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1.
用两亚点阵MFT分析了R2Fe17-xMx合金的饱和磁化强度与温度的关系。得到了分子场系数nRR、nRF和nFF,计算出了居里温度,给出了分子场HR(T)、HFe(T)与温度的关系曲线。计算结果表明,在R2Fe17中用Al、Ga替代部分Fe离子后,分子场系数nFF明显增大,除Pr2Fe17的HR(T)外,分子场强度在很大温度范围内显著增加  相似文献   

2.
用两亚点阵MFT分析了R2Fe17-xMx合金的饱和磁化强度与温度的关系。得到了分子场系数nRR、nRF和nFF,计算出了居里温度,给出了分子场HR(T)、HFe(T)与温度的关系曲线。计算结果表明,在R2Fe17中用Al、Ga替代部分Fe离子场系数nFF明显增大,除Pr2Fe17的HR(T)外,分子场强度在很大温度内显著增加。  相似文献   

3.
在高Tc超导体Bi_1.6Pb_0.4Sr_2Ca_3Cu_4(1-x)Fe_4xOy中,我们发现由于Cu部分被Fe元素替代,其超导特性发生改变,样品的电阻——温度关系,交流磁化率——温度关系都与不同Fe含量有关。同时研究了得到铋系单相性好的超导材料的烧结工艺。  相似文献   

4.
用单离子模型晶场理论计算了Sm2Fe17-xGaxCy化合物的磁晶各向异性场随温度和Ga、C含量的变化关系,讨论了不同晶位的Ga原子和间隙位C原子对磁晶各向异性的贡献。从而解释了Ga原子对Sm2Fe17-xGax和Sm2Fe17-xGaxCy化合物磁晶各向异性的影响。  相似文献   

5.
使用LCAO对永磁系列Y2Fe17Cx(x=0,1,2,3,)的电子结构计算结果,计算了该系列模型材料的居里温度,并和基底材料Y2Fe17作了对比.居里温度的增长系数和实验符合较好.  相似文献   

6.
用分子场理分析分析了稀土化合物R2Fe17-xMx和R2Fe17N3(R=Ce,Pr,Nd:M=Al;x=0,2)的温度磁化曲线,计算出分子场 数nRR,nRF,nFF。由分子场系数,计算了Fe-Fe、R-R、R-Fe的相互作用对Tc的贡献TFF、TRR、TRF。  相似文献   

7.
本文报道用晶体场理论对新型稀磁半导体Zn_(1-x)Co_xSe和Zn_(1-x)Co_xS中Co ̄(2+)离子不同能级间的跃迁进行计算的结果。与实验观测结果进行了比较,获得了相应的晶场参量D_q,Racah静电参量B,C和自旋-轨道耦合参数λ。本文对Zn_(1-x)Co_xSe和Zn_(1-x)Co_xS分别指认了观测到的Co ̄(2+)离子能级间的跃迁。对较低能级部分,实验结果与理论计算符合较好。  相似文献   

8.
】用二亚点阵MFT分析R2Fe17Mx的饱和磁化与温度的关系。得到了分子场系数nRR、nRF和nFF,计算出了居里温度,给出了交换场HR(T)、HFe(T)与温度的关系曲线。结果表明,在R2Fe17中渗入N或D后,M2Fe(0)和nFF明显增大,交换场也相应增大,居里温度主要取决于M2Fe(0)和nFF。  相似文献   

9.
在温度为295K~80K范围内,应用穆斯堡尔效应方法,测量了Er2Fe17CxNy系稀土化合物Er2Fe17CN的穆斯堡尔谱.结果表明,用C,N原子掺杂渗入Er2Fe17化合物替换Er3+离子后形成的Er2Fe17CN化合物,影响了Er2Fe17化合物原来的自旋重定转换温度TC,并使自旋重定转换角度θ也发生了变化,出现了两个自旋重定转换温度TC1,TC2.TC1200K,TC280K.这说明稀土化合物Er2Fe17CN磁矩是突变的(一级相变).  相似文献   

10.
用化学共沉淀工艺制备了可望用作高密度垂直磁记录介质的Co-Sn替代钡铁氧体系列微软样品BaFe_(12-2x)Co_xSn_xO_(19),其中x可取值为0,0.2,0.4,0.5,0.6,0.8,1.2.给出了最佳制备条件:反应温度t=80℃,体系的pH值pH=11.8,热处理温度T_h=925℃。对所制备的系列样品进行了透射电镜(TEM)观测和x光衍射(XRD)测试,给出了颗粒的形貌和大小以及晶体结构和晶格常数。用振动样品磁强计(VSM)对宏观磁性进行了测试,给出了宏观磁性与替代浓度关系。  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.
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   

13.
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   

14.
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   

15.
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-  相似文献   

16.
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-  相似文献   

17.
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  相似文献   

18.
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  相似文献   

19.
Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of  相似文献   

20.
<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with  相似文献   

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