钙处理齿轮钢中氧硫复合夹杂物的热变形能力

采用金相分析、扫描电镜和能谱仪等分析手段,研究了钙处理加硫的DIN 18CrNiMo7-6齿轮钢中氧硫复合夹杂物的形貌、成分和热变形行为. 结果表明:外围硫化物的钙抑制了氧硫复合夹杂物的变形,当外围硫化物的钙原子分数约为5.0%时抑制作用达到饱和;高熔点核心氧化物的面积分数增加,复合夹杂物的变形能力降低,而低熔点核心氧化物对复合夹杂物变形能力的影响不明显.     

高级别管线钢钙处理冶金效果研究

针对管线钢L360QS进行了钙处理实验研究,考查钢液中[Ca]、[S]对夹杂物变性的影响.结果表明,钢中的硫被脱到0.002%～0.003%(质量分数)范围内的较低水平,脱硫率最高达85.0%,与实验预期吻合.随着钢液中[S]增加,夹杂物中CaS+MnS的平均质量分数相应增加,但夹杂物中的CaS含量不一定增加.钙对夹杂物变性作用非常明显,[Ca]相对高的管线钢,其夹杂物绝大多数都变性为球形的含CaS钙铝酸盐复合夹杂,不存在MnS夹杂和MgO.Al2O3夹杂.为使氧化夹杂和硫化夹杂都变性完全,钢液中的硫的质量分数应控制在0.002%左右,钙的质量分数应控制在0.003 5%～0.004 0%,且[Ca]/[S]>1.9.     

两种易切削钢的研究

对未知工艺的两种易切削钢进行研究。采用电感耦合等离子体原子发射光谱法测定化学成分,通过金相显微镜观察其组织及夹杂物的形貌,使用扫描电镜分析其夹杂物,最后进行了力学及切削性能的测试。结果表明,两种钢均为低碳高硫易切削钢,其组织绝大部分为铁素体,夹杂物大多数为（Mn,Fe）S和硫化物包裹氧化物,少数为MnS;含碳量低、铁素体组织、长条状硫化物（夹杂物）是造成硬度低和切削性能差的主要原因。     

钙处理对LG510钢夹杂物的影响及热力学分析

在热力学计算的基础上,对某厂钙处理前后的汽车大梁钢LG510进行取样研究,探讨钙处理对汽车大梁钢LG510夹杂物的影响。结果表明,钙处理后钢中Al2O3夹杂物得到有效变性,夹杂物的数量明显减少,夹杂物尺寸也明显减小,夹杂物形状更加规则;钢液相线温度为1873K、钢中w[Al]为0.028%时,钢中w[O]、w[Ca]分别控制在2.8×10-6~11.5×10-6、0.14×10-6~7×10-6范围内,Al2O3夹杂变性效果良好;同时将钢中w[S]控制在0.011%以下,既可生成液态铝酸钙夹杂物,也可减少CaS夹杂生成。     

易切削钢中夹杂物的纳米压痕表征

利用纳米压痕技术对钢中BN、MnS、Al2O3、TiN等夹杂物进行纳米压痕表征,详细讨论了BN夹杂物对钢的切削性能的改善作用,并分析了纳米压痕表征及宏观硬度测量的误差.研究表明:铸态BN夹杂物硬度低于MnS夹杂物,锻造态BN夹杂物硬度高于MnS夹杂物,三者均远低于钢基体;铸态与锻造态BN夹杂物均能在钢中起到应力集中源、润滑及包裹硬质点的作用,改善钢的切削性能;纳米压痕表征及宏观硬度测量均存在一定的误差.     

钙处理过程夹杂物演变及热力学分析

通过检测分析钙处理前后钢中夹杂物的形貌和成分的变化,探讨钢液钙处理过程中夹杂物演变规律.利用热力学计算,优化钙处理工艺.结果表明,钙处理可以将钢液中不规则固态夹杂物改性为球形液态夹杂物;1873 K下,当[ Al ]为0.030%时,[O]控制在5×10-6~17×10-6,[Ca]控制在0.7×10-6~30×10-6,钢中夹杂物变性效果良好;当[Al]为0.030%时,[ S]控制在6×10-6~19×10-6,既能使钢中Al2 O3夹杂生成液态铝酸钙夹杂物,同时又可以减少CaS生成.     

易切削钢中夹杂物及锡的形态

研制了一种新型含锡易切削钢.在锡含量小于0.05%(质量分数)时,钢材具有良好的易切削性能,其力学性能也达到了国家标准.在扫描电镜下观察了钢中夹杂物和断口的形貌,利用能谱分析了夹杂物的成分.结果表明,钢中的复合夹杂物主要由氧化物和Mns组成.多数呈球形或纺锤形,在断口及夹杂物的表面上锡明显偏析.     

石油钻杆钢冶炼过程中夹杂物的析出和衍变

系统分析了国内某钢厂复合脱氧工艺下Cr Mo石油钻杆钢夹杂物在EAF-LF-VD-CC流程中的析晶和衍变规律.由于铝酸盐的上浮,LF冶炼前钢中T[O]含量较低,冶炼过程中氮含量逐渐升高.电镜下钢中大尺寸夹杂物(50μm左右)只出现在LF-VD阶段,主要为低熔点的硅锰酸盐、包含Na2O的混合物和含有少量Ca O的镁铝尖晶石,中间包阶段大尺寸夹杂物完全消失.小尺寸夹杂物(<10μm)出现在精炼全过程中,主要成分是Mg、Al、Si和Ca的复合氧化物、Ca S以及二者的复合物,LF冶炼前到中间包阶段小尺寸夹杂物粒径相似,铸坯中其粒径稍微增加.随着精炼过程的进行,钢中小尺寸夹杂物的成分逐渐向复合氧化物的低熔点区域转移,夹杂物中Ca O和Mg O含量存在竞争关系.铸坯中大型夹杂物(>100μm)包括卷渣引起的复合夹杂,耐材剥落产生的Mg O-Ca O夹杂和钢液内生的铝酸盐夹杂.内生铝酸盐与精炼过程中小尺寸夹杂物成分相似,外层包覆Ca S,轧制过程中容易破碎成链状引发钻杆钢裂纹.建议适当延长VD处理后钢液的镇静时间,以去除钢中大型铝酸盐夹杂,提高钻杆钢质量.     

硫化锰夹杂物在YF45MnV钢中行为的原位观察

采用共焦激光扫描显微镜首次原位观察YF45MnV钢中MnS夹杂在连续升温过程中的变化.结果表明:在匀速加热过程中,细长条状MnS首先转变为近球状硫化物组成的串状夹杂物,然后近球状硫化物发生扩散长大,数量减少;温度增加到一定程度后,MnS夹杂发生固溶现象,其面积反而减小.     

易切削结构钢中非金属夹杂物与切削性能的相关性

本文以钙硫系易切削结构钢为主要研究对象,借助于定量图像分析仪、电子探针、扫描电镜等仪器和设备,探讨了钢中非金属夹杂物与钢切削性能的相关性。研究钢中非金属夹杂物尺寸对刀具寿命的影响,结果表明:本试验条件下夹杂物对刀具寿命的临界影响尺寸为8μm。还研究了非金属夹杂物的间距、均匀性及数量对刀具寿命的影响。 最后,建立了描述非金属夹杂物特征参数与刀具寿命关系的数学模型。 试验表明,刀具寿命(T)主要受钢中非金属夹杂物有效颗粒数(Ne)和分布均匀度(H)的影响。     

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.     

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.     

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.     

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.     

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。     

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.     

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.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that