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1.
通过熔融插层法制备了聚碳酸亚丙酯(PPC)/有机蒙脱土(OMMT)复合材料。XRD分析表明:PPC/OMMT复合材料形成了插层型纳米复合结构。相对于纯PPC材料,纳米复合材料的拉伸性能和抗冲击性能得到了显著提高,但复合材料的断裂伸长率降低。当OMMT含量为6%时,PPC/OMMT纳米复合材料具有最优的力学性能和最高的玻璃化温度。  相似文献   

2.
通过熔融插层法制备了聚碳酸亚丙酯(PPC)/有机蒙脱土(OMMT)复合材料。XRD分析表明:PPC/OMMT复合材料形成了插层型纳米复合结构。相对于纯PPC材料,纳米复合材料的拉伸性能和抗冲击性能得到了显著提高,但复合材料的断裂伸长率降低。当OMMT含量为6%时,PPC/OMMT纳米复合材料具有最优的力学性能和最高的玻璃化温度。  相似文献   

3.
以二茂铁和硫磺粉作为铁源和硫源,乙醇或邻二氯苯为溶剂,利用溶剂热法一步合成了FeS2/石墨烯和Fe2S8/石墨烯纳米复合材料;采用X射线衍射(XRD)法、扫描电子显微镜(SEM)和透射电子显微镜(TEM)对产物的晶相结构和形貌进行了分析与表征;并研究了原料的配比及溶剂对产物的组成和形貌的影响.当二茂铁与硫磺粉的摩尔比为1:2.5时,所得产物为Fe7S8/石墨烯纳米复合材料;而当它们的摩尔比为1:2时,所得产物为FeS2/石墨烯纳米复合材料,使用乙醇或邻二氯苯为溶剂合成所得FeS2/石墨烯纳米复合材料的形貌有较大的差异.  相似文献   

4.
以无压烧结方式制备了Al2O3/20%Ni(Ti)(体积分数)复合材料.通过分析Ti元素的分布状态,研究了Ti添加剂对Al2O3/20%Ni复合材料相界面润湿及力学性能的影响规律.结果表明,Ti元素集中分布在Al2O3/Ni相界面附近,并通过促进相界面润湿,强化相界面结合而显著改善复合材料的力学性能.实验成分范围内,随Ti含量增加,三点弯曲强度提高,而断裂韧性在3%Ti(质量百分数)时具有最大值,为6.2MPam12.断口形貌分析表明,复合材料的增韧机理为桥接机理  相似文献   

5.
通过熔融插层法制备了聚碳酸亚丙酯(PPC)/有机蒙脱土(OMMT)纳米复合材料。研究了OMMT对PPC/OMMT纳米复合材料热氧老化的影响。结果表明,老化以后复合材料的拉伸强度以及断裂伸长率的保留率均高于纯PPC。加入OMMT后,复合材料的热老化性能明显改善。  相似文献   

6.
为了改善聚合物HDPE的强韧性,利用扫描电子显微镜、微机控制电子万能试验机和液晶式摆锤冲击试验机等研究了表面处理剂、增容剂对HDPE/CaCO3共混材料力学性能的影响。结果表明,用表面处理剂硬脂酸处理的纳米级CaCO3粉体对HDPE相界面粘接作用有一定的改善,纳米CaCO3粉体在基体HDPE中的均匀分散性得到改善;加入增容剂(HDPE—g—MAN)后使得HDPE/纳米CaCO3共混材料力学性能进一步提高,为HDPE/纳米CaCO3复合材料的设计和生产运用提供重要的理论依据。  相似文献   

7.
利用高密度聚乙烯(HDPE)与尼龙54(PA54),并加入一定量的增容剂锌中和乙烯丙烯酸三元共聚物(Zn-EAA),熔融共混制备阻隔型HDPE/PA54共混体系.讨论了W(PA54)含量、增容剂W(Zn—EAA)含量、加工温度及共混时转子转速对共混体系熔体力矩、甲苯的阻隔性能及拉伸屈服强度的影响.研究发现,增加W(PA54)含量,共混体系的熔体力矩有所降低,对甲苯的阻隔性能有所上升,但拉伸屈服强度降低,过高的W(ZnEAA)对阻隔性能不利;升高共混温度,共混体系的熔体力矩下降,阻隔性能先上升后下降,拉伸屈服强度基本不变;增加共混时转子转速,共混体系的熔体力矩升高,阻隔性能有所下降,拉伸屈服强度略有上升.当W(HDPE/PA54)一60/40、Zn—EAA相对于PA54质量含量为15%、共混加工温度为180—190℃、螺杆转速为80-95r/min时,HDPE/PA54共混体系的阻隔性能和力学性能最优.  相似文献   

8.
在乙醇-水(y(乙醇):y(水)=9:1)的反应介质中,以SiO,@A100H为硬模板,加入镍钴盐前驱体和碱源,水热法制备了花瓣状镍钴层状双金属氢氧化物微球(NiCo.LDHM)。采用扫描电子显电镜、透射电镜和电化学工作站等对此复合材料进行了表征。研究发现,该微球平均粒径约2.5μm,呈多孔结构,由厚度10nm左右纳米片自组装形成。在1A/g的电流密度下,该产物电极的比电容量达到1108.8F/g,明显优于普通镍钴层状双金属氢氧化物电极(710.5F/g)的比电容量。当电流密度增加到7A/g,比电容量为700.8F/g,恒电流充一放电l500次后比电容量仍高于94.5%,由此说明了复合材料具有优异的超级电容性能。  相似文献   

9.
抗热震性能是结构陶瓷材料的重要性能之一.以抗热震断裂参数表征材料的抗热震性能,采用理论与实验相结合的方法,建立了基于抗热震性能的陶瓷复合材料的组分设计模型,并采用计算机辅助优化设计技术求得材料的最优组分.结果表明:当Ti(C,N)和SiC的体积含量分别为10.4%和27.1%时,该材料具有最高的抗热震性能,比纯氧化铝陶瓷提高约55%.在此基础上,利用热压技术制得一种SiC/Ti(C,N)/Al2O3复合陶瓷材料.将该材料制成切削刀具,并在切削实验中通过设计切削条件使得刀具主要承受热载荷和热应力的作用,从而发生热)中击破损.实验发现,SiC/Ti(C,N)/Al2O3复合陶瓷刀具切削淬火钢时的抗热)中击破损性能较纯Al2O3陶瓷提高约62-68%,与抗热震性能设计的理论预测基本吻合.这表明,该设计方法是可行的.  相似文献   

10.
以元素单质粉Ti,Al,C,Cu为原料,采用机械合金化和放电等离子烧结(SPS),成功制备了Cu/Ti3AlC2复合材料块体,并对其进行了组织性能分析。实验结果表明:采用SPS烧结技术制备的Cu/Ti3AlC2复合材料,随着Ti3AlC2含量的增加,其显微硬度逐渐提高,相同烧结工艺条件下(900℃烧结,保温20min)添加15vol%Ti3AlC2复合材料的硬度比纯Cu提高近2倍;添加适量的Ti3AlC2可显著提高复合材料的耐磨性,当复合材料中含5vol%Ti3AlC2时,磨损量降低30%以上。  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

14.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

15.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

16.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

17.
Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.  相似文献   

18.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

19.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

20.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

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