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Using radium isotopes to quantify submarine groundwater discharge at different scales in the Huanghe River Estuary,China
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作者 Haowei Xu Disong Yang +6 位作者 Xiaoyi Guo Maosheng Gao Guangquan chen Diansheng Ji shengtao chen Huaming Yu Bochao Xu 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2023年第8期32-39,共8页
As an important land-ocean interaction process,submarine groundwater discharge(SGD)is composed of multiple dynamical processes at different scales and plays an important role in the study of coastal ocean geochemical ... As an important land-ocean interaction process,submarine groundwater discharge(SGD)is composed of multiple dynamical processes at different scales and plays an important role in the study of coastal ocean geochemical budgets.However,most of the existing studies focus on the quantification of the total groundwater discharge,few studies are about the differentiation and quantification of groundwater discharge processes at different scales(i.e.,short-scale SGD and long-scale SGD).As a world-class river,the Huanghe River is highly turbid and heavily regulated by humans.These natural and anthropogenic factors have a significant impact on groundwater discharge processes in the Huanghe River Estuary(HRE).In this study,the distribution patterns of the natural geochemical tracer radium isotopes(^(224)Ra and^(223)Ra)and other hydrological parameters in the HRE were investigated during four cruises.By solving the mass balance of^(224)Ra and^(223)Ra in the HRE,the long-scale SGD flux was quantified as 0.01−0.19 m/d,and the short-scale SGD flux was 0.03−0.04 m/d.The rate of short-scale SGD remained essentially constant among seasons,while the rate of long-scale SGD varied considerably at different periods and showed a synchronous trend with the variation of river discharge.The results of this study are significant for understanding the SGD dynamics in the HRE and the contribution of SGD to the ocean geochemical budgets. 展开更多
关键词 radium isotopes submarine groundwater discharge Huanghe River Estuary
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ILIDViz:An incremental learning-based visual analysis system for network anomaly detection
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作者 Xuefei TIAN Zhiyuan WU +2 位作者 Junxiang CAO shengtao chen Xiaoju DONG 《Virtual Reality & Intelligent Hardware》 EI 2023年第6期471-489,共19页
Background With the development of information technology,there is a significant increase in the number of network traffic logs mixed with various types of cyberattacks.Traditional intrusion detection systems(IDSs)are... Background With the development of information technology,there is a significant increase in the number of network traffic logs mixed with various types of cyberattacks.Traditional intrusion detection systems(IDSs)are limited in detecting new inconstant patterns and identifying malicious traffic traces in real time.Therefore,there is an urgent need to implement more effective intrusion detection technologies to protect computer security.Methods In this study,we designed a hybrid IDS by combining our incremental learning model(KANSOINN)and active learning to learn new log patterns and detect various network anomalies in real time.Conclusions Experimental results on the NSLKDD dataset showed that KAN-SOINN can be continuously improved and effectively detect malicious logs.Meanwhile,comparative experiments proved that using a hybrid query strategy in active learning can improve the model learning efficiency. 展开更多
关键词 Intrusion detection Machine learning Incremental learning Active learning Visual analysis
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Demonstration of Orbital-Angular-Momentum-Based Optical Switching Using Dual-Area Mirrors
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作者 shengtao chen Xizheng Ke 《Optics and Photonics Journal》 2021年第8期351-359,共9页
We have designed an optical separation device called dual-area mirror for the data link of orbital angular momentum (OAM) multiplexing. Experiments show that the OAM multiplexed beams can be switched by using dual-are... We have designed an optical separation device called dual-area mirror for the data link of orbital angular momentum (OAM) multiplexing. Experiments show that the OAM multiplexed beams can be switched by using dual-area mirrors, using OOK to modulate four channels separately to form two inputs, channel A and channel B. There are two OAM beams that are multiplexed in each of channel A and channel B, using a spatial light modulator (SLM) to convert the OAM multiplexed beams in each channel. One of the beams is converted into a Gaussian beam, and then separated by a dual-area mirror, so as to realize the switch of a beam carrying different data in the two channels. Then these channels are detected. The waveform indicates that the switch is successful, and the measured optical power indicates that the dual-area mirror can reduce the bit error rate in the communication links. In addition, the device reduces the experimental cost, is easy to implement, is easy to integrate, and increases the angle between the separated beams. 展开更多
关键词 Optical Communication Dual-Area Mirror SWITCHING Optical Network
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用于光催化能量转换的Z-型异质结的研究进展 被引量:6
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作者 刘东 陈圣韬 +1 位作者 李仁杰 彭天右 《物理化学学报》 SCIE CAS CSCD 北大核心 2021年第6期45-75,共31页
受植物光合作用的启发,研究者发展了多种模拟光合作用体系用于光分解水、二氧化碳光还原和氮光固定以生产"太阳燃料"(如氢气、甲烷和氨气),以期缓解当前的能源短缺和环境污染。尽管基于人造半导体材料的光合作用是一种潜在、... 受植物光合作用的启发,研究者发展了多种模拟光合作用体系用于光分解水、二氧化碳光还原和氮光固定以生产"太阳燃料"(如氢气、甲烷和氨气),以期缓解当前的能源短缺和环境污染。尽管基于人造半导体材料的光合作用是一种潜在、理想的以"太阳燃料"的化学键形式存储太阳能的方法,但是构筑能够在规模和成本方面与化石燃料竞争的生产"太阳燃料"的人工光合作用体系仍然存在巨大的挑战。因此,开发低成本的高效光催化剂对于促进人工光合作用的三种主要光催化过程(光俘获、电荷产生与分离,以及表面/界面催化反应)具有重要的意义。在已研究的各类光催化剂中,Z-型异质结复合体系不仅可以提高光俘获能力和显著抑制电荷载流子复合,而且还可通过保持光激发电子/空穴的强还原/氧化能力来促进表面/界面催化反应,因而受到广泛关注。将太阳能转化为化学能的Z-型纳米异质结的研究证明这些异质结在提高生产"太阳燃料"的光催化反应体系的整体效率方面的重要性。该综述主要介绍了Z-型异质结的发展历史和直接Z-型异质结相较于传统II型异质结、液相Z-型和全固态Z-型异质结的优势,并阐述了两步激发Z-型光催化体系的反应机理和途径。然后,从材料组成角度重点介绍了近5年来不同类型Z-型纳米结构材料(无机,有机和无机-有机复合材料)在光催化能源转换领域的应用,以及提高Z-型纳米结构材料光催化性能的各种调控/工程策略(如扩展光谱吸收区、促进电荷转移/分离和表面化学改性等)。此外,还讨论了Z-型光催化机理的表征方法与策略(如金属负载法、牺牲试剂测试法、自由基捕集实验、原位X-射线光电子能谱、光催化还原实验、Kelvin探针力显微镜、表面光电压光谱、瞬态吸收光谱及理论计算等)及光催化性能的评价方法和标准。最后,介绍了Z-型异质结光催化体系目前面临的挑战和发展方向。我们希望该综述能为光催化体系的性能突破方向提供新的认识,并为新型Z-型光催化材料的设计和构筑提供指导。 展开更多
关键词 半导体 光催化 Z-型异质结 能源转化 反应机理
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