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co.position characterization and transformation mechanism of dissolved organic phosphorus in wastewater treatment using 31P NMR spectrosco.y

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Frontiers of Environmental Science & Engineering 2024年第3期18卷 103-113页

作者： Yuting Zhang Wei Shang SoonThiam Khu Xingcan Zheng Yongli Sun Pengfeng Li Miao Gu Wen-an Zhang Huanmei Ma National Engineering Research Center For Urban water&Wastewater North China Municipal Engineering Design&Research Institute Co.Ltd.Tianjin 300381China School of Environment Science&Engineering Tianjin UniversityTianjin 300350China

The migration and transformation of phosphorus co.ponents in wastewater treatment plants(WWTPs)play a crucial role in the co.vergence and circulation of ***,the co.position and variation of dissolved organic phosphorus(DOP)in WWTPs were unclear because of its co.plex nature,hindering its efficient *** this study,the DOP species and their transformation during the treatment process in WWTP were co.prehensively ***,two enrichment methods were assessed for their effectiveness at facilitating wastewater analysis:lyophilization and aluminum salt *** salt precipitation was found to be better because its application allowed 31P nuclear magnetic resonance(31P NMR)spectrosco.y to identify more species in the seco.dary effluent:orthophosphate(Ortho-P)(81.1%–89.3%of the dissolved total phosphorus),pyrophosphates(Pyro-P)(0%–2.3%),orthophosphate monoesters(Mono-P)(7.0%–10.77%),orthophosphate diesters(Di-P)(1.0%–2.96%),and phosphonate(Phos-P)(1.7%–5.16%).Furthermore,the variation and transformation mechanism of phosphorus,particularly those of DOP,during the entire sewage-treatment process were *** the treatment steps,biological treatment co.bined tertiary treatment achieved better DOP removal ***,biological treatment mainly removed Mono-P and Di-P with removal efficiencies of 33.3%and 41.7%co.pared with the effluent of the grit ***-P has higher bioavailability and is more easily co.verted and utilized by microorganisms than ***,Phos-P,with low bioavailability,was hardly utilized by microorganisms,which showed only 18.4%removal efficiency in biological *** tertiary treatment,co.gulation process exhibited higher removal ability of Ortho-P(69.1%)and partial removal efficiencies of DOP,resulting in an increase in the DOP proportion in *** addition,Phos-P co.ld not be effectively removed through the biological treatment and was only partially reduced via the adsorption pro

关键词： Municipal wastewater Dissolved organic phosphorus co.position Transformation 31P nuclear magnetic resonance

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Detection of Nonlinear Behavior Induced by Hard Limiting in Voltage Source co.verters in Wind Farms Based on Higher-order Spectral Analysis

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Journal of Modern power Systems and Clean Energy 2024年第2期12卷 630-645页

作者： Zetian Zheng Shaowei Huang Qiangsheng Bu Chen Shen Jun Yan State Key Laboratory of power Systems Department of Electrical EngineeringTsinghua UniversityBeijing 100084China State Grid Jiangsu Electric power co. Ltd.Research InstituteNanjingChina

In recent years, sub-synchronous oscillation accidents caused by wind power integration have received extensive attention. The reco.ded co.stant-amplitude waveforms can be induced by either linear or nonlinear oscillation mechanisms. Hence, the nonlinear behavior needs to be distinguished prior to choosing the analysis method. Since the 1960s, the higher-order statistics(HOS) theory has beco.e a powerful tool for the detection of nonlinear behavior(DNB) in production quality co.trol wherein it has mainly been applied to mechanical co.dition monitoring and fault diagnosis. This study focuses on the hard limiters of the voltage source co.verter(VSC) co.trol systems in the wind farms and attempts to detect the nonlinear behavior caused by bi-or uni-lateral saturation hard limiting using the HOS analysis. First, the co.ventional describing function is extended to obtain the detailed frequency domain information on the bi-and uni-lateral saturation hard limiting. Furthermore, the bi-and tri-spectra are introduced as the HOS, which are extended into bi-and tri-co.erence spectra to eliminate the effects of the linear parts on the harmonic characteristics of hard limiting in the VSC co.trol system, respectively. The effectiveness of the HOS in the DNB and the classification of the hard-limiting types is proven, and its detailed derivation and estimation procedure is presented. Finally, the quadratic and cubic phase co.pling in the signals is illustrated, and the performance of the proposed method is evaluated and discussed.

关键词： Bi-co.erence spectrum detection of nonlinear behavior hard limiting higher-order statistics tri-co.erence spectrum voltage source co.verter wind farms.

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Carbon Emission Factors Prediction of power Grid by Using Graph Attention Network

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Energy Engineering 2024年第7期121卷 1945-1961页

作者： Xin Shen Jiahao Li YujunYin Jianlin Tang Weibin Lin Mi Zhou Measurement Center Yunnan Power Grid Co.Ltd.Kunming650000China Electric power Research institute China Southern Power Grid Co.Ltd.Guangzhou510530China Guangdong Provincial Key Laboratory of Intelligent Measurement and Advanced Metering of power Grid Guangzhou510530China

Advanced carbon emission factors of a power grid can provide users with effective carbon reduction advice,which is of immense importance in mobilizing the entire society to reduce carbon *** method of calculating node carbon emission factors based on the carbon emissions flow theory requires real-time parameters of a power ***,it cannot provide carbon factor information *** address this issue,a prediction model based on the graph attention network is *** model uses a graph structure that is suitable for the topology of the power grid and designs a supervised network using the loads of the grid nodes and the co.responding carbon factor *** network extracts features and transmits information more suitable for the power system and can flexibly adjust the equivalent topology,thereby increasing the diversity of the *** input and output data are simple,without the power grid *** demonstrated its effect by testing IEEE-39 bus and IEEE-118 bus systems with average error rates of 2.46%and 2.51%.

关键词： Predict carbon factors graph attention network prediction algorithm power grid operating parameters

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Two-Stage Optimal Scheduling of co.munity Integrated Energy System

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Energy Engineering 2024年第2期121卷 405-424页

作者： Ming Li Rifucairen Fu Tuerhong Yaxiaer Yunping Zheng Abiao Huang Ronghui Liu Shunfu Lin New power System Technology Research institute The Electric Power Research Institute of State Grid Xinjiang Electric Power Co.Ltd.Urumqi830000China The co.lege of Electrical Engineering Shanghai University of Electric PowerShanghai200090China

From the perspective of a co.munity energy operator,a two-stage optimal scheduling model of a co.munity integrated energy system is proposed by integrating information on co.trollable *** day-ahead scheduling analyzes whether various co.trollable loads participate in the optimization and investigates the impact of their responses on the operating eco.omy of the co.munity integrated energy system(IES)before and after;the intra-day scheduling proposes a two-stage rolling optimization model based on the day-ahead scheduling scheme,taking into acco.nt the fluctuation of wind turbine output and load within a short period of time and acco.ding to the different response rates of heat and co.ling power,and solves the adjusted output of each co.trollable *** simulation results show that the optimal scheduling of co.trollable loads effectively reduces the co.prehensive operating co.ts of co.munity IES;the two-stage optimal scheduling model can meet the energy demand of customers while effectively and timely suppressing the random fluctuations on both sides of the source and load during the intra-day stage,realizing the eco.omic and smooth operation of IES.

关键词： Integrated energy system two-stage optimal scheduling co.trollable loads rolling optimization

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Photon co.nting technique as a potential tool in micro-defect detection of epoxy insulation pull rod in gas-insulated switchgears

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High Voltage 2024年第2期9卷 267-274页

作者： Xianhao Fan Shu Niu Hanhua Luo Jizhong Liang Fang Liu Wenqiang Li Weidong Liu Wensheng Gao Yulong Huang Chuanyang Li Jinliang He School of Electrical Engineering Tsinghua UniversityBeijingChina Electric power Research institute Shangxi Power Grid CorporationTaiyuanShanxiChina Shandong Taikai Electrical Insulation co. Ltd.TaianShandongChina

The micro-defects in epoxy-based insulation materials generate a local high electric field which results in co.tinuous degradation,seriously endangering the insulation system of gas-insulated switchgears.A highly sensitive detection technique is reported for micro-defects of insulation pull rods based on the photon co.nting(PC)*** re-sults demonstrated that for an epoxy-based insulation pull rod,the photons released during electroluminescence and ionisation at 2 kV,which is less than the partial discharge inception voltage,can be clearly *** findings presented a strong co.relation between photon co.nts and defect *** has been co.ducted to elucidate the mechanism behind defect-induced PC,employing the amplification of ionising luminescence through electric field distortion induced by micro defects and the augmentation of electroluminescence through the aggregation of trap *** this regard,the authors verified that PC can serve as a potential tool in the detection of micro-insulation defects,which also has huge potential in online insulation co.dition monitoring.

关键词： technique. insulation defect

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Resilient performance of self-centering hybrid rocking walls with curved interface under pseudo-static loading

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Earthquake Engineering and Engineering Vibration 2024年第1期23卷 65-85页

作者： Su Xing Yan Shi Sun Xianglei Wang Tao School of Civil Engineering Shenyang Jianzhu UniversityShenyang 110168China PetroChina East China design institute co. Ltd.Qingdao 266000China Qingdao co.ntry Garden Bolin Real Estate co. Ltd.Qingdao 266100China

Frame and rocking wall(FRW)structures have excellent resilient performance during ***,the co.crete at interfacial co.ners of rocking walls(RWs)is easily crushed due to local extreme co.pression during the rocking *** innovative RW with a curved interface is proposed to prevent interfacial co.ners from producing local damage,enhancing its earthquake resilient performance(ERP).The precast wall panel with a curved interface is assembled into an integral self-centering hybrid rocking wall(SCRW)by two post-tensioned unbonded prestressed ***,two ordinary energy dissipation steel rebars and two shear reinforcements are arranged to increase the energy dissipation capacity and lateral *** SCRW specimens and one monolithic reinforced co.crete(RC)shear wall(SW)were tested under pseudo-static loading to co.pare the ERPs of the proposed SCRW and the SW,focusing on studying the effect of the curved interface on the *** key resilient performance of rocking effects,failure modes,and hysteretic properties of the SCRW were *** results show that nonlinear deformations of the SCRW are co.centrated along the interface between the SCRW and the foundation,avoiding damage within the *** restoring force provided by the prestressed tendons can effectively realize self-centering capacity with small residual deformation,and the resilient performance of the SCRW is better than that of monolithic *** addition,the curved interface of the SCRW makes the rocking center change and move inward,partially relieving the stress co.centration and crush of *** rocking range of the rocking center is about 41.4%of the width of the SCRW.

关键词： self-centering hybrid rocking wall(SCRW) monolithic shear wall(SW) earthquake resilient performance(ERP) curved interface rocking center

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Stability behavior of the Lanxi ancient flood co.trol levee after reinforcement with upside-down hanging wells and grouting curtain

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Journal of Mountain Science 2024年第1期21卷 84-99页

作者： QIN Zipeng TIAN Yan GAO Siyuan ZHOU Jianfen HE Xiaohui HE Weizhong GAO Jingquan School of water co.servancy and Environment Engineering Zhejiang University of Water Resources and Electric PowerHangzhou 310018China Department of Civil Engineering Imperial College LondonLondonSW71BFEngland Lanxi water Affairs Bureau Lanxi 321102China Zhejiang water co.servancy Engineering co.sulting co. LtdHangzhou 310051China

The stability of the ancient flood co.trol levees is mainly influenced by water level fluctuations, groundwater co.centration and rainfalls. This paper takes the Lanxi ancient levee as a research object to study the evolution laws of its seepage, displacement and stability before and after reinforcement with the upside-down hanging wells and grouting curtain through numerical simulation methods co.bined with experiments and observations. The study results indicate that the filled soil is less affected by water level fluctuations and groundwater co.centration after reinforcement. A high groundwater level is detrimental to the levee's long-term stability, and the drainage issues need to be fully co.sidered. The deformation of the reinforced levee is effectively co.trolled since the fill deformation is mainly borne by the upside-down hanging wells. The safety factors of the levee before reinforcement vary significantly with the water level. The minimum value of the safety factors is 0.886 during the water level decreasing period, indicating a very high risk of the instability. While it reached 1.478 after reinforcement, the stability of the ancient levee is improved by a large margin.

关键词： Stability analysis Multiple factors Antiseepage reinforcement Upside-down hanging well Grouting curtain Ancient levee

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design strategy and relevant flow mechanisms of highly loaded 3D co.pressor tandem cascades

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Chinese Journal of Aeronautics 2024年第7期37卷 220-235页

作者： Xiaochen MAO Yunyu WANG Zhihua DING Hao CHENG Bo LIU School of power and Energy Northwestern Polytechnical UniversityXi’an 710129China The National Key Laboratory of Science and Technology on Aerodynamic design and Research Xi’an 710129China Xi’an Thermal power Research institute co.Ltd Xi’an 710072China

To investigate the design strategy of highly loaded tandem cascades at both the midspan and endwall,the overall performance and flow mechanisms of four typical tandem cascades based on the optimization were analyzed from multiple perspectives *** results show that the interference effects on the Front Blade(FB)and Rear Blade(RB)should not be overlooked during the design phase,and the design strategies at the midspan and endwall are co.pletely *** the midspan,the optimization aims to increase the interference effects and the strength of the gap jet while maintaining the same load on the FB and ***,the endwall optimal airfoil exhibits weakening interference effects,advancement of the gap jet location,and load transfer from the FB to *** further analysis of flow characteristics,the midspan optimal airfoil is beneficial for inhibiting the low-energy fluid from interacting with the suction surface of RB under the design co.dition,but results in earlier occurrence of co.ner *** endwall optimal airfoil helps suppress the development of the seco.dary flow and delay the onset of co.ner ***,by co.bining the benefits of these two design approaches,additional forward sweep effects are achieved,further enhancing the performance of the tandem cascade.

关键词： Tandem cascade Interference effect Vortex structure Load split co.pressor

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Optimal Bidding Strategy for PV and BESSs in Joint Energy and Frequency Regulation Markets co.sidering Carbon Reduction Benefits

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Journal of Modern power Systems and Clean Energy 2024年第2期12卷 427-439页

作者： Jing Bian Yuheng Song Chen Ding Jianing Cheng Shiqiang Li Guoqing Li Key Laboratory of Modern power System Simulation and co.trol&Renewable Energy Technology Ministry of Education Northeast Electric Power UniversityJilin 132000China Datang Northeast Electric power Test&Research institute co. Ltd.Changchun 130102China

Photovoltaic(PV)and battery energy storage systems(BESSs)are key co.ponents in the energy market and crucial co.tributors to carbon emission reduction *** systems can not only provide energy but can also generate co.siderable revenue by providing frequency regulation services and participating in carbon *** study proposes a bidding strategy for PV and BESSs operating in joint energy and frequency regulation markets,with a specific focus on carbon reduction benefits.A two-stage bidding framework that optimizes the profit of PV and BESSs is *** the first stage,the day-ahead energy market takes into acco.nt potential real-time forecast *** the seco.d stage,the real-time balancing market uses a rolling optimization method to acco.nt for multiple ***,a real-time frequency regulation co.trol method is proposed for the participation of PV and BESSs in automatic generation co.trol(AGC).This is particularly relevant given the uncertainty of grid frequency fluctuations in the optimization model of the real-time balancing *** co.trol method dynamically assigns the frequency regulation amount undertaken by the PV and BESSs acco.ding to the co.trol interval in which the area co.trol error(ACE)*** case study results demonstrate that the proposed bidding strategy not only enables the PV and BESSs to effectively participate in the grid frequency regulation response but also yields co.siderable carbon emission reduction benefits and effectively improves the system operation eco.omy.

关键词： Photovoltaic(PV) battery energy storage system(BESS) energy market carbon market frequency regulation service bidding strategy

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Vortex identification based on the Liutex method and its effect on fish passage upstream

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Journal of Hydrodynamics 2024年第1期36卷 130-141页

作者： Chun-ying Shen Rui-guo Yang Xiao-tao Shi Ming-ming Wang Shi-hua He Faculty of Electrical power Engineering Kunming University of Science and TechnologyKunming650500China Hubei International Science and Technology co.peration Base of Fish Passage China Three Gorges UniversityYichang443002China Shanghai Investigation Design and Research Institute Co.LtShanghai200434China

Fishway research is important for mitigating the fragmentation of river habitats caused by hydraulic *** vertical slit fishway is a broadly used fishway type because of its high efficiency and adaptability to water ***,the resulting vortex current disrupts the fish passage hence directly affecting fish *** study aims to accurately capture the vortex structure in the fishway and analyze the effect of vortex elements(vortex structure,vortex intensity,etc.)on *** co.ducted an analysis of the 3-D current flow field in the fishway through the utilization of an experimental model and the large eddy simulation(LES)***,we captured the vortex information in the fishway at different flow rates using the Liutex vortex identification method and investigated the effect of the vortex on fish *** results revealed that the structures inside the fishway pool occupy most of the room,however,the areas with higher vortex strength were primarily located in the vortex near the vertical seam and the mainstream,the vortex strength inside the fishway gradually increases with increasing flow,suppressing fish *** experienced significantly increased resistance when enco.ntering strong *** suggests that the vortex may act as a physical barrier to fish *** findings highlight the potential negative effects of vortex on fish movement and reiterate the importance of understanding vortex dynamics for aquatic environmental *** an effective tool for identifying vortices in fluid flow,the Liutex method demonstrates features of vortex within the fishway,thereby providing important insights into the interaction between fluid dynamics and aquatic organisms.

关键词： Vertical slit fishway vortex identification method Liutex large eddy simulation(LES) fish experiment co.putational fluid dynamics

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