复合孕育剂在发动机缸体上的应用研究

采用较高碳当量的铁水成分，分别加入几种孕育剂对其进行孕育处理，同时加入合金元素。试验及实际生产结果表明，选择６０％BaSi 40%SiFe作为高碳灰铸铁件缸体的复合孕育剂并加入合金元素，其抗拉强度能稳定在２５０ＭＰa以上，并减小白口宽度和断面敏感性，达到了设计要求，笔者对孕育机理进行探讨，并对孕育后的组织进行分析。     

复合孕育剂在发动机缸体上的应用研究

采用较高碳当量的铁水成分 ,分别加入几种孕育剂对其进行孕育处理 ,同时加入合金元素 试验及实际生产结果表明 ,选择 60 %BaSi+40 %SiFe作为高碳灰铸铁件缸体的复合孕育剂并加入合金元素 ,其抗拉强度能稳定在 2 50MPa以上 ,并减小白口宽度和断面敏感性 ,达到了设计要求 笔者对孕育机理进行探讨 ,并对孕育后的组织进行分析     

镁—钛系复合合金处理蠕墨铸铁的试验研究——高珠光体蠕墨铸铁缸套的获得

本文主要叙述镁-钛系复合合金蠕化剂处理蠕墨铸铁稳定性的初步试验研究结果,并探讨高珠光体含量蠕墨铸铁的获得方法. 试验结果表明:铁水含碳量在较宽范围内波动,甚至含碳量降低至3.05%(碳当量为3.96%),含硫量高达0.105%,用镁-钛系复合合金处理也能较稳定地获得蠕墨铸铁;适当降低含碳量及提高复合合金的钛/镁此,可以获得高珠光体含量的蠕墨铸铁.蠕墨铸铁硼缸套铸件与灰铸铁硼缸套相比,蠕墨铸铁缸套的相对磨损率为它的63%. 我们认为已研制的镁-钛系复合合金处理的蠕墨铸铁可推广应用于润滑磨损条件下的缸套、压缩机缸体等零部件.     

复合孕育剂及复合孕育处理工艺的研究

在冲天炉生产条件下，对复合孕育剂及复合孕育处理工艺进行了试验研究．结果表明，SRB-1复合孕育剂具有良好的抗衰退性能和孕育效果．炉前包内冲锰铁，用SRB-1孕育剂孕育的复合孕育处理工艺可提高灰铸铁强度．     

复合能剂及复合孕育处理工艺的研究

在冲天炉生产条件下，对复合能剂及复合孕育处理工艺进行了试验研究，结果表明，ＳＲＢ－１复合孕育剂具有良好的抗衰退性能和孕育效果，炉前包内冲锰铁，用ＳＲＢ－１孕育剂孕育的复合孕育处理工艺可提高灰铸铁强度。     

机床导轨用含磷耐磨铸铁的研究

本文从铸造合金角度,用大量实验数据验证磷含量、碳当量、孕育、熔炼和孕育温度对普通机床导轨用含磷耐磨铸铁性能的影响;并指出含磷耐磨铸铁的耐磨性,除金属基体外更主要决定于磷共晶及石墨的含量、形状和分布。 本文根据实验数值并用理论分析了铸铁共晶团与磷共晶间的关系,指出其规律:凡是细化共晶团的因素,大都是细化磷共晶的因素,同时亦是形成A型石墨的因素,而有利于耐磨性能的提高。 为了细化共晶团,含磷耐磨铸铁必须具备一定的含磷量,碳当量,采用孕育处理且应孕育温度适宜(不宜过高);此外并指出采用双重孕育可能更为有利。 本文否定了习惯的看法:铸铁的耐磨性能与抗张强度,尤其是与硬度之间有直接比例的关系,提出应用综合性能来衡量铸铁的质量,并认为比强度、比硬度等指标有其实际意。 本研究确定了机床导轨含磷耐磨铸铁最适宜的化学成分及熔炼处理工艺,供生产参考。 铸铁成分为C≈3.0～3.3％;P≈0.5～0.7％;CE=3.8～4.0％;Mn=0.6～0.8％;S<0.12％(导轨壁厚约40～60毫米)。 熔炼处理工艺:过热温度1400～1480℃;孕育温度1380～1440℃;孕育剂数量0.6～0.8％硅铁(75％Si);浇注温度1300～1360℃。 本文还对微量合金化和摩擦对的硬度配比作了一定的探讨。     

大断面球铁石墨变态影响因素的研究

本试验采用热分析法模拟大断面球铁的凝固过程。对球化剂用量,碳硅含量、硅铁孕育量等影响石墨形态的几个主要因素进行了正交试验。结果表明,球化剂用量和碳含量是影响石墨形态的最显著因素。进一步的验证试验使相当于φ200mm 砂型铸件凝固速度的模拟试样,获得了良好的球化效果。依据本试验所得数据,绘制出一球化剂用量与碳当量的组织图。组织图明确显示了球化与墨化因素的交互作用规律。依据组织图,可对大断面球铁中各种类型变态石墨的成因、以及解决措施获得清晰的认识。本试验还证明,铈组轻稀土合金对大断面球铁件也是有效的球化剂。     

药芯焊丝焊缝金属冷裂敏感性研究

用Ｇ－ＢＯＰ实验对药芯焊丝焊缝金属抗冷裂纹能力进行了研究，探讨了其机理，并提出了新的设想。对三种类型—碱性、酸性和金属型共２７种药芯焊丝焊缝金属的硬度、预热温度、扩散氢量、线能量、化学成份和微观结构等进行了测定，用回归分析法得到了焊缝金属裂纹率和诸因素之间的函数关系式。得出随药芯焊丝强度等级增加，硬度和碳当量增加，当碳当量Ｅ＿ｗ＞０．４时，焊缝金属裂纹率可达１００％；碱性药芯焊丝焊缝对裂纹敏感性要比酸性和金属型低；降低焊缝中的氢含量，可有效地降低裂纹敏感性．     

电磁相分离法制备自生表层复合材料

采用电磁相分离法制备出以初生富铁相（AlSiFeMn复杂金属间化合物）为增强相，表层硬度为HB62．25，基体硬度为HB59．00的Al-11.70%Si-1.20?-1.50%Mn合金自生表层复合材料，增强相的显微硬度为HV 842。87，大小为20－80μm，该表层复合材料同基体材料相比，耐磨性提高了57．41％，所用方法工艺过程简单，成本低，为解决材料在服役环境中不同部位，不同性能的问题提供了新途径。     

柴油机活塞环-缸套典型材料摩擦磨损特性的研究

作者利用M200型摩擦磨损试验机、2001型轮廓仪、S-570型扫描电子显微镜Talyserf-S200型圆度仪等测试仪器,对中小型柴油机活塞环—缸套摩擦副常用的典型材料,进行交替配对组成九对摩擦副、在一定的速度及润滑条件下,以载荷及时间为参变量,考察它们的摩擦磨损特性。试验表明,合适的材料组配可以大大提高摩擦副的摩擦磨损性能,摩擦系数随载荷的变化而变化,在一定的载荷作用下,由于材料的塑性变形及石墨的润滑作用可使摩擦系数降低,摩擦系数与磨损量之间不能建立对应的函数关系。在合适的金相组织范围内较硬材质具有较高耐磨性,而活塞环材质硬度比缸套材质硬度较高时(本试验为40HB)摩擦副的磨损量最小。     

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.     

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.     

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.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

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     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the