CeO2对原位自生Al2O3-TiCP/Al基复合材料组织结构的影响

利用Al-TiO2-C体系熔铸法制备含稀土CeO2原位自生Al2O3-TiCP/Al基复合材料.借助差示扫描量热仪(DSC)、扫描电子显微镜(SEM)、能谱分析仪(EDS)、X射线衍射仪(XRD)等测试技术,对Al-TiO2-C体系的组织结构进行了详尽的分析,讨论了对稀土CeO2铝对Al2O3-TiCP/Al基复合材料的影响规律.实验结果表明,稀土CeO2的加入可改善陶瓷颗粒Al2O3和TiC与熔体的润湿性,而且有效的细化和净化了组织,降低了反应温度.稀土CeO2添加剂含量为0.5%时利用熔铸法制备的复合材料中原位形成的Al2O3,TiC颗粒尺寸较小,分布均匀.     

TiC-Al2O3颗粒增强钢基复合材料的制备及耐磨性研究

选取Ti-C-Al-Fe2O3体系采用铸造/SHS(自蔓延高温合成)两种工艺相结合,成功制备出原位自生TiC、Al2O3两种陶瓷颗粒增强钢基复合材料.通过改变Ti-C-Al-Fe2O3体系稀土元素含量以及施加不同载荷等参数的变化,研究体系的耐磨性能.添加稀土CeO2加入量为0.8wt.%时,相对耐磨性为10.2,达到最大值;同一成分的材料随着载荷从7N增加到21N,相对耐磨性也进一步提高.     

TiC增强Fe3Al基复合材料的显微组织与力学性能

运用原位合成反应工艺制备了TiC颗粒增强Fe3Al基复合材料 .显微分析研究表明 ,在Fe3Al中引入TiC颗粒 ,可以有效地细化材料的显微组织 ,从而改善材料的热变形加工工艺性能 .TiC增强体不仅本身具有很高的热稳定性 ,而且也大幅度提高了复合材料的热稳定性 .对复合材料进行的一系列性能测试结果显示 ,在Fe3Al中加入TiC颗粒后 ,材料的室温和高温强度和抗蠕变性能得到显著提高 ,但是在一定程度上降低了材料的室温塑性     

高能球磨对TiC0.5/Cu(Al)复合材料组织和性能的影响

以Ti2AlC和Cu粉作为原料,分别采用滚筒球磨和高能球磨对原料粉进行预混处理,在1 150℃下原位热压反应制备了TiC0.5/Cu(Al)复合材料.实验结果表明,Al从Ti2AlC溶出进入Cu中,Ti2AlC分解并转变成TiC0.5相,然而滚筒球磨制备的复合材料中生成少量AlCu2Ti相.通过对原料粉高能球磨处理,制备后的复合材料AlCu2Ti相消失,细小的TiC0.5颗粒均匀分布于基体中.两种不同方法制备的复合材料的弯曲强度和维氏硬度试验结果表明,高能球磨工艺能提高TiC0.5/Cu(Al)复合材料的弯曲强度,同时维氏硬度略有降低.其中,高能球磨处理后制备的27％ TiC0.5/Cu(Al)复合材料的弯曲强度达到981 MPa,维氏硬度为2.43 GPa.     

CeO_2对SiCp/Al-Si复合材料组织及性能的影响

采用粉末冶金法制备SiCp/Al-Si复合材料,以CeO2为变质剂,制备含CeO2的SiCp/Al-Si复合材料。研究CeO2的添加量(质量分数)对复合材料组织和力学性能的影响,探讨复合材料中CeO2在烧结过程中的作用机理。研究结果表明:添加CeO2可以有效提高复合材料的致密度和室温拉伸性能,复合材料的致密度和室温拉伸性能随CeO2添加量(质量分数:0%~1.80%)的增加先升高后降低,在CeO2的添加量(质量分数)为0.60%时出现峰值。随着CeO2添加量的增加,CeO2颗粒发生集聚长大。当稀土添加量(质量分数)为0.60%时,变质效果最好。此时,硅相的平均尺寸最小且形态明显球化,硅颗粒的平均直径从7μm下降到5μm以下。     

CeO2对 SiCp/Al-Si 复合材料组织及性能的影响

采用粉末冶金法制备 SiCp ／Al-Si 复合材料,以 CeO2为变质剂,制备含 CeO2的 SiCp ／Al-Si 复合材料。研究 CeO2的添加量（质量分数）对复合材料组织和力学性能的影响,探讨复合材料中 CeO2在烧结过程中的作用机理。研究结果表明：添加 CeO2可以有效提高复合材料的致密度和室温拉伸性能,复合材料的致密度和室温拉伸性能随 CeO2添加量（质量分数：0％～1．80％）的增加先升高后降低,在 CeO2的添加量（质量分数）为0．60％时出现峰值。随着 CeO2添加量的增加,CeO2颗粒发生集聚长大。当稀土添加量（质量分数）为0.60％时,变质效果最好。此时,硅相的平均尺寸最小且形态明显球化,硅颗粒的平均直径从7μm 下降到5μm以下。     

A1/TiC复合材料铸造流动性的研究

通过实验研究了基体Al合金和TiC颗粒含量不同的四种Al／TiC复合材料的流动性．并根据流动性的差异,提出了不同的铸造工艺成型方法．     

颗粒增强Al基复合材料组织和性能的研究

采用高能球磨粉末冶金法制备颗粒增强Al基复合材料,分别以ZrO2,SiC和α-Al2O3为增强体,对比分析了不同颗粒增强Al基复合材料的组织与性能.以α-Al2O3颗粒为主增强体,分析了不同粒度α-Al2O3对复合材料组织性能的影响.研究结果表明,ZrO2/Al和 SiC/Al 复合材料的界面结合不如α-Al2O3/Al复合材料的界面结合紧密,α-Al2O3颗粒粒径为45μm时,复合材料性能更好地得到改善,添加适量的Ce能改善基体与增强体的界面结合,并显著地提高了颗粒增强Al基复合材料的性能.     

放电等离子烧结合成TiC/TiB_2颗粒增强的超细晶钛基复合材料

采用放电等离子烧结技术结合非晶晶化法制备了不同体积分数的TiC/TiB2颗粒增强的超细晶钛基复合材料.运用X射线衍射分析、扫描电子显微镜和万能材料试验机等实验手段,对合成的超细晶钛基复合材料进行测试分析.结果表明：随着外加TiC/TiB2颗粒的增加,钛基复合材料试样的致密度逐渐降低.TiC颗粒与基体不发生反应,而TiB2颗粒的加入改变了TiB2颗粒与基体界面的组织形貌,但对远离界面处的基体组织形貌没有影响,其组织均由-Ti（Nb）相和（Cu,Ni）-Ti2相组成,且-Ti（Nb）相连续分布.同时,TiC颗粒的增强效果优于TiB2颗粒,35vol.%（体积分数）TiC颗粒增强的复合材料试样的断裂强度最高,达2209MPa.     

TiC/316L复合材料的致密化和力学性能试验

采用真空烧结法制备出TiC颗粒增强316L不锈钢复合材料.通过对试样进行光学显微分析并测定其相对密度和拉伸性能,研究了增强相含量和模压压力对复合材料的致密化和拉力学性能的影响,并对断口形貌进行分析.结果表明:添加TiC颗粒有利于复合材料的烧结致密化;TiC颗粒的体积分数对复合材料的拉力学性能有较大影响,当TiC的体积分数从0%增加到10%时,复合材料的抗拉强度从543MPa提高到655MPa,而断裂应变却从0.325减至0.052;在较低的模压压力下,提高模压压力有利于复合材料的相对密度、抗拉强度的增加;但过高的模压压力会使试样在烧结后残余封闭孔隙,降低复合材料的塑性性能和抗拉强度.当模压压力为500MPa时,可得到相对密度高、组织致密、增强相颗粒分布均匀、拉伸性能良好的复合材料.     

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.