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Negative permittivity of reduced graphene oxide/polyvinylidene fluoride membranous composites adjusted by heat treatment

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Rare Metals 2024年第11期43卷 5964-5974页

作者： Kai Sun Min-Hui Zhao Peng-Tao Yang Min Chen Qing Hou Wen-Xin Duan run-Hua fan College of Ocean Science and Engineering Shanghai Maritime UniversityShanghai 201306China School of Civil Engineering Shandong Jiaotong UniversityJinan250357China Institute of Photonic Chips University of Shanghai for Science and TechnologyShanghai 200093China

Flexible composites with negative permittivity have a very broad development prospect in flexible electronics and wearable ***,how to control the negative permittivity except for from their intrinsic properties of components is still a *** this study,the negative permittivity and frequency dispersion were adjusted by changing the heat treatment *** fluoride(PVDF)was selected as the flexible matrix and reduced graphene oxide(rGO)as the functional filler to prepare rGO/PVDF membranous *** negative permittivity was observed in rGO/PVDF composites film,and the effect of heat treatment temperature on the negative permittivity was further *** indicated that a higher heat treatment temperature contributed to the formation of conductive network,so as to obtaining negative *** the molding temperature was 70℃,the negative permittivity spectrum conformed to the Drude model was only observed in the composites with 35 wt%content of *** the heat treatment temperature reached 180℃,when the content of rGO decreased to 25 wt%,the composites film achieved negative permittivity(~-10),which had a low-frequency dispersion in the test frequency *** negative permittivity of in composites can be regulated by adjusting the heat treatment temperature,which promotes the application and development of flexible metamaterials in underwater sensing and detection,etc.

关键词： Flexible composites Negative permittivity Heat treatment Metamaterial

A Stellar Ranging Scheme Based on the Second-order Correlation Measurement

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Research in Astronomy and Astrophysics 2022年第1期22卷 229-236页

作者： Jian Li Can Xu Yinshen Liu Yaqi Ma Xinyao Liu Xiaochen Ma run fan An-Ning Zhang Center for Quantum Technology Research and Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurements(MOE) School of PhysicsBeijing Institute of TechnologyBeijing 100081China School of Astronomy&Space Science Nanjing UniversityNanjing 210023China

Stellar ranging is the basis for stellar dynamics research and in-depth research on astrophysics. The parallax method is the most widely used and important basic method for stellar ranging. However, it needs to perform highprecision measurement of the parallax angle and the baseline length together. We aim to propose a new stellar ranging scheme based on second-order correlation that does not require a parallax angle measurement. We hope our solution can be as basic as the parallax method. We propose a new stellar ranging scheme by using the offset of second-order correlation curve signals. The optical path difference between the stars and different base stations is determined by the offset of the second-order correlation curve signals. Then the distance of the stars could be determined by the geometric relation. With the distance to stars out to 10 kpc away, our astrometric precision can be better compared to Gaia by simulation. We also design an experiment and successfully demonstrate the feasibility of this scheme. This stellar ranging scheme enables further and more accurate stellar ranging without requiring any prior information or angle measurement.

关键词： astrometry techniques:miscellaneous methods:observational methods:miscellaneous instrumentation:miscellaneous

Flexible silver nanorods/carbon fiber felt metacomposites with epsilon-near-zero property adjusted by compressive deformation

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Rare Metals 2023年第10期42卷 3318-3325页

作者： Jia-Hong Tian run-Hua fan Peng-Tao Yang Hai-Kun Wu Shan Jiang Yun-Lei Zhou Andrey Karlovich Sarychev College of Ocean Science and Engineering Shanghai Maritime UniversityShanghai201306China Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials(Ministry of Education) Shandong UniversityJinan250012China Hangzhou Institute of Technology Xidian UniversityHangzhou311231China State Key Laboratory of Digital Manufacturing Equipment and Technology Flexible Electronics Research CenterHuazhong University of Science and TechnologyWuhan430074China Institute for Theoretical and Applied Electrodynamics Russian Academy of ScienceMoscow125412Russia

Epsilon-near-zero(ENZ) materials exhibit great potentials in the practical applications of sensors,electronic skin,and wearable devices,when they own the properties of flexibility and *** this work,the silver nanorods(AgNRs)/carbon fiber felt(CFF) composites with ENZ property from 1 kHz to 1 MHz were achieved by adjusting the content of AgNRs and the compressed elastic deformation.

关键词： composites nanorods silver

(+)/(-)-Mycosphatide A,a pair of highly oxidized polyketides with lipid-lowering activity from the mangrove endophytic fungus Mycosphaerella ***-DZG01

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Chinese Chemical Letters 2024年第9期35卷 210-213页

作者： Qi Tan run-Zhu fan Wencong Yang Ge Zou Tao Chen Jianying Wu Bo Wang Sheng Yin Zhigang She School of Chemistry Sun Yat-sen UniversityGuangzhou 510006China School of Pharmaceutical Sciences Sun Yat-sen UniversityGuangzhou 510006China

(±)-Mycosphatide A(1a/1b),a pair of highly oxidized enantiomeric polyketides featuring a unique5/5/6/5-fused tetracyclic ring system,were isolated from the mangrove endophytic fungus Mycosphaerella *** structures were established by extensive spectroscopic analyses,single crystal Xray diffraction,and experimental electronic circular dichroism(ECD)spectra *** plausible biosynthetic pathway of 1 was proposed,which involved the generation of a key spiro[4.5]decane ***(+)-1a and(-)-1b exhibited significant lipid-lowering activity in 3T3-L1 adipocytes model,with EC50values of 7.85±1.56 and 8.87±0.80μmol/L,respectively.

关键词： Mangrove endophytic fungus Mycosphaerella sp. Polyketide Highly oxidized Lipid-lowering activity

Magnetic properties and special morphology of barium ferrite via electrospinning

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Rare Metals 2017年第2期36卷 113-117页

作者： Gui-fang Liu run-Hua fan Zi-Dong Zhang Jing Li Min Chen Qian-Qian Li Lu Lu Pei-Tao Xie Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials Ministry of EducationShandong UniversityJinan 250061China

Barium ferrite micro-/nanofibers with special morphology,nanowires with diameters of 100 nm,nanoribbons with diameters of 1μm,and nanotubes with outer diameter of about 300 nm while inner diameter of 100 nm were successfully prepared via electrospinning using different solvents（dimethyl formamide（DMF）,solutions of deionized water and ethyl alcohol,and solutions of deionized water and acetic acid,respectively）.The barium ferrite micro-/nanofibers were characterized by scanning electron microscope（SEM）,X-ray diffraction analysis（XRD）,and vibration sample magnetometer（VSM）.The results demonstrate that the pure BaFe12O19 ferrite phase is successfully *** the SEM results show excellent *** magnetic hysteresis loops demonstrate that their magnetic properties are quite different with different *** specific saturation magnetization is approximately the same（46.12-49.17 A·m^2·kg^-1）,but the coercivity of the BaFe12O19 increases from wires（190.08 kA·m^-1）,ribbons（224.16 kA·m^-1） to tubes（258.88 kA·m^-1）.

关键词： Electrostatic spinning Barium ferrite Hollow fiber Ribbon fiber

An impregnation-reduction method to prepare graphite nanosheet/alumina composites and its high-frequency dielectric properties

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Rare Metals 2017年第3期36卷 205-208页

作者： Ke-Lan Yan run-Hua fan Min Chen Kai Sun Xu-Ai Wang Qing Hou Shi-Bing Pan Ming-Xun Yu Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials(Ministry of Education) Shandong UniversityJinan 250061China Shandong Non-Metallic Materials Research Institute Jinan 250031 China

he nano-graphite sheet/alumina composites were prepared in situ by a facile impregnation-reduction *** microstructure of the composites was analyzed by X-ray diffraction （XRD）,and the final phase composition after reduction is Al2O3,metal Fe and graphite *** electron microscopy （SEM） images show that the particle size of Fe is about 20 nm,and the lamellae thickness of the graphite is about 30 ***,the dielectric properties and conductive mechanism of the composites were investigated experimentally in the frequency range of 0.01-1.00 GHz by impedance *** results show that the real part of permittivity of composites increases with Fe3＋ concentration,which is due to the increase in interfacial polarization between Fe and A12O3 and the three-dimensional network of lamellar graphite ***,tunable microtopography and electrical parameters of nano-graphite sheet/alumina composites can be realized by changing Fe3＋ concentration.

关键词： Impregnation-reduction method Ceramicmatrix composites Graphite sheet Complex permittivity Conductivity

Electromagnetic attenuation property of multiphase Fe–Fe_3O_4–Al_2O_3 cermets near percolation threshold

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Rare Metals 2017年第1期36卷 42-45页

作者： Kai Sun run-Hua fan Zi-Dong Zhang Ke-Lan Yan Xi-Hua Zhang Chuan-Bing Cheng Min Chen Pei-Tao Xie Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials Shandong University Jinan 250061China

Cermets are widely applied as attenuating materials due to high electromagnetic loss and better mechanical properties. In this paper, multiphase cermets composed of iron, iron oxide and alumina were successfully prepared by a two-step in situ synthesis process,which includes pressureless sintering and a selective reduction in hydrogen atmosphere. The phase composition and microstructure of cermets were analyzed by X-ray diffraction(XRD) and scanning electron microscopy(SEM), respectively. It is shown that nanosized cuboid Fe particles and octahedral FeOparticles are distributed in alumina matrix. The permittivity and permeability of composites were tested with radio frequency impedance analyzer(0.01–1.00 GHz). The results show that permittivity presents obvious frequency dispersion. Furthermore,dielectric constants of multiphase cermets get enlarged due to the enhancement of interfacial polarization. On the other hand, there is a magnetic loss peak in permeability spectra,which indicates typical relaxation behavior. It is possible to achieve better electromagnetic attenuation property by adjusting process parameters.

关键词： Cermets Attenuating materials Percolative phenomenon Microwave absorption Metamaterials

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弹道明胶老化初级阶段的模型

高分子学报 2017年第8期27卷 1382-1388页

作者：马小林范毓润浙江大学机械工程学院流体动力及机电系统国家重点实验室杭州310027

用流变震荡模式研究了10 wt%浓度的弹道明胶在冷却和等温下的老化行为.对明胶从sol-gel点冷却到某个目标温度的过程,通过不同冷却速率的实验,建了一个弹性模量与温度的线性关系.不同温度下明胶的等温老化实验表明,弹性模量-时间曲线具... 详细信息

用流变震荡模式研究了10 wt%浓度的弹道明胶在冷却和等温下的老化行为.对明胶从sol-gel点冷却到某个目标温度的过程,通过不同冷却速率的实验,建了一个弹性模量与温度的线性关系.不同温度下明胶的等温老化实验表明,弹性模量-时间曲线具有相似的形状.依据Normand提出的二级反应动力学模型,引入一个表征明胶老化行为的速率常数,构建了一个预测弹道明胶在老化初级阶段的弹性模量演化的模型.该模型中模量-温度关系在初始和无穷大时是直线,其他模量-温度线是近似直线,并交于sol-gel点.老化速率常数和过冷度之间符合Flory-Weaver方程.对弹性模量和老化时间进行归一化处理,可将不同温度下的老化曲线叠加成一条主曲线.

关键词：弹道明胶冷却模型等温老化模型二级反应动力学老化速率常数

Discovery of a highly potent and orally available importin-β1 inhibitor that overcomes enzalutamide-resistance in advanced prostate cancer

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Acta Pharmaceutica Sinica B 2023年第12期13卷 4934-4944页

作者： Jia-Luo Huang Xue-Long Yan Dong Huang Lu Gan Huahua Gao run-Zhu fan Shen Li fang-Yu Yuan Xinying Zhu Gui-Hua Tang Hong-Wu Chen Junjian Wang Sheng Yin School of Pharmaceutical Sciences Sun Yat-sen UniversityGuangzhou 510006China School of Pharmacy Guizhou Medical UniversityGuian New DistrictGuizhou 550025China School of Medicine University of California DavisSacramentoCA 95817USA

Nuclear transporter importin-β1 is emerging as an attractive target by virtue of its prevalence in many ***,the lack of druggable inhibitors restricts its therapeutic proof of *** the present work,we optimized a natural importin-β1 inhibitor DD1 to afford an improved analog DD1-Br with better tolerability(>25 folds)and oral ***1-Br inhibited the survival of castration-resistant prostate cancer(CRPC)cells with sub-nanomolar potency and completely prevented tumor growth in resistant CRPC models both in monotherapy(0.5 mg/kg)and in enzalutamidecombination *** study revealed that by targeting importin-β1,DD1-Br markedly inhibited the nuclear accumulation of multiple CRPC drivers,particularly AR-V7,a main contributor to enzalutamide resistance,leading to the integral suppression of downstream oncogenic *** study provides a promising lead for CRPC and demonstrates the potential of overcoming drug resistance in advanced CRPC via targeting importin-β1.

关键词： Importin-β1 CRPC Drug discovery Enzalutamide-resistance Natural product Cancer Daphnane diterpenoid Nuclear transporter