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Transient Stability Analysis of Converter-based Islanded Microgrids Based on Iterative Equal Area Criterion Considering Reactive Power Loop Dynamics and Varying Damping

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Journal of Modern Power Systems and Clean Energy 2024年第4期12卷 1170-1182页

作者： Xilin Li Jingyi Zhang Zhen Tian Xiaoming Zha wei Wang Meng huang Chong shao Hubei Key Laboratory of Power Equipment&System Security for Integrated Energy School of Electrical Engineering and AutomationWuhan UniversityWuhanChina NARI Technology Co. Ltd.NanjingChina State Grid Gansu Electric Power Company LanzhouChina

With the rapid increase in the installed capacity of renewable energy in modern power systems,the stable operation of power systems with considerable power electronic equipment requires further *** converter-based islanded mi-crogrid(CIM)systems equipped with grid-following(GFL)and grid-forming(GFM)voltage-source converters(VSCs),it is chal-lenging to maintain stability due to the mutual coupling effects between different VSCs and the loss of voltage and frequency sup-port from the power *** previous studies,quantitative transient stability analysis was primarily used to assess the active power loop of ***,frequency and voltage dy-namics are found to be strongly coupled,which strongly affects the estimation result of stability *** addition,the vary-ing damping terms have not been fully *** bridge these gaps,this paper investigates the transient stability of CIM consid-ering reactive power loop dynamics and varying ***,an accuracy-enhanced nonlinear model of the CIM is derived based on the effects of reactive power loop and post-disturbance frequency jump *** these effects will elimi-nates the risk of *** reactive power loop dynamics make the model coefficients be no longer constant and thus vary with the power *** evaluate quantitatively the effects of re-active power loop and varying damping on the transient stability of CIM,an iterative criterion based on the equal area criterion theory is *** addition,the effects of parameters on the stable boundary of power system are analyzed,and the dynamic interaction mechanisms are *** and experiment results verify the merits of the proposed method.

关键词： Transient stability converter iterative criterion reactive power loop post-disturbance frequency jump

Distribution System Restoration with Cyber Failures Based on Co-dispatching of Multiple Recovery Resources

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Journal of Modern Power Systems and Clean Energy 2024年第4期12卷 1096-1112页

作者： Zhengze wei Kaigui Xie Bo Hu Yu Wang Changzheng shao Pierluigi Siano Jun Zhong National Key Laboratory of Power Transmission Equipment Technology Chongqing UniversityChongqing 400044China Department of Management and Innovation Systems University of SalernoFisciano 84084Italyand he is also with the Department of Electrical and Electronic Engineering ScienceUniversity of JohannesburgJohannesburg 2006South Africa Shenzhen Power Supply Co. Ltd.China Southern Power GridShenzhen 518000China

Improving the restoration efficiency of a distribu-tion system is essential to enhance the ability of power systems to deal with extreme *** distribution system restoration(DSR)depends on the interaction among the electric network(EN),cyber network(CN),and traffic network(TN).However,the coordination of these three networks and co-dispatching of multiple recovery resources have been mostly *** paper proposes a novel DSR framework,which is formulated as a mixed-integer linear programming(MILP)*** fail-ures in cyber lines result in cyber blind areas,which restrict the normal operation of remote-controlled *** acceler-ate the recovery process,multiple recovery resources are uti-lized including electric maintenance crews(EMCs),cyber main-tenance crews(CMCs),and emergency communication vehicles(ECVs).Specifically,CMCs and ECVs restore the cyber func-tion of switches in cooperation,and EMCs repair damaged elec-tric *** travel time of these three dispatchable resources is determined by *** effectiveness and superiority of the proposed framework are verified on the modified IEEE 33-node and 123-node test systems.

关键词： Distribution system restoration(DSR) network coupling maintenance crew co-dispatching emergency communicationvehicle

Infrared microspectroscopy beamline BL06B at SSRF

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Nuclear Science and Techniques 2024年第1期35卷 10-17页

作者： Te Ji hua-Chun Zhu wei-wei Peng Jie Wang Hong-wei Zhao Ai-Guo Li Min Chen Shanghai Synchrotron Radiation Facility Shanghai Advanced Research InstituteChinese Academy of SciencesShanghai 201210China

The infrared microspectroscopy beamline(BL06B) is a phase Ⅱ beamline project at the Shanghai Synchrotron Radiation Facility(SSRF). The construction and optical alignment of BL06B were completed by the end of 2020. By 2021, it became accessible to users. The synchrotron radiation infrared(SRIR) source included edge radiation(ER) and bending magnet radiation(BMR). The extracted angles in the horizontal and vertical directions were 40 and 20 mrad, respectively. The photon flux, spectral resolution, and focused spot size were measured at the BL06B endstation, and the experimental results were consistent with theoretical calculations. SRIR light has a small divergence angle, high brightness, and a wide wavelength range. As a source of IR microscopy, it can easily focus on a diffraction-limited spatial resolution with a high signal-to-noise ratio(SNR). The BL06B endstation can be applied in a wide range of research fields, including materials, chemistry, biology, geophysics, and pharmacology.

关键词： Synchrotron radiation Infrared beamline Infrared microspectroscopy

Synthesis of poly(thiourethane-alt-thioester)by alternating ring-opening copolymerization of N-thiocarboxyanhydrides and episulfides

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Science China Chemistry 2024年第9期67卷 3091-3097页

作者： wei Xiong Tianjun Yue Haiwang Lai Chunyan Lyu weimin Ren hua Lu Beijing National Laboratory for Molecular Sciences Center for Soft Matter Science and EngineeringKey Laboratory of Polymer Chemistry and Physics of Ministry of EducationCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871China State Key Laboratory of Fine Chemicals Dalian University of TechnologyDalian 116081China

Polythiourethanes(PTU)and polythioesters(PTE)derived from renewable sources are emerging sustainable polymers for their excellent degradability and ***,P(TU-alt-TE)copolymers have been rare and challenging to ***,we report the efficient synthesis of novel P(TU-alt-TE)copolymers via the alternating copolymerization of N-thiocarboxyanhydrides(NTA)/episufides(ES)and provide mechanistic insight into the alternating chain propagation process via density functional theory(DFT)*** incorporation of ESs into traditional peptide backbone is capable of adjusting the glass transition temperature below thermal decomposition temperature,which confers better thermal processability by regulating the rigidity of the backbone and the hydrogen bond interaction among the polymer *** PTUs with tailored properties are accessible by altering the feeding ratio of NTAs and(bifunctional)***,the thiourethane in the backbone can endow interesting underwater adhesion properties to the *** the broad scope of NTA and ES monomers,this method is expected to provide a promising and general route to a wide range of P(TU-alt-TE)copolymers with diverse properties.

关键词： poly(thiourethane-alt-thioester) alternating ring-opening copolymerization N-thiocarboxyanhydrides episulfides

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Enhancing energy storage density of poly(arylene ether nitrile)via incorporating modified barium titanate nanorods and hotstretching

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Nano Research 2024年第8期17卷 7574-7584页

作者： Zhengjiao Zhang Lingyun Zhou Lingling Wang Qingqing Hao Xiufu hua Renbo wei School of Chemical Engineering Northwest UniversityXi’an 710069China Yangtze Delta Region Institute Tsinghua UniversityJiaxing 314006China

Dielectric energy storage materials that are extensively employed in capacitors and other electronic devices have attracted increasing attentions amid the rapid progress of electronic ***,the commercialized polymeric and ceramic dielectric materials characterized by low energy storage density face numerous limitations in practical *** this study,we report the simultaneous enhancement of dielectric properties of poly(arylene ether nitrile)(PEN)through the incorporating of sulfonated PEN(SPEN)modified barium titanate nanorods(BTNR)(SPEN@BTNR)and *** is synthesized using a two-step hydrothermal method,aminated with KH550,and then reacted with SPEN to form the cladding-modified SPEN@*** to the intrinsic high permittivity of barium titanate(BT)and enhanced compatibility between SPEN@BTNR and PEN stemming from the cladding of SPEN,the dielectric constant and breakdown strength of SPEN@BTNR/PEN composite are as high as 14.0 at 103 Hz and 198.1 kV/mm at the doping amount of 15 wt.%,*** a result,the energy storage density of SPEN@BTNR/PEN is increased to 2.43 J/cm^(3),compared with that of 0.82 J/cm^(3)for *** addition,derived from the rearrangement of SPEN@BTNR and orientation of PEN after hot-stretching,the dielectric constant and breakdown strength of SPEN@BTNR/PEN with 15 wt.%fillers are further enhanced to 17.1 and 204.8 kV/mm,respectively,resulting in an energy storage density of 3.36 J/cm^(3).The boosting of energy storage density up to 310%provides a new idea for improving the performances of dielectric energy storage materials.

关键词： barium titanate nanorods poly(arylene ether nitrile) dielectric constant breakdown strength energy density

Circ_0004592:An auxiliary diagnostic biomarker for gastric cancer

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World Journal of Gastrointestinal Oncology 2024年第6期16卷 2757-2768页

作者： Shan Kong Yan-hua Xu Ming Zheng shao-Qing Ju Heng-Chuan Shi Department of Laboratory Medicine Jiangsu Province Official HospitalNanjing 210000Jiangsu ProvinceChina Department of Laboratory Medicine Northern Jiangsu People’s HospitalYangzhou 225000Jiangsu ProvinceChina Department of Laboratory Medicine The Affiliated Hospital of Nantong UniversityNantong 226001Jiangsu ProvinceChina

BACKGROUND Gastric cancer(GC)has a high mortality rate,and robust diagnostic biomarkers are currently ***,the clinical relevance of circular RNAs(circRNAs)as GC biomarkers remains largely *** To evaluate the potential of novel circRNA circ_0004592 in the early screening and prognosis of *** High-throughput sequencing of circRNAs was performed to screen for potential target ***_0004592 expression was examined in GC tissues,cells,and *** samples were collected from healthy subjects’patients,as well as from patients with benign lesions,precancerous lesions,and GC,whereafter the diagnostic accuracy of circ_0004592 was *** correlation between circ_0004592 levels in plasma and clinicopathological data of patients with GC was further *** Circ_0004592 was upregulated in both the tissue and plasma of patients with ***,circ_0004592 expression was higher in patients with precancerous lesions than in healthy controls while being highest in patients with *** the same patient,the postoperative plasma level of circ_0004592 was lower than that in the preoperative ***,circ_0004592 level was significantly correlated with tumor differentiation,tumor depth,and lymph node *** area under the curve(AUC)of plasma circ_0004592 exhibited high sensitivity and specificity for differentiating patients with GC from healthy *** based on circ_0004592,carcinoembryonic antigen,and cancer antigen 199 achieved a superior AUC and was highly *** Plasma circ_0004592 may represent a potential non-invasive auxiliary diagnostic biomarker for patients with GC.

关键词： Biomarker Circular RNA Diagnosis Gastric cancer Plasma

On the Performances of Estimating Stellar Atmospheric Parameters from CSST Broad-band Photometry

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Research in Astronomy and Astrophysics 2024年第4期24卷 161-173页

作者： Rui-Feng Shi Yang huang Xin-Yi Li hua-wei Zhang School of Astronomy and Space Science University of Chinese Academy of SciencesBeijing 100049China South-Western Institute for Astronomy Research Yunnan UniversityKunming 650500China CAS Key Lab of Optical Astronomy Key Laboratory of Space Astronomy and TechnologyNational Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China College of Physics and Electronic Engineering Qilu Normal UniversityJinan 250200China Department of Astronomy School of PhysicsPeking UniversityBeijing 100871China Kavli Institute for Astronomy and Astrophysics Peking UniversityBeijing 100871China

Deriving atmospheric parameters of a large sample of stars is of vital importance to understand the formation and evolution of the Milky *** surveys,especially those with near-ultraviolet filters,can offer accurate measurements of stellar parameters,with the precision comparable to that from low/medium resolution *** this study,we explore the capability of measuring stellar atmospheric parameters from Chinese Space Station Telescope(CSST)broad-band photometry(particularly in the near-ultraviolet bands),based on synthetic colors derived from model *** find that colors from the optical and near-ultraviolet filter systems adopted by CSST show significant sensitivities to the stellar atmospheric parameters,especially the *** to our mock data tests,the precision of the photometric metallicity is quite high,with typical values of0.17 and 0.20 dex for dwarf and giant stars,*** precision of the effective temperature estimated from broad-band colors are within 50 K.

关键词： methods:data analysis stars:abundances surveys

Clinical characteristics and treatment of splenic infarction in children with systemic lupus erythematosus

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World Journal of Pediatrics 2024年第5期20卷 525-531页

作者： Yan Li Yu-Rong Piao Tong-Xin Han hua-wei Mao Department of Immunology Ministry of Education Key Laboratory of Major Diseases in ChildrenBeijing Key Laboratory for Genetics of Birth DefectsNational Center for Children’s HealthBeijing Children’s HospitalCapital Medical UniversityNo.56 Nan Li Shi LuBeijing100045China

Splenic infarction(SI)is a rare clinical phenomenon that occurs when the blood supply to the spleen is interrupted,resulting in tissue ischemia and necrosis[1].There are many causes of SI;in adult patients,cardioembolism,hematological malignancy,and infectious disease are the most common[2].Rheumatic diseases,especially systemic lupus erythematosus(SLE)and granulomatosis with polyangitis,can also lead to SI[3];however,only a few cases have been *** are currently no statistically meaningful data on the etiology of SI in *** most patients with SI can recover after conservative treatment,a small number of patients develop complications,such as splenic abscess,splenic rupture,splenic hemorrhage,and hemoperitoneum,and may even undergo splenectomy in severe cases.

关键词： erythematosus lupus treatment

Time-dependent model for two-phase flow in ultra-high water-cut reservoirs: Time-varying permeability and relative permeability

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Petroleum Science 2024年第4期21卷 2536-2553页

作者： shao-Chun Wang Na Zhang Zhi-Hao Tang Xue-Fei Zou Qian Sun wei Liu College of Energy Resources Chengdu University of Technology College of Petroleum Engineering Shandong Institute of Petroleum and Chemical Technology

For the ultra-high water-cut reservoirs, after long-term water injection exploitation, the physical properties of the reservoir change and the heterogeneity of the reservoir becomes increasingly severe, which further aggravates the spatial difference of the flow field. In this study, the displacement experiments were employed to investigate the variations in core permeability, porosity, and relative permeability after a large amount of water injection. A relative permeability endpoint model was proposed by utilizing the alternating conditional expectation(ACE) transformation to describe the variation in relative permeability based on the experimental data. Based on the time dependent models for permeability and relative permeability, the traditional oil-water two-phase model was improved and discretized using the mimetic finite difference method(MFD). The two cases were launched to confirm the validation of the proposed model. The impact of time-varying physical features on reservoir production performance was studied in a real water flooding reservoir. The experimental results indicate that the overall relative permeability curve shifts to the right as water injection increases. This shift corresponds to a transition towards a more hydrophilic wettability and a decrease in residual oil saturation. The endpoint model demonstrates excellent accuracy and can be applied to time-varying simulations of reservoir physics. The impact of variations in permeability and relative permeability on the reservoir production performance yields two distinct outcomes. The time-varying permeability of the reservoir results in intensified water channeling and poor development effects. On the other hand, the time-varying relative permeability enhances the oil phase seepage capacity, facilitating oil displacement. The comprehensive time-varying behavior is the result of the combined influence of these two parameters, which closely resemble the actual conditions observed in oil field expl

关键词： Mimetic finite difference Water flooding reservoir Time-varying physical properties Numerical simulation