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Interaction analysis and enhanced design of grid-forming control with hybrid synchronization and virtual admittance loops

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iEnergy 2023年第1期2卷 71-84页

作者： Hong Gong xiongfei wang Vestas Aarhus 8200Denmark KTH Royal Institute of Technology Stockholm 11428Sweden

The hybrid power-and voltage-based synchronization control method has shown potential for enhancing the stability of grid-forming(GFM)***,its effectiveness may be compromised if other control loops are not properly *** address the control-loop interactions,this paper presents a design-oriented analysis method for multiloop-controlled GFM *** method begins by identifying the dominant oscillation modes through modal *** sensitivities of damping ratios to control parameters are then determined for the dominant modes,which allows for characterization of control-loop interactions.A co-design method of GFM control is next developed based on the sensitivity ***,simulations and experimental results are presented to confirm the effectiveness of the method.

关键词： Grid-forming inverter hybrid synchronization controller virtual admittance damping ratio controller design

Transition and fracture shift behavior in LCF test of dissimilar welded joint at elevated temperature

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Journal of Materials Science & Technology 2018年第4期34卷 720-731页

作者： xiongfei wang ChendongShao Xia Liu Fenggui Lu Shanghai Key Laboratory of Materials Laser Processing and Modification School of Materials Science and EngineeringShanghaiJiao Tong UniversityShanghai 200240China Shanghai Turbine Plant of Shanghai Electric Power Generation Equipment Co.Ltd. Shanghai 200240China

This work focused on the low-cycle fatigue （LCF） behavior of modified 9Cr/CrMoV dissimilar welded joint at elevated temperature. Narrow gap submerged arc welding （NG-SAW） process via multi-pass and multi-layer techniques was employed to fabricate the welded joint. LCF tests at different strain amplitude range from 0.22% to 0.75% were performed at strain ratio R = -1. The two-slope behavior based on fracture location shift was presented both on the cyclic stress-strain （CSS） curve and Manson-Coffin （M-C） curve, which could be applied to predict the fatigue life more precisely especially at relatively low strain amplitude. The results indicated that the joint failed in CrMoV-base metal （BM） at relatively low strain amplitude below 0.4% while failure shifted to CrMoV-over tempered zone （OTZ） at higher strain amplitude above 0.4%. Fatigue failure occurred in CrMoV-BM at low strain amplitude could be attributed to temperature softening effect in CrMoV-BM combined with cyclic strengthening in CrMoV- OTZ. While CrMoV-OTZ with a comparable number of grain boundaries and much lower hardness than that of CrMoV-BM was deemed to be the weakest zone across the welded joint at higher strain amplitude. EBSD investigations also revealed that CrMoV-BM experienced more fatigue damage at relatively low strain amplitude, while CrMoV-OTZ accumulated more plastic strain at higher strain amplitude.

关键词： Low-cycle fatigue 9Cr/CrMoV dissimilar welded joint Elevated temperature Fracture transition EBSD analysis

Investigation on LCF Behavior of Welded Joint at Di erent Temperatures for Bainite Steel

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Chinese Journal of Mechanical Engineering 2019年第2期32卷 73-80页

作者： Ke Xu xiongfei wang Haichao Cui Fenggui Lu Shanghai Key Laboratory of Materials Laser Processing and Modifcation School of Materials Science and Engineering Shanghai Jiao Tong University

The current research of low cycle fatigue(LCF) is mainly focused on the components with uniform *** with these typical components, LCF behavior of welded components are more complex due to their great gradient microstructure, especially for di erent temperature. In this paper, LCF properties were conducted on the welded joint at di erent temperatures for bainite steel, and the failure mechanism was systematically *** parameters derived from fitting curves indicated that welded joint had worse plastic deformation resistance and experienced more significantly strain hardening e ect at 300 °C. The joint failed in the weld metal at room temperature, which attributed to the softening in weld metal combined with cyclic strain hardening e ect in heata ected zone, which meant the joint was more sensitive with the hardness at this condition. When it came to 300 °C,more cracks appeared near to HAZ and the heterogeneous distributed surface inclusion was responsible for the fracture transition to HAZ adjacent to bainite steel rather than the softest zone in HAZ, reflecting the joint was more sensitive with the surface inclusion at 300 °C. This research could support the design on loading of welded component at di erent temperature, and further ensure the safe operation.

关键词： Low cycle fatigue Welded joint Di erent temperatures Failure mechanism

Editorial for the Special Issue on Operation and Control of Power Electronics Dominated Power Systems

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Chinese Journal of Electrical Engineering 2021年第4期7卷 1-2页

作者： xiongfei wang Ning Zhang Kai Sun Aalborg University Denmark Tsinghua University China

With the ever increasing penetration of renewable energy and power electronics,the current energy network is being transformed to power electronics dominated power system(PEDPS).Different from conventional power grid,PEDPS has its own characteristics such as much lower inertia,lower short circuit capacity,multi-timescale dynamic behavior,*** features bring tremendous challenges to the analysis,design,modeling and control of the modem power grid systems.

关键词： Power modem transformed

Microstructure characterization and HCF fracture mode transition for modified 9Cr-1Mo dissimilarly welded joint at different elevated temperatures

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Journal of Materials Science & Technology 2017年第12期33卷 1610-1620页

作者： Chendong Shao Fenggui Lu xiongfei wang Yuming Ding Zhuguo Li Shanghai Key Laboratory of Materials Laser Processing and Modification School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration Shanghai 200240China Shanghai Turbine Plant of Shanghai Electric Power Generation Equipment Co.Ltd. Shanghai 200240China

The high cycle fatigue（HCF） tests of modified 9 Cr-1 Mo dissimilarly welded joint were carried out at different elevated temperatures and the fracture mechanism was systematically revealed. The fatigue strength at 108 cycles based on S-N curve can be estimated as a half of weld joint＇s yield strength for all conducted temperatures, which can be a reliable criterion in predicting the fatigue life. The results show that the inter-critical heat affected zones（IC-HAZs） of both sides are the weak zones due to their low hardness and inferior fatigue resistance property. HAZ of COST-FB2（BM2） is the weakest zone at room temperature due to the existence of numerously distributed defects and the initiation of cracks, either in the surface or interior zone, impacting a crucial effect on the fatigue life of the joint. While at elevated temperatures, fatigue life was controlled mostly by the intrusion-extrusion mechanism at the specimen surface under high stress level and subsurface non-defect fatigue crack origin（SNDFCO） from the interior material under low stress amplitude. With increasing temperature, more and more fatigue failures began to occur at the HAZ of COST-E（BM1） due to its higher susceptibility of temperature. Besides, it is found that the-ferrite in the BM1 has no harm to the HCF behavior of the joint at the conducted temperatures.

关键词： High cycle fatigue Dissimilarly welded joint Life time Fatigue failure Fracture mode

Local field potentials,spiking activity,and receptive fields in human visual cortex

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Science China(Life Sciences) 2024年第3期67卷 543-554页

作者： Lu Luo xiongfei wang Junshi Lu Guanpeng Chen Guoming Luan Wu Li Qian wang Fang Fang School of Psychological and Cognitive Sciences and Beijing Key Laboratory of Behavior and Mental Health Peking UniversityBeijing 100871China School of Psychology Beijing Sport UniversityBeijing 100084China Department of Neurosurgery Sanbo Brain HospitalCapital Medical UniversityBeijing 100093China Beijing Key Laboratory of Epilepsy Epilepsy CenterSanbo Brain HospitalCapital Medical UniversityBeijing 100093China IDG/McGovern Institute for Brain Research Peking UniversityBeijing 100871China Peking-Tsinghua Center for Life Sciences Peking UniversityBeijing 100871China Beijing Institute for Brain Disorders Beijing 100069China State Key Laboratory of Cognitive Neuroscience and Learning and IDG/McGovern Institute for Brain Research Beijing Normal UniversityBeijing 100875China

The concept of receptive field(RF) is central to sensory neuroscience. Neuronal RF properties have been substantially studied in animals,while those in humans remain nearly unexplored. Here, we measured neuronal RFs with intracranial local field potentials(LFPs) and spiking activity in human visual cortex(V1/V2/V3). We recorded LFPs via macro-contacts and discovered that RF sizes estimated from lowfrequency activity(LFA, 0.5–30 Hz) were larger than those estimated from low-gamma activity(LGA, 30–60 Hz) and high-gamma activity(HGA, 60–150 Hz). We then took a rare opportunity to record LFPs and spiking activity via microwires in V1 simultaneously. We found that RF sizes and temporal profiles measured from LGA and HGA closely matched those from spiking activity. In sum, this study reveals that spiking activity of neurons in human visual cortex could be well approximated by LGA and HGA in RF estimation and temporal profile measurement, implying the pivotal functions of LGA and HGA in early visual information processing.

关键词： human visual cortex receptive field intracranial EEG local field potential spiking activity

Laminar Distribution of Neurochemically-Identified Interneurons and Cellular Co-expression of Molecular Markers in Epileptic Human Cortex

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Neuroscience Bulletin 2018年第6期34卷 992-1006页

作者： Qiyu Zhu Wei Ke Quansheng He xiongfei wang Rui Zheng Tianfu Li Guoming Luan Yue-Sheng Long Wei-Ping Lia Yousheng Shu State Key Laboratory of Cognitive Neuroscience and Learning and IDG/McGovern Institute for Brain Research Beijing Normal UniversityBeijing 100875China College of Pharmaceutical Sciences Brain InstituteCapital Medical UniversityBeijing 100069China Department of Neurosurgery Epilepsy CenterSanbo Brain Hospital of Capital Medical UniversityBeijing Key Labo-ratory of EpilepsyEpilepsy InstitutionBeijing Institute for Brain DisordersBeijing 100093China Institute of Neuroscience and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University Key Laboratory of Neurogenetics and Chan-nelopathies of Guangdong Province and the Ministry of Education of ChinaGuangzhou 501260China

Inhibitory GABAergic interneurons are fundamental elements of cortical circuits and play critical roles in shaping network activity. Dysfunction of interneurons can lead to various brain disorders, including epilepsy,schizophrenia, and anxiety. Based on the electrophysiological properties, cell morphology, and molecular identity,interneurons could be classified into various subgroups. In this study, we investigated the density and laminar distribution of different interneuron types and the coexpression of molecular markers in epileptic human *** found that parvalbumin(PV) and somatostatin(SST)neurons were distributed in all cortical layers except layer I, while tyrosine hydroxylase(TH) and neuropeptide Y(NPY) were abundant in the deep layers and white ***(CCK) neurons showed a high density in layers IV and VI. Neurons with these markers constituted*7.2%(PV), 2.6%(SST), 0.5%(TH), 0.5%(NPY), and4.4%(CCK) of the gray-matter neuron population. Doubleand triple-labeling revealed that NPY neurons were also SST-immunoreactive(97.7%), and TH neurons were more likely to express SST(34.2%) than PV(14.6%). A subpopulation of CCK neurons(28.0%) also expressed PV, but none contained SST. Together, these results revealed the density and distribution patterns of different interneuron populations and the overlap between molecular markers in epileptic human cortex.

关键词： Interneuron Epilepsy Human cortex Cell type Immunostaining Parvalbumin Somatostatin Tyrosine hydroxylase Neuropeptide Y Cholecystokinin

Mapping of Sentinel Lymph Node Micrometastasis in Dukes-B Colorectal Carcinoma and Its Clinical Significance

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Clinical oncology and cancer researeh 2009年第5期6卷 347-353页

作者： xiongfei Yang Tao wang Weisheng Zhang Lili Feng Binbin Du Aili Zhang Department of Colorectal Surgery Gansu People's Hospital Lanzhou 730000 Gansu Province. China.

OBJECTIVE To investigate the detection of sentinel lymphnode (SLN) micrometastasis (MM) and the clinical significancein patients with Dukes-B colorectal carcinoma (CRC) using H&Estained *** In a prospective study of 64 patients with Dukes-BCRC undergoing radical surgery,routine H&E staining combinedwith the immunohistochemical SP method was used to detect theexpression of the cytokeratin 20 (CK20) and telomerase (TLMA)in 122 SLNs from 61 of the 64 *** a 3-year follow up,the patients'clinicopathologic parameters data,survival and theirrelationship were collected and *** i) In 6 out of the 61 cases with successful mapping,9SLNs were positive after routine detection using H&E ***) In the other 55 with negative results from H&E staining,thepositive rate of CK20 expression was 27.3% (15/55),and thepositive rate of TLMA 21.8% (12/55),after immunohistochemicalexamination (IHC) on the ***) Detection by combining the 2methods showed that the micrometastasis rate was 38.2% (21/55).iv) The recurrence or metastasis rate of CRC was significantlyhigher in the Dukes-B patients with sentinel lymph nodemicrometastasis (SLNMM) (+) than in those with SLNMM (-)(P<0.05),and simultaneously,the survival rate decreased by alarge margin in the patients with SLNMM (+),compared to thosewith SLNMM (-) (P<0.05).There were significant differences inthe recurrence or metastasis rate of cancer and the survival ratebetween the Dukes-B patients with SLNMM (-) and the Dukes-Cpatients (P<0.05).CONCLUSION Examination of anti-CK20 and anti-TLMA usingimmunohistochemical staining can be used to detect SLNMM,andthe combined examination of the 2 can increase the detection *** detection of SLNMM can precisely determine the Dukes stageof colorectal carcinoma,which is of help in directing postoperativeadjunctive therapy and in assessing prognosis.

关键词： colorectal carcinoma sentinel lymph node micrometastasis.

Hainan; Nandu River; Soil nutrient; Spatial distribution

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Agricultural Biotechnology 2018年第5期7卷 259-263页

作者： Qing MAI xiongfei wang Rongxiang wang Hua wang Agricultural Science Institute of Tunchang Tunchang 571600 China Hainan soil and fertilizer station Haikou 570203 China Tropical Crops Genetic Resources Institute CATAS Danzhou 571737 China

[Objectives] Within a research area on basin scale, soil nutrient distribution characteristics and main causes were analyzed, to provide a basis for soil nutrient management on basin scale.[Methods] With the Nandu River Basin of Hainan Island as the research area, by means of geostatistics and spatial analysis methods, the distribution available of soil pH, organic matter, alkali-hydrolyzale nitrogen, available phosphorus, available potassium and available trace elements were studied.[Results] The cultivated land in the Nandu River Basin of Hainan Province is overall acidic, with an average pH of 5.2. The soil organic matter content is overall lower, and its spatial differences are also significant. Soil alkali-hydrolyzable nitrogen, exchangeable calcium and exchangeable magnesium content are at a medium level, but the soil lacks available phosphorus and available potassium.[Conclusions] The differences in pH within the research area might be related to parent materials distribution and fertilizer applications. The main reasons for the low soil organic matter content are inadequate and uneven input of organic fertilizer and high-temperate rainy climate. The lack of soil phosphorus and potassium is mainly caused by unreasonable fertilizer application and climatic and terrain factors.

关键词： Hainan Nandu River Soil nutrient Spatial distribution