首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 321 毫秒
1.
纳米碳酸钙和SBS复合改性沥青的性能   总被引:4,自引:0,他引:4  
用直接剪切的方法制备纳米碳酸钙和SBS复合改性沥青,对纳米碳酸钙和SBS复合改性沥青的常规技术性能、SHRP技术性能及动态力学性能等进行试验研究。研究结果表明,在SBS改性沥青(SBS含量为5%)中掺入纳米碳酸钙后,随着纳米碳酸钙含量的增加,复合改性沥青的软化点、针入度指数提高,但5℃时延度降低;纳米碳酸钙和SBS含量均为5%的复合改性沥青满足PG 76—22的指标要求;纳米碳酸钙和SBS复合改性沥青的贮能模量E′、损耗模量E″在试验温度区间(-30~30℃)均比SBS改性沥青的高,但复合改性沥青的损耗角正切(tanδ)在10℃以下略比SBS改性沥青的高,而在10℃以上则略比SBS改性沥青的低,说明在SBS改性沥青中掺入纳米碳酸钙获得了良好的增强效果,且低温下的韧性有所提高。  相似文献   

2.
速生杨木动态黏弹性与初始含水率的关系   总被引:1,自引:0,他引:1  
对初始含水率分别为0%、12%、18%、30%、50%、80%、100%和水饱和8种速生杨木试件进行动态黏弹性分析,采用动态热机械分析仪(DMA)进行测定,其操作参数为:温度范围35~350℃,升温速度5℃/min,测量频率1、10、50 Hz。储能模量的变化趋势表明:含水率为0%的试件在95℃附近其储能模量出现极大值;含水率为12%、18%、30%试样的储能模量在75℃之前下降缓慢,在温度75~130℃之间迅速下降,含水率为12%试样的降幅最小;含水率为50%、80%、100%和水饱和试件的储能模量变化点在135℃之后,随含水率的增大储能模量转变点的温度增加,并在转变点处出现储能模量最小值。损耗模量的变化表明:在试验温度范围内含水率为0%的试件不发生玻璃化转变;在所有含水试件中,含水率为12%试件的初始损耗模量和发生次转变时的损耗模量均为最低,同含水率为18%和30%试件相比,发生次转变时温度最高,含水率为30%试样在所有含水试样中具有最大的黏性。损耗因子的变化表明:所有含水试样均发生玻璃化转变过程,含水率为30%试样的玻璃化转变温度最低。在1~50 Hz之间,不同频率对储能模量、损耗模量及损耗因子影响较小,随着测量频率的升高,各力学松弛过程的描述曲线向高温方向有微小移动。  相似文献   

3.
为解决相变材料用于沥青混合料热稳定性与力学性能不足的问题,采用环氧树脂与十五烷定形封装相变材料制备新型环氧树脂复合相变材料,并采用等体积替换法将其用于沥青混合料中。采用差示扫描量热仪(DSC)、热重分析仪(TG)与导热系数仪进行环氧树脂复合相变材料相变与热物特性测试分析;通过相变沥青混合料温度调控试验分析其调温性能与效果,并对相变沥青混合料路用性能进行验证。研究结果表明:环氧树脂复合相变材料相变焓值可达60 J/g以上,在180℃以内几乎不发生热损失,储热密度高、热稳定性良好;相变区间内表观比热容显著增大,升、降温过程中最大值分别为10.9和6.7 J/(g·℃);相变材料掺量(质量分数)越大温度调控效果越好;调温性能与混合料位置相关,相变沥青混合料最大调温温差和最大温度变化速率降低值随深度增大而增大;各掺量下相变沥青混合料均具有显著的调温效果,掺量小于4%时相变沥青混合料均可满足路用性能要求。  相似文献   

4.
采用Q800动态力学分析仪对4个温度水平下(-2℃、10℃、20℃和30℃)的库尔勒香梨果肉进行振荡剪切试验,以探讨温度对香梨果肉组织动态粘弹力学特性的影响,为香梨机械防损和质地品质保持提供指导。试验结果表明:不同温度下果肉的储能模量G′均远高于损耗模量G″,损耗正切tanδ(G″/G′)范围为0.082~0.095,表明香梨是以弹性为主导的粘弹体。香梨果肉组织的储能模量(G′)和损耗模量(G″)不受频率影响,均随温度下降呈上升趋势;当温差10℃时,各动态模量之间无显著差异,表明只有较大的变温幅度温才会对香梨果肉的粘弹特性和机械耐损性能有显著影响。  相似文献   

5.
采用基质沥青、增容剂、复配的羧酸固化剂和环氧树脂共混制备了热固性环氧沥青材料,通过力学性能测试、DMA、荧光显微镜及SEM照片分析研究了复配固化剂对环氧沥青固化体系力学性能和相态结构的影响.结果表明,在癸二酸中复配8g甲基四氢苯酐(MeTHPA)和改性桐油酸酐(TOA),拉伸强度由1.94MPa增加至2.36MPa和2.26MPa,25℃时针入度由31.8降低为10.1和16.0,Tg由25℃增加至54℃和41℃,tanδ>0.3的温度区间更宽,说明复配固化剂可以与环氧树脂形成交联密度更高、刚性更强的网络结构,更有效的提高环氧沥青的拉伸强度和高温阻尼特征;沥青在环氧树脂中的分散粒径和分布间距变得不均匀,但固化体系仍为沥青为分散相、环氧树脂为连续相的海岛状两相结构.  相似文献   

6.
为了研究冻结温度对砂质泥岩峰值强度、粘聚力、内摩擦角及残余强度的影响规律,分析围压与峰值强度、残余强度的关系,从甘肃新庄煤矿采集砂质泥岩,对加工后的岩样进行干燥和饱水处理,开展常温(+20℃)和不同冻结温度(0℃、-5℃、-10℃、-20℃和-30℃)条件下单轴、三轴力学试验。研究结果表明:冻结温度对饱和状态下试件力学特性影响较大,温度由-5℃降到-30℃时,峰值强度提高了138.13%~161.60%,粘聚力提高了97.52%,残余强度提高了174.94%~324.30%,内摩擦角提高了15.09%,相对而言,冻结温度对内摩擦角影响小;冻结温度对干燥状态下岩石试件力学特性影响相对较小;同一温度条件下,试件峰值强度、残余强度均随围压增大而增大,经拟合呈线性关系,饱和状态下试件峰值强度、残余强度增加幅度大于干燥状态下的相应值。  相似文献   

7.
为探究超高性能轻型组合桥面 UHPC-沥青面层黏层材料动态力学性能,采用伺 服液压系统 UTM-30 对 UHPC-SMA 界面施加动态剪切荷载,通过 5 ℃、15 ℃、25 ℃、35 ℃、45 ℃、60 ℃六种温度和0.1 Hz、0.5 Hz、1 Hz、5 Hz、10 Hz、25 Hz六种加载频率下动态剪切试验,获 得热熔型改性环氧树脂 202、高黏高弹改性沥青 PG100两种典型黏层材料的动态剪切模量和 相位角的变化规律;基于时间-温度等效原理和Sigmoidal函数,采用最小二乘法拟合得到动态 模量主曲线和相位角主曲线. 试验研究表明:动态模量随着温度的升高而减小,随着频率的增 加而变大;而相位角却随着温度的升高而变大,随着频率的增加而减小;黏层材料具有黏弹性 材料动力响应特征. 在相同温度、相同频率下,树脂202的动态模量明显大于沥青PG100,其相 位角明显小于沥青 PG100,且随着温度的升高这种现象更明显;60 ℃时,树脂 202动态模量仍 大于 1.13 MPa,而沥青 PG100 仅为 0.15 MPa 左右;树脂 202 比沥青 PG100 具备更好的抗剪性 能. UHPC-沥青面层黏层最不利工况为高温与低频,与25 ℃、25 Hz(相当于120 km/h)相比,60 ℃、5 Hz(相当于 30 km/h)条件下,树脂 202、沥青 PG100 的动态剪切模量分别下降 34.9%、 88.8 %. 树脂 202、沥青 PG100动态模量主曲线拟合优度 R2 分别为 0.993、0.996,相位角主曲线 拟合优度R2 分别为0.978、0.989,回归方程的拟合度优良. 通过动态性能主曲线,不仅可以获得 高频率和长时间下的材料特征,同时也可以预测黏层材料的寿命和长期使用性能.  相似文献   

8.
采用动态热机械分析(DMA)研究了杉木积成材(OLSL)及其构成单元——杉木木束条的动态力学性能。结果表明:杉木木束条和杉木积成材的储能模量(E′)随着温度的升高而迅速下降,而损耗模量(E″)和损耗角正切却随着温度的升高而迅速上升;杉木木束条制成杉木积成材后其储能模量下降;杉木木束条和杉木积成材的玻璃化转变温度分别为95、80℃。动态热机械分析可为优化杉木积成材的制造工艺提供依据。  相似文献   

9.
采用动态热机械分析(DMTA)测试毛竹材的储能模量(E')和损耗模量(E″),分析在不同初含水率、笔壁径向部位、竹龄及距毛竹基部高度下毛竹材的储能模量和损耗模量及玻璃化转变温度(Tg)。结果表明:①毛竹材储能模量随着温度的升高呈逐渐减小的趋势,损耗模量随着温度的变化出现两个峰,当温度达到玻璃化转变温度时达到第1个峰值。②储能模量和损耗模量受初含水率的影响较大,随着含水率的增加呈相对减小的趋势; 在竹壁径向上,储能模量和损耗模量由内而外依次增大; 在同一温度下,毛竹材的储能模量和损耗模量具有随毛竹高度的增加而降低的趋势; 不同竹龄毛竹材的储能模量和损耗模量略有差别,基本上随竹龄的增大而增大。③毛竹材Tg随含水率的增加而降低,在绝干状态时Tg为217~223 ℃; 含水率为15%到饱水状态时,Tg在113~134 ℃之间; 沿竹壁径向的竹青、竹肉和竹黄的Tg略有差别,30%含水率时的Tg在123~135 ℃之间; 不同竹龄毛竹材的Tg并无较大差异,在120~123 ℃之间; 不同高度的毛竹材Tg也无显著差异,在123~126 ℃之间。研究表明,在毛竹材的实际生产中可通过增加毛竹材周边温度和含水率以增加其塑性,使竹材的竹龄和高度选择更加宽泛。  相似文献   

10.
本文主要介绍低熔点玻璃非匹配封接的原理及工艺,所用封接试件的膨胀系数从(40~80)×10~(-7)/℃,封接用的低熔点玻璃胀膨系数为(80~100×10~(-7)/℃,封接温度550℃以下,封接试件用质谱检漏并进行常规排气试验,封接方法可用高频封,炉封等.  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.
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   

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 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.  相似文献   

15.
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   

16.
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.  相似文献   

17.
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   

18.
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.  相似文献   

19.
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   

20.
赵英华 《科技信息》2008,(12):219-220
0.Preface China has long been boasting of its colorful and immense culture which comprises of Taoism,Confucianism and Buddhism.The interwoven influence among the religions on Chinese way of thinking,on the nation's behavior in their social life throughout the long history is beyond list.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号