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1.
研究了非晶合金Fe78B13Si9 、(Fe099 Mo001)78B13Si9 的激波晶化特点. 用Cluster 模型讨论了在激波作用下晶化相的形成, 并把激波晶化与非晶高压变态作了比较. 为了更好地理解激波与非晶合金的相互作用, 还需要更进一步的实验工作和理论研究  相似文献   

2.
在气体激波管中,利用激波对非晶的直接作用,在微秒量级时间内,成功地将FeBSI,FeMoBSi及FeCuNbBSi等非晶合金转变成为纳米晶,主晶化相晶粒平均尺寸在20-60nm范围,晶化相分数〉95%和常规退火晶化比较,激波晶化在晶化相,晶化动力学和晶化机理等方面具有一系列独有的特点。  相似文献   

3.
采用动态差示扫描量热法( D S C) 和 X 射线衍射法( X R D) 研究了快淬 Nd Fe B合金的晶化行为。非晶态 Nd8 .5 Fe86 B5 .5 合晶化由三个过程组成,各转变有效晶化激活能分别为4 .8e V、15 .2e V 和5 .4e V。非晶态 Nd7 .5 Dy1 Fe85 B45 Ga2 合金直接由非晶态转变为α- Fe和 Nd2 Fe14 B 相,有效晶化激活能为5 .8e V。  相似文献   

4.
非晶晶化法制备纳米晶双相永磁合金的磁性   总被引:6,自引:0,他引:6  
采用快淬及退火工艺,通过非晶晶化制备了两种成分的纳米晶,即Nd2F314B/α-Fe永磁合金。研究了添加Dy+Ga和晶化工艺对合金磁性能的影响,研究结果表明,三元Nd8.5Fe86B5.5合金晶化是由3个过程组成的,而添加Dy+Ga的Nd7.5Dy1Fe85Ga2合金化是由2个过程组成的,与三元合金相比,添加Dy+Ga可改变α-Fe和Nd2F14B相的形成温度及细化两相晶粒,可以显著提高合金的磁性  相似文献   

5.
应用XRD,TEM,DSC等实验方法研究了第三组元Ni对Fe-Ti二元混合元素粉机械合金化反应的影响.试验中原子数百分比分别以5%和15%Ni取代部分Fe元素.研究结果表明固态合金化合成晶粒尺寸分别为12nm和6nm的纳米晶B2相.合金化中经历球磨“退火”过程,微观点阵畸变逐渐减弱,晶粒长大.Ni元素能使合成的B2结构纳米晶TiFe相的点阵畸变减小.合成的纳米晶相在973K产生相分解,析出低温马氏体TiNi相  相似文献   

6.
Fe78B13Si9非晶合金纳米晶化的亚结构   总被引:1,自引:0,他引:1  
用高密度脉冲电流处理Fe78B13Si9非晶合金,随电流密度的变化在不同的温度下和相同的时间内实现了试样的纳米晶化,透射电镜观察及X射线衍射分析表明,在由电脉冲方法所制备的纳米晶Fe78B13Si9合金中存在着亚晶和孪晶等亚结构,三种晶化相是α-Fe(Si)Fe2B和少量的Fe3B.随着电流密度的增加,试样中Fe2B相略有增加并出现了有序的Fe3Si结构,但平均晶粒尺寸保持不变,由Sherrer方  相似文献   

7.
铁基非晶态合金晶化过程激活能的测定   总被引:1,自引:0,他引:1  
阐述了Ozawa图法和Kissinger图法在测定铁基非晶态合金晶化过程激活能方面的应用,在满足不同加速率下的晶化温度所对应的晶化程度相同的前提下,用Ozawa图法和Kissinger图法测出的非晶态Fe79B16Si5合金预晶化相α-Fe析出阶段的激自觉自愿能分别为382~407Kj/mol(Ozaw图法)和374~339Kj/mol(Kissinger图法)测定结果十分接近,说明上述2种方法测  相似文献   

8.
采用玻璃晶化法制备适合磁记录用的Co-Ti替代型钡铁氧体BaFe_(12-2x)Co_xTi_XO_(19)(x=0,0.5,0.6,0.7,0.8,0.85,0.9)微粉。动态(变温)X射线衍射和DTA曲线分析表明,在非晶薄片基体的晶化过程中,随热处理温度的升高,首先晶化出BaB_2O_4和Ba_2B_2O_7相,随后出现钡铁氧体相;温度到达850℃后,非磁性相消失,仅剩有磁性的钡铁氧体相.晶化过程为先成核而后长大。有关晶化条件对钡铁氧体微粉粒子尺寸及分布的影响、对形貌的影响也作了详细的探讨。  相似文献   

9.
添加Dy和Nb的纳米复合Pr2Fe14B/α-Fe永磁合金结构和磁性   总被引:1,自引:0,他引:1  
研究了添加Dy和Nb对纳米复合Pr2Fe14B/α-Fe永磁合金形成,组织结构及磁性的影响。结果表明:Pr9Fe85B6非晶带的晶化过程,在α-Fe相初始晶化之后,出现Pr2Fe23B3亚稳相,最终形成Pr2Fe14B+α-Fe两相组织.而添加Dy或同时添加Dy和Nb后晶化过程不出现亚稳相.添加Dy和Nb元素显著地提高了纳米复合永磁合金的磁性能。最终获得了磁性能为Hci=702.4kA/m,Br=1.03T,(BH)max=132.6kJ/m3的纳米晶复合Pr8Dy1Fe84Nb1B6永磁材料。  相似文献   

10.
采用示差扫描量热计(DSC)和X射线衍射方法研究了Ni82.5Cr7Si4.5B3Fe3多元非晶态合金钎料在加热时的晶化特性。实验指出:随加热速率的增大,其晶化特征温度逐渐提高,晶化前所需孕育时间延长,并且晶化后的二次相变过程消失;探讨了该钎料的真空钎焊工艺性能和钎焊接头力学性能,以及预晶化处理对它们的影响,并与相同成分的粉状和粘带状晶态钎料进行了系统的比较。研究结果指出:非晶态钎料在工艺性能方面  相似文献   

11.
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.  相似文献   

12.
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.  相似文献   

13.
何延凌 《科技信息》2008,(4):258-258
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.  相似文献   

14.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

15.
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。  相似文献   

16.
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.  相似文献   

17.
本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。  相似文献   

18.
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.  相似文献   

19.
20.
The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to  相似文献   

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