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Observation of Dirac nodal line states in topological semimetal candidate PrSbTe

Physical Review B 2024年第4期109卷 045113-045113页

作者： Dengpeng Yuan Dajian Huang Xin Ma Xu Chen Huifen Ren Yun Zhang Wei Feng Xiegang Zhu Bo Wang xuwen he Jian Wu Shiyong Tan Qunqing Hao Qiang Zhang Yi Liu Qin Liu Zhengtai Liu Chao Cao Qiuyun Chen Xinchun Lai Science and Technology on Surface Physics and Chemistry Laboratory Mianyang 621907 China Center for Correlated Matter and School of Physics Zhejiang University Hangzhou 310058 China Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing 100190 China Shanghai Synchrotron Radiation Facility Shanghai Advanced Research Institute Chinese Academy of Sciences Shanghai 201210 China

The interplay among topology, crystal symmetry, magnetic order, and strong electron correlation can give rise to a plethora of exotic physical phenomena. The ZrSiS family is known as typical topological Dirac semimetals, among them LnSbTe (Ln denotes lanthanide) compounds exhibit intriguing characteristics due to the presence of Ln 4f electrons, resulting in quantum states and unique properties. In this paper, the topological electronic structure of PrSbTe is systematically studied by angle-resolved photoemission spectroscopy (ARPES), combined with magnetic, specific heat measurements, and band structure calculations. The detailed three-dimensional electronic structure of PrSbTe has been obtained, and a diamond-shaped Fermi surface and multiple Dirac nodal lines have been observed, which are in remarkable agreement with theoretical calculations. Moreover, the 4f electrons in PrSbTe are rather localized, which can be revealed by on-resonant ARPES data and further confirmed by the rather small Sommerfeld coefficient of γ=2.6231mJ/molK2. Our results provide more detailed information about the LnSbTe family, which gives a deeper understanding of the interaction between Ln 4f electrons and the topological states.

关键词： Electronic structure Fermi surface Topological materials Dirac semimetal Node-line semimetals Angle-resolved photoemission spectroscopy Magnetic techniques Specific heat measurements

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Magnetic Flocculation Treatment of Coal Mine Water and a Comparison of Water Quality Prediction Algorithms

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MINE WATER AND The ENVIRONMENT 2019年第2期38卷 391-401页

作者： Zhang, Xiaohang he, xuwen Wei, Ming Li, Fuqin Hou, Pin Zhang, Chunhui China Univ Min & Technol Beijing Sch Chem & Environm Engn Xueyuan Rd Beijing 100083 Peoples R China Hebei Vocat Coll Polit & Law Party Comm 569 North Friendship St Shijiazhuang 050061 Hebei Peoples R China Hebei Univ Engn 199 Guangming Nan Str Handan City 056038 Hebei Peoples R China

In this study, laboratory-scale magnetic flocculation systems were set up and the optimal coagulant and flocculent dosage, magnetic seed immersion, pH, stirring intensity, and precipitation time were all evaluated. A total of 729 expansion reaction conditions were generated, and 700 of the expansion reaction conditions were used to train a back-propagation neural network (BPNN) and general regression neural network (GRNN). The other 29 conditions were used to verify the networks' regression ability. The optimum coagulant was poly-aluminum chloride at a dosage of 100mg/L;the optimum flocculent was anionic polyacrylamide at a dosage of 4mg/L;the optimum size of the magnetic seed was 200 mesh at a dosage of 1g/L;and the optimum stirring intensities were 300 r/min for the coagulation tank, 200 r/min for the mixing tank, and 100 r/min for the flocculation tank. Comparing BPNN and GRNN, the GRNN's regression performance better matched the relationship between the reaction conditions and results. ZusammenfassungIn dieser Studie wurden magnetische Flockungssysteme im Laborma ss stab eingerichtet. Als Prufbedingungen wurden die Dosierung des Fallungs-mittels, des Flockungsmittels, der pH-Wert der Losung mit den magnetischen Tragerpartikeln, die Ruhrintensitat und die Fallungszeit ausgewahlt. Basierend auf einzelnen Werten dieser Prufbedingungen wurden insgesamt 729 Versuchsbedingungen erzeugt. Fur das Training der Neuronalen Netze (Fehlerfortpflanzungsnetzwerk - BPNN und Regressionsnot signnetzwerk - GRNN) wurden 700 Versuchsbedingungen verwendet. Die ubrigen 29 Versuchsbedingungen wurden zur uberprufung der Eignung der neuronalen Netze genutzt. Folgende optimale Werte der Prufparameter wurden ermittelt: Polyaluminiumchlorid (PAC) als Fallungsmittel mit einer Dosierung von 100 mg/L;anionische Polyacrylamide (PAM) als Flockungsmittel mit einer Dosierung von 4 mg/L;eine Gitterweite von 200 Maschen fur die magnetischen Tragerpartikel und einer Dosierung von 1 g/L sowie eine Ruh

关键词： Magnetic seed Back-propagation neural network General Regression Neural Network Regression ability

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Investigation of fluoride and turbidity removal from coal mine water by combined micro-flocculation and membrane filtration: Lab to pilot scale

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Journal of Environmental Sciences 2025年

作者： Liping Zhang Weiwei Wang Yiyun An Huaran Sun Eryong Wu xuwen he Siwei Peng Cun Zhang School of Chemical and Environmental Engineering China University of Mining and Technology-Beijing Beijing 100083 China Datang Environmental Industry Group Co. Ltd Beijing 100097 China School of Mines Key Laboratory of Deep Coal Resource Ministry of Education of China China University of Mining & Technology Xuzhou Jiangsu 221116 China

The concentration of turbidity and fluoride in mine drainage exceeding the discharge standard, which impede coal mine water broader application. In this study, micro-flocculation, which was based on the fluoride removal agent (CFYJ-L) developed by our research group, was combined with direct filtration membrane (MFDMF) to remove the high concentrations of turbidity and fluoride. Firstly, we investigated the impacts of factors on fluoride, turbidity removal by the CFYJ-L, explored the mechanisms of fluoride removal and screened cleaning agents for membrane fouling. Findings indicate that the optimal process parameters were a dosage of 1.16 g/L, pH 6.11, stirring time 10.90 min, which would let F − concentration from 20 to 0.453 mg/L. Suspended solids (SS), Cl − , SO 4 2− and CO 3 2- all seems not reduced fluoride removal efficiency. The fluoride removal mechanism is primarily through electrostatic adsorption, ion exchange, complexation and hydrogen bonding, resulting in the formation of precipitates that remove fluoride. Meanwhile, the optimal process parameters for treating simulated fluorinated coal mine water with MFDMF process was an operating pressure of 0.2 MPa. Membrane fouling was mainly characterized by cake filtration, accompanied by pore clogging. The best cleaning agent for membrane fouling was 0.2 % HCl, which can increase the membrane flux recovery rate from 70 % to 91 %. A 90-day pilot site continuous operation demonstrated the stability of the MFDMF process, with a treatment cost was reduced from over 3.36 RMB/m 3 to 2.60 RMB/m 3 and land area reduction exceeding 40 % compared to existing process.

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基于横波检测柱状材料内部缺陷的数值模拟研究

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应用激光 2022年第5期42卷 109-119页

作者：崔缙郭华玲郑宾刘辉张钰龙邓祎昕贺旭文中北大学电气与控制工程学院山西太原030051

小口径金属圆柱体的缺陷检测是无损检测领域的一个难题。通过有限元方法对金属圆柱中横波传播特性以及与缺陷作用机理进行数值模拟。探究了横波的方向性变化、圆孔缺陷半径对横波传播影响、不同位置和不同长度的缺陷对横波传播的影响。... 详细信息

小口径金属圆柱体的缺陷检测是无损检测领域的一个难题。通过有限元方法对金属圆柱中横波传播特性以及与缺陷作用机理进行数值模拟。探究了横波的方向性变化、圆孔缺陷半径对横波传播影响、不同位置和不同长度的缺陷对横波传播的影响。研究表明横波在传播过程中主要能量范围由15°~36°变为20°~35°,提出了近似正三角形的传播路径并进行验证,发现横波到达表面后发生模态转换,一部分声波以略面纵波的速度沿表面传播;对于圆孔缺陷,圆孔半径在3.4~4.6mm范围内可通过幅值变化判断孔径信息,半径在4.6~5.8mm范围内可通过接收时间判断孔径信息;对于不同位置的矩形缺陷,当缺陷进入到横波主要能量范围内,C扫图中出现近似线性的高能量区域,探测角度随着缺陷位置增加而增大,此范围内的缺陷可通过反射信号的探测角度判断位置信息;对于不同长度的矩形缺陷,随着缺陷长度增加,透射波能量减弱并且探测角度减小,呈现出近似线性的能量分布,通过探测透射波到达外表面的角度可判断缺陷长度信息。提出了相应的传播路径和长度计算公式,计算结果得到的误差百分比控制在6.5%以内,验证了该缺陷长度检测方法的有效性。

关键词：横波柱状材料激光超声内部缺陷数值模拟

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Synthesis of Composite Carbon-Based Nano-Zero-Valent Iron Micro-Electrolytic Material and Removal of Dichloromethanesulfonic Acid in Drinking Water

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NANO 2019年第5期14卷

作者： Liu, Kai Shangguan, Zhonghua Zhang, Xiaohang Shi, Yali Wang, Hao Yang, Shipeng he, xuwen China Univ Min & Technol Sch Chem & Environm Engn 11 Xueyuan Rd Beijing 100083 Peoples R China Xian Zhongdi Environm Technol Co Ltd Xian Geol Survey Ctr China Geol Survey Youyi East Rd Xian 710054 Shanxi Peoples R China Chinese Acad Sci Res Ctr Ecoenvironm Sci 18 Shuangqing Rd Beijing 100085 Peoples R China Tsinghua Univ Sch Environm 30 Shuangqing Rd Beijing 100084 Peoples R China

Composite carbon-based nano-zero-valent iron materials not only have excellent characteristics of nano materials, but also solve the difficulty of recycling nano materials after use, and overcome the shortcomings of the nano materials. The introduction of copper increases the redox reaction activity of the micro-electrolytic material and expands the applicable pH range of the reaction environment. In the range of pH = 3-9, the removal efficiency of dichloromethanesulfonic acid (Cl-2-MSA) was maintained at 95.5-99.7% after 30 min. Continuous dynamic simulation experiments verified that the composite carbon-based nano zero-valent iron material has a stable removal effect on the target pollutants.

关键词： Nano-zero-valent iron micro-electrolytic dichloromethanesulfonic acid

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Spectroscopic study on transformations of dissolved organic matter in coal-to-liquids wastewater under integrated chemical oxidation and biological treatment process

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Journal of Environmental Sciences 2018年第8期30卷 206-216页

作者： Siwei Peng xuwen he Hongwei Pan Department of Chemical and Environmental Engineering China University of Mining and Technology(Beijing)Beijing 100083China School of Water Conservancy North China University of Water Resources and Electric PowerZhengzhou 450045China

A large amount of wastewater containing various toxic organic contaminants is produced during coal-to-liquids process. In this study, several spectroscopic methods were used to monitor the transformation of organic pollutants during an integrated chemical oxidation and biological process. The results showed that the hydrophobic acid fraction increased after Fenton oxidation, which was likely due to the production of small-molecule organic acids. Soluble microbial products were generated during biological treatment processes,which were degraded after ozonation; meanwhile, the hydrophilic base and acid components increased. Ultraviolet-visible spectroscopic analysis indicated that peaks at the absorption wavelengths of 280 and 254 nm, which are associated with aromatic substances, were detected in the raw water. The aromatic substances were gradually removed, becoming undetectable after biological aeration filter（BAF） treatment. Fourier transform infrared spectroscopy analysis revealed that the functional groups of phenols;benzene, toluene, ethylbenzene, and xylene（BTEX）; aromatic hydrocarbons; aliphatic acids;aldehydes; and esters were present in raw wastewater. The organic substances were oxidized into small molecules after Fenton treatment. Aromatic hydrocarbons were effectively removed through bioadsorption and biodegradation after BAF *** organic matter was reduced and finally became undetectable after anoxic–oxic treatment in combination with a membrane bioreactor. Four fluorescent components were fractionated and obtained via excitation–emission matrix parallel factor analysis（EEM-PARAFAC）. Dissolved organic matter fractionation in conjunction with EEM-PARAFAC was able to monitor more precisely the evolution of characteristic organic contaminants.

关键词： Coal-to-liquids wastewater Spectroscopic analysis Dissolved organic matter fractionation UV–visible spectrum Excitation–emission matrix parallel factor analysis （EEM-PARAFAC）

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heterogeneous temporal graph powered DRL algorithm for channel allocation in Maritime IoT Systems

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COMPUTER COMMUNICATIONS 2024年 213卷 260-270页

作者： Li, Zongwang Xie, Zhuochen he, Xiaohe Liang, xuwen Chinese Acad Sci Innovat Acad Microsatellites 1 Xueyang Rd Shanghai 201304 Peoples R China Univ Chinese Acad Sci 1 Yanqihu East Rd Beijing 101408 Peoples R China

In actual maritime Internet of Things systems, the communication environment is characterized by its time-varying nature and the presence of highly heterogeneous network structures. Those attributes present considerable challenges in devising resource allocation strategies. Given the limited availability of frequency resources, designing a reasonable and flexible channel allocation strategy (CAS) is the primary task for meeting diverse and dynamic communication demands. In this paper, a heterogeneous temporal graph powered deep reinforcement learning algorithm is proposed to optimize the CAS to maximize the channel efficiency in a real-world maritime Internet of Things system. Specifically, we build relation-based heterogeneous edges to connect different types of terminal nodes and adopt a time encoding technology to capture the dynamic evolution of communication scenarios over time. The memory and public mailbox modules are constructed as the implementation entities of the information aggregation method based on the attention mechanism. In addition, we develop a corresponding heterogeneous temporal neural network to estimate the real-time resource requirements of target terminals, and subsequently learn the optimal CAS based on the deep reinforcement learning algorithm from the perspective of maximizing the cumulative channel efficiency. Simulation results prove that the proposed algorithm significantly outperforms the other state-of-the-art algorithms in terms of the channel efficiency and generalization ability.

关键词： Maritime IoT heterogeneous temporal graph Deep reinforcement learning

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矿井水直接超滤试验研究

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工业用水与废水 2024年第1期55卷 49-53,75页

作者：李福勤梁桢王瑾王世奕何绪文代其彬田莉河北工程大学能源与环境工程学院河北邯郸056038 河北省水污染控制与水生态修复技术创新中心河北邯郸056038 污水处理及资源化利用河北省工程研究中心河北邯郸056038 中国矿业大学(北京)化学与环境工程学院北京100083 冀中能源峰峰集团有限责任公司河北邯郸056001

为了解决矿井水处理现有工艺流程长、出水水质不稳定等问题,优化矿井水处理工艺,以河北某矿井水为研究对象,采用直接超滤短流程工艺进行试验研究,探究反洗时长、反洗周期、工作压力等工艺参数对超滤的影响,并筛选膜污染清洗药剂。结果表... 详细信息

为了解决矿井水处理现有工艺流程长、出水水质不稳定等问题,优化矿井水处理工艺,以河北某矿井水为研究对象,采用直接超滤短流程工艺进行试验研究,探究反洗时长、反洗周期、工作压力等工艺参数对超滤的影响,并筛选膜污染清洗药剂。结果表明:最佳工艺参数为反洗时长120 s,反洗周期60 min,跨膜压差0.25 MPa,在此条件下经过300 min试验测试,膜通量为136 L/(m^(2)·h),维持在初始膜通量的91%,出水浊度稳定在0.05 NTU以下;膜污染最佳清洗药剂为0.2%HCl,对污染前后及酸洗碱洗后的膜片进行SEM和EDS测试分析,结果表明造成酸洗碱洗效果差异的主要因素为矿井水中的硬度离子和铝离子。

关键词：直接超滤矿井水悬浮物膜比通量膜污染

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Molecular Dynamics Simulation of the Interaction between Common Metal Ions and Humic Acids

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WATER 2020年第11期12卷 3200-3200页

作者： Wu, Xu Xia, Yu Yuan, Lianhua Xia, Kaiyu Jiang, Yu Li, Na he, xuwen China Univ Min & Technol Beijing Sch Chem & Environm Engn Beijing 100083 Peoples R China

Humic acids (HAs) have important environmental and geochemical effects on soil, water environments and sediment. HAs strongly complex some metal ions, which affects the migration of metal ions and the colloidal aggregation of HA. here, the complexation of Ca2+ and Mg2+ with HA in aqueous solution under neutral conditions has been systematically studied by molecular dynamics (MD) simulation. The results show that the aggregation of HA is caused by the complexation of HA and metal ions, mainly due to the intermolecular bridging between Ca2+, Mg2+ and COO- groups. Monodentate and bidentate coordinations have been found between Ca2+ and COO- groups of different HA molecules in the same simulation system. Mg2+ only has a monodentate coordination with COO- group.

关键词： humic acids metal ions aggregation molecular dynamics simulation

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Comparing Electrochemical Passivation and Surface Film Chemistry of 654SMO Stainless Steel and C276 Alloy in Simulated Flue Gas Desulfurization Condensates

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MATERIALS 2024年第8期17卷 1827页

作者： Liao, Luhai Cheng, Yifan Zhang, he Yuan, xuwen Li, Fengguang Wuhan Univ Sci & Technol Key Lab Ferrous Met & Resources Utilizat Minist Educ Wuhan 430081 Peoples R China Wuhan Univ Sci & Technol Hubei Prov Key Lab New Proc Ironmaking & Steel Mak Wuhan 430081 Peoples R China Hubei Univ Automot Technol Sch Mat Sci & Engn Shiyan 442002 Peoples R China

This research examines the behavior of electrochemical passivation and the chemistry of surface films on 654SMO super austenitic stainless steel and C276 nickel-based alloy in simulated condensates from flue gas desulfurization in power plant chimneys. The findings indicate that the resistance to polarization of the protective film on both materials initially rises and then falls with either time spent in the solution or the potential of anodic polarization. Comparatively, 654SMO exhibits greater polarization resistance than C276, indicating its potential suitability as a chimney lining material. Mott-Schottky analysis demonstrates that the density of donors in the passive film formed on 654SMO exceeds that on C276, potentially due to the abundance of Fe oxide in the passive film, which exhibits the characteristics of an n-type semiconductor. The primary components of the passive films on both materials are Fe oxides and Cr oxides. The formation of a thin passive film on C276 in the simulated condensates is a result of the low Gibbs free energy of nickel oxide and low Cr content. The slower diffusion coefficient of point defects leads to the development of a thicker and more compact passive film on the surface of 654SMO.

关键词： super austenitic stainless steel nickel-based alloy electrochemical passivation behavior flue gas desulfurization passive film

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