低铬白口铸铁的冲蚀磨损与断裂韧性

通过稀土硅铁合金炉前孕育和热处理工艺改善碳化物形态分布及基体组织的强韧性,从而获得性能较为优越的低铬白口铸铁,对其进行断裂韧性测定和较系统的冲蚀磨损试验.结果表明:孕育处理使碳化物由连续网状分布转变为断续网状分布,同时细化了晶粒,导致断裂韧性K_(IC)的提高;并改善其冲蚀抗力;且表现为磨料越硬效果越显著,说明磨料硬度对低铬白口铸铁冲蚀抗力有显著影响:当磨料为较软的玻璃砂时,冲蚀抗力随材料基体硬度的提高而提高;当磨料为硬的碳化硅时,冲蚀抗力随断裂韧性K_(IC)的提高而提高;当材料硬度相近时,则断裂韧性越高,越耐冲蚀.文中结合冲蚀断口的扫描电镜观察及残留奥氏体转变量的X射线测定对试验结果及冲蚀机理进行了分析讨论.     

高铬白口铸铁抗磨粒磨损耐磨性与断裂韧性的研究

本文研究了两种基体组织状态及碳化物体积分数对高铬白口铸铁抗磨粒磨损耐磨性、断裂韧性K_(IC)、K_(Id)及亚临界裂纹扩展速率da/dN的影响。结果表明:高铬白口铸铁耐磨性与磨损系统有关;而其断裂韧性及亚临界裂纹扩展速率与基体组织状态、碳化物体积分数及其形态与分布有关。综合研究结果,从高铬白口铸铁耐磨性与断裂韧性最优化角度考虑,如果用软磨料,宜选用马氏体基体;采用硬磨料,则宜选用奥氏体基体。     

含硼高铬铸铁的组织及性能

在成分为2.7%C-17%Cr-0.7%M_0的高铬铸铁中设计了含硼量变化范围为0.1～1.2%的五种白口铸铁.考察了其铸态及热处理态的组织;进行了石英砂磨料和绿碳化硅磨料的三体磨损试验及湿式橡胶轮磨损试验;测定了材料的硬度、冲击韧性和断裂韧性.试验结果表明:硼促使化合物体积分数增加,并有新的硼碳化物形成;基体组织中铸态己有马氏体析出,具有更好的淬硬性;三体磨损石英砂磨料时随含硼量增加耐磨性显著提高,对碳化硅磨料则相反;在湿式橡胶轮磨损试验中约在0.9%B 处耐磨性出现了最大值;化合物量相近时,含硼与无硼高铬铸铁的韧性相当.     

高铬铸铁在不同工作条件下磨料磨损耐磨性的研究

对含铬１５％、２０％、２８％,含碳２％～４％,含硼和不含硼,不同的热处理工艺,共计７２种成分状态的高铬系铸铁进行了低应力和冲击条件下的磨料磨损试验;测定了其宏观硬度,显微组织和碳化物数量;对宏观硬度、碳化物数量与耐磨性进行了相关分析。结果表明：磨损条件不同,磨损机理不同,其耐磨性的影响因素也不同,低应力磨料磨损的耐磨性与碳化物数量明显相关,冲击磨损的耐磨性与宏观硬度明显相关。此结论对根据不同工作条件合理选用高铬铸铁的成分和热处理工艺有指导意义。     

高铬铸铁在不同工作条件下磨料磨损耐磨性的研究

本文对含铬１５％、２０％、２８％，含碳２％～４％，含硼和不含硼，不同的热处理工艺，共计７２种成分状态的高铬系铸铁进行了低应力和冲击条件下的磨料磨损试验；测定了其宏观硬度，显微组织和碳化物数量；对宏观硬度、碳化物数量与耐磨性进行了相关分析。结果表明：磨损条件不同，磨损机理不同，其耐磨性的影响因素也不同，低应力磨料磨损的耐磨性与碳化物数量明显相关，冲击磨损的耐磨性与宏观硬度明显相关。此结论对根据不同工作条件合理选用高铬铸铁的成分和热处理工艺有指导意义．     

奥氏体基体和马氏体基体高铬铸铁的冲蚀磨损特性

本文模拟抛丸机叶片使用工况,采用玻璃砂和少量石英砂混和磨料,考察了奥氏体基体和马氏体基体高铬铸铁在不同冲击角度下的冲蚀磨损特性。结果认为无论马氏体基体还是奥氏体基体,高角度冲击下的耐磨性都低于低角度冲击;无论冲击角度高低,马氏体基体耐磨性都高于奥氏体基体;奥氏体基体对碳化物的支撑不如马氏体基体,造成碳化物在深层范围内的碎裂。     

锰白铜基铸造碳化钨复合材料的二体磨料磨损特性

以高铬铸铁为参考材料,研究了真空熔铸法制备的锰白铜基铸造碳化钨复合材料的二体磨料磨损特性.研究结果表明,使用不同硬度磨料时锰白铜基铸造碳化钨复合材料的耐磨性比高铬铸铁的耐磨性均有大幅度的提高,特别是使用石榴子石及绿SiC磨料时耐磨性提高的幅度分别达8倍及10倍以上,锰白铜基体的时效硬化对锰白铜基铸造碳化钨复合材料的二体磨料磨损耐磨性影响不大.     

湿法选矿用奥氏体高铬铸铁材质

通过对高铬铁代钼、镍合金元素的选择研究发现,锰会增加高铬铸铁中的残奥含量和降低高铬铸铁的硬度.但对其耐磨性的影响则要取决于磨损系统的条件,在有些条件下(如高应力磨损),加锰引起的残奥增加反而会提高材料的耐磨性.     

CrMnSi铸铁与Cr13RE铸铁耐磨性比较

在ML-10型二体磨损试验机和自制的腐蚀磨粒磨损试验机上,比较了经两种热处理后的CrMnSi铸铁与Cr13RE铸铁的耐磨性.结果表明:在二体磨损采用SiC和SiO_2磨料时,Cr13RE铸铁的耐磨性并不明显超过Ⅱ CrMnSi铸铁(用第二种热处理方法),Ⅱ CrMnSi铸铁磨损形式为切削和犁沟,Cr13RE铸铁为犁沟和相当靛量的剥落;在腐蚀磨粒磨损采用中性和碱性介质时,Cr13RE铸铁表现出良好的耐磨性.采用酸性介质时,Cr13RE铸铁的耐蚀性很差,磨面上存在大量的腐蚀磨损坑;Ⅱ CrMnSi铸铁硬度HRC约60,冲击值?>12.5J/cm~2.明显高于普通抗磨铸铁水平.     

烧结亚共晶高铬铸铁制备及其显微组织与性能

以水雾化高铬铸铁粉末为原料,通过压制/烧结工艺制备了一种亚共晶高铬铸铁(SHCCI),对其显微组织、物理力学性能和冲击磨粒磨损工况下的耐磨性能开展了系统的观察、分析与检测,并与成分相近的传统铸造高铬铸铁(CHCCI)进行了对比研究.试验结果表明,通过超固相线液相烧结可以制备出密度达到7.44g/cm~3的亚共晶高铬铸铁,其Cr_7C_3型碳化物呈细小短杆状,沿晶界均匀地分布在由马氏体和奥氏体混合组成的基体中;烧结态高铬铸铁的硬度为HRC58,抗弯强度为2 122MPa,冲击韧性达到6.5J/cm~2(无缺口试样尺寸为5mm×5mm×50mm);与铸造高铬铸铁相比,由于碳化物形貌、大小和分布均匀性的明显改善,以及基体中有更多的马氏体,烧结高铬铸铁在各种冲击载荷下均展现出明显的抗磨粒磨损性能优势,是一种十分优异的耐磨材料.     

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.     

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.