沥青混合料轴向局部加载试验研究

轴向局部加载试验能模拟实际路面的受力特性,可以提供沥青混合料设计的性能参数.为确定其实验条件并提出能客观评价沥青混合料高温抗剪切性能的试验指标,在不同的试验条件下对不同混合料的圆柱形试件进行轴向局部加载试验.通过有限元分析和相关试验确定了轴向局部加载试验的合理试件尺寸和压头大小;通过轴向局部加载试验指标与车辙动稳定度的相关性分析确定了试验温度和加载速率,并提出评价沥青混合料高温性能的力学参数.结果表明:60℃条件下采用40mm压头、50mm/min的加载速率的轴向局部加载试验得到的破坏模量与车辙试验结果具有很好的相关性,可以充分反映沥青混合料的高温性能.     

沥青混合料动态模量主曲线方法对比分析

为了更好地研究沥青混合料的动态特性,在4.4、21.1、37.8、54.4℃这4个试验温度下对沥青混合料进行简单性能试验(SPT),获得动态模量随加载频率的变化规律,然后基于时-温转换原理,采用WLF法和二次多项式法对数据进行非线性拟合,以此建立动态模量主曲线模型,并对两种方法进行分析。结果表明:1)相同试验温度下,沥青混合料动态模量随荷载加载频率增大而增大,相同加载频率下,沥青混合料动态模量随试验温度升高而降低,且试验温度越低时,加载频率的影响越显著;2)WLF法和二次多项式法均可拟合动态模量主曲线,拟合度分别为0.899和0.998。相较而言,二次多项式法能有效减少预测误差,主曲线模型拟合度和光滑程度更高,能够更准确地描述沥青混合料粘弹性动态响应的影响。     

冻融循环条件下沥青混合料强度衰减的评价方法

对沥青混合料在不同冻融循环条件下的破坏机理及其强度衰减评价方法进行研究.通过比较不同温度、不同频率及不同冻融循环条件下沥青混合料动态模量及其损伤变量的变化规律,探讨沥青路面冻融破坏机理,并确定冻融循环条件下其强度衰减的评价方法及指标.研究结果表明:当温度在5～15℃之间时,沥青混合料的动态模量迅速变化,温度继续升高之后趋于稳定;比较直接冻融、饱水加载后冻融和加载冻融同时作用3种不同冻融循环试验方法,以加载冻融同时作用的条件最为苛刻;确定在25℃和10 Hz下,进行900 N边加载边冻融试验作为沥青混合料强度衰减评价方法,损伤变量达到10%时作为沥青混合料的损伤破坏评价指标.     

石墨密封垫片的循环压缩回弹性能

通过试验研究了核级石墨密封垫片的循环压缩回弹性能。在常温下对垫片开展了加载速率分别为0. 25 MPa/s、0. 5 MPa/s及1 MPa/s的循环加载试验。在加载速率固定为0. 5 MPa/s时,对比研究了垫片在100℃及300℃下的循环加载性能,得到了不同工况下的应力-变形曲线,并计算出垫片在各工况下不同循环内的最大压缩量、压缩率及压缩模量。研究结果表明,在常温下,垫片的压缩模量随加卸载速率的增大而增大;在0. 5 MPa/s的加卸载速率下,垫片的压缩模量随温度升高而增大;而在每一种工况下,垫片的压缩模量均随试验循环次数的增加而减小,最大压缩量均随循环次数增加而增加,出现明显的塑性应变累积现象。     

不同受力模式下沥青混合料强度的速度特性试验研究

为了了解不同加载速率对沥青混合料强度参数的影响以及不同受力模式下沥青混合料的破坏原因,对不同加载速率下单轴压缩、弯曲、直接拉伸和劈裂强度进行试验研究,并从沥青混合料结构组成对不同受力模式下强度差异进行解释.研究结果表明:加载速率对沥青混合料强度有显著影响,强度与加载速率呈近似幂函数关系；沥青混合料黏聚力c随加载速率增大先急剧增大而后趋于平稳,内摩擦角(φ)随加载速率变化规律正好与黏聚力规律相反,先急剧减小而后趋于平稳；在相同应变率条件下,沥青混合料的强度受加载方式的影响,不同受力模式下的强度由大至小依次为抗压强度、弯拉强度、直接拉伸强度和劈裂强度,试验结果为建立沥青混合料强度理论与破坏准则奠定了基础.     

环氧沥青的粘弹特性研究

应用动态粘弹力学的理论和方法,对环氧沥青进行了不同应力、应变、温度和时间条件下的流变学性能试验研究。试验结果表明,与普通改性沥青相比,其蠕变柔量小约4个数量级;复数模量随频率降低（温度升高）而降低并与贮存模量共同趋于定值,而在高频（低温）条件下则显示出一定的粘性特征;各项粘弹性参数远远大于改性沥青和普通沥青,具有很好的抵抗流动变形能力。环氧沥青是一种完全不同于普通沥青和改性沥青的粘弹性材料。     

硬质沥青混合料动态、静态模量的试验研究

采用针入度为10/20的硬质沥青和石灰岩集料制备高模量沥青混合料,同时选择了一种PG76—22的SBS改性沥青,进行性能对比。基于体积法的配合比设计完成后,采用马歇尔稳定度试验、车辙试验、三点弯曲试验、间接拉伸试验来评价硬质沥青混合料的高温性能、低温性能和水稳定性。静态回弹模量与动态复数模量均采用单轴压缩试验来完成,采用不同的加载模式,回弹模量采用7级静态加载,复数模量采用不同频率的正弦波动态加载。深入研究了温度对两种模量的影响。基于反曲函数绘制了动态模量主曲线,同时采用Cole-Cole平面分析硬质沥青混合料的黏弹特征。研究认为,硬质沥青可以制备抗车辙性能优异的高模量沥青混合料,相同温度下,硬质沥青混合料的复数模量均高于SBS改性沥青混合料,但37.8℃以上温度时,硬质沥青混合料的黏性流动比例较大。     

单向拉伸应力状态下沥青混合料强度和刚度特性

为了解单向拉伸应力状态下沥青混合料的强度、刚度特性及破坏原因,进行不同加载速度的直接拉伸动回弹模量、静回弹模量及强度试验,揭示沥青混合料强度、回弹模量、破坏应变、应变能等参数随加载速度的变化规律。建立初始开裂对应的各个力学参数与加载速度之间的幂函数关系,并从破坏机理上将材料设计与结构层的设计相统一。研究结果表明:在单轴拉伸试验中,沥青混合料的动、静回弹模量随加载速度的增大而呈幂函数增大,且动回弹模量随着温度的升高而降低;进行不同加载速度的破坏试验时,试件的初始开裂应变基本保持稳定,且表现为拉应变破坏特征,故拉应变是导致沥青混合料发生破坏的原因,用第二强度理论作为直接拉伸条件下的破坏准则较合适。     

基于拉压差异的沥青混合料强度与疲劳特性

【目的】探究沥青混合料的拉压差异力学特性。【方法】开展了典型沥青混合料直接拉伸和四点弯曲强度及疲劳试验,基于材料拉压模量差异特性推导并得到了区别于传统四点弯曲梁的真实四点弯曲强度计算公式,分析了传统四点弯曲、真实四点弯曲及直接拉伸应力状态下强度、疲劳寿命及模量衰变规律。【结果】真实四点弯曲强度约为传统四点弯曲强度的80%,在相同加载速率下,不同应力状态强度中直接拉伸强度最小,且其对加载速率的敏感性亦最低;在相同应力水平下,直接拉伸疲劳寿命最小,但在相同真实应力比下直接拉伸疲劳寿命最大,真实四点弯曲疲劳寿命约为传统四点弯曲疲劳寿命的46%;真实四点弯曲疲劳试验的模量衰变速率远小于直接拉伸模量衰变速率,且破坏时前者的模量衰减幅度更小。【结论】材料的拉压差异特性对其力学参数的测试结果及变化规律影响显著,研究成果可为考虑拉压差异的沥青路面结构设计参数取值提供参考。     

沥青麻片垫层压缩蠕变性能的试验研究

本文通过对各种不同规格沥青麻片试件进行分级加载和一次加载的压缩蠕变试验研究表明,沥青麻片呈粘弹性,其应变-时间关系基本符合四参数粘弹性流体模型。文中介绍了利用试验资料求四参数的基本方法;从理论上推导出模型转换关系,并以试验资料做了验证;讨论了运用粘弹性理论和模型转换关系及试验资料解决实际工程问题。     

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.     

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.     

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.     

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.     

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.     

On Tragic Consciousness In The Works By Ernest Hemingway

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.