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Stability Investigation and Improvement for DC Cascade Systems with Simplified Impedance-based Stability Criterion

CSEE Journal of Power and Energy Systems 2024年第3期10卷 1044-1052页

作者： Junbin Fang Zhikang Shuai Yang Li Zhibing Wang xiangyang wu xia Shen Z.John Shen College of Electrical and Information Engineering Hunan UniversityChangsha 410082China Renewable Energy Department of China Electric Power Research Institute Beijing 100192China Department of Electrical and Computer Engineering Illinois Institute of TechnologyChicagoIL 60616USA IEEE

In DC distributed power systems(DPSs),the complex impedance interactions possibly lead to DC bus voltage oscillation or *** previous research,the stability analysis of DPSs is implemented based on mathematical analysis in control *** specific mechanisms of the instability of the cascade system have not been intuitively *** this paper,the stability analysis of DPSs based on the traditional Nyquist criterion is simplified to the resonance analysis of the seriesconnected port impedance(Z=R+jX)of source and load *** reveals that the essential reason for impedance instability of a DC cascade system is that the negative damping characteristic(R<0)of the port the overall impedance amplifies the internal resonance source at reactance zero-crossing *** simplified stability criterion for DC cascade systems can be concluded as:in the negative damping frequency ranges(R<0),there exists no zero-crossing point of the reactance component(i.e.,X=0).According to the proposed stability criterion,the oscillation modes of cascade systems are classified.A typical one is the internal impedance instability excited by the negative damping,and the other one is that the external disturbance amplified by negativity in a low stability ***,the impedance reshaping method for stability improvement of the system can be further *** validity of the simplified criterion is verified theoretically and experimentally by a positive damping reshaping method.

关键词： DC cascaded system,impedance model impedance reconstruction stability criterion

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Sparse antenna array design methodologies:A review

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Journal of Electronic Science and Technology 2024年第3期22卷 1-15页

作者： Pan wu Yan-hui Liu Zhi-Qin Zhao Qing-Huo Liu School of Electronic Science and Engineering University of Electronic Science and Technology of ChinaChengdu611731China Eastern Institute of Technology Ningbo315200China

Designing a sparse array with reduced transmit/receive modules(TRMs)is vital for some applications where the antenna system’s size,weight,allowed operating space,and cost are *** arrays exhibit distinct architectures,roughly classified into three categories:Thinned arrays,nonuniformly spaced arrays,and clustered *** numerous advanced synthesis methods have been presented for the three types of sparse arrays in recent years,a comprehensive review of the latest development in sparse array synthesis is *** work aims to fill this gap by thoroughly summarizing these *** study includes synthesis examples to facilitate a comparative analysis of different techniques in terms of both accuracy and ***,this review is intended to assist researchers and engineers in related fields,offering a clear understanding of the development and distinctions among sparse array synthesis techniques.

关键词： Clustered array Nonuniformly spaced array Sparse antenna array Synthesis method Thinned array

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Nucleophilic amino acids as a renewable alternative to petrochemically-derived amines in glycerol epoxy resins

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Journal of Bioresources and Bioproducts 2024年第2期9卷 222-232页

作者： Yunyi Liang Yonghong Luo Yingji wu xiaona Li Quyet Van Le Jianzhang Li Changlei xia Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources International Innovation Center for Forest Chemicals and MaterialsCollege of Materials Science and EngineeringNanjing Forestry UniversityNanjing 210037China Department of Materials Science and Engineering Institute of Green Manufacturing TechnologyKorea UniversitySeoul 02841South Korea

The standard epoxy resin curing agents revealed are from unsustainable petroleum-based sources,which produce poisonous exhaust when *** acids,a bio-based epoxy curing agent with amino and carboxyl groups,are another potential curing ***-soluble epoxy resins cured with lysine(Lys),glutamic acid(Glu),leucine(Leu),and serine(Ser)as amino acids were *** results showed that the water-soluble epoxy resin(glycerol epoxy resins,GER)was cured with Lys and Glu after *** transform infrared(FT-IR)spectroscopic analysis of the GER-Lys showed that the amino and carboxyl groups of Lys primarily reacted with the epoxy groups of *** elongation at break of Lys-cured GER(GER-Lys)cured at 70℃ with a molar ratio of 1꞉0.75 was 75.32%.The fact that elongations at break of GER-Lys(79.43%)were higher than those of GER-Glu(17.33%),respectively supports the decrease of crosslinking density by the amino acid-cured GER *** potential of Lys and Glu alternatives for petrochemical amines is demonstrated and provides promising opportunities for industrial application.

关键词： Curing agent Amino acids Bio-based epoxy resins Lysine Glutamic acid

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Monomeric and self-assembled crystal phases of TNBT

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Rare Metals 2024年第10期43卷 5442-5448页

作者： Yun-hui wu Hua-Bei You Wei-Kai Cui Zhi-Qian Cao xiao Dong Zi-hui Meng Ming Huang School of Chemistry and Chemical Engineering Beijing Institute of Technology Institute of Chemical Materials China Academy of Engineering Physics

（3,3′,5,5′-Tetranitro-4,4′-bi-1,2,4-Triazole） TNBT was designed and predicted more than three decades ago as a high energy *** with many other designed molecules,TNBT has not been successfully synthesized and has not been computationally studied in *** this work,theoretical calculations at density functional theory （DFT）level of theory were carried out for both the gas phase molecule and its possible bulk crystal *** （DFT） computations show that TNBT is comparable to CL-20 with high bulk density,

关键词： Density functional theory

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Methylthio side-chain modified quinoidal benzo-[1,2-b:4,5-b']dithiophene derivatives for high-performance ambipolar organic field-effect transistors

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Science China Chemistry 2024年第10期67卷 3357-3365页

作者： Li Chen xiaoqi Luo Nuoya Li Shaoqian Peng Qing Jiang Di wu Jianlong xia State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Center of Smart Materials and DevicesWuhan University of TechnologyWuhan 430070China School of Chemistry Chemical Engineering and Life ScienceWuhan University of TechnologyWuhan 430070China Department of Chemistry National University of SingaporeSingapore 117543Singapore

Quinoidal small molecule semiconductors hold huge potential in ambipolar organic field-effect transistors(OFETs)and organic spintronic ***,two quinoidal molecules with methylthio side chains were synthesized to develop molecular semiconductors with high ambipolar mobility,designated QBDTS and *** theoretical calculation results reveal that QBDTS has a closed-shell structure while QTBDTS showed an open-shell structure with a biradical character(y0)of 0.46 and its magnetic properties were further investigated using electron paramagnetic resonance(EPR)and superconducting quantum interference device(SQUID)*** methyl side chains showed a large impact on the molecular orbital *** HOMO/LUMO levels of QBDTS and QTBDTS were measured to be-5.66/-4.56 and-5.27/-4.48 eV,respectively,which are favorable for ambipolar charge transport in ***,the spin-coated QBDTS displayed hole and electron mobilities of 0.01 and 0.5 cm^(2)V^(-1)s^(-1)while QTBDTS showed a record high hole mobility of 1.8 cm^(2)V^(-1)s^(-1)and electron mobility of 0.3 cm^(2)V^(-1)s^(-1).Moreover,comparative studies of the thin film morphologies also manifested the beneficial influence of methyl side chains on film crystallinity and molecule *** results strongly proved that methyl side chain engineering can be a simple but efficient strategy for modulating electronic properties and molecular stacking *** work also represents a big advancement for quinoidal molecular semiconductors in ambipolar OFET applications.

关键词： side-chain modification quinoidal molecules ambipolar diradicals organic field-effect transistors

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OCTA characteristics in non-arteritic central retinal artery occlusion and correlation with visual acuity

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International Journal of Ophthalmology(English edition) 2024年第2期17卷 289-296页

作者： Hong-xia Gong Bin wu Shi-Yong Xie Wei Zhang Song Chen Tianjin Key Lab of Ophthalmology and Visual Science Department of Ophthalmology for Integrated Traditional Chinese and Western MedicineTianjin Eye HospitalTianjin 300020China Clinical College of Ophthalmology Tianjin Medical UniversityTianjin 300010China Eye Hospital Affiliated to Nankai University Tianjin 300020China

AIM:To observe the retinal and choroidal circulations in patients with non-arteritic permanent central retinal artery occlusion(NA-CRAO)via optical coherence tomography angiography(OCTA)and analyze their correlation with visual ***:Sixty-two eyes with clinically confirmed acute NA-CRAO were included in the study and divided into:A type(mild n=29),B type(moderate n=27)and C type(severe n=6)based on the degree of visual loss,retinal edema,and arterial blood flow delay in fundus fluorescence angiography(FFA).Contralateral healthy eyes were used as the control ***-corrected visual acuity(BCVA),slit lamp microscopy,indirect ophthalmoscopy,fundus color photography,OCTA,and FFA were ***’s correlation analysis was used to determine the correlations between retinal and choroidal vessels and visual ***:There were no statistically significant differences in age,gender,and intraocular pressure among the three types and the control group(P>0.05).Vessel density in deep capillary plexus(VD-DCP)significantly decreased(P<0.05)in all three types of NA-CRAO patients compared to the control *** density in superficial vascular plexus(VD-SVP)significantly decreased(P<0.05)in type A patients and choriocapillaris flow area significantly decreased(P<0.05)in type B and type C patients compared to the control group;while outer retinal flow areas significantly increased in the type A(P<0.05)and decreased in type C patients(P<0.05).The retinal thickness significantly increased in type C group(P<0.05).The VD-SVP at fovea in the type A was significantly lower than both of type B and *** VD-SVP at nasal parafovea in type A and B was significantly lower than type C(P<0.05).The logMAR BCVA of type A was significantly better than that of type B and C groups(P<0.05).Spearman’s correlation analysis showed that the logMAR BCVA was positively correlated with VD-SVP at fovea(r=0.679,P=0.031)and nasal parafovea(r=0.826,P=0.013).CONCLUSION:OCTA is valua

关键词： non-arteritic central retinal artery occlusion fundus fluorescence angiography optical coherence tomography angiography retinal vessel density visual acuity

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Metal complexes of bipyridine-functionalized covalent organic frameworks as efficient electrocatalysts for oxygen evolution reaction

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Rare Metals 2024年第7期43卷 3096-3106页

作者： Zhuang-Zhuang wu Tian xia Ying Liang Yong-Peng Li Zhu-Yin Sui Li-Juan Feng Dao-Xiong wu Xin-Long Tian Qi Chen State Key Laboratory of Marine Resource Utilization in South China Sea School of Marine Science and EngineeringHainan UniversityHaikou 570228China School of Chemistry and Chemical Engineering Yantai UniversityZhuhai519041China School of Bioengineering Zhuhai Campus of Zunyi Medical UniversityZhuhai519041China

Electrocatalytic water splitting is considered a clean and practic al method for producing *** this study,COF-Bpy,a bipyridine-functionalized covalent organic framework(COF),was prepared via post-synthetic modification,after which electrocatalysts for the oxygen evolution reactions(OER)were formed through coordination to single-or double-transition metals(Fe,Co,Ni,FeCo,FeNi or CoNi).COF-Bpy@FeNi delivered the best OER performance among the studied electrocatalysts,with an overpotential of 399 mV at 10 mA·cm^(-2)in an alkaline electrolyte(1.0 mol·L^(-1)KOH aqueous).Notably,the electrocatalytic performance of COF-Bpy@FeNi showed slight degradation during durability testing,which is ascribable to its irreversible benzoquinoline structure and strong metal *** expected,COF-Bpy@FeNi exhibited a low overpotential of 347 mV at a turnover frequency(TOF)of 0.1 s^(-1),which suggests that COF-Bpy@FeNi possesses excellent intrinsic electroc atalytic OER ***,density functional theory(DFT)calculations reveal that the Ni site plays a major role,while the Fe site adjusts the electronic structure of the Ni ions,which rationalizes the excellent OER properties of COF-Bpy@*** study not only provides a simple and efficient method for complexing COFs with transition metals,but also offers a novel strategy for designing porous organic polymer electrocatalysts.

关键词： Covalent organic framework Oxygen evolution reactions(OER)electrocatalyst Nickel-iron synergy Water splitting

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Thickness dependence of superconductivity in layered GeP_(5)

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Rare Metals 2024年第3期43卷 1323-1328页

作者： Lin wu Ke-Meng Yang Wei Gan Rui-Chun xiao Ya-Jie Dai Xi Tang Hong Lin hui Han hui Li Information Materials and Intelligent Sensing Laboratory of Anhui Province Institute of Physical Science and Information TechnologyAnhui UniversityHefei230601China

Understanding the relationship between dimensionality and superconductivity has attracted substantial research *** this work,we report the effective modulation of superconductivity in GeP_(5)through *** superconducting phase transition temperature improves by~10%as the thickness of GeP_(5)decreases from bulk to~96 nm,behaving as a unique negative relationship between the superconducting phase transition temperatureand thickness.

关键词： superconductivity dimensionality

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Acupuncture and moxibustion for irritable bowel syndrome:An umbrella systematic review

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Journal of Integrative Medicine 2024年第1期22卷 22-31页

作者： Yue-ying Ma Zhou Hao Zi-yi Chen Yan-xi Shen hui-rong Liu Huan-gan wu Chun-hui Bao Shanghai Clinical Research Centre for Acupuncture and Moxibustion Yueyang Hospital of Integrated Chinese and Western MedicineShanghai University of Traditional Chinese MedicineShanghai 200437China Key Laboratory of Acupuncture and Immunological Effects Shanghai University of Traditional Chinese MedicineShanghai 200030China

BackgroundIrritable bowel syndrome(IBS)is a functional bowel disease characterized by abdominal pain or discomfort associated with altered bowel *** clinical studies have demonstrated the effectiveness of acupuncture and moxibustion for *** systematic reviews of acupuncture and moxibustion for IBS have been published in recent years,but their results are not entirely *** evaluate the methodological,reporting,and evidence quality of systematic reviews of acupuncture and moxibustion for *** strategySystematic reviews of acupuncture and moxibustion for IBS published before February 20,2023 were searched in eight databases:PubMed,Embase,Cochrane Library,Web of Science,China National Knowledge Infrastructure,Wanfang Data,VIP Database for Chinese Technical Periodicals,and China Biology *** keywords used for literature search were acupuncture,moxibustion,systematic review,meta-analysis,and irritable bowel *** criteriaSystematic reviews and meta-analyses of randomized controlled trials of acupuncture and moxibustion for IBS were *** extraction and analysisRelevant information was independently extracted by two *** A MeaSurement Tool to Assess systematic Reviews 2(AMSTAR 2),Preferred Reporting Items for Systematic Reviews and Meta-Analyses(PRISMA 2020),and Grading of Recommendations Assessment,Development and Evaluation(GRADE)were used to evaluate the methodological quality,reporting quality and evidence quality,*** total of 342 studies were retrieved and 15 systematic reviews were *** results of AMSTAR 2 showed low methodological quality in 2 studies and very low methodological quality in the remaining 13 studies,with main issues being failure to register a protocol,incomplete search strategy,not providing a list of excluded studies,incomplete consideration of the risk of bias in the included studies,and a failure to assess the publication *** results of

关键词： Irritable bowel syndrome Acupuncture Moxibustion Umbrella systematic review Systematic review

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Unlocking the Potential of Poly(butylene succinate)through Incorporation of Vitrimeric Network Based on Dynamic Imine Bonds

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Chinese Journal of Polymer Science 2024年第10期42卷 1414-1424,I0006页

作者： Shan-Song wu hui-Juan Lu Yi-Dong Li Shui-Dong Zhang Jian-Bing Zeng Chongqing Key Laboratory of Soft-Matter Material Manufacturing School of Chemistry and Chemical EngineeringSouthwest UniversityChongqing400715China School of Mechanical and Automotive Engineering South China University of TechnologyGuangzhou510640China

Poly(butylene succinate)(PBS)exhibits many advantages,such as renewability,biodegradability,and impressive thermal and mechanical properties,but is limited by the low melt viscosity and strength resulted from the linear *** address this,vitrimeric network was introduced to synthesize PBS vitrimers(PBSVs)based on dynamic imine bonds through melt polymerization of hydroxyl-terminated PBS with vanillin derived imine containing compound and hexamethylene diisocyanate using trimethylolpropane as a crosslinking *** with different crosslinking degrees were synthesized through changing the content of the crosslinking *** effect of crosslinking degree on the thermal,theological,mechanical properties,and stress relaxation behavior of the PBSVs was studied in *** results demonstrated that the melt viscosity,melt strength,and heat resistance were enhanced substantially without obvious depression in crystallizability,thermal stability,and mechanical properties through increasing crosslinking *** addition,the PBSVs exhibit thermal reprocessability with mechanical properties recovered by more than 90%even after processing for three ***,PBSV with improved melt properties shows significantly improved foamability compared to commercial *** research contributes to the advancement of polymer technology by successfully developing PBS vitrimers with improved properties,showcasing their potential applications in sustainable and biodegradable materials.

关键词： Poly(butylene succinate) Vitrimer Imine bonds Foamability

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