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1.
研究了锰67.61~73.58%,碳0.51~0.96%范围内的锰—铝—碳永磁合金的磁性、显微组织和亚稳态铁磁性τ相的稳定性。从高温平衡态ε相控速冷却或淬火随后回火均能获得τ相,但控速冷却样品的磁性能低。由于碳的作用,使ε相转变减缓,ε相区下移,临界温度降低80℃~100℃。τ相的稳定性随锰、碳含量而变化,在合适的含C量范围内,随Mn含量增加,τ相稳定性降低;淬火样品在不同温度加热60分钟,组成为71.76%Mn0.96%C的样品700℃τ相开始分解;组成为72.48%Mn0.7%C的样品600℃τ相开始分解。  相似文献   

2.
为了提出La-Mg-Ni(PuNi3型)系贮氢合金的电化学循环稳定性,在La2Mg(Ni0.85Co0.15)9合金中添加微量的B,用铸造及快淬工艺制备La2Mg(Ni0.85Co0.15)9Bx(x=0,0.05,0.10,0.15,0.20)贮氢合金,分析测试铸态及快淬态合金的微观结构与电化学性能,研究硼对合金微观结构及电化学性能的影响。结果表明:铸态合金具有多相结构,包括主相(La,Mg)Ni3相(PuNi3型)和LaNi5相,一定量的LaNi2相和微量的Ni2B相经快淬处理后,Ni2B相消失,且其他相的相对量随淬速的变化而变化。硼的加入提高了铸态及快淬态合金的循环稳定性,但使铸态合金的容量下降;铸态合金的电化学容量随B含量的增加单调下降,而快淬态合金的容量随B含量的增加有一极大值,B对铸态及快淬态合金电化学性能的影响机理是完全不同的。  相似文献   

3.
为了研究淬火速度及Mn掺杂对纳米复合Nd-Fe-B磁性材料微结构的影响,利用XAFS技术对不同淬火速度的Nd9Fe84.5B6Mn0.5样品及退火和未退火的Nd9Fe84.5B6Mn0.5(x-0.5和1.0)样品,进行了Fe原子局域结构的分析。结果表明,纳为复合Nd9Fe84.5B6Mn0.5噘性材料随着淬火速度的增另,Fe原子的最近邻配位距离单上,而配位无序度的变化较为复杂。退火前,掺杂微量Mn原子进入磁体的Nd2Fe14B主相晶体结构,掺杂量不同对主相局域结构的影响有明显差异。退火后,Mn原子退出磁体的主相结构,进入晶界或产生富集,没有发现掺杂量不同对主相局域 结构的影响,但对整个磁体的磁性仍然有不同的影响。  相似文献   

4.
通过固体反应法制备出了Mn位Te掺杂氧化物:LaMn1-xTexO3+δ.X光电子能谱测量结果表明Te离子在样品中具有Te4+价态,Mn3+离子因受富氧及Te4+替换影响而部分转变成Mn2+和Mn4+,以致LaMn1-xTexO3系列样品中同时存在Mn2+,Mn3+,Mn4+三种价态,当Mn3+在样品中的含量远大于Mn2+及Mn4+两者含量和时,样品则具有绝缘态特征,但当Mn3+含量与Mn2+及Mn4+两者含量和相当时,样品则随温度的升高而产生了金属-绝缘态相变.对于这种反常的磁输运现象,用双交换(DE)机制进行了的分析和讨论.  相似文献   

5.
采用传统固相反应法制备多晶样品La1.2-xDyxSr1.8Mn2O7(x=0.00,0.05),通过测量样品的磁化强度与温度变化曲线(M-T)以及不同温度下磁化强度与外加磁场的变化曲线(M-H)对样品的磁性和类Griffiths 相进行了研究. 研究发现,两个样品分别在15-400 K 的测量温度范围内,在类Griffiths 相温度(TG≈368、360 K)以上处于纯顺磁态;在奈尔温度(TN≈210、183 K)-TG范围内,系统处于反铁磁-铁磁共存态,存在类Griffiths 相,随温度的降低,样品的铁磁性逐渐增强;在TN以下,随温度的降低,铁磁性逐渐减弱,反铁磁性增强,样品呈现出了团簇玻璃行为. 通过对比两个样品后发现,掺杂后样品x=0.05 比未掺杂样品的磁性、三维长程居里温度(Tc3D)和类Griffiths相温度(TG)均降低,这是由于Dy3+离子半径比La3+离子半径小,掺杂之后导致晶格畸变所引起的.  相似文献   

6.
采用草酸盐共沉淀工艺制备了组成为(χ/2)Gd_2O_3+(1-χ)BaO+6Fe_2O_3的草酸盐粉料,预烧、成型后在不同温度下进行烧结。用热中子透射法测定了样品中的含钆量。用 X 射线衍射物相分析和磁分析方法研究了烧结过程中生成物的相组成及其相变。当χ≤0.12时,在1310℃烧结得到纯 M 相。在1400℃烧结得到的样品中,当χ≤0.15时为 X 相;当0.4≤χ≤0.6时主要相为 W 相。测量了样品的磁性、电阻率和 M(?)ssbauer 谱。发现在 X 结构化合物中,室温下的磁晶各向异性常数随含钆量的增加而增加;W 相化合物的居里温度比文献报导的数据高80℃左右。讨论了在含钆的 M 型六角铁氧体中,Gd~(3+)对磁性和电阻率的影响,以及 Gd~(3+)和 Fe~(3+)间的交换作用。  相似文献   

7.
纳米复合永磁材料的原始淬态组织对最终的显微组织结构和磁性有着决定性的影响,为了弄清其影响规律,研究了成分为Pr7Fe88B5的双相纳米复合永磁材料的淬态组织在回火时相转变的过程和晶化后的组织结构及磁性。X射线谱和Mossbauer谱的研究结果表明,在不同辊速下制得的快淬带样品的组织结构是不同的。原始淬态组织的不同导致回火时的不同相变过程,它们分别是(1)非晶相Am Pr2Fe14B α-Fe→Pr2Fe14B α-Fe;(2)非晶相Am α-Fe→(Am)′ α-Fe→α-Fe 1:7相+Pr2Fe14B→Pr2Fe14B α-Fe;(3)Am→Am′+α-Fe→1:7相+α-Fe→Pr2Fe14B α-Fe。虽然样品最终的相组成均为α-Fe和Pr2Fe14B,但不同原始态的样品晶化后的显微组织和磁性并不同相同。  相似文献   

8.
采用溶胶-凝胶法制备了Ca2-xNaxFeMoO6(0≤x≤0.4)系列样品.利用X-射线衍射和X-射线精修分析了样品的晶体结构和晶胞参数随Na含量的变化关系.利用超导量子干涉仪和振动样品磁强计分别研究了样品的低温磁性和高温磁性,得到了样品的磁化强度随温度和掺杂量的变化规律,测量了样品的居里温度.初步探索了Na+掺杂后所引入的空穴掺杂效应.  相似文献   

9.
本文用热膨胀分析、X 射线衍射、金相组织观察和磁性测量等方法研究了 Fe-Ni 20~30% 的合金及含少量 Mn 的 Fe-Ni 合金在加热和冷却过程中的相变及磁性,讨论了合金成份、组织结构与磁性的关系。  相似文献   

10.
通过高温固相法制备了单相多晶样品,对样品的磁性质进行测量与分析.XRD结构分析表明,该样品为单相正交结构,空间群为Pnma.磁性的测量表明,低温下样品为相分离态.ZFC和FC出现分叉,表现出典型的相分离特征,在ZFC曲线6K处出现一个小峰.红外吸收光谱分析表明了Al掺杂引起MnO_6八面体的畸变.Sm_(0.5)Ca_(0.5)Mn_(0.90)Al_(0.10)O_3交流磁化率曲线实部峰没有随频率的变化发生很明显的温度偏移,而其虚部峰随频率的增加而下降.  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 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.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
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.  相似文献   

14.
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   

15.
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   

16.
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.  相似文献   

17.
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.  相似文献   

18.
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   

19.
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.  相似文献   

20.
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   

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