碳纤维／环氧树脂复合材料的热氧老化机理

以碳纤维/环氧树脂复合材料为研究对象，分别采用失重法、静态与动态（DMTA）力学性能测试和IR分析，研究了其热氧老化规律与机理。结果表明：在热氧老化条件下，碳纤维/环氧树脂复合材料的失重率与时间之间的关系服从指数规律；其弯曲强度保留率在25℃热氧老化条件下与老化时间无关，而在100和150℃条件下则随时间呈指数规律衰减，并且温度越高，其弯曲强度保留率下降越快；DMTA与IR分析结果一致，25和100℃的条件下，碳纤维/环氧树脂复合材料的老化形式为物理老化，而在150℃的条件下，则既有物理老化，又有化学老化。     

静态热老化对NR硫化胶交联结构及力学性能的影响

研究了老化时间和环境对三种硫化体系的天然橡胶 ( NR)硫化胶的交联结构与力学性能的影响 .结果表明 ,三种 NR硫化胶的交联密度、定伸应力相近 ,多硫键含量最多的 CV体系硫化胶拉伸强度和伸长率最大 ,单硫键含量最大的 EV体系的拉伸强度和伸长率最小 ;有氧和绝氧热老化均使 NR硫化胶中多硫键减少 ,单硫键增加 .未填充的 NR硫化胶 ,其交联密度随热氧老化先增后减 .对于 N330填充的 NR硫化胶 ,有氧和绝氧热老化都使交联密度增加 ,拉伸强度和伸长率降低 ,而定伸应力和硬度增加 ,但 CV体系的性能保持率最低 ,EV体系最高     

静态热老化对NR硫化胶交联结构及力学性能的影响

研究了老化时间和环境对三种硫化体系的天然橡胶(NR)硫化胶的交联结构与力学性能的影响．结果表 明,三种NR硫化胶的交联密度相近,定伸应力相近,多硫键含量最多的CV体系硫化胶拉伸强度和伸长率最大,单 硫键含量最大的Ev体系的拉伸强度和伸长率最小;有氧和绝氧热老化均使NR硫化胶中多硫键减少、单硫键增 加．未填充的NR硫化胶,其交联密度随热氧老化先增后减．对于N330填充的NR硫化胶,有氧和绝氧热老化都使 交联密度增加、拉伸强度和伸长率降低,而定伸应力和硬度增加,但CV体系的性能保持率最低,EV体系最高．     

超热老化对浇注式沥青混合料高温性能影响研究

浇注式沥青混合料拌合温度高达240℃,拌合时间超过45 min,该条件下浇注式沥青将发生严重的热氧老化,然而超热老化温度和老化时间对浇注式沥青混合料高温性能的影响规律报道较少。对此采用车辙试验对不同超热老化温度和老化时间的浇注式沥青混合料高温性能变化规律进行了研究。研究结果表明:动稳定度与超热老化温度高度相关,高温抗变形能力随超热老化温度升高而不断升高;动稳定度与超热老化时间具有较高的指数相关性,随着超热老化时间延长,动稳定度值呈先缓慢上升到快速上升趋势。在确保浇注式沥青混合料高温性能的同时,必须合理控制老化温度和老化时间,解决由于超热老化导致其抗疲劳开裂能力降低的问题。     

环氧树脂热氧老化实验研究

为了评估干式变压器的寿命 ,必须研究环氧树脂的老化机理。介绍了环氧树脂样品的热氧老化加速寿命试验的原理和方法。文中试品采用 60 mm× 1 5mm× 6mm的长方体。用热质量损失作为描述老化特性的性能指标。通过加速寿命实验研究 ,求得在设定温度为 1 70℃及 1 55℃条件下 ,样品热质量损失与暴露时间的关系曲线 ,及求得质量损失达到 3.4%时 ,老化时间分别为 360 0 h和 2 80 0 0 h,温度指数为 1 60℃。并发现 ,在同一暴露时间 ,热质量损失服从正态分布。     

热老化对碳烟颗粒氧化特性的影响

针对柴油机排气颗粒被捕集在柴油机颗粒捕集器中后不能立即得到氧化再生,将受到高温排气一段时间的热老化的问题.基于热重分析仪,探究了不同温度、时间和氧体积分数条件下热老化对碳烟颗粒氧化性能的影响规律.采用高分辨率透射电镜得到了相应的老化颗粒的微观结构图,并与热重试验结果进行对比分析.结果表明:随着老化温度的增加,颗粒的活化能逐渐增加;随着老化时间的增加,颗粒活化能先增加而后趋于不变;与无氧条件下热老化相比,有氧条件下热老化后的颗粒活化能相对较高,且氧体积分数的大小对颗粒活化能无明显影响;老化温度越高、老化持续时间越长以及老化氧体积分数增加时,基本碳粒的直径和内核区域变小,外层结构更加致密,形成更为稳定的外壳.     

ZN － 1阻尼橡胶材料的老化机理研究

采用加速老化试验方法对ZN－１阻尼橡胶材料的热氧老化性能进行了研究,获得了不同老化温度 及老化时间对硅橡胶泡沫材料力学性能及阻尼性能的影响规律。研究结果表明,随着老化温度的升高及老 化时间的延长, ZN－１的拉伸强度出现了先下降后升高的现象,而扯断伸长率则表现为单调下降的趋势。同 时,还研究了ZN－１阻尼橡胶材料在热氧老化条件下微观结构与性能变化之间的关系,得到了ZN－ １阻尼橡 胶材料的热老化机理。     

热塑性聚氨酯弹性体的老化机理

采用傅里叶变换红外光谱、核磁共振波谱和紫外-可见吸收光谱3种表征方法 ,对热塑性聚氨酯弹性体(TPU)在紫外光老化、微波老化和热氧老化条件下的老化行为进行了研究,探讨了TPU的老化机理.研究结果表明:在微波老化和热氧老化中,TPU有着相同的老化机理,初期因热导致TPU样品的后熟化,使样品中残余的异氰酸酯与水解得到的伯胺反应生成脲基,并进一步反应生成缩二脲基团.延长微波老化时间至30min后,大部分的TPU硬段分解,主产物为TPU链段组成之一的聚己二酸丁二醇酯(PBA).微波老化可明显加快热氧老化进程,TPU在微波下老化15min等效于热氧老化600h.TPU在紫外光下老化,其化学结构无明显变化,随老化时间的延长,氢键化的氨酯基增多,氢键含量增大,仅少量氨酯键断裂,生成烯胺,导致外观变黄.     

软模板法合成介孔InVO_4纳米材料及应用

以P123为软模板,In(NO_3)_3·4.5H_2O和NH_4VO_3为金属源,乙醇-水为溶液,用溶剂热法合成纳米钒酸铟颗粒。考察了不同溶剂热温度、不同溶剂热时间对晶体形貌的影响,并用XRD、SEM、TEM、氮气吸附-脱附等分析方法对样品进行表征。结果表明通过控制水热温度和水热时间可以得到不同形貌的晶体,在溶剂热温度150℃、时间24 h时可以制得具有立方体结构的介孔In VO4,孔径为54.8 nm,比表面积为29.7 m2/g,在500W氙灯模拟可见光条件下,该光催化剂在H2O2协同作用下,120 min对Rh B的降解率为42.7%。     

平纹铺层及三维角联锁复合材料热氧老化后低速冲击及剩余弯曲性能

以平纹铺层和三维角联锁碳纤维/环氧树脂复合材料为研究对象,探究其在180℃高温下分别老化4、8、16和32 d后的低速冲击响应,并结合其冲击后弯曲性能,比较两种结构复合材料抗冲击性能随老化时间的变化规律。结果表明:随着老化时间的增加,冲击加载下平纹铺层和三维角联锁纤维环氧树脂两种复合材料试件的最大冲击载荷减小,能量吸收率增大,承载性能退化;相同老化条件下,三维角联锁结构试件的剩余模量和强度保留率均高于平纹铺层试件。两者微观形貌的分析表明:平纹铺层结构试件易在热氧老化过程中形成连续的层间裂纹,并在外加载荷作用下扩展造成层间失效;三维角联锁结构试件因厚度方向的接结纱作用,界面裂纹扩展受阻,从而缓解热氧老化引起的界面性能退化。     

Markedness and its Interpretation in Language Use

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.     

Lower Paleozoic oil relationships within Williston Basin, Canada

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.     

An Analysis of Catherine＇s Character——Wuthering Heights

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.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

Features of Women's language

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.     

Design and analysis of generic LBS application developing platform

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.     

橡胶颗粒沥青混合料低温抗裂性试验研究

以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

低渗透非均质砂岩油藏启动压力梯度研究

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。     

Quantitative trait loci （QTLs） for quality traits related to protein and starch in wheat

Quality traits in wheat （Triticum aestirum L.） were studied by quantitative trait locus （QTL） analysis in a recombinant inbred line （RIL） population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross （ChSh）. Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.