7055铝合金的淬火敏感性研究

通过测定时间-温度-硬度曲线并采用透射电镜研究7055铝合金的淬火敏感性.研究结果表明：7055铝合金的淬火敏感温度区间为235～415℃,鼻尖温度约为355℃;7055铝合金的过饱和固溶体在355℃保温时快速分解,析出大量无强化作用的粗大η相,减小基体中溶质原子浓度,降低时效强化效果;该合金较佳的淬火制度为：适当减小高温区间的冷却速率,加大淬火敏感温度区间235～415℃的冷却速率.在此淬火制度下,既可减小铝合金残余应力,又可保证其较佳的力学性能.     

基于末端淬火试验研究3种7000系铝合金的淬透性

通过末端淬火方法研究7055,7050和7085 3种铝合金厚板的淬透性,采用扫描电镜和透射电子显微镜对微观组织进行分析。研究结果表明:3种合金的淬透层深度分别约45 mm,60 mm和100 mm以上,两端的硬度分别为14%,12%和6%,3种合金的硬度与冷却速率的对数呈线性关系,曲线斜率依次减小。7055和7050合金中Zn与Mg质量比低(Mg含量高),Cu含量高,导致淬火速率低时晶内析出尺寸更大、数量更多的η平衡相,同时也促进了T相和S相的析出,时效后平衡相的周围出现明显的无沉淀析出带,导致硬度下降明显,合金的淬透性大大降低。     

ZK60镁合金铸态显微组织分析

作为高强度变形镁合金研究的基础工作,较系统研究了ZK60镁合金的铸态组织.光学显微分析表明,铸态组织中存在很明显的枝晶;有相当数量的共晶组织沿晶界或枝晶边界断续分布.差热分析(DSC)表明,在加热和冷却速度分别为15 K/min和10 K/min时共晶组织的熔化温度为345℃,凝固析出温度为328.7℃.x-衍射分析初步确定,在铸态ZK60镁合金中主要有α-Mg,MgZn,MgZn23种合金相.透射电子显微分析发现,共晶组织类型、组成和分布具有多样性,选区电子衍射花样标定共晶组织主要由α-Mg和MgZn两相构成.     

Al-5.0Zn-3.0Mg-1.0Cu-0.1Zr合金的淬火敏感性

通过分级淬火的方法确定Al-5.0Zn-3.0Mg-1.0Cu-0.1Zr合金的时间-温度-性能(TTP)曲线,并结合7050及7085合金考察成分对淬火敏感性的影响。研究结果表明:Al-5.0Zn-3.0Mg-1.0Cu-0.1Zr合金T76状态的TTP曲线鼻尖温度为325℃,临界时间为1.554 s,99.5%的TTP曲线保温时间为100 s,合金的淬火敏感区间为200~410℃;该合金在等温保温过程中析出η相,消耗Zn和Mg,降低合金的过饱和程度,削弱后续时效强化的效果;合金时效后,在这些η相周围形成无沉淀析出区;Al-5.0Zn-3.0Mg-1.0Cu-0.1Zr合金具有较低的淬火敏感性,该合金淬火冷却速度可以选择介于7050合金冷却速度与7085合金冷却速度之间。     

4种均匀化态Al-Zn-Mg-Cu合金的淬透性

通过末端淬火方法研究7075,7050,7055和7085这4种均匀化态合金的淬透性,采用扫描电镜和透射电子显微镜对微观组织进行分析。研究结果表明:这4种均匀化态合金距离喷水端98 mm处的维氏硬度比3 mm处的维氏硬度分别下降33%,6%,7%和5%,7075合金淬透层深度为23 mm,其余3种合金淬透层深度均在100 mm以上;7075合金慢速淬火时,更多大尺寸的η平衡相和T相倾向于在非共格的E相上析出;时效后平衡相的周围出现明显无沉淀析出带,导致维氏硬度明显下降,淬透性大大降低,而其余3个合金中弥散粒子(Al3Zr)与基体共格,析出的平衡相粒度较小且数量较少,因而淬透性均较好。     

HB450低合金超高强耐磨钢组织与性能

在实验室条件下,设计了一种新型Ti-Cr-B系列HB450高韧性低合金超高强耐磨钢.研究了该类钢的基本特征、显微组织、析出物形态以及冷却速度对其组织和性能的影响.研究结果表明,试验钢具有良好的淬透性,在冷速大于20℃/s时即可获得大量的马氏体组织;试验钢在控制轧制后以950℃淬火,250～300℃回火时可获得细小均匀的回火马氏体+残余奥氏体组织,其布氏硬度达到450左右,具有良好的强韧性配合,满足HB450低合金耐磨钢性能要求;透射电镜分析表明,在250℃回火时,大量ε-FexC在马氏体板条内析出,该类碳化物对试验钢的强化起着极其重要的作用.     

均匀化处理温度对6082铝合金组织和性能的影响

采用硬度、电导率测试、金相显微镜、X线衍射、扫描电镜、透射电镜和能谱分析技术,研究均匀化温度对合金组织和性能的影响.研究结果表明:铸态合金由α-Al固溶体和非平衡共晶相组成;490～510℃均匀化,Mg2Si相从过饱和固溶体中析出,在510℃以上均匀化,随着温度的升高,Mg2Si又逐步回溶到基体中,560℃均匀化,Mg2Si相和过剩单质Si完全溶解;随着均匀化温度的升高,非平衡析出物鱼骨状共晶形态逐渐消失,针状β-AlMnFeSi溶解、断裂,转变为具有更高(Mn+Fe)/Si比值颗粒状α-Al(MnFe)Si相,析出相在高温均匀化过程中聚集、球化;560℃均匀化,析出物的连续网状结构转变成链状结构,析出物演化为等轴粒状α-Al(MnFe)Si相.均匀化过程中合金中析出弥散α-Al(MnFe)Si相;在490～560℃保温6h均匀化处理,温度升高,合金的硬度和电导率分别升高和降低.     

淬火介质对2519铝合金抗剥落腐蚀性能的影响

采用显微硬度测试与透射电镜分析,研究淬火介质对2519铝合金抗剥落腐蚀性能的影响.结果表明:采用空气、沸水和室温水(20 ℃)淬火后,各合金在时效过程中都表现出3个阶段时效特性:欠时效、峰值时效及过时效.合金经空气淬火并峰值时效后,晶界析出相呈不连续分布,且无沉淀析出带的平均宽度为100 nm;合金经室温水淬并峰值时效后,晶界析出相呈链状连续分布,无沉淀析出带平均宽度为60 nm;经室温水(20 ℃)淬火并峰值时效后合金抗剥落腐蚀性能最好,经100 ℃水淬火并峰值时效后的合金次之,经空气淬火并峰值时效后的合金抗剥落腐蚀性能最差.     

过饱和Al-Zn-Mg-Cu-Mn合金热分解的XRD研究

利用雾化及高能低温球磨的方法制备了过饱和的Al-Zn-Mg-Cu-Mn合金粉,并利用XRD方法,研究了所得过饱和铝合金粉的热分解过程.研究结果表明,在350℃以下热分解时,过饱和固溶体析出的平衡相为η(MgZn2),XRD未检测出含锰相的存在.含锰铝合金粉在高于350℃分解时,除η(MgZn2)相外,析出相中还有Al6Mn,但未发现其他任何类型的亚稳含锰相,说明Al6Mn直接从过饱和的α-Al中析出,而非是先析出含锰的亚稳过渡相,由中间相转变为平衡相.     

控轧控冷工艺参数对高碳钢SWRH77B组织的影响

在Gleeble-1500热模拟实验机上测定高碳钢SWRH77B的连续冷却转变(CCT)曲线,并利用光学显微镜和透射电镜分析其终轧温度、冷却速度下的组织演变和相变规律.结果表明,随着冷却速度的加快,高碳钢SWRH77B在950 ℃变形时,其珠光体的片层间距变细;冷却速度达到5 ℃/s时,有马氏体组织析出.高碳钢SWRH77B在终轧温度为950 ℃、冷却速度约为4 ℃/s时,其珠光体的片层间距约为97 nm,索氏体含量达到95.7%左右,表明此时的组织为最佳索氏体组织.     

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.