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3D Lamellar-Structured Graphene Aerogels for Thermal Interface Composites with High Through-Plane Thermal Conductivity and Fracture Toughness

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Nano-Micro Letters 2021年第2期13卷 13-27页

作者： pengfei liu Xiaofeng li peng Min Xiyuan Chang Chao Shu yun Ding Zhong-Zhen Yu Beijing Key Laboratory of Advanced Functional Polymer Composites Beijing University of Chemical TechnologyBeijing 100029People’s Republic of China State Key Laboratory of Organic-Inorganic Composites College of Materials Science and EngineeringBeijing University of Chemical TechnologyBeijing 100029People’s Republic of China Beijing Advanced Innovation Center for Soft Matter Science and Engineering Beijing University of Chemical TechnologyBeijing 100029People’s Republic of China

Although thermally conductive graphene sheets are efficient in enhancing in-plane thermal conductivities of polymers,the resulting nanocomposites usually exhibit low through-plane thermal conductivities,limiting their application as thermal interface ***,lamellarstructured polyamic acid salt/graphene oxide(PAAS/GO)hybrid aerogels are constructed by bidirectional freezing of PAAS/GO suspension followed by ***,PAAS monomers are polymerized to polyimide(PI),while GO is converted to thermally reduced graphene oxide(RGO)during thermal annealing at 300℃.Final graphitization at 2800℃ converts PI to graphitized carbon with the inductive effect of RGO,and simultaneously,RGO is thermally reduced and healed to high-quality ***,lamellar-structured graphene aerogels with superior through-plane thermal conduction capacity are fabricated for the first time,and its superior through-plane thermal conduction capacity results from its vertically aligned and closely stacked high-quality graphene *** vacuum-assisted impregnation with epoxy,the resultant epoxy composite with 2.30 vol% of graphene exhibits an outstanding through-plane thermal conductivity of as high as 20.0 W m^−1 K^−1,100 times of that of epoxy,with a record-high specific thermal conductivity enhancement of 4310%.Furthermore,the lamellar-structured graphene aerogel endows epoxy with a high fracture toughness,~1.71 times of that of epoxy.

关键词： Anisotropic aerogels Graphene Thermal conductivity Epoxy composites Fracture toughness

Passivity breakdown of 13Cr stainless steel under high chloride and CO_2 environment

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International Journal of Minerals,Metallurgy and Materials 2019年第3期26卷 329-336页

作者： Hui-xin li Da-peng li Lei Zhang Ya-wen Wang Xiu-yun Wang Min-xu Lu Institute for Advanced Materials and Technology University of Science and Technology Beijing Safetech Research Institute (Beijing) Co. Ltd. CRRC Beijing Locomotive Co. Ltd.

Herein, the effect of high chloride ion(Cl^-) concentration on the corrosion behavior and passive film breakdown of 13Cr martensitic stainless steel under CO_2 environment was demonstrated. The Cl^- concentration was varied from 30 to 150 g/L and cyclic potentiodynamic polarization was conducted to investigate the influence of the Cl^- concentration on the corrosion potential(E_(corr)), passive breakdown potential(E_(pit)), and repassivation potential(E_(rep)). The results of the polarization curves revealed that 13Cr stainless steel is susceptible to pitting under high Cl^- concentration. The passive breakdown potential and repassivation potential decreased with the increase of Cl-concentration. The semiconducting behavior of the passive film was investigated by Mott-Schottky analysis and the point defect model(PDM). It was observed that the iron cation vacancies and oxygen vacancies were continuously generated by autocatalytic reactions and the higher Cl^- concentration resulted in higher vacancies in the passive film. Once the excess vacancies condensed at the metal/film interface, the passive film became locally detached from the metal, which led to the breakdown of the passive film.

关键词： 13Cr stainless steel electrochemical characterization pitting corrosion high chloride concentration passive film breakdown

Artematrovirenolides A—D and Artematrolides S—Z,Sesquiterpenoid Dimers with Cytotoxicity against Three Hepatoma Cell lines from Artemisia atrovirens

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Chinese Journal of Chemistry 2022年第1期40卷 104-114页

作者： li-Hua Su Tian-ze li yun-Bao Ma Chang-An Geng Xiao-Yan Huang Xin Zhang Zhen Gao Ji-Jun Chen State Key Laboratory of Phytochemistry and Plant Resources in West China Yunnan Key Laboratory of Natural Medicinal ChemistryKunming Institute of BotanyChinese Academy of SciencesKunmingYunnan 650201China University of Chinese Academy of Sciences Beijing 100049China

Inspired by the intriguing structures and remarkable activities of sesquiterpenoid dimers,12 new sesquiterpenoid dimers,artematrovirenolides A—D(1—4)and artematrolides S—Z(8—12),were isolated from the EtOAc fraction of Artemisia atrovirens through a bioactivity-guided *** structures were elucidated by comprehensive spectroscopic data and absolute configuration was assigned based on single crystal X-ray diffraction data and ECD ***,all compounds are presumably formed via[4+2]cycloaddition involving three connecting *** 1—4 are four novel hetero-dimeric[4+2]Diels-Alder adducts dimerized from a rotundane-type unit and a guaiane-type monomer,and compounds 5—12 are eight new homo-dimeric[4+2]adducts derived from two guaianolide moieties.A putative biosynthetic pathway for compounds 1—4 was also *** 4,6,7,and 10 demonstrated moderate cytotoxicity against HepG2,SMMC-7721,and Huh7 cell lines with IC50 values ranging from 9.3 to 62.3μmol/***,compounds 5 and 11 manifested cytotoxicity with IC50 values of 13.6 and 12.8(HepG2),18.5 and 13.1(SMMC-7721),and 16.5 and 19.4μmol/L(Huh7),respectively,which were equivalent to the positive control,*** investigation suggests that compounds 5 and 11 might be considered as potent antihepatoma candidates and deserve further structural modification and mechanism study.

关键词： Artemisia atrovirens Sesquiterpenoid dimers Structure elucidation X-ray diffraction Antihepatoma activity

An improved synthesis of(lS,4S)-2-oxa-5-azabicyclo[2.2.1]heptane

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Chinese Chemical Letters 2014年第3期25卷 479-481页

作者： Dong-Feng Zhang peng li Zi-yun lin Hai-Hong Huang Beijing Key Laboratory of Active Substance Discovery and Druggability Evaluation Institute of Materia MedicaPeking Union Medical College & Chinese Academy of Medical Sciences

An improved and efficient method for synthesis of （1S,4S）-2-oxa-5-azabicyclo[2.2.1]heptane （1） from trans-4-hydroxy-L-proline was developed. Using benzyloxycarbonyl （Cbz） as protection group of amine, the reacti... 详细信息

关键词： Synthesistrans-4-Hydroxy-L-prolineBridged morpholine

Insights into the mechanism of shortened developmental duration and accelerated weight gain associated with Wolbachia infection in Hylyphantes graminicola

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Integrative Zoology 2022年第3期17卷 420-429页

作者： Chunfen li Meng HE Yinjie CUI Yu peng Jie liU Yueli yun State Key Laboratory of Biocatalysis and Enzyme Engineering School of Life SciencesHubei UniversityWuhanChina

Wolbachia infection is known to affect host reproduction and *** date,however,the underlying mechanism related to the effects of Wolbachia on host development has not yet been ***,we compared the developmental duration and body weight in different instars of Wolbachia-positive(W+)and Wolbachia-negative(W−)spiders(Hylyphantes graminicola)and detected the relative expression levels of 6 insulin-related genes and 3 ecdysone-related genes using reverse transcription *** showed that the developmental duration was significantly shortened in W+spiders compared with W−***,W+spiders were significantly heavier thanW−spiders at the 3rd and 4th instars,although no significant differences in body weight were observed after *** also found that the expression levels of insulin-like growth factor-2 mRNA-binding protein-1,insulin-degrading enzyme,and ecdysone-inducible protein-1 genes were significantly down-regulated in W+spiders compared with W−spiders,whereas the expression levels of insulin-like growth factor-binding protein-1,insulin-like peptide receptor,insulin receptor substrate 2-B,insulin-like,ecdysone-induced protein-2,and ecdysone receptor genes were significantly up-regulated inW+*** results suggest thatWolbachia may influence host development by affecting insulin and ecdysone signaling pathways.

关键词： ecdysone Hylyphantes graminicola insulin Wolbachia

Constraints on ultracompact minihalos using neutrino signals from gravitino dark matter decay

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Research in Astronomy and Astrophysics 2014年第10期14卷 1215-1220页

作者： yun-Long Zheng Yu-peng Yang Ming-Zhe li Hong-Shi Zong Department of Physics Nanjing University Department of Astronomy Nanjing University College of Physics and Electrical Engineering Anyang Normal University Joint Center for Particle Nuclear Physics and CosmologyNanjing University-Purple Mountain Observatory Interdisciplinary Center for Theoretical Study University of Science and Technology of China

Ultracompact dark matter minihalos （UCMHs） would be formed during the early universe if there were large density perturbations. If dark matter can decay into particles described by the standard model, such as neutrinos, these objects would become potential astrophysical sources of emission which could be detected by in- struments such as IceCube. In this paper, we investigate neutrino signals from nearby UCMHs due to gravitino dark matter decay and compare these signals with the back- ground neutrino flux which is mainly from the atmosphere to obtain constraints on the abundance of UCMHs.

关键词： dark matter -- early universe -- dark matter halos

Effects of bias on spin-polarized transport properties in double magnetic tunnel junctions

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功能材料 2004年第z1期35卷 519-521页

作者： li yun Department of Materials Science and Engineering Yunnan UniversityKunming 650091China

Spin-polarized transport properties in Fe /insulator (Ⅰ) (semiconductor (S)) / Co / I (S) / Fe double junction systems are investigated theoretically, current density is asymmetry as function of the direction of applied bias, and evaluated using generalized formalism base on the non-equilibrium Green's function, which is implemented with calculation of real space Green's function in tight-binding model in linear response region.

关键词： spin-polarized transport magnetic tunneljunction spin accumulation tunneling

Bioinspired Nanostructured Superwetting Thin-Films in a Self-supported form Enabled“Miniature Umbrella”for Weather Monitoring and Water Rescue

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Nano-Micro Letters 2022年第2期14卷 174-189页

作者： Shan li peng Xiao Wei Zhou yun liang Shiao-Wei Kuo Tao Chen Key Laboratory of Marine Materials and Related Technologies Zhejiang Key Laboratory of Marine Materials and Protective TechnologiesNingbo Institute of Materials Technology and EngineeringChinese Academy of SciencesNingbo 315201People’s Republic of China School of Chemical Sciences University of Chinese Academy of Sciences19A Yuquan RoadBeijing 100049People’s Republic of China Department of Material and Optoelectronic Science National Sun Yat-Sen UniversityKaohsiung 804TaiwanPeople’s Republic of China

Two-dimensional(2D)soft materials,especially in their self-supported forms,demonstrate attractive properties to realize biomimetic morphing and ultrasensitive *** extensive efforts on design of self-supported functional membranes and integrated systems have been devoted,there still remains an unexplored regime of the combination of mechanical,electrical and surface wetting properties for specific ***,we report a self-supported film featured with elastic,thin,conductive and superhydrophobic *** a well-defined surface modification strategy,the surface wettability and mechanical sensing can be effectively *** resulted film can function as a smart umbrella to achieve real-time simulated raining with diverse frequencies and *** addition,the integrated umbrella can even response sensitively to the sunlight and demonstrate a positively correlation of current signals with the intensity of sun ***,the superhydrophobic umbrella can be further employed to realize water rescue,which can take the underwater object onto water surface,load and rapidly transport the considerable *** importantly,the whole process of loaded objects and water flow velocity can be precisely *** self-supported smart umbrella can effectively monitor the weather and realize a smart water rescue,demonstrating significant potentials in multifunctional sensing and directional actuation in the presence of water.

关键词： Self-supported Superhydrophobic thin films Multifunctional sensing Water rescue

Genome-wide identification and transcriptome profiling reveal great expansion of SWEET gene family and their wide-spread responses to abiotic stress in wheat (Triticum aestivum L.)

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Journal of Integrative Agriculture 2020年第7期19卷 1704-1720页

作者： QIN Jin-xia JIANG Yu-jie LU yun-ze ZHAO peng WU Bing-jin li Hong-xia WANG Yu XU Sheng-bao SUN Qi-xin liU Zhen-shan State Key Laboratory of Crop Stress Biology for Arid Areas College of AgronomyNorthwest A&F UniversityYangling 712100P.R.China Department of Plant Genetics&Breeding China Agricultural UniversityBeijing 100193P.R.China College of Landscape and Ecological Engineering Hebei University of EngineeringHandan 056021P.R.China

The Sugars Will Eventually be Exported Jransporter(SWEET)gene family,identified as sugar transporters,has been demonstrated to play key roles in phloem loading,grain filling,pollen nutrition,and plant-pathogen *** date,the study of SWEET genes in response to abiotic stress is very *** this study,we performed a genome-wide identification of the SWEET gene family in wheat and examined their expression profiles under mutiple abiotic *** identified a total of 105 wheat SWEET genes,and phylogenic analysis revealed that they fall into five clades,with clade V specific to wheat and its closely related *** the 105 wheat SWEET genes,59%exhibited significant expression changes after stress treatments,including drought,heat,heat combined with drought,and salt stresses,and more up-regulated genes were found in response to drought and salt *** hierarchical clustering analysis revealed that SWEET genes exhibited differential expression patterns in response to different stress treatments or in different wheat ***,different phylogenetic clades also showed distinct response to abiotic stress ***,we found that homoeologous SWEET genes from different wheat subgenomes exhibited differential expression patterns in response to different abiotic stress *** genome-wide analysis revealed the great expansion of SWEET gene family in wheat and their wide participation in abiotic stress *** expression partitioning of SWEET homoeologs under abiotic stress conditions may confer greater flexibility for hexaploid wheat to adapt to ever changing environments.

关键词： wheat sugar transporter abiotic stress homoeologous gene expression partitioning