IF钢凝固过程中Al_2O_3-TiN复合夹杂物的形成机理

以理论分析和实验研究相结合的方式分析了IF钢凝固过程中Al2O3-TiN复合夹杂物的形成机理.结果表明,以凝固分率0.9为界限,钢水凝固过程中Al2O3和TiN先后通过异质形核方式析出并结合形成Al2O3-TiN复合夹杂物;冷却速率越小,复合夹杂物粒径越大;在冷却速率一定时,可作为异质形核核心的夹杂物的粒径越大,凝固过程中析出的复合夹杂物的长大程度越小;复合夹杂物内层Al2O3粒径越小,外层TiN长大程度越明显.     

低碳低硫钢中MnS析出行为分析

本文研究铝含量、硫含量、冷却速率等对低碳低硫钢中MnS夹杂物的成分、形貌和析出量的影响,并利用Scheil凝固方程及FactSage 6.1软件对MnS析出行为进行了理论计算。结果表明,冷却速率较低(5K/min)时,钢中夹杂物为双层结构,核心氧化物为Al2O3-SiO2和Al2O3-SiO2-MnO,MnS在氧化物表面局部或包裹析出;冷却速率较高(900K/min)时,钢中夹杂物主要为Al2O3-SiO2-MnO,高铝钢样中没有MnS析出,而低铝钢样中有极少量MnS析出;MnS在夹杂物上的析出率随着冷却速率的降低、钢中铝含量的减少(硫含量随之增加)而提高;复合氧化夹杂中的MnO+SiO2对MnS的析出影响较大,MnO+SiO2含量越高,MnS越容易在氧化物上析出;在低硫(w[S]0.0050%)条件下,MnS不能在液相中单独析出,但能在夹杂物上复合析出。     

齿轮钢氧含量及夹杂物控制技术研究

利用热力学软件计算了齿轮钢氧含量与夹杂物成分控制、夹杂物转变条件.结果表明,20CrMoH钢中具有较高塑性的非金属夹杂物成分(质量分数)为:SiO2 0%～10%、Al2O3 22%～55%、CaO 42%～60%、MgO 5%～10%,与之平衡的钢液中铝的质量分数大于0.020%,钙的质量分数大于0.7×10-6,a[O]为0.0005%左右;选择组成为CaO>40%、Al2O3≤37%、MgO10%、(%CaO+%MgO)/%SiO2为10、SiO2含量尽量低的渣系,钢中Al2 O3、MgO.Al2 O3夹杂物可转变为低熔点的钙铝酸盐.试验发现LF和RH精炼结束时钢液T[O]含量均随炉渣碱度增加而降低,采用高Al2O3含量的炉渣对降低T[O]含量有利;精炼过程钢液中夹杂物按"Al2O3系夹杂物→MgO--Al2O3系夹杂物→CaO--MgO--Al2O3系夹杂物"顺序发生转变,其中MgO--Al2 O3系夹杂物向CaO--MgO--Al2 O3系夹杂物的转变是由外向内逐步进行的,转变速度相对较慢;降低T[O]含量有利于生成较低熔点的CaO--MgO--Al2O3系夹杂物.     

GCr15轴承钢中MnS-Al_2O_3复合夹杂物析出行为

对于钢液铝脱氧精炼过程产生的Al_2O_3夹杂物严重影响钢的性能,而在钢液凝固过程中MnS夹杂物容易包裹着Al_2O_3夹杂物形成复合夹杂物,这种复合夹杂物改善钢材的性能有重要意义。通过场发射扫描电镜和能谱对国内某钢厂连铸坯中夹杂物形貌以及组成进行观察与分析,发现大量MnS包裹Al_2O_3复合夹杂物。同时通过理论热力学阐述MnS包裹Al_2O_3复合夹杂物的析出机理,计算得出:Al_2O_3夹杂物在钢液中形成,Mn S夹杂物在钢液凝固过程中形成,由于Al_2O_3夹杂物先析出,Mn S夹杂物可以在先析出的Al_2O_3夹杂物进行形核与长大,为钢中MnS包裹Al_2O_3复合夹杂物生成提供了理论依据。     

低碱度顶渣控制帘线钢中MnO-Al2O3-SiO2类夹杂物成分的实验研究

在实验室中使用高温管式炉对以工业纯铁为原料配制的帘线钢进行脱氧和顶渣熔炼，研究了顶渣成分对MnO-Al2O3-SiO2类夹杂物的成分的影响。结果表明，在顶渣碱度为0．7～1．36时，随着顶渣中Al2O3含量的增加，夹杂物中的Al2O3含量也随之增加，当顶渣中Al2O3含量低于8％时，MnO—Al2O3—SiO2类夹杂物的成分在塑性区范围，通过控制脱氧条件和项渣的成分可以把MnO-Al2O3—SiO2类夹杂物的成分控制在塑性区内的。     

Ti-Mg复合脱氧钢中夹杂物细化机制

为了探讨钢中细小夹杂物的形成机制,采用扫描电镜和能谱仪表征了钢中夹杂物的形貌、尺寸、成分及数量,理论计算了脱氧产物的生成优势区图,讨论了夹杂物长大的影响因素.钢中夹杂物的组成以MgO-A12 O3-TiOx为核心,表面包裹析出MnS,钢液中未发现单独的Al2O3和TiOx夹杂;夹杂物的形貌为近球形,平均尺寸为1μm左右,数量在1000 mm-2以上.镁含量较高的钢中含有少量以MgO-Al2O3和MgO为核心的夹杂物,不利于夹杂物的球形化,镁含量宜控制在50×10-6以下.镁的脱氧能力强,形核临界尺寸小、形核数量多以及钢液中镁、铝和钛复合脱氧的高熔点产物的特性有效地控制了钢中夹杂物的扩散与碰撞长大趋势.     

气瓶钢精炼过程中的MgO·Al_2O_3夹杂物

研究了EAF-LF-VD-CC流程冶炼气瓶钢30CrMo时精炼过程中含MgO.Al2O3夹杂物的生成和转化,对夹杂物进行了三维分析观察.研究结果表明:LF精炼30min后夹杂物中Mg含量减小,Ca含量增加,MgO.Al2O3夹杂物消失.LF精炼后期Mg含量变化不大,Ca含量减小,未出现MgO.Al2O3夹杂物;VD精炼过程中夹杂物中的Mg含量增加,Ca含量变化不大,重新生成了MgO.Al2O3夹杂物;精炼过程中MgO.Al2O3夹杂物可以向复合夹杂物转变的,但为防止精炼后期MgO.Al2O3夹杂物重新生成必须保证钢液中具有一定的钙含量.     

稀土处理C-Mn钢显微组织和夹杂物演化

对稀土处理C-Mn钢的夹杂物和显微组织进行分析,统计稀土处理C-Mn钢中针状铁素体形核核心尺寸,并将稀土处理钢在不同温度下淬火,研究稀土夹杂物生成和长大过程. 实验结果表明:C-Mn钢加入少量稀土后钢中夹杂物从MnS﹢硅铝酸盐夹杂转变为La2 O2 S﹢LaAlO3 ﹢MnS﹢硅铝酸盐夹杂,尺寸得到细化,显微组织也从马氏体﹢贝氏体组织变成侧板条铁素体、针状铁素体和块状铁素体组织;稀土处理C-Mn钢中针状铁素体有效形核核心的尺寸集中在1~4μm,主要是在钢液中形成,冷却和凝固过程形成的数量较少;稀土夹杂物在钢液温度和冷却及凝固过程容易碰撞黏合长大,上浮从钢液中去除, MnS能在稀土夹杂物颗粒间析出.     

精炼渣成分对高强度低合金钢中非金属夹杂物影响

采用渣钢平衡的实验方法研究了1600℃下不同碱度和不同Al2O3含量的强还原性精炼渣对高强度低合金钢中非金属夹杂物的影响.结果表明:渣钢反应平衡后,炉渣中CaO和SiO2的质量比为1.9～4.5、Al2O3质量分数为21%～33%,钢中夹杂物主要为球状的CaO-MgO-Al2O3-SiO2系,尺寸在5μm以下,炉渣成分对夹杂物的成分影响很大.夹杂物主要分布在SiO2含量一定的CaO-MgO-Al2O3-SiO2伪三元相图中1 400～1 500℃的低熔点区,随着炉渣碱度的提高和Al2O3含量的降低,部分夹杂物逐渐偏离低熔点区域,夹杂物的总数量逐渐减小.当渣中Al2O3质量分数为21.22%、碱度为3.27时,有大量夹杂物分布在高熔点区域,夹杂物的总数量最小.     

铝含量对TWIP钢中夹杂物特征及AlN析出行为的影响

采用扫描电镜、X射线能谱仪以及扫描电镜配置的夹杂物自动扫描统计软件(INCAFeature)表征了Fe-Mn-C(-Al)系TWIP钢中夹杂物的成分、形貌和数量,考察了Al质量分数在0.002%~1.590%的四种TWIP钢中夹杂物的特征和Al含量对AlN析出行为的影响.并在此基础上,采用了适合TWIP钢中高锰高铝特点的热力学参数对AlN夹杂物进行了系统的热力学分析.研究表明,在含有相似N质量分数(0.0078%~0.0100%)的TWIP钢中,当钢中Al质量分数升高至0.75%时,AlN夹杂物开始在钢中析出,并在MnS(Se)-Al2O3上局部析出形成MnS(Se)-Al2O3-AlN复合夹杂;当Al质量分数升高至1.07%时,热力学计算表明AlN已经可以在TWIP钢液相中形成,经不断长大后在MnS(Se)夹杂物表面局部析出形成MnS(Se)-AlN复合夹杂物;在Al质量分数为1.59%的TWIP钢中,AlN的平衡析出温度比其液相线温度高出42 ℃,在液相中形成的AlN可以作为异质核心,MnS(Se)夹杂在其表面包裹形成MnS(Se)-AlN复合夹杂物.另外,在Fe-18.21%Mn-0.64%C-1.59%Al体系的TWIP钢中,AlN在液相中析出所需的最低氮的质量分数仅为0.0043%.因此,在TWIP钢的冶炼过程中,应尽可能的降低钢中的氮含量,避免生成过量的AlN夹杂.     

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.