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Review of the Analysis and Suppression for High-frequency Oscillations of the Grid-connected Wind Power Generation System

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CES Transactions on Electrical Machines and Systems 2024年第2期8卷 127-142页

作者： bo pang Qi Si Pan Jiang Kai Liao Xiaojuan Zhu Jianwei Yang Zhengyou He College of Electrical Engineering Southwest Jiaotong University

High-frequency oscillation(HFO) of gridconnected wind power generation systems(WPGS) is one of the most critical issues in recent years that threaten the safe access of WPGS to the grid. Ensuring the WPGS can damp HFO is becoming more and more vital for the development of wind power. The HFO phenomenon of wind turbines under different scenarios usually has different mechanisms. Hence, engineers need to acquire the working mechanisms of the different HFO damping technologies and select the appropriate one to ensure the effective implementation of oscillation damping in practical engineering. This paper introduces the general assumptions of WPGS when analyzing HFO, systematically summarizes the reasons for the occurrence of HFO in different scenarios, deeply analyses the key points and difficulties of HFO damping under different scenarios, and then compares the technical performances of various types of HFO suppression methods to provide adequate references for engineers in the application of technology. Finally, this paper discusses possible future research difficulties in the problem of HFO, as well as the possible future trends in the demand for HFO damping.

关键词： Damping Economics Reviews Wind power generation Hafnium oxide Market research Wind turbines

Transient AC Overvoltage Suppression Orientated Reactive Power Control of the Wind Turbine in the LCC-HVDC Sending Grid

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CES Transactions on Electrical Machines and Systems 2024年第2期8卷 152-161页

作者： bo pang Xiao Jin Quanwang Zhang Yi Tang Kai Liao Jianwei Yang Zhengyou He IEEE College of Electrical Engineering Southwest Jiaotong University State Grid Zhejiang Electric Power Company

High-voltage direct current(HVDC) transmission is a crucial way to solve the reverse distribution of clean energy and loads. The line commutated converter-based HVDC(LCCHVDC) has become a vital structure for HVDC due to its high technological maturity and economic advantages. During the DC fault of LCC-HVDC, such as commutation failure, the reactive power regulation of the AC grid always lags the DC control process, causing overvoltage in the AC sending grid, which brings off-grid risk to the wind power generation based on power electronic devices. Nevertheless, considering that wind turbine generators have fast and flexible reactive power control capability, optimizing the reactive power control of wind turbines to participate in the transient overvoltage suppression of the sending grid not only improves the operational safety at the equipment level but also enhances the voltage stability of the system. This paper firstly analyses the impact of wind turbine's reactive power on AC transient overvoltage. Then, it proposes an improved voltage-reactive power control strategy, which contains a reactive power control delay compensation and a power command optimization based on the voltage time series prediction. The delay compensation is used to reduce the contribution of the untimely reactive power of wind turbines on transient overvoltage, and the power command optimization enables wind turbines to have the ability to regulate transient overvoltage, leading to the variation of AC voltage, thus suppressing the transient overvoltage. Finally, the effectiveness and feasibility of the proposed method are verified in a ±800kV/5000MW LCC-HVDC sending grid model based on MATLAB/Simulink.

关键词： Voltage control Reactive power Wind turbines Transient analysis HVDC transmission Reactive power control Circuit faults

The mechanisms of thermal solidification agent promoting steam diversion in heavy oil reservoirs

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Petroleum Science 2024年第3期21卷 1902-1914页

作者： Zhan-Xi pang Qian-Hui Wang Qiang Meng bo Wang Dong Liu State Key Laboratory of Petroleum Resources and Engineering China University of Petroleum (Beijing) Liaohe Oilfield Institute CNPC China Henan Oilfield Institute Sinopec China Tianjin Branch of China National Offshore Oil Company (CNOOC) Ltd.

At high cycles of steam huff & puff, oil distribution in reservoirs becomes stronger heterogeneity due to steam channeling. Thermal solidification agent can be used to solve this problem. Its solution is a lowviscosity liquid at normal temperature, but it can be solidified above 80°C. The plugging degree is up to 99% at 250°C. The sweep efficiency reaches 59.2%, which is 7.3% higher than pure steam injection. In addition, simultaneous injection of viscosity reducer and/or nitrogen foams can further enhance oil recovery. The mechanism of this technology depends on its strong plugging ability, which changes the flowing pattern of steam to effectively mobilize remaining oil. Viscosity reducer and nitrogen foams further expand the sweep range and extends the effective period. Therefore, thermal solidification agent can plug steam channeling paths and adjust steam flowing direction to significantly enhance oil recovery at high cycles of steam huff & puff.

关键词： Heavy oil reservoir Steam huff & puff Steam channeling Steam diversion Plugging performance Mechanism analysis

Study on the Effect of Ginaton on Reducing Cerebral Vasospasm and Early Brain Injury after Hemorrhagic Stroke by Inhibiting Inflammatory Response

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World Journal of Traditional Chinese Medicine 2024年第1期10卷 33-39页

作者： Xue-bo pang Xiao-Lin Zhang Mei-Rong Wang Ying Yuan Xiao Zhang Department of Neurology Xingtai Third HospitalXingtaiChina

Objective:The objective of this study was to investigate the effects and possible mechanisms of action of ginseng on cerebral vasospasm and early brain injury(EBI)following hemorrhagic stroke.Materials and Methods:Sprague-Dawley(SD)rats(n=48)were randomly divided into sham operation(sham group),subarachnoid hemorrhage(SAH)model(SAH group),normal saline(NS group),and Ginaton(Extract of Ginkgo Biloba Leaves Drops)intervention(gin group)groups.MCP-1 m RNA and tumor necrosis factor levels were detected using reverse transcription-polymerase chain reaction.The relative expression of m RNA was detected by Western blotting.Results:(1)Compared with the sham group,the SAH,NS,and gin groups had different degrees of neurological dysfunction.Compared with the SAH and NS groups,the neurological deficits in the gin group were significantly improved(P<0.05).(2)Compared with the sham group,the relative expression levels of MCP-1 m RNA in the SAH,NS,and gin groups were 5.1±0.9,3.4±0.6,and 2.5±0.4,respectively;the relative expression levels of m RNA were 13.3±2.4,11.2±1.8,and 3.8±0.6,respectively.(3)The apoptosis rates of brain tissue in the sham,SAH,NS,and gin groups were 4.8±0.7,54.2±10.3,50.1±7.4,and 28.4±4.5,respectively.(4)Western blot showed that the relative expression levels of toll-like receptor-4(TLR-4)protein in the sham,SAH,NS,and gin groups were 0.29±0.03,0.87±0.15,0.65±0.13,and 0.41±0.17,respectively;the relative expression levels of B protein were 0.21±0.04,0.96±0.14,0.73±0.18,and 0.30±0.05,respectively.Gin treatment could inhibit TLR-4 and nuclear factor-κB(NF-κB)protein expression.Conclusions:Dona tablets may inhibit activation of the NF-κB signaling pathway,and SAH-induced inflammatory response,so as to reduce cerebral vasospasm and EBI.

关键词： Cerebral hemorrhage early brain injury ginaton neurological deficit nuclear factor-κB

Differences in leaf cuticular wax induced by whole-genome duplication in autotetraploid sour jujube

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Horticultural Plant Journal 2024年第1期10卷 66-76页

作者： Meng Li Chenxing Zhang Lu Hou Xinru Liu Hanqing Zhao Xiaoming pang Wenhao bo Yingyue Li National Engineering Research Center of Tree Breeding and Ecological Restoration College of Biological Sciences and TechnologyBeijing Forestry UniversityBeijing 100083China Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants Ministry of EducationCollege of Biological Sciences and TechnologyBeijing Forestry UniversityBeijing 100083China The Tree and Ornamental Plant Breeding and Biotechnology Laboratory of National Forestry and Grassland Administration Beijing Forestry UniversityBeijing 100083China

Drought-resistant plants exhibit strong water retention capability.In this regard,the autotetraploid sour jujube leaves exhibit better water retention than diploid leaves.Morphological comparisons and physiological comparisons of diploid and autotetraploid leaves showed that the autotetraploid leaves had thicker leaf cuticles and more leaf wax accumulation than the diploid leaves,which could reduce cuticle permeability and improve the drought tolerance of leaves.In this study,the cuticular wax crystalloids on the adaxial and abaxial sides of young and mature jujube leaves were observed in the two ploidy types,and unique cuticular wax crystalloids covering a large area of the cuticle on autotetraploid sour jujube leaves may provide an advantage in reducing leaf non-stomata transpiration and improving plant drought tolerance.Based on the transcriptome,115 differentially expressed genes between diploids and autotetraploids were further analyzed and found to be involved in the accumulation of cuticular wax components,including terpenoids,fatty acids,and lipids,as well as ABC transporter and wax biosynthetic process.Finally,14 genes differentially expressed between glossy autotetraploid leaves and nonglossy diploid leaves,such as LOC107414787,LOC107411574 and LOC107413721,were screened as candidate genes by qRT-PCR analysis.This findings provided insights into how polyploidization improved drought tolerance.

关键词： Autotetraploid Jujube Drought tolerance Cuticular wax RNA-seq

A high-performance lithium anode based on N-doped composite graphene

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Rare Metals 2024年第3期43卷 1030-1036页

作者： Can Jiao Hao-bo Sun Li Zhang Shang-Qian Zhao Guo-Yao pang Chun-Rong Zhao Shi-Gang Lu General Research Institute for Nonferrous Metals Beijing100088China China Automotive Battery Research Institute Co.Ltd Beijing101407China

Lithium(Li)metal is the most promising electrode for next-gene ration rechargeable batteries.In order to push the commercialization of the lithium metal batteries,a kind of nitrogen(N)-doped composite graphene(NCG)adopted as the Li plating host was prepared to regulate Li metal nucleation and suppress dendrite growth.Furthermore,a new kind of sandwich-type composite lithium metal(STCL)electrode was developed to improve its application.The STCL electrode can be used as convenient as a piece of Li foil but no dendrite growth.In a symmetric battery,the STCL electrode cycled for more than 4500 h with the overpotential of less than 40 mV.And due to the creative design,the STCL promises the Li-S battery with a prolonged cycling lifespan.

关键词： Lithium metal anode Lithiophilic N-doped composite graphene Sandwich-type composite lithium metal electrode

Preparation and Properties of Magnesium Oxysulfide Cement Based Foam board Absorbing Material

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Journal of Wuhan University of Technology(Materials Science) 2024年第1期39卷 118-125页

作者：刘军崔宝栋庞博 School of Materials Science and Engineering Shenyang Ligong UniversityShenyang 110159China

In order to better solve the problem of electromagnetic pollution in the civil building cement,to improve the absorption capacity of magnesium oxysulfide cement based materials,and to better use sulfur oxide magnesium cement foamed sheet for improvement of electromagnetic industry,this paper uses the excellent microwave absorbing properties of ferrite and the modified sulfur oxide magnesium cement foam board,and discusses the microwave absorbing performance,aiming at improving the electromagnetic pollution in daily life.The effects of ferrite and silicon carbide doping on microwave absorption properties of modified magnesium oxysulfate cement were studied.At the same time,the wave absorbing properties of the corresponding samples were detected by bow method,and the causes of the corresponding phenomena were analyzed by scanning electron microscopy (SEM).The results show that the lowest reflectance of the material is-17.9 dB at 34.1 GHz and the average reflectance of the whole band is-15.9 dB under the target frequency band of 26.5-40 GHz.Under the action of external magnetic field,the absorbing particles are affected by magnetization force,magnetic dipole and resistance coupling,and play the absorbing effect in the cement base solidified completely in the electromagnetic field environment.The lowest reflectance is-17.3dB at 36.4GHz and the average reflectance is-14.3dB for the whole band.

关键词： magnesium oxysulfide cement silicon carbide ferrite absorption properties

Driving forces and their relative contributions to hydrocarbon expulsion from deep source rocks: A case of the Cambrian source rocks in the Tarim Basin

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Petroleum Science 2023年第1期20卷 20-33页

作者： bo pang Jun-Qing Chen Xiong-Qi pang Tao Hu Yue Sheng State Key Laboratory of Petroleum Resources and Prospecting China University of PetroleumBeijing102249China College of Geosciences China University of PetroleumBeijing102249China College of Science China University of PetroleumBeijing102249China Laboratory of Optical Detection Technology for Oil and Gas China University of PetroleumBeijing102249China Basic Research Center for Energy Interdisciplinary China University of PetroleumBeijing102249China CNPC Economics&Technology Research Institute Beijing100029China

To thoroughly understand the dynamic mechanism of hydrocarbon expulsion from deep source rocks,in this study,five types of hydrocarbon expulsion dynamics(thermal expansion,hydrocarbon diffusion,compaction,product volume expansion,and capillary pressure difference(CPD))are studied.A model is proposed herein to evaluate the relative contribution of different dynamics for hydrocarbon expulsion using the principle of mass balance,and the model has been applied to the Cambrian source rocks in the Tarim Basin.The evaluation results show that during hydrocarbon expulsion from the source rocks,the relative contribution of CPD is the largest(>50%),followed by compaction(10%-40%),product volume expansion(5%-30%),and thermal expansion(2%-20%).The relative contribution of diffusion to hydrocarbon expulsion is minimal(bon expulsion process of deep source rocks.The hydrocarbon expulsion process of source rocks can be categorized into three stages based on the contribution of different dynamics to the process:the first stage is dominated by compaction and diffusion to expel hydrocarbons,the second stage is dominated by product volume expansion and CPD,and the third stage is dominated by product volume expansion and CPD.This research offers new insights into hydrocarbon exploration in tight oil and gas reservoirs.

关键词： Driving force Dynamic mechanism Hydrocarbon expulsion Deep oil and gas exploration Tarim Basin

The Establishment and Application of a Kraken Classifier for Salmonella Plasmid Sequence Prediction

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China CDC weekly 2022年第49期4卷 1110-1116页

作者： Zhenpeng Li bo pang Xin Lu Biao Kan State Key Laboratory of Infectious Disease Prevention and Control National Institute for Communicable Disease Control and PreventionChinese Center for Disease Control and PreventionBeijing MunicipalityChina School of Public Health Shandong UniversityJinan CityChina.

Introduction:Salmonella is a key intestinal pathogen of foodborne disease,and the plasmids in Salmonella are related to many biological characteristics,including virulence and drug resistance.A large number of plasmid contigs have been sequenced in bacterial draft genomes,however,these are often difficult to distinguish from chromosomal contigs.Methods:In this study,three different customized Kraken databases were used to build three different Kraken classifiers.Complete genome benchmark datasets and simulated draft genome benchmark datasets were constructed.Five-fold cross-validation was used to evaluate the performance of the three different Kraken classifiers by two benchmark datasets.Results:The predictive performance of the classifier based on all National Center for Biotechnology Information plasmids and Salmonella complete genomes was optimal.This optimal Kraken classifier was performed with Salmonella isolated in China.The plasmid carrying rate of Salmonella in China is 91.01%,and it was found that the Kraken classifier could find more plasmid contigs and antibiotic resistance genes(ARGs)than results derived from a plasmid replicon-based method(PlasmidFinder).Moreover,it was found that in the strains carrying ARGs,plasmids carried more ARGs[three,95%confidence interval(CI):1–14]than chromosomes(one,95%CI:1–7).Discussion:We found building a high-quality customized database as a Kraken classifier to be ideal for the prediction of Salmonella plasmid sequences from bacterial draft genomes.In the future,the Kraken classifier established in this study will play a significant role in ARG monitoring.

关键词： classifier database Application