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Flow control characteristics of the digital and mechanical redundancy control electric modulation valve

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2022年第8期23卷 599-609页

作者： He liU Bin ZHAO Bo WANG Long QUAN yun-xiao HAO yun-wei li Key Laboratory of Advanced Transducers and Intlligent Control System of Ministry of Education and Shanxi Province Taiyuan University of TechnologyTaiyuan 030024China Deparment of Electrical and Computer Engineering University of AlbertaEdmonton ABT6G1H9Canada

The electrical modulation valve can provide proportional output valve element displacement,flow,or pressure according to a continuously changing input electrical signal.It is the core component of electro-hydraulic proportional control technology.To remove the influence of pressure difference changes on the output flow,the traditional scheme is to use a pressure compensation valve,which increases the difficulty of both manufacturing and maintaining the valve.To solve this problem,a method of digital and mechanical redundancy control flow is proposed.Pressure sensors are installed at the inlet and outlet of the valve,and the controller adjusts the displacement of the valve element according to the pressure difference between the valve ports to realize high-precision control of the flow.A pressure compensation valve is installed in front of the valve,and a three-way solenoid valve is used to control the working of the compensation valve.In the case of sensor failure,the valve is switched to the mechanical compensation differential pressure mode,to control the flow and to achieve redundancy control.The system security is thereby improved.The feasibility of this scheme is verified through simulation and tests.The results show that,both for digital compensation and mechanical compensation,the output flow can be kept constant when the pressure difference changes,and the system has good static and dynamic characteristics.The principle can be applied to the displacement-flow feedback type electrical modulation valve,and can realize accurate control of the flow of the pilot valve and,finally,accurate control of the flow in the main valve.

关键词： Electrical modulation valve Control characteristics Co-simulation Redundancy control

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A Harmonic Compensation Approach for Interlinking Voltage Source Converters in Hybrid AC-DC Microgrids with Low Switching Frequency

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CSEE Journal of Power and Energy Systems 2018年第1期4卷 39-48页

作者： Hao Tian Xiaohan Wen yun wei li Department of Electrical and Computer Engineering University of AlbertaEdmontonABT6G 2V4Canada China Mobile Group liaoning Co. Ltd.ShenyangChina

In recent years,the hybrid AC-DC microgrid has been well accepted as it combines the advantages of both AC and DC systems.As the microgrid contains both DC sub-grids and AC sub-grids,interlinking DC-AC converters are essential.Meanwhile,considering the nonlinear AC loads may deteriorate the voltage quality of the AC bus,embedding an ancillary harmonic compensation function to the interlinking converters is promising.However,the conventional harmonic control methods used for active power filters(APFs)may not be suitable for the interlinking converters due to the main purpose of it is to exchange real and reactive power between the DC and AC sub-grids.The switching frequency is preferred to be lower than the APFs when the capacity of the microgrid is large.At low switching frequency,harmonic compensation performance or even the system stability may be affected.In this paper,a harmonic compensation approach suitable for hybrid AC-DC interlinking converters at low switching frequency is proposed.Through feeding the PWM reference signal with the harmonic compensation component directly to avoid the multi-loop control path of the fundamental component,the proposed method can achieve the effective harmonics compensation without being limited by the closed-loop control bandwidth.The proposed method,modeling approaches,stability analysis,as well as detailed virtual impedance design are presented.Experimental verification is also provided.

关键词： Harmonic compensation hybrid AC-DC microgrid virtual impedance

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Clinical Manifestations of Adenomyosis Patients with or without Coexisting Endometriosis

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Chinese Medical Journal 2018年第20期131卷 2495-2498页

作者： yun-wei li Yu-Ting liu Shu Wang Hong-Hui Shi Qing-Bo Fan Lan Zhu Jin-Hua Leng Da-wei Sun Jian Sun Jing-He Lang Department of Gynecology and Obstetrics Peking Union Medical College Hospital Chinese Academy of Medical Sciences and Peking Union Medical College Beijing 100730 China Department of Pathology Peking Union Medical College Hospital Chinese Academy of Medical Sciences and Peking Union Medical College Beijing 100730 China

To the Editor： Uterine adenomyosis （AM） is caused by the ectopic growth of endometrial glands and stroma in the myometrium of the uterus, accompanied by hyperplasia and hypertrophy of the surrounding smooth muscle ...

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Multilevel Current Source Converters for High Power Medium Voltage Applications

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CES Transactions on Electrical Machines and Systems 2017年第3期1卷 306-314页

作者： li Ding Yujuan lian yun wei li Department of Electrical and Computer Engineering University of AlbertaEdmontonABCanada 不详

In medium voltage high power applications,multi-level current source converters(CSCs)are good candidate to increase system power region,reliability,and the quality of output waveforms.Compared with widely researched voltage source multi-level converters(MLCs),the current source MLCs have the advantages of inherent short-circuit protection,high power capability and high quality of output current waveforms.The main features of MLCs include reduced harmonics,lower switching frequency and reduced current stress on each device which is a particularly important for high power application with low voltage and high current requirements.This paper conducts a general review of the current research about MLCs in higher power medium voltage application.The different types of parallel structure based MLCs and the modulation methodologies will be introduced and compared.Specifically,the circuit analysis of the common-mode(CM)loop for parallel structures will be conducted,the common-mode voltage(CMV)and circulating current suppression methods developed on the base of multilevel modulations will be addressed.

关键词： Circulating current common-mode voltage current source converters multi-level converter high power medium voltage parallel structure

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Torque limit-based Inertial Control Method Based on Delayed Support for Primary Frequency Control of Wind Turbines

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Journal of Modern Power Systems and Clean Energy 2024年第2期12卷 561-570页

作者： wei Gu Zaiyu Chen Qun li Minghui Yin Qiang li yun Zou School of Automation Nanjing University of Science and TechnologyNanjing 210094China State Grid Jiangsu Electric Power Co. Ltd.Research InstituteNanjing 211103China

To avoid the secondary frequency dip caused by the steep drop of the electrical power of wind turbines(WTs)at the end of frequency support stage,the torque limit-based iner-tial control(TliC)method sets the power reference as a linear function of rotor speed,rather than the step form for the step-wise inertial control.However,the compensation effect on the frequency nadir(FN)caused by the load surge is weakened as the TliC power is no longer in the step form.Specifically,the maximum point of the frequency response component(FRC)contributed by TliC occurs earlier than the minimum point of FRC corresponding to the load surge,so that the FN cannot be adequately raised.Therefore,this paper first investigates the relation between the peak and nadir times of FRCs stimulated by the TliC and load power.On this basis,with the compensation principle of matching the peak and nadir times of FRCs,the improved TliC method based on delayed support is proposed.Finally,the effectiveness of the proposed method is validated via the experiments on the test bench of wind-integrated power system.

关键词： Wind turbine frequency response component torque limit inertial control delayed support

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Safety and efficacy of transcatheter arterial embolization in autosomal dominant polycystic kidney patients with gross hematuria: Six case reports

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World Journal of Clinical Cases 2024年第11期12卷 1954-1959页

作者： wei-Fan Sui yun-Xin Duan Jian-yun li wei-Bin Shao Jian-Hua Fu Department of Interventional Radiology Zhenjiang First People's HospitalZhenjiang 212000Jiangsu ProvinceChina Department of Nephrology Zhenjiang First People’s HospitalZhenjiang 212000Jiangsu ProvinceChina

BACKGROUND To retrospectively report the safety and efficacy of renal transcatheter arterial embolization for treating autosomal dominant polycystic kidney disease(ADPKD)patients with gross hematuria.CASE SUMMARY The purpose of this study is to retrospectively report the safety and efficacy of renal transcatheter arterial embolization for treating ADPKD patients with gross hematuria.Materials and methods:During the period from January 2018 to December 2019,renal transcatheter arterial embolization was carried out on 6 patients with polycystic kidneys and gross hematuria.Renal arteriography was performed first,and then we determined the location of the hemorrhage and performed embolization under digital subtraction angiography monitoring.Improvements in routine blood test results,routine urine test results,urine color and postoperative reactions were observed and analyzed.Results:Renal transcatheter arterial embolization was successfully conducted in 6 patients.The indices of 5 patients and the color of gross hematuria improved after surgery compared with before surgery.No severe complication reactions occurred.CONCLUSION For autosomal dominant polycystic kidney syndrome patients with gross hematuria,transcatheter arterial embolization was safe and effective.

关键词： Renal artery Autosomal dominant polycystic kidney disease Gross hematuria Interventional radiology Embolization Case report

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A robust genomic-based prognostic model for the assessment ofcancer stemness and survival for patients with hepatocellularcarcinoma

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Hepatobiliary & Pancreatic Diseases International 2024年第1期23卷 97-102页

作者： Cheng-li Du Shen-Yu wei yun-Hao Chen Kang-Jie Chen Division of Thoracic Surgery First Affiliated HospitalZhejiang University School of MedicineHangzhou 310003China Zhejiang University School of Medicine Hangzhou 310003China Division of Hepatobiliary Pancreatic Surgery First Affiliated HospitalZhejiang University School of MedicineHangzhou 310003China

To the Editor:Hepatocellular carcinoma(HCC)is an aggressive malignancy with poor long-term prognosis[1].liver cancer stem cell(CSC)can drive the metastasis,drug resistance,and recurrence of HCC[2].The regulatory mechanisms about liver cancer stemness have been investigated,which encouraged the identification and characterization of novel prognostic and therapeutic strategies for HCC[3].

关键词： cancer prognosis liver

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Tailoring chaotic motion of microcavity photons in ray and wave dynamics by tuning the curvature of space

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Science China(Physics,Mechanics & Astronomy) 2024年第7期67卷 107-112页

作者： wei lin Yechun Ding Yongsheng Wang Peng li Yanpeng Zhang Feng yun Feng li Key Laboratory for Physical Electronics and Devices of the Ministry of Education Shaanxi Key Lab of Information Photonic TechniqueSchool of Electronic Science and EngineeringFaculty of Electronic and Information EngineeringXi’an Jiaotong UniversityXi’an 710049China Department of Electrical and Photonics Engineering Technical University of DenmarkKgs.Lyngby 2800Denmark Center for Regenerative and Reconstructive Medicine Med-X InstituteThe First Affiliated Hospital of Xi’an Jiaotong UniversityXi’an 710061China Solid-State lighting Engineering Research Center Xi’an Jiaotong UniversityXi’an 710049China

Microcavity photon dynamics in curved space is an emerging interesting area at the crossing point of nanophotonics,chaotic science,and non-Euclidean geometry.We report the sharp difference between the regular and chaotic motions of cavity photons subjected to the varying space curvature.While the island modes of regular motion rise in the phase diagram in the curved space,the chaotic modes show special mechanisms to adapt to the space curvature,including the fast diffusion of ray dynamics,and the localization and hybridization of the Husimi wavepackets among different periodic orbits.These observations are unique effects enabled by the combination of the chaotic trajectory,the wave nature of light,and the non-Euclidean orbital motion,and therefore make the system a versatile optical simulator for chaotic science under quantum mechanics in curved space-time.

关键词： microcavity chaotic motion curved space

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Humic acid-mediated transport of a typical soil passivation remediation product(chloropyromorphite)in saturated porous media

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Journal of Environmental Sciences 2024年第7期141卷 51-62页

作者： Xinying li Mengjia Zhang Siyuan li wei wei School of Environment Jiangsu Engineering Lab of Water and Soil Eco-remediationJiangsu Province Engineering Research Center of Environmental Risk Prevention and Emergency Response TechnologyNanjing Normal UniversityNanjing 210023China Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application Nanjing 210023China

Conversion of labile Pb species into chloropyromorphite(CPY)using phosphorus-bearing amendments was considered to be an ideal strategy in soil passivation remediation.However,the fate and transport of CPY in the soil are poorly understood.This study aims to fill the knowledge gap by evaluating the fate and transport of CPY under environmentally relevant conditions of humic acid(HA),pH,electrolyte concentration,and species through the saturated sandy medium.Results showed that bare CPY colloids are basically immobile in sandy porous media while the co-existence of HA made the transport of CPY improved by30%-93.5%.Facilitated transport of CPY was attributed to the increased stability of CPY and the repulsive interaction between CPY particles and sands due to HA adsorption.The mobility of CPY was also increased with increasing pH from 5.0 to 9.0.When the pH was 9 with a10 mmol/L NaCl background solution,the stronger energy barrier between CPY and sand led to enhanced transport behavior.The divalent Ca^(2+)had a more dramatic effect than monovalent Na^(+)on the aggregation and sedimentation of CPY colloids due to its effectivescreening of the surface charge of CPY and bridging interaction with CPY particles.Derjaguin-LandauVerwey-Overbeek theory and attachment efficiency calculation indicated that high energy barriers were responsible for the high mobility of CPY colloids,while the retention of CPY in sands was mainly caused by secondary energy minimum and physically straining.The findings of this work can help to evaluate the fate of soil passivation remediation products in natural water and soil.

关键词： Chloropyromorphite DLVO theory Stability Saturated porous medium Transport

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Human influence on the duration of extreme temperature events in Asia's hotspot regions

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Advances in Climate Change Research 2024年第2期15卷 312-326页

作者： Zi-Meng WANG Hong-yun MA wei li Hai-Shan CHEN Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD)/Key Laboratory of Meteorological Disaster Ministry of Education(KLME)Nanjing University of Information Science and TechnologyNanjing 210044China

Observations and models indicate that human activities exert a considerable impact on the frequency and intensity of extreme temperature events,which are associated with global warming.However,changes in the duration of extreme temperature events and their association with human influence have not been considered in most studies.Thus,the possible relationship between the observed changes in the warm and cold spell duration(WSDI and CSDI)in hotspot regions during 1960-2014 and human influence was investigated based on the NCEP/NCAR reanalysis version 1 and Coupled Model Inter-comparison Project Phase 6(CMIP6)data.Constraint projection based on these attribution results was also performed.The optimal fingerprinting technique was used to compare observed changes in WSDI and CSDI to simulated changes averaged across eight CMIP6 models.Results show that anthropogenic(ANT)forcing contributed to the observed increase in WSDI in the three hotspot regions(West Asia,South Asia and Southeast Asia),with the majority of the changes being attributed to greenhouse gas forcing.However,a generally weak ANT signal can be observed in the decreasing trend of CSDI and can be detected in South and Southeast Asia.The influence of aerosol forcing remains undetected in either WSDI or CSDI,which differs from the results for frequency and intensity of extreme temperatures.The attribution results revealed that the constrained projection of WSDI is lower than the raw projection for 2015-2100 in West Asia and Southeast Asia.However,no differences in future CSDI changes are found in Southeast Asia between the constrained and raw projections.

关键词： Extreme temperature events Duration Detection attribution Constraint projection Hotspot regions

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