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Phase separation morphology and mode II interlaminar fracture toughness of bismaleimide laminates toughened by thermoplastics with triphenylphosphine oxide group

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Science China(Technological Sciences) 2017年第3期60卷 444-451页

作者： SUN ShuJun GUO MiaoCai YI XiaoSu zhang zuoguang Key Laboratory of Aerospace Materials and Performance(Ministry of Education) School of Materials Science and EngineeringBeihang University National Key Laboratory of Advanced Composites Beijing Institute of Aeronautical Materials

Toughness improvement of bismaleimide(BMI)resin is very important for its application in composite materials.Blending

关键词： thermoplastic phase separation blends triphenylphosphine oxide bismaleimide ex-situ toughening interlaminar fracture toughness

Imaging the interphase of carbon fiber composites using transmission electron microscopy:Preparations by focused ion beam, ion beam etching, and ultramicrotomy

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Chinese Journal of Aeronautics 2015年第5期28卷 1529-1538页

作者： Wu Qing Li Min Gu Yizhuo Wang Shaokai zhang zuoguang Key Laboratory of Aerospace Materials and Performance (Ministry of Education) School of Materials Science and Engineering Beihang University

Three sample preparation techniques, focused ion beam （FIB）, ion beam （IB） etching, and ultramicrotomy （UM） were used in comparison to analyze the interphase of carbon fiber ＇epoxy composites using transmission electron microscopy. An intact interphase with a relatively uniform thickness was obtained by FIB. and detailed chemical analysis of the interphase was investigated by electron energy loss spectroscopy. It shows that the interphase region is 200 mn wide with an increasing oxygen-to-carbon ratio from 10% to 19% and an almost constant nitrogen-to-carbon ratio of about 3%. However, gallium implantation of FIB tends to hinder fine structure analysis of the interphase. For IB etching, the interphase region is observed with transition morphology frona amorphous resin to nano-crystalline carbon fiber, but the uneven sample thickness brings difficulty for quantitative chemical analysis. Moreover, UM tends to cause damage and/or deformation on the interphase. These results are meaningful for in-depth understanding on the interphase characteristic of carbon fiber composites.

关键词： Carbon fiber compositeChemical analysis Focused ion beams lnterphase Ion beam etching Microstructure Ultramicrotomy

Investigation of carbon fiber composite stiffened skin with vacuum assisted resin infusion/prepreg co-curing process

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Science China(Technological Sciences) 2014年第10期57卷 1956-1966页

作者： MA XuQiang GU YiZhuo LI Min LI YanXia zhang zuoguang Key Laboratory of Aerospace Advanced Materials and Performance (Ministry of Education) School of Materials Science and EngineeringBeihang University

Co-cured vacuum assisted resin infusion process(co-VARI process),which combined vacuum assisted resin infusion(VARI)with prepreg vacuum bag only process(VBO),was adopted to fabricate T-shaped stiffened skin with non-crimp fabric(NCF)stiffener and prepreg skin.During compaction stage of co-VARI process,prepreg resin impregnated fiber fabric under elevated temperature and vacuum pressure.This phenomenon was characterized by fluorescent micrographs with different holding temperature and time.Its influences on processing quality and mechanical performance for co-VARI stiffened skin with different filler materials at triangular region were further analyzed by optical micrographs and pull-off test,respectively.The results show that increasing holding temperature and prolonging holding time can promote prepreg resin impregnation in fiber fabric.Moderate prepreg resin impregnation is favorable to reduce resin rich region and increase fiber volume fraction at prepreg-fabric interface.Moreover,prepreg resin impregnation effect plays significant roles on pull-off performance for co-VARI stiffened skin with fabric filler but has negligible influences on specimens with prepreg filler.In addition,compared with stiffened skin with fabric filler,superior processing quality and pull-off performances are achieved for co-VARI stiffened skin with prepreg core filler.These results are helpful to optimize processing procedures and fabricate composite structure by coVARI process.

关键词：树脂浸渍预浸料碳纤维复合材料真空袋皮肤固化过程 VARI 纤维织物

Influence of processing temperature on interfacial behavior of HKT800 carbon fiber with BMI and epoxy matrices

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Chinese Journal of Aeronautics 2015年第4期28卷 1255-1262页

作者： Gao Aijun Gu Yizhuo Wu Qing Yuan Chao Li Min zhang zuoguang Key Laboratory of Aerospace Advanced Materials and Performance (Ministry of Education) School of Materials Science and Engineering Beihang University

This paper aims to study the effect of processing temperature on interfacial behavior of HKT800 carbon fiber composites with epoxy and Bismaleimide（BMI） matrix.Referring to the processing conditions of the composite, various processing-heat treatments were conducted on HKT800 and the extracted sizing content declines with increasing temperature.Chemical analysis shows that the HKT800 sizing is epoxy-type and reactive at 200 C.The interfacial shear strength（IFSS） of HKT800/epoxy and HKT800/BMI was investigated by micro-droplet method, for which the composites were fabricated with modeling temperature schemes referring to different diffusion, cure and post-cure stages.It shows that diffusion temperature and conversion degree of the resin both enhance the interfacial adhesion of HKT800/epoxy composite.For the HKT800/BMI composite,the diffusion temperature shows a insignificant effect on the IFSS.FTIR analysis indicates that sufficient reactions are achieved between HKT800-sizing and epoxy resin, however only partial reactions are observed between the sizing and BMI.Moreover, the presence of the sizing can evidently improve the wettability of HKT800 with epoxy resin but is unfavorable for HKT800 with BMI.

关键词： Bismaleimide Carbon fiber Epoxy Interfacial shear strength Temperature scheme

经鼻高流量加温加湿吸氧对COPD急性加重期患者动脉血气及生命体征的影响

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临床研究 2024年第6期32卷 54-57页

作者：张作光河南省范县人民医院急诊医学科河南濮阳457500

目的分析经鼻高流量加温加湿吸氧对慢性阻塞性肺疾病急性加重期(AECOPD)患者动脉血气及生命体征的影响。方法选取2019年6月至2021年5月河南省范县人民医院接收的104例COPD急性加重期患者作为此次研究对象,并将2019年6月至2020年5月收治... 详细信息

目的分析经鼻高流量加温加湿吸氧对慢性阻塞性肺疾病急性加重期(AECOPD)患者动脉血气及生命体征的影响。方法选取2019年6月至2021年5月河南省范县人民医院接收的104例COPD急性加重期患者作为此次研究对象,并将2019年6月至2020年5月收治患者分为常规组,而2020年6月至2021年5月为HFNC组,均为52例。常规组予以传统鼻导管氧疗方案氧疗,HFNC组予以经鼻高流量(HFNC)方案氧疗,比较两组血气功能[动脉血氧分压(PaO_(2))、动脉血二氧化碳分压(PaCO_(2))、氧合指数(PaO_(2)/FiO_(2))]、呼吸功能[呼吸频率(RR)、心率(HR)、平均动脉压(MAP)]、痰液粘稠度。结果两组干预24 h及干预72 h的PaO_(2)及PaO_(2)/FiO_(2)较干预前上升,且干预72 h上升更为显著,差异有统计学意义(P<0.05),两组干预24 h及干预72 h的PaCO_(2)较干预前下降,且干预72 h下降更为显著,差异有统计学意义(P<0.05);HFNC组干预72 h的PaO_(2)及PaO_(2)/FiO_(2)均较常规组上升更为显著,干预72 h的PaCO_(2)较常规组下降更为显著,差异有统计学意义(P<0.05)。两组干预24 h及干预72 h的HR、RR及MAP均较干预前下降,且干预72 h下降更为显著,差异有统计学意义(P<0.05);HFNC组干预72 h的HR、RR及MAP均较常规组下降更为显著,差异有统计学意义(P<0.05)。干预后,两组痰液粘稠Ⅲ级较干预前显著减少,且HFNC组改善情况优于常规组,差异有统计学意义差异有统计学意义(P<0.05)。结论HFNC较传统氧疗手段于COPD急性加重期患者而言,可更稳定血气功能及生命体征,降低患者痰液粘稠度,提高满意度及舒适度,值得应用于临床。

关键词：慢性阻塞性肺疾病氧疗动脉血气分析

Influence of Surface State on Moisture Sensitivity of Carbon Fiber and Its Composite Interfacial Properties

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Journal of Wuhan University of Technology(Materials Science) 2016年第4期31卷 757-764页

作者：王星星李敏 wu qing gu yizhuo li yanxia wang shaokai zhang zuoguang Key Laboratory of Aerospace Materials and Performance (Ministry of Education) School of Materials Science and Engineering Beihang University Beijing 100191 China

The influence of surface state on the moisture sensitivity of carbon fiber was analyzed by applying a T800 grade carbon fiber with five different surface conditions,namely,with and without surface oxidation,in the presence or absence of sizing agent.The interfacial properties of their composites in the presence of two epoxy matrices（respectively EP07 and EP10） were also characterized by micro-droplet tests.The overall results show that both oxidized and sizing-coated fibers have higher moisture equilibrium content than that of the pristine unsurface-treated fiber,due to higher amount of activated carbon groups.After moisture absorption of the carbon fibers,almost all the fiber/epoxy systems show decrease in the interfacial shear strength and the unsurface-treated fiber system exhibits the largest decline.Moreover,both interfacial shear strength and interlaminar shear strength of carbon fiber/EP10 composite demonstrate better water resistance performance than that of the carbon fiber/EP07 composite,consistent with DSC results of the two resins.

关键词： moisture sizing epoxy resins interfacial coated sized curing applying droplet

STUDY ON THERMAL EXPANSION COEFFICIENT AND DESIGN FOR ZERO－EXPANSION OF SlNGLE AND HYBRID MULTI－DIRECTIONA

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Chinese Journal of Aeronautics 1994年第2期7卷 131-137页

作者： Zhong Wethong zhang zuoguang Song Huancheng(Faculty 104, Beijing University of Aeronautics and Astronautics,Beijing, China, 100083)

AbstractThermal expansion properties of single and hybrid multi-directional composites fromr.t. to 150℃ are studied. The theoretical formulae for predicting coefficient of thermal ex-pansion (CTE) value are established. In the experiments, carbon/glasa andcarbon / Keviar are accepted to be the hybrid form. The variation of CTE values of hybridcomposites with structure parameter is analyzed. Besides, hybrid composites with zeroCTE arc studied and designed. And some typical ply forms of laminates with zero CTE arepresented. The investigation shows that it is easier for hybrid multi-directional compositesto meet the requirements of zero-expansion.

关键词： MULTI EXPANSION DESIGN DIRECTIONA AND FOR HYBRID COEFFICIENT OF STUDY

基于低温氦气循环换热的TMS内冷系统设计研究

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低温与超导 2024年第2期52卷 54-59页

作者：张璐张展周超赵川漪李佐光万佳昊王冬虎中国科学技术大学合肥230026 中国科学院合肥物质科学研究院合肥230031 合肥综合性国家科学中心能源研究院合肥230001

经颅磁刺激线圈工作中伴随大量交流热损耗,文章提出了一种基于低温氦气循环换热设计,以应对TMS线圈应用中不断提高的脉冲电流幅值和频率。本文设计了一种由中空铜线绕制而成的TMS八字形线圈,采用液氮预冷及低温氦气协同冷却的机制实现... 详细信息

经颅磁刺激线圈工作中伴随大量交流热损耗,文章提出了一种基于低温氦气循环换热设计,以应对TMS线圈应用中不断提高的脉冲电流幅值和频率。本文设计了一种由中空铜线绕制而成的TMS八字形线圈,采用液氮预冷及低温氦气协同冷却的机制实现线圈高效换热,并通过构建传热平衡方程及电磁热流多物理场耦合仿真对TMS线圈的刺激过程进行了分析研究。结果表明,与未加换热时相比,经由氦气换热后的刺激线圈整体热损耗降低了70%,实现了TMS线圈的低损耗与高效换热,验证了基于低温氦气循环换热设计可以在TMS系统中应用。

关键词： TMS 八字形线圈流动换热低温氦气热损耗

THE IMPACT PROPERTIES OF HYBRID COMPOSITES

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Chinese Journal of Aeronautics 1990年第1期5卷 42-48页

作者： zhang zuoguang and Song Huancheng Beijing University of Aeronautics and Astronautics

In this paper an experimental investigation on the impact behaviour of hybrid composites is conducted by instrumental Charpy impact test. The variation of impact strength and impact toughness index of C/K and C/G hybrid composites of different matrices with hybrid ratio and interface number is revealed. The dynamic hybrid effect is also investigated from different aspects. Meanwhile, the estimating model for impact strength is established and the estimated values are in good agreement with experimented ones. The hybrid effect coefficients based on different definitions are organically related by the model. This provides a basis for the further study of the impact constitutive equation of hybrid composites.

关键词： instrumental toughness behaviour IMPACT constitutive fibres hardly matrices estimating elongation