一种低焊接裂纹敏感性钢的奥氏体粗化温度研究

通过高温淬火试验观察试验钢奥氏体晶粒尺寸的变化情况.结合金相和TEM观察、显微硬度和第二相粒子的溶解度积公式分析了加热温度和保温时间对试验钢奥氏体晶粒粗化温度、第二相粒子的溶解情况以及显微硬度值的影响.结果表明:试验钢的奥氏体粗化温度在1200℃附近.当加热温度低于1200℃时,大量细小的第二相粒子阻碍奥氏体晶粒粗化;当加热温度高于1200℃时,细小的第二相粒子溶解,奥氏体晶粒出现异常长大.确定试验钢的合理加热温度为1150～1200℃,在此范围内可获得淬火组织的显微硬度值低于HV330.     

加热温度对软氮化层组织结构的影响

本文对经过600℃×6小时软氮化的20钢及35钢试样再进行650°—900℃不同温度加热急冷处理,然后分别对各试样进行金相、电子金相等物理检验和各种力学性能试验。其结果表明,经过软氮化后的钢件再在650℃加热30分钟时,铁的氮化物(ε·Υ′)开始分解,在750℃加热15分钟氮化物分解完毕,同时N原子向深层扩散,淬火后可获得一定厚度C—N马氏体层,进而提高了各项力学性能指标。检验发现再加热时ε相先在其和α及Υ相相界面上分解,然后在ε相相同界面分解,析出的氮原子向深层扩散。试验确定了软氮化后再加热时渗层组织变化和温度及加热时间的关系。     

中碳钢软氮化复合处理的研究

本文对570℃×5h软氮化后的40Gr钢试样再进行650～850℃不同温度加热急冷处理,然后分别对各试样进行金相、电子金相和力学性能试验。试验结果表明,经过软氮化后的中炭铬钢在650℃加热30分钟铁的氮化物开始分解,在750℃加热15分钟时氮化物层基本分解完毕。ε相先在和α(或γ)相相界面上分解,然后在ε相的相界面分解,析出的氮原子向深层扩散,这些和低炭钢的试验结果相同,钢含碳量的提高和少量的铬含碳量对ε相的分解过程影响不大。 由于钢加热时表面层ε相的分解和氮原子向深层扩散,中炭钢软氮化再加热淬火后可获得含氮的针状隐晶马氏体组织。本文在试验结果基础上提出了最佳的软氮化复合处理工艺。     

热处理工艺对新型高锰钢组织和性能的影响

研究了热处理工艺对Cr、Mo、Ti、Al、Ca、RE新型高锰钢组织和力学性能的影响.试验结果表明,热处理工艺对新型高锰钢组织和力学性能有显著影响.低温等温预处理温度为580 ℃,保温3 h;高温水韧处理加热温度为 1 040～1 050 ℃, 保温3 h.可以改善高锰钢金相组织和力学性能,使σb=954 MPa , σs=507 Mpa,δ=46.8%,αK=338 J/cm2,HBS219.新型高锰钢履带板装车寿命考核结果,使用寿命由原来的3 200 Km提高到7 000 Km以上,取得了明显的经济效益.     

65Cr4W3Mo2VNb钢马氏体和析出相电镜分析

本文应用JEM-100CX Ⅱ透射电子显微镜研究了65Cr4W3Mo2VNb钢退火,不同温度淬火和回火的高倍微观形貌与相结构,讨论了合金组织和性能的关系。 一、实 验 方 法1.试验用钢及热处理 经化学分析确定,试验用钢成分为:碳0.65%,铬4.13%,钨3.32%,钼1.94%,钒0.97%,铌0.26%,硅0.25%,锰0.19%,磷0.009%,硫0.007%. 纲材在1150—1170℃加热,1100℃始锻,锻后埋沙缓冷。球化退火工艺为:860±10℃保温3h,炉冷至740±10℃等温6h,炉冷到500℃后出炉空冷,退火硬度为HB217.2.电镜样品制备 试验样品用电火花机床切割厚度为200—500μm的薄片,机械减薄至70—10…     

再结晶退火对含磷冷轧高强度钢板显微组织的影响

对含磷冷轧高强度钢板的再结晶退火工艺进行了研究，测定了含磷冷轧高强度钢的再结晶软化曲线，并得出再结晶温度。通过试样硬度的测定以及金相组织的观察分析，研究了冷轧高强度钢工艺、组织结构和硬度之间的关系。结果表明，冷轧高屈服强度钢的再结晶温度在450℃左右，再结晶完成温度大约为700℃：随着退火温度的升高，冷轧高强度钢再结晶组织晶粒不断粗大，渗碳体变化不明显，但其硬度呈明显下降趋势。     

回火温度对新型冷作模具钢显微组织和性能的影响

由于莱氏体钢中含有大量的碳化物,常用的AISID2冷作磨具钢具有很高的耐磨性,但由此而易于崩裂且不易锻造及线切割加工。为此,调整其成分和热处理工艺而开发了一种新型模具钢(实验钢)。采用金相显微镜、硬度计及冲击实验机研究了回火温度对该新型钢显微组织硬度和冲击韧性的影响。结果表明,在1050℃淬火及500℃回火处理时,实验钢与D2钢相比所含碳化物较少且颗粒尺寸较小,而且在各种回火温度下其冲击韧性和硬度均高于D2钢。例如经500℃回火处理,其硬度与冲击韧性分别为HRC64和45J/cm2·由于排除了其中的粗大又不均匀的碳化物,实验钢组织大为改善,由此而消除了在使用中的崩裂失效现象并延长了使用寿命·     

凹模裂纹的成因及其防止措施

对120 mm×80 mm×15 mm报废的CrWMn钢凹模取样,通过硬度检测、烧伤检查、显微组织观察、工艺试验等试验方法,分析了CrWMn钢凹模裂纹形成的淬火温度过高、严重回火不足、磨削工艺不当等原因。在此基础上,提出了选择适当淬火温度和冷却速度、均匀加热、充分回火、合理磨削等防止措施。     

修正步冷试验方法

以广泛应用于加氢反应器材料2.25Cr-1Mo钢为研究对象,对步冷试验温度曲线进行分析.进行了步冷加524 ℃×24 h和步冷加524 ℃×27 h热处理试验.结果表明,步冷试验温度曲线中的第三阶段524 ℃×24 h热处理在再次步冷试验过程中具有脆化倾向.同时对步冷试验温度曲线进行修正,提出了修正步冷试验温度曲线.     

回火方式和时间对高速钢的组织与性能的影响

采用透射电镜、X—射线等手段研究了不同回火方式和时间下 W6Mo5Cr4V2高速纲力学性能与组织的变化。发现淬火该钢经560和630℃多次回火后马氏体内孪晶清晰完整,板条马氏体中仍然存在着以魏氏组织形态分布的 M_3C 型碳化物。证实380℃×(0.5～5)h+560℃×1h×2次的低高温配合回火工艺与560℃×1h×3次的普通回火相比,可使高速钢的硬度、红硬性及冲击韧性提高.采用560℃×(1～3)h×3次的回火工艺时,随每次回火时间延长,高速钢的强度、冲击韧性和断裂韧性提高,红硬性变化不大,但硬度则稍稍下降(约1HRC).     

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.