecast of Flood in Chaohu Lake Basin of China Based on Grey-Markov Theory

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Chinese Geographical Science 2007年第1期17卷 64-68页

作者： li Xiang WANG Xinyuan SHAO Wei XIA linyi ZHANG Guangsheng TIAN Bing li wenda PENG Peng National Resources and Tourism College Anhui Normal University Wuhu 241000 China Department of Earth and Space Sciences University of Science and Technology of China Hefei 230026 China Institute of Hydroelectricity of Lu＇an Lu＇an 237000 China

Flood is one kind of unexpected and the most common natural disasters, which is affected by many factors and has complex mechanism. At home and abroad, there is still no mature theory and method used for the long-term forecast of natural precipitation at present. In the present paper the disadvantages of grey GM (1, 1) and Markov chain are ana- lyzed, and Grey-Markov forecast theory about flood is put forward and then the modifying model is developed by making prediction of Chaohu Lake basin. Hydrological law was conducted based on the theoretical forecasts by grey system GM (1, 1) forecast model with improved Markov chain. The above method contained Stat-analysis, embodying scientific approach, precise forecast and its reliable results.

关键词： Grey-Markov theory GM (1, 1) Markov chain flood forecast Chaohu Lake basin

芬顿-ABR厌氧-生物接触氧化法组合工艺处理化学合成制药废水的工程应用

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中国沼气 2024年第3期42卷 56-59页

作者：朱亚飞刘峻杨伟纳李文达郑州亿众环境科技有限公司河南郑州450006 江苏润环环境科技有限公司河南分公司河南郑州450006

化学合成制药废水具有有机物浓度高且成分复杂的特点,通过研究废水特征,探索一种高效稳定的处理工艺。以某工程为例,采用芬顿氧化-ABR厌氧-生物接触氧化法-混凝沉淀-活性炭过滤组合工艺,对工艺进行了详细介绍。化验结果显示,废水COD、BO... 详细信息

化学合成制药废水具有有机物浓度高且成分复杂的特点,通过研究废水特征,探索一种高效稳定的处理工艺。以某工程为例,采用芬顿氧化-ABR厌氧-生物接触氧化法-混凝沉淀-活性炭过滤组合工艺,对工艺进行了详细介绍。化验结果显示,废水COD、BOD_(5)、SS、NH_(3)-N的质量浓度分别为5200~5400 mg·L^(-1)、1100~1250 mg·L^(-1)、180~200 mg·L^(-1)、50~60 mg·L^(-1)、色度为80~100度。经105 d系统调试,不断优化运行控制参数,出水COD、BOD_(5)、SS、NH_(3)-N的质量浓度分别达到180 mg·L^(-1)、30 mg·L^(-1)、10 mg·L^(-1)、20 mg·L^(-1)以下,色度达到10度以下,主要污染物指标可达到《化学合成类制药工业水污染物间接排放标准》(DB41/756—2012)中的B级标准。针对此类化学合成制药废水,采用芬顿-ABR厌氧-生物接触氧化法组合工艺,技术可行,具有良好的环境效益。

关键词：芬顿氧化 ABR厌氧生物接触氧化法化学合成制药废水

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风险管控思路的土壤重金属污染及防治策略

环境保护科学 2024年第4期50卷 169-174页

作者：李文达翟文静朱亚飞杨伟纳江苏润环环境科技有限公司河南分公司郑州450000 河南工学院新乡453000 郑州亿众环境科技有限公司郑州450000

以河南省郑州市某矿区周边农田为例,基于风险管控思路,对土壤重金属污染进行了研究。结果表明;5种重金属Zn、Cr、Pb、Cu、Cd在各土层的质量分数顺序均为Zn>Cr>Pb>Cu>Cd,其质量分数随土层深度增加而减小;在0~15 cm土层中,Cu、Cr、Zn、Pb... 详细信息

以河南省郑州市某矿区周边农田为例,基于风险管控思路,对土壤重金属污染进行了研究。结果表明;5种重金属Zn、Cr、Pb、Cu、Cd在各土层的质量分数顺序均为Zn>Cr>Pb>Cu>Cd,其质量分数随土层深度增加而减小;在0~15 cm土层中,Cu、Cr、Zn、Pb质量分数明显高于下层土壤,其来源可能主要为工厂排放烟尘、大气降尘、汽车尾气等,其中Cu、Cd、Pb平均质量分数分别高于研究区背景值20.30%、93.10%、57.47%;重金属向下层迁移作用不显著,主要在表层富集,且从土壤进入食物链风险加大;土壤重金属间均显著正相关,Zn、Cu相关性最高,Cr、Cd、Pb间相关性较弱。Cd变异性在第一主成分中较大,高值区主要分布于水泥厂附近,确定“三废”、农田施肥、交通运输等人为活动为第一主成分。提出针对优先保护类和安全利用类等土壤重金属污染的防治对策。

关键词：风险管控重金属污染防治策略土壤