检索结果-南通市图书馆

TiN/BN composite with excellent thermal stability for efciency microwave absorption in wide temperature spectrum

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2022年第35期130卷 249-255页

作者： yupeng Shi Dan Li Haoxu si Zhiyang Jiang Mengyuan Li Chunhong Gong Institute of Functional Polymer Composites College of Chemistry and Chemical EngineeringHenan UniversityKaifeng 475004China National&Local Joint Engineering Research Center for Applied Technology of Hybrid Nanomaterials Henan UniversityKaifeng 475004China

High-efficiency and temperature-insensitive microwave absorbing materials(MAMs) are ideal for hightemperature electromagnetic ***,the titanium nitride/boron nitride(TiN/BN) composite with TiN as the loss unit and BN as the impedance matching unit has been constructed by the in-situ synthesis *** insulating BN not only effectively regulates and optimizes the conductivity and impedance matching of the material but also imparts steady cyclic microwave absorption *** steady dielectric loss ensures that TiN/BN composite has robust high-temperature absorption properties at X-band,with a minimum reflection loss(RL_(min)) of-16.74 db at 873 K and an effective absorption bandwidth(EAB) of 3.26 GHz in the temperature range of 293-873 *** with the TiN/siO2absorbers with a single system,the TiN/BN/siO2composite keeps reliable high temperature absorbing properties at873 *** work confirms that wave-transparent materials for dielectric property modulation can resolve poor temperature stability of effective absorption and non-reusability for high-temperature absorbing materials,providing inspirations for designing efficiency high-temperature microwave absorbers.

关键词： TiN/BN High-temperature Microwave absorption Dielectric properties Impedance matching

Magnetic-conductive bi-gradient structure design of CP/PGFF/Fe 3 O 4 composites for highly absorb e d EMI shielding and balanced mechanical strength

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2023年第2期133卷 102-110页

作者： Qiang Peng Meng Ma si Chen yanqin Shi Huiwen He Xu Wang College of Materials Science and Engineering Zhejiang University of TechnologyHangzhou 310014China Key Laboratory of Plastic Modification and Processing Technology in Zhejiang Province Hangzhou 310014China

Developing excellent absorption-dominant electromagnetic interference(EMI)shielding composites is an urgent demand for the rapid development of 5 G technology and electronic ***,a simple strategy is employed to fabricate carbon nanotubes-polypropylene fibers(CP)/polypropylene-glass fibers felt(PGFF)/Fe 3 O 4 composites with superior EMI shielding effectiveness and low reflection due to the magnetic-conductive bi-gradient structure which is naturally formed by deposition during the vacuum-assisted filtration *** difference in dimensionality between one-dimensional CNT with outstand-ing electrical conductivity and zero-dimensional magnetic Fe 3 O 4 nanoparticles is the theoretical basis for the successful construction of the magnetic-conductive bi-gradient structure in a gap-rich PGFF matrix that endows the composites with“absorb-reflect-reabsorb”EMI ***-magnetic waves are incident from the magnetic layer,the EMI shielding effectiveness(SE)reaches 48.9 db as the weight percentage of the conductive layer increases,more importantly,the reflection coefficients are reduced by more than 0.32 compared with that of another incident ***’s more,the re-sultant composites exhibit an outstanding signal shielding function in the *** work paves a convenient pathway for designing a magnetic-conductive bi-gradient structure and efficient absorbing EMI shielding composites applied in the next-generated electronic information and communication field.

关键词： Electromagnetic interference shielding Magnetic-conductive bi-gradient structure Absorption-dominant Dimensionality Polypropylene-glass fibers felt

Ultrathin polyamide nanofiltration membrane prepared by triazine-based porous organic polymer as interlayer for dye removal

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2023年第5期57卷 193-201页

作者： yongbo Liu Zhihao si Cong Ren Hanzhu Wu Peng Zhan yuqing Peng Peiyong Qin National Energy R&D Center for Biorefinery Beijing University of Chemical TechnologyBeijing 100029China College of Life Science and Technology Beijing University of Chemical TechnologyBeijing 100029China Beijing Key Laboratory of Membrane Science and Technology College of ChemicalEngineeringBeijing University of Chemical TechnologyBeijing 100029China

Separation membrane with high flux is generally encouraged in industrial application,because of the tremendous needs for decreasing membrane areas,usage costs and space *** most effective and direct method for obtaining the high flux is to decrease membrane ***(PA)nanofiltration membrane is conventionally prepared by the direct interfacial polymerization(IP)on substrate surface,and results in a thick PA *** this work,we proposed a strategy that constructing triazine-based porous organic polymer(TRZ-POP)as the interlayer to prepare the ultrathin PA nanofiltration ***-POP is firstly deposited on the polyethersulfone substrate,and then the formed TRZ-POP provides more adhesion sites towards PA based on its high specific surface *** chemical bonding between terminal amine group of TRZ-POP and the amide group of PA further improves the binding force,and strengthens the stability of PA *** importantly,the high porosity of TRZPOP layer causes the higher polymerization of initial PA owning to the stored sufficient amino monomer;and H-bonding interaction between amine groups of TRZ-POP and piperazine(PIP)can astrict the release of ***,IP process is controlled,and the thinnest thickness of prepared PA layer is onlyye *** build of TRZPOP interlayer develops a new method for obtaining a high-flux nanofiltration membrane.

关键词： Polyamide Nanofiltration Interfacial polymerization Triazine-based porous organic polymer

Ginsenoside Rb1 alleviates chronic intermittent hypoxia-induced diabetic cardiomyopathy in db/db mice by regulating the adenosine monophosphate-activated protein kinase/Nrf2/heme oxygenase-1 signaling pathway

在线全文

学校读者我要写书评

暂无评论

Journal of Traditional Chinese Medicine 2023年第5期43卷 906-914页

作者： LIU Bingbing LI Jieru si Jianchao CHEN Qi yANG Shengchang JI Ensheng Department of Physiology Hebei University of Chinese MedicineShijiazhuang 050200China Hebei Technology Innovation Center of TCM Combined Hydrogen Medicine Shijiazhuang 050200China

OBJECTIVE:To examine the protective effect of ginsenoside Rb1(Rb1),the main component of Renshen(Radix Ginseng),on cardiomyopathy in db/db mice exposed to chronic intermittent hypoxia(CIH)and explore the potential underlying mechanism of Rb1 in treating diabetic cardiomyopathy(DCM).METHODS:The db/db mice were randomly separated into five groups:normal control group,model group,Rb120 mg/kg group,Rb140 mg/kg group,and glucagon-like peptide-1(GLP-1)*** were exposed to aircondition or CIH for 8 weeks,and Rb1 and GLP-1 were administrated before CIH exposure every *** glucose tolerance test(OGTT),intraperitoneal insulin tolerance test(IPITT),total cholesterol(TC),triglyceride(TG),and high-density lipoprotein cholesterol(HDL-C)were detected to evaluate glycolipid *** level of insulin was detected by a mouse enzyme-linked immunosorbent assay(ELISA).Cardiac function was detected by echocardiography,and myocardial pathology was observed by hematoxylin-eosin and Masson *** expression of collagenⅠand collagenⅢwas detected by *** monophosphate-activated protein kinase(AMPK)/Nrf2/heme oxygenase-1(HO-1)signaling pathway was detected by Western blot and ***:Rb1 treatment could improve glucose tolerance and the level of cardiac function indexes,and inhibit the level of oxidative stress indexes and the expression of collagenⅠand collagenⅢ.Moreover,Rb1 treatment enhanced AMPK phosphorylation and increased Nrf2 and HO-1 ***:Rb1 treatment alleviated CIH-induced diabetic cardiomyopathy and glycolipid metabolism disorders in db/db mice by inhibiting oxidative stress and regulating the AMPK/Nrf2/HO-1 signaling pathway.

关键词： ginsenosides diabetic cardiomyopathies oxidative stress AMP-activated protein kinases heme oxygenase-1 signal transduction chronic intermittent hypoxia

Reduced graphene oxide@carbon sphere based metacomposites for temperature-insensitive and efficient microwave absorption

在线全文

学校读者我要写书评

暂无评论

Nano Research 2022年第9期15卷 8546-8554页

作者： Zhiyang Jiang Haoxu si yi Li Dan Li Huihui Chen Chunhong Gong Jingwei Zhang Institute of Functional Polymer Composites College of Chemistry and Chemical EngineeringHenan UniversityKaifeng 475004China National&Local Joint Engineering Research Center for Applied Technology of Hybrid Nanomaterials Henan UniversityKaifeng 475004China

With the increasing advance of fifth generation(5G)network and the gradual expansion of digital devices,harsh working environment for electronic devices has spawned higher requirements for microwave absorbing materials(MAMs).since both the electromagnetic response and energy conversion character vary with temperature,to achieve temperature insensitive microwave absorption behaviour in wide temperature range has become extremely *** this work,structured metacomposites containing sub-wavelength reduced graphene oxide(RGO)@carbon spheres were fabricated,and the microwave absorption was further improved through structural and composition design of the RGO@carbon *** to the unique anti-reflection effect on microwave of the metacomposites,the temperature-insensitive electromagnetic performance at elevated temperature could be ***,both the dielectric relaxation behaviour and microwave absorption proformance of the system could be further *** a result,the effective absorption bandwidth(reflection loss(RL)db)of the metacomposites with only 3.0 wt.%filler content could cover the entire X-band(8.2–12.4 GHz)frequency ranging from 298 to *** metacomposite proposed in this work provides a“de-correlating”strategy to break the linkage between microwave absorption behaviour and temperature,which offers an interesting plateau for fabricating efficient high-temperature microwave absorption structures with tunable and designable advantages.

关键词： metacomposites subwavelength functional units temperature-insensitive microwave absorption

Acoustics Performance Research and Analysis of Light Timber Construction Wall Elements Based on Helmholtz Metasurface

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Renewable Materials 2022年第11期10卷 2791-2803页

作者： si Chen yuhao Zhou Sarah Mohrmann Haiyan Fu yuying Zou Zheng Wang Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources College of Materials Science and TechnologyNanjing Forestry UniversityNanjing210037China College of Civil Engineering Nanjing Forestry UniversityNanjing210037China

Based on the efficient sound absorption characteristics of Helmholtz resonance structures in the range of medium and low frequency acoustic waves,this paper investigates an effective solution for light timber construction walls with acoustic *** study takes the light timber construction wall structure as the research *** on the Helmholtz resonance principle,the structure design of the wall unit,impedance tube experiment and COMSOL MULTIPHysiCS simulation calculation were carried out to obtain the change rule of acoustic performance of the Helmholtz resonance wall unit *** research results show that the overall stability of sound insulation of the structure is improved,and the frequency range with sound transmission loss more than 50 db in the experimental group is 640–1600 Hz,while in the control group is 500–906 Hz and 1238–1600 Hz;the sound absorption performance of the structure is obviously better than that of the ordinary structure,especially in the low frequency acoustic wave range of 100–320 Hz,the sound absorption coefficient of the experimental group is more than 0.49,while the sound absorption coefficient of the control group is less than *** is expected that these results will contribute to the optimization of the acoustic performance of light timber construction walls and have high application and popularization value.

关键词： Acoustic metasurface aperture embedded helmholtz resonance structure light timber construction low frequency

Utilization of Specific Attenuation for Rainfall Estimation in Southern China

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Tropical Meteorology 2021年第1期27卷 48-61页

作者： ZHANG A-si HUANG Chao-ying CHEN Sheng ZHANG Peng-fei HU Dong-ming XIAO Liu-si School of Atmospheric Sciences/Key Laboratory of Tropical Atmosphere-Ocean System Sun Yat-sen UniversityZhuhaiGuangdong 519000 China Southern Laboratory of Ocean Science and Engineering ZhuhaiGuangdong 519000 China Cooperative Institute for Mesoscale Meteorological Studies University of Oklahomaand NOAA/OAR/National Severe Storms LaboratoryOKC 73072 USA Guangzhou Meteorological Observatory Guangzhou 511430 China

This study uses rain gauge observations to assess the performance of different radar estimators R(ZH),R(KDP)and R(A)in estimating precipitation based on the observations of an S-band polarimetric radar over southern China during a typical convective storm and an extremely severe typhoon,i.e.,Typhoon *** radar estimators were derived from observations of a local autonomous particle size and velocity(Parsivel)unit(APU)disdrometer.A key parameter,alpha(α),which is the ratio of specific attenuation A to specific differential phase KDP with three fixed values(α=0.015 db deg^(-1),α=0.0185 db deg^(-1)andα=0.03 db deg^(-1))was examined to test the sensitivity of the R(A)rain *** results show that:(1)All radar estimators can capture the spatio-temporal patterns of two precipitation events,R(A)withα=0.0185 db deg^(-1)is well correlated with gauge measurement via higher Pearson’s correlation coefficient(CC)of 0.87,lower relative bias(RB)of 16%,and lower root mean square error(RMSE)of 17.09 mm in the convective storm while it underestimates the typhoon event with RB of 35%;(2)R(A)withα=0.03 db deg^(-1)shows the best statistical scores with the highest CC(0.92),lowest RB(7%)and RMSE(25.74 mm)corresponding to Typhoon Manghkut;(3)R(A)estimates are more efficient in mitigating the impact of partial beam *** results indicate thatαis remarkably influenced by the variation of drop size ***,more work is needed to establish an automated and optimizedαfor the R(A)relation during different rainfall events over different regions.

关键词： QPE S-band dual polarization weather radar southern China

Effect of pyridone agent on blood-retinal barrier in diabetic mice

在线全文

学校读者我要写书评

暂无评论

International Journal of Ophthalmology(English edition) 2017年第6期10卷 890-895页

作者： si-Qi Xiong Hai-Bo Jiang Hui-Zhuo Xu Xiao-Bo Xia Department of Ophthalmology Xiangya Hospital Central South University Changsha 410008 Hunan Province China

AIM： To evaluate the therapeutic effect of fluorofenidone on disrupted blood-retinal barrier in the diabetic mice and uncover its underlying mechanism. METHODS： db/db mice were randomly chosen for treatment with daily doses of fluorofenidone or placebo at 5-week-old, treatment continued until mice reach 24-week- old. Then, expression of transcriptiona factor insulin gene enhancer binding protein-1 （Islet-I） and vascular endothelial growth factor （VEGF） in murine retinas were evaluated. Retinal vascular permeability was assessed by examining the level of albumin in db/db murine retinas. Furthermore, the retinal vessel tight junction was estimated by checking the level of occludin in the murine retinal tissues. RESULTS： After occurrence of diabetic retinopthy in db/ db mice, expressions of transcritpional factor Islet-1 was found to be upregulated in db/db murine retinas compared with non-diabetic controls. similar to expression pattern of Islet-l, VEGF were also demonstrated to be increased in retinas of db/db mice, which was accompanied by increased retinal vascular leakage and decreased tight junction protein level. Systemetic administration of fluorofenidone repaired broken retinal vascular tight junction by restoring occludin expression in db/db retinal tissue. Consequently, retinal vascular premeability were indicated to be reduced by examining the transudative albumin level in diabetic retinal tissues. Both Islet-1 and VEGF expression were inhibited in the retinas of db/db mice after treatment with fluorofenidone. CONCLUsiON： Fluorofenidone significantly protectes retinal tight junction and reduces retinal vascular leakage. The phenomenon can be partially attributed to reducing overexpression of Islet-1 and VEGF in diabetic retinal tissues.

关键词： pyridone agent diabetic retinopathy blood-retinal barrier

Investigation of MXene nanosheets based radio-frequency electronics by skin depth effect

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2024年第4期17卷 3061-3067页

作者： Rongguo Song yunfa si Wei Qian Haoran Zu Bilei Zhou Qinglei Du Daping He yongliang Wang Air Force Early Warning Academy Wuhan 430019China Hubei Engineering Research Center of RF-Microwave Technology and Application Wuhan University of TechnologyWuhan 430070China Hainan Research Institute Wuhan University of TechnologySanya 572000China

Various new conductive materials with exceptional properties are utilized for the preparation of electronic *** ultra-high conductivity is crucial to attain excellent electrical ***,there is a lack of systematic research on the impact of conductor material thickness on device ***,we investigate the effect of conductor thickness on power transmission and radiation in radio-frequency(RF)and microwave electronics based on MXene nanosheets material transmission lines and *** MXene transmission line with thickness above the skin depth exhibits a good transmission coefficient of approximately-3 db,and the realized gain of MXene antennas exceeds 2 ***,the signal transmission strength of MXene antenna with thickness above the skin depth is higher than 5-μm MXene antenna approximately 5.5 *** lines and antennas made from MXene materials with thickness above the skin depth exhibit stable and reliable performance,which has significant implications for obtaining high-performance RF and microwave electronics based on new conductive materials.

关键词： MXene film radiao-frequency electronics antenna transmission line skin depth