Physica B-Condensed Matter
The spin-lattice coupling coefficients G11 and G44 for InP:Fe3+ and GaP:Mn2+ crystals have been calculated from the expressions based on the spin-orbit coupling mechanism. The results, as well as those for GaP:Fe3+ in my previous paper, show good agreement with the experimental findings. It appears that this mechanism is applicable to the explanations of the spin-lattice coupling coefficients for 3d5 ions in III-V compounds. The disparity between theory and experiment for the coefficients G11 and G44 of GaAs:Fe3+ crystals is discussed.
关键词:
transition-metal impurities;electronic states;inp
吕涛
,
王越
,
杨承承
,
孙瑞雪
材料热处理学报
以锡酸钠、偏钒酸钠为主盐,通过化学转化处理的方法在AZ91D镁合金表面制备了一种新型Sn-V复合化学转化膜.运用扫描电子显微镜(SEM)及能谱仪(EDS)、X射线衍射(XRD)等测试方法研究了Sn-V复合转化膜的表面形貌与成分组成.结果表明,Sn-V复合化学转化膜由扁圆形颗粒紧密堆积而成,同单一钒酸盐转化膜相比,表面粗糙度增加,裂纹数量减少;复合转化膜膜层厚度为2～3 μm,与基体结合良好.电化学测试及浸泡试验结果表明,Sn-V复合转化膜有效的提高了AZ91D镁合金的耐腐蚀性能,且提高幅度明显高于单一钒酸盐转化膜.
关键词:
镁合金
,
钒酸盐
,
锡酸盐
,
化学转化膜
,
耐腐蚀性能
Radiation Effects and Defects in Solids
The empirical superposition model has been used to analyse the zero-field splitting of 3d5(Mn2+, Fe3+) ions in crystals with approximately C3v symmetry. The negative signs of intrinsic parameters b2BAR(R0) for these crystals are the same as the normal b2BAR(R0) which is obtained from the 3d' ions in many oxygen octahedra. The magnitude of b2BAR(R0) for Mn2+ or Fe3+ ion in the case of isocharge substitution is consistent with the respective normal value of Mn2+ or Fe3+ ion. Whereas in the case of charge misfitting substitution, the small disparity of b2BAR(R0) is found between the calculated and normal values. This can be attributable to the local lattice relaxation caused by the fact that the interacting forces between impurity and ligands are different from those of host crystals. It appears that the anomaly related to the signs of b2BAR in Al2O3:Fe3+, MgTiO3:Mn2+ and MgTiO3:Fe3+ crystals pointed out by some researchers does not exist and the empirical superposition model is applicable to 3d5 ions in C3v symmetry.
关键词:
electron paramagnetic resonance;superposition model;mn2+;fe3+;al2o3;mgtio3;linbo3;litao3;sites;epr
朱杰武
,
柳永宁
,
许雁
,
冯耀荣
机械工程材料
doi:10.3969/j.issn.1000-3738.2005.06.007
在不同温度下测试了X70管线钢动态断裂韧度K1d、J1d和止裂韧度K1a以及夏氏V型缺口冲击韧度Ak,对三者的关系进行了分析.结果表明:温度和加载速率都对断裂韧度产生影响;加载速率变化引起的韧-脆断裂转变具有热激活特征,在热激活分析基础上,在应力强度因子速率K=15 MPa·m1/2s-1条件下,得出断裂韧度、止裂韧度和冲击韧度三者的关系:Ak=4.84×106T-2.8K1d(或K1a).可以用小试样Ak数据计算得到K1d和K1a.
关键词:
管线钢
,
断裂韧度
,
止裂韧度
,
韧-脆断裂转变
Science in China Series a-Mathematics Physics Astronomy
The complete strong-field-matrices for d2,8(C3v*) ions are constructed within an O(h)- point-group representation. Based on the eigenvalues and eigenvectors of these matrices, a complete-configuration-mixing EPR theory is established for Ni2+ ions in CsMgX (X = Cl, Br,I) kind crystals, and accordingly, a uniform calculation is performed for the optical absorption spectrum, the zero-field-splitting and Zeeman splitting of the ground state, the EPR parameters D and g and the EPR conditions (B,h-nu) of Ni2+ impurity ions in a CsMgCl3 crystal. The results are in very good agreement with the experimental, thus a uniform theoretical interpretation is achieved for the optical and magnetic properties of Ni2+:CsMgCl3 for the first time.
关键词:
complete strong-field-matrix for d2,8(c3v-star);complete-configuration-mixing epr theory;csmgcl3;ni2+;optical and;magnetic properties;strong-field scheme;spectrum
庄厚川
,
陈铮
,
王永欣
,
伍林
稀有金属材料与工程
应用耦合共格弹性畸变的微观弹性相场法研究D022型Ni3(V,Al)相沉淀过程中的应力取向效应.结果表明,在弹性内应力作用下,D022沉淀相表现出明显的位向性:相颗粒倾向于沿应力软方向[100]生长而在[001]方向受抑制,即生长方向与长轴[001]方向垂直,D022相最终沉淀形貌呈“层”状 ;沉淀过程中三类D022相变体相互协调以减小共格畸变能,最终D022-variant Ⅲ消失,存留的两类中D022-variant Ⅰ体积比占优.
关键词:
三维
,
应力取向效应
,
D022相变体
曾霞
,
杨晓平
,
刘磊
材料科学与工艺
为揭示合金固态相变初期新相形成机制，尤其是D022相变孪晶形成机制，利用三元微观相场模型对Ni75 Al7．5 V17．5合金于1273 K 下等温时效沉淀过程的前3个阶段进行了模拟．计算结果表明，L12结构的Ni3Al有序相首先沿惯析面（100）从母相中共格形核，而后D022结构的Ni3V有序相在先析出的L12相和母相的相界形核．由于{100}的反相畴界上形成较大的共格失配，导致能量较高且不稳定，反相畴界在两相生长中遭到破坏，而晶面{110}的界面能比{100}的反相畴界能低，生长过程中D022的3种变体互相正交排列形成阶梯状结构的{110}孪晶面．
关键词:
L12 沉淀相
,
D022沉淀相
,
孪生
,
微观相场
