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Molecular Chain Flexibility and Dielectric Loss at High-Frequency:Impact of Ester Bond Arrangement in Poly(ester imide)s

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Chinese Journal of Polymer Science 2024年第8期42卷 1122-1133页

作者： Ya-Dong Li Hong Li Lu-Kun feng feng Bao Ming-Liang wang cai-Zhen Zhu Zhao-Hui Zheng Xiao-Bin Ding Jian Xu Chengdu Institute of Organic Chemistry Chinese Academy of SciencesChengdu 610041China University of Chinese Academy of Sciences Beijing 100081China Institute of Low-Dimensional Materials Genome Initiative College of Chemistry and Environmental EngineeringShenzhen UniversityShenzhen 518060China

The evolution of high-frequency communication has accentuated the significance of controlling dielectric properties in polymer ***,it has been theorized that rigid molecular chains lead to lower dielectric ***,the validity of this proposition at high frequencies remains *** scrutinize the correlation between chain flexibility and dielectric properties,we synthesized six poly(ester imide)s(PEIs)with systematically varied molecular chain flexibilities by modifying the ester's substitution on the aromatic *** introduction of ester bonds bestowed all PEI films with a low dielectric dissipation factor(D_(f)),ranging from 0.0021 to 0.0038 at 10 GHz in dry *** dry D_(f)displayed a pattern consistent with volume polarizability(P/V).Unexpectedly,PI-mmm-T,featu ring the most flexible molecular chain,exhibited the lowest dielectric loss under both dry(0.0021@10 GHz)and hygroscopic(0.0029@10 GHz)***,the observed increase in D_(f)after humidity absorption suggests that the high dielectric loss of PEI in applications may be attributed to its hygroscopic *** simulations and characterization of the aggregation structure revealed that the smaller cavities within flexible molecular chains,after close stacking,impede the entry of water *** sacrificing high-temperature resistance,the precursor exhibited enhanced solubility properties and could be processed into high-quality *** research unveils new insights into the relationship between flexibility and highfrequency dielectric loss,offering innovative perspectives on synthesizing aromatic polymers with exceptional dielectric properties.

关键词： 5G communications Poly(ester imide)s Molecular chain flexibility Dielectric properties Humidity absorption

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Defect engineering on constructing surface active sites in catalysts for environment and energy applications

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Frontiers of Chemical Science and Engineering 2024年第7期18卷 11-32页

作者： Yawen cai Baowei Hu Xiangke wang School of Life Science Shaoxing UniversityShaoxing 312000China College of Environmental Science and Engineering North China Electric Power UniversityBeijing 102206China

The precise engineering of surface active sites is deemed as an efficient protocol for regulating surfaces and catalytic properties of *** engineering is the most feasible option to modulate the surface active sites of *** specific active sites on the catalyst allows precise modulation of its electronic structure and physicochemical ***,we outlined the engineering of several types of defects,including vacancy defects,void defects,dopant-related defects,and defect-based single atomic *** overview of progress in fabricating structural defects on catalysts via de novo synthesis or post-synthetic modification was ***,the applications of the well-designed defective catalysts in energy conversion and environmental remediation were carefully ***,current challenges in the precise construction of active defect sites on the catalyst and future perspectives for the development directions of precisely controlled synthesis of defective catalysts were also proposed.

关键词： defect engineering vacancy void defects doping single atomic sites

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Preparation of a high-performance synthetic pitch from aromatic hydrocarbons containing N/Cl

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新型炭材料（中英文） 2024年第4期39卷 655-667页

作者： ZHANG Yu-kun LIN Xiong-chao GAO Hong-feng XI Wen-shuai wang cai-hong wang Yong-gang School of Chemical&Environmental Engineering China University of Mining and Technology(Beijing)Beijing 100083China

The preparation of a synthetic pitch from aromatic monomers could easily regulate structure orientation at the molecu-lar level,which would be useful in *** isotropic synthetic pitch was prepared by a chlorine-and/or nitrogen-induced sub-stitution polymerization reaction method using aromatic hydrocarbon precursors containing Cl and N,which for this study were chloromethyl naphthalene and *** method was verified by investigating the structural changes under different synthesis conditions,and the synthesis mechanism induced by aromatics containing Cl was also *** result shows that the pyridinic N in quinoline contains a lone pair of electrons,and is an effective active site to induce the polymerization reaction by coupling with aromatic hydrocarbons containing *** reaction between such free radicals causes strong homopolymerization and oligomeriza-tion.A higher reaction temperature and longer reaction time significantly increased the degree of polymerization and thus increased the softening point of the pitch.A linear molecular structure was formed by the Cl substitution reaction,which produced a highly spinnable pitch with a softening point of 258.6℃,and carbon fibers with a tensile strength of 1163.82 MPa were *** study provides a relatively simple and safe method for the preparation of high-quality spinnable pitch.

关键词： Quinoline 1-Chloromethyl-naphthalene Synthetic pitch Spinnability Carbon fiber

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Dielectric Constant Calculation of Poly(vinylidene fluoride)Based on Finite Field and Density Functional Theory

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Chinese Journal of Polymer Science 2024年第5期42卷 655-662,I0009页

作者： Yong-Zhi Lin Lu-Kun feng Ya-Dong Li Chao-Fan Chang cai-Zhen Zhu Ming-Liang wang Jian Xu College of Chemistry and Environmental Engineering Shenzhen UniversityShenzhen518055China Chengdu Institute of Organic Chemistry Chinese Academy of SciencesChengdu610041China

In this study,we proposed a novel method that integrates density functional theory(DFT)with the finite field method to accurately estimate the polarizability and dielectric constant of *** approach effectively accounts for the influence of electronic and geometric conformation changed on the dielectric *** validated our method using polyethylene(PE)and polytetrafluoroethylene(PTFE)as benchmark materials,and found that it reliably predicted their dielectric ***,we explored the impact of conformation variations in poly(vinylidene fluoride)(PVDF)on its dielectric constant and *** resulting dielectric constants ofα-andγ-PVDF(3.0)showed excellent agreement with crystalline PVDF in *** findings illuminate the relationship between PVDF’s structural properties and its electrical behavior,offering valuable insights for material design and applications.

关键词： Dielectric constant PVDF Finite field DFT

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A novel method for AFRPs burrs removal:Principle of mechanochemo-induced fiber fracture

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Chinese Journal of Aeronautics 2024年第7期37卷 522-538页

作者： Jie XU Bo LI Pingfa feng Qiang wang feng feng Division of Advanced Manufacturing Tsinghua Shenzhen International Graduate SchoolTsinghua UniversityShenzhen 518055China Department of Mechanical Engineering Tsinghua UniversityBeijing 100084China Changhe Aircraft Industry(Group)Co.Ltd Jingdezhen 333000China

Burrs generated during the machining of Aramid-Fiber-Reinforced Composites(AFRPs)pose a challenge for the production efficiency of aircraft and helicopter housing *** studies have generally attempted to suppress burrs by referring to delamination suppression *** contrast to stratification,burrs are remediable machining *** such,a mechanochemical method with burrs trimming technological strategy are implemented to effectively combat ***,we clarify the mechanism by which aramid fibers cannot be cut off using analytical and numerical *** addition,the mechanism of fiber fracture with Modified Polyurethane Reactive Polymer(M-PUR),and development of anti-burr devices(thermostatic adhesive sealed generator)are ***,the experimental results show that the reduction rate in burr length is 87%-91%through the mechanochemical *** method not only opens a new avenue to solve the burr problem of aramid fibers but also builds an interdisciplinary bridge between polymer science and composite machining.

关键词： Mechanochemical method Burrs Orthogonal cutting Aramid fiber-reinforced composites Milling

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High-Performance Recyclable Furan-based Epoxy Resin and Its Carbon Fiber Composites with Dense Hydrogen Bonding

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Chinese Journal of Polymer Science 2024年第1期42卷 73-86,I0008页

作者： Chang-Bo Zhao Lu-Kun feng Hui Xie Ming-Liang wang Bing Guo Zhi-Yong Xue cai-Zhen Zhu Jian Xu Advanced Materials Research Institute North China Electric Power UniversityBejing 102206China Institute of Low-Dimensional Materials Genome Initiative College of Chemistry and Environmental EngineeringShenzhen UniversityShenzhen 518060China Chengdu Institute of Organic Chemistry Chinese Academy of SciencesChengdu 610041China School of Science and Shenzhen Key Laboratory of Flexible Printed Electronics Technology and Shenzhen Key Laboratory of Advanced Functional Carbon Materials Research and Comprehensive ApplicationHarbin Institute of TechnologyShenzhen 518055China

The emerging biomass-based epoxy vitrimers hold great potential to fulfill the requirements for sustainable development of *** the existence of dynamic chemical bonds in vitrimers often reduces both the thermal and mechanical properties of epoxy resins, it is challenging to produce recyclable epoxy vitrimers with both excellent mechanical properties and good thermal stability. Herein, a monomer 4-(((5-(hydroxymethyl)furan-2-yl)methylene)amino)phenol(FCN) containing furan ring with potential to form high density of hydrogen bonding among repeating units is designed and copolymerized with glycerol triglycidyl ether to yield epoxy resin(FCN-GTE), which intrinsically has dual hydrogen bond networks, dynamic imine structure and resultant high performance. Importantly, as compared to the BPA-GTE, the FCN-GTE exhibits significantly improved mechanical properties owing to the increased density of hydrogen bond network and physical crosslinking interaction. Furthermore, density functional theory(DFT) calculation and in situ FTIR analysis is conducted to decipher the formation mechanism of hydrogen bond network. In addition, the FCN-GTE possesses superior UV shielding, chemical degradation, and recyclability because of the existence of abundant imine bonds. Notably, the FCN-GTE-based carbon fiber composites could be completely recycled in an amine *** study provides a facile strategy for synthesizing recyclable biomass-based high-performance epoxy vitrimers and carbon fiber composites.

关键词： Furan Hydrogen bond network Dynamic Schiff base Carbon fiber composites Recycling

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Leech Poecilobdella manillensis protein extract ameliorated hyperuricemia by restoring gut microbiota dysregulation and affecting serum metabolites

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World Journal of Gastroenterology 2024年第29期30卷 3488-3510页

作者： Xia Liu Xing-Qiu Liang Tian-cai Lu Zhe feng Min Zhang Nan-Qing Liao feng-Lian Zhang Bo wang Li-Sheng wang Medical College Guangxi UniversityNanning 530004Guangxi Zhuang Autonomous RegionChina Department of Traditional Chinese Medicine HIV/AIDS Clinical Treatment Center of Guangxi(Nanning)The Fourth People’s Hospital of NanningNanning 530023Guangxi Zhuang Autonomous RegionChina Department of Science and Technology Ruikang Hospital Affiliated to Guangxi University of Chinese MedicineNanning 530011Guangxi Zhuang Autonomous RegionChina General Manager’s Office Guangxi Fuxinyi Biological Technology Co.Ltd.Pingnan 537300Guangxi Zhuang Autonomous RegionChina Department of Joint and Sports Medicine Ruikang Hospital Affiliated to Guangxi University of Chinese MedicineNanning 530011Guangxi Zhuang Autonomous RegionChina Department of Gerontology Nanning Social Welfare HospitalNanning 530004Guangxi Zhuang Autonomous RegionChina

BACKGROUND Hyperuricemia(HUA)is a public health concern that needs to be solved *** lyophilized powder of Poecilobdella manillensis has been shown to significantly alleviate HUA;however,its underlying metabolic regulation remains *** To explore the underlying mechanisms of Poecilobdella manillensis in HUA based on modulation of the gut microbiota and host *** A mouse model of rapid HUA was established using a high-purine diet and potassium oxonate *** mice received oral drugs or ***,16S rRNA sequencing and ultra-high performance liquid chromatography with quadrupole time-of-flight mass spectrometry-based untargeted metabolomics were performed to identify changes in the microbiome and host metabolome,*** levels of uric acid transporters and epithelial tight junction proteins in the renal and intestinal tissues were analyzed using an enzyme-linked immunosorbent *** The protein extract of Poecilobdella manillensis lyophilized powder(49 mg/kg)showed an enhanced anti-trioxypurine ability than that of allopurinol(5 mg/kg)(P<0.05).A total of nine bacterial genera were identified to be closely related to the anti-trioxypurine activity of Poecilobdella manillensis powder,which included the genera of Prevotella,Delftia,Dialister,Akkermansia,Lactococcus,Escherichia_Shigella,Enterococcus,and ***,22 metabolites in the serum were found to be closely related to the anti-trioxypurine activity of Poecilobdella manillensis powder,which correlated to the Kyoto Encyclopedia of Genes and Genomes pathways of cysteine and methionine metabolism,sphingolipid metabolism,galactose metabolism,and phenylalanine,tyrosine,and tryptophan *** analysis found that changes in the gut microbiota were significantly related to these *** The proteins in Poecilobdella manillensis powder were effective for ***,they are associated with improvements in g

关键词： Gut microbiota Metabolism Multi-omics Poecilobdella manillensis Sphingolipid metabolism pathway Galactose metabolism pathway Hyperuricemia

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Derivation of Expanded Isospectral-Nonisospectral Integrable Hierarchies via the Column-vector Loop Algebra

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Acta Mathematicae Applicatae Sinica 2024年第3期40卷 778-800页

作者： Hai-feng wang Yu-feng ZHANG School of Science Jimei UniversityXiamen 361021China School of Mathematics China University of Mining and TechnologyXuzhou 221116China

A scheme for generating nonisospectral integrable hierarchies is *** on the method,we deduce a nonisospectral hierarchy of soliton equations by considering a linear spectral *** follows that the corresponding expanded isospectral and nonisospectral integrable hierarchies are deduced based on a 6 dimensional complex linear space ■.By reducing these integrable hierarchies,we obtain the expanded isospectral and nonisospectral derivative nonlinear Schr?dinger *** using the trace identity,the biHamiltonian structure of these two hierarchies are also ***,some symmetries and conserved quantities of the resulting hierarchy are discussed.

关键词： expanded isospectral-nonisospectral integrable hierarchies column-vector loop algebra bi-Hamiltonian structure symmetry

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Total flavonoids of Astragalus membranaceus protect against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced neurotoxicity in mice by inhibiting ferroptosis through SLC7A11/GPX-4 signaling pathway

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Food Science and Human Wellness 2024年第1期13卷 414-420页

作者： Zitian Gao Gaorui wang Yujie Chen Wuke Yuan Jun cai Aiping feng Jie Fang Qi Xu Xiaojun Wu School of Public Health Shanghai University of Traditional Chinese MedicineShanghai 201203China Shanghai Key Laboratory of Compound Chinese Medicines The Ministry of Education(MOE)Key Laboratory for Standardization of Chinese MedicineInstitute of Chinese Materia MedicaShanghai University of Traditional Chinese MedicineShanghai 201203China Longhua Hospital affiliated to Shanghai University of Traditional Chinese Medicine Shanghai University of Traditional Chinese MedicineShanghai 201203China

Parkinson’s disease(PD)is a common neurodegenerative disorder with no *** membranaceus is used in Chinese culture as a food supplement to boost *** present study aimed to explore the neuroprotective effects of total flavonoids extracted from ***(TFA)and their protective *** offered neuroprotection against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine(MPTP)in the mouse model of Parkinsonism,by improving behavior performance in the gait analysis and pole test,and inhibiting the decline of tyrosine hydroxylase(TH)positive neurons and TH protein expression in substantia nigra of *** also prevented 1-methyl-4-phenylpyridinium(MPP+)induced neurotoxicity in SHSY5Y cells,by increasing GSH and GSH/GSSG ratio,and reducing reactive oxygen *** addition,the neuroprotective effects of TFA were associated with its ability to restore MPTP/MPP+induced downregulation of SLC7A11 and glutathione peroxidase 4(GPX-4).In conclusion,we demonstrated that TFA exerted significant neuroprotection against MPTP/MPP+induced neurodegeneration by inhibiting ferroptosis through the regulation of SLC7A11/GPX-4 axis,suggesting the use of TFA as a possible food supplement in the prevention of PD.

关键词： Parkinson’s disease Total fl avonoids of Astragalus membranaceus Ferroptosis SLC7A11

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Study on crustal thickness and the prediction of prolific depressions:the Bohai Basin as an example

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Acta Oceanologica Sinica 2024年第4期43卷 92-104页

作者： Mengke cai Gongcheng Zhang Wanyin wang Dingding wang College of Geological Engineering and Geomatics Chang’an UniversityXi’an 710054China China National Offshore Oil Corporation(CNOOC)Research Institute Co. Ltd.Beijing 100028China Key Laboratory of Marine Geology and Environment Chinese Academy of SciencesQingdao 266071China National Engineering Research Center of Offshore Oil and Gas Exploration Beijing 100028China Department of Earth Environment and Resources SciencesUniversity of Naples FedericoⅡNaples 80138Italy

The deep crustal structure is closely related to oil and gas *** the oil and gas enrichment of depressions based on the Moho depth and crustal thickness is a promising research topic with significant implications for guiding exploration in petroliferous *** this study,seismic data were used as a constraint on the use of satellite gravity anomaly inversion to obtain the distribution of Moho depth and crustal thickness in the Bohai *** factors were calculated to analyze the differential distribution of deep crustal structural *** indicators,including the minimum Moho depth,minimum crustal thickness,sum of Moho stretching factors,and sum of crustal stretching factors,were *** component analysis was applied to reduce the dimensionality of the multi-indicator system and obtain an oil and gas enrichment score for quantitative prediction of favorable prolific *** deviation between the inverted Moho depth and seismic constraints was small;thus,the data effectively reflect the variations in the characteristics of each *** analysis revealed significant statistical features related to the minimum Moho depth/crustal thickness and the sum of Moho/crustal stretching factors associated with prolific *** on the oil and gas enrichment score,the depressions were classified into four categories related to their different deep crustal structural *** active ClassⅠ,ClassⅡ,and ClassⅢdepressions are predicted to be favorable prolific *** study expands the research on quantitatively predicting favorable prolific depressions in the Bohai Basin using the deep crustal structure and can contribute to reducing production costs and improving exploration efficiency in future explorations.

关键词： Bohai Basin satellite gravity anomaly deep crustal structure Moho depth crustal thickness favorable prolific depression

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