共晶自生复合材料的晶形转变

自生复合材料的晶形转变受到成分过冷与曲面过冷两个因素的控制.非金属相具有较大的熔化熵且易形成小平面是改变领先相的因素,而领先相的改变则可能是晶形转变的根本原因.     

定向凝固法制备YBC超导体的若干材料学问题

讨论了定向凝固法制备YBCO超导体涉及的包晶转变与包晶反应，成分过冷，扩散控制生长模型，界面效应及定向凝固YBCO生长晶体学等问题。     

Solid-solution hardening and softening by Fe additions to NiAl

Solid-solution hardening in the case of a ternary alloy addition to a B2 compound with the triple defect structure has been investigated. The fact that the ternary element may occupy either of two sublattices or may affect the concentration of other types of point defects present in the material makes this a very interesting problem to consider. Ni-rich (40 at% Al), stoichiometric (50 at% Al), and Al-rich (52 at% Al) alloys were doped with up to 12 at% Fe. Lattice parameter, bulk density and hardness measurements were performed on samples quenched from 1000 °C. It was found that solid-solution softening actually occurs in the Ni-rich alloys, while hardening was observed in the stoichiometric and Al-rich alloys. The vacancy concentration was determined from the experimental data, and the site occupancies of the Fe atoms were estimated from a thermodynamic model. Through careful consideration of all point defect concentrations the solid-solution hardening and softening behaviors could be effectively rationalized.     

再结晶退火对Ni_（47）Ti_（44）Nb_9合金冷轧板相组成及板材织构的影响

采用Ｘ射线衍射术和ＯＤＦ研究了再结晶退火对Ｎｉ４７Ｔｉ４４Ｎｂ９合金冷轧板相组成和织构的影响。结果表明，冷轧板材的相组成为Ｂ２＋β－Ｎｂ＋Ｂ１９＇；织构类型为面织构｛００１｝ｐ＋｛１１０｝ｐ再结晶退火期间，马氏体相Ｂ１９＇逆转变为母相Ｂ２，合金的相组成为：Ｂ２十β－Ｎｂ，而再结晶织构为：｛００１｝＜１１０＞ｐ。     

混凝土单轴受压本构模型及其应用

通过一个细观模型,从损伤的角度解释混凝土在压应力作用下应力-应变关系的非线性和应变软化,根据等效应变假设和损伤力学基本原理,建立了单轴受压混凝土的弹塑性损伤本构模型,可导出已有单轴受压本构关系,并能反映混凝土的刚度退化和卸载后的残余变形;提出一类损伤函数和塑性变形经验表达式,利用应力-应变曲线特征条件和优化算法确定模型参数;与已有受压试验结果相比较,结果吻合良好.     

简论宪法惯例

宪法惯例是宪法制度的重要组成部分 ,在立宪制国家它是宪政运行中对宪法的重要创造性补充。起源于政治惯例的宪法惯例的构成必须具备三方面的重要特征。在中国法治化拓进的今天 ,深入探讨宪法惯例的作用具有较强的现实意义     

尖点突变模型描述土应力应变特性的可行性

根据尖点突变模型的基本方程和土的应力一应变关系特点，通过坐标变换导出了在三轴条件下以轴应变、孔隙比和广义剪应力表示的土本构方程表达式。表达式中只有3个参数，可以通过统计方法由三轴试验数据得到。与Duncan-Chang模型和砂土及粘土的实测数据进行比较后得出结论：该模型是有效的。     

Stability of a crystal surface in fractional crystallization on a band

The problem on the morphological and thermal stability of a crystal surface in fractional crystallization on a band has been investigated theoretically. A model to describe the dynamics of the development of a striped perturbation of the crystal surface is suggested. It is used as a basis for analyzing the influence of the main factors on the stability, and a stability criterion has been derived. It has been established theoretically that the thermal instability must appear at small Reynolds numbers (Re < 10). Numerical experiments have shown that an increase in the length of the band, its inclination angle, as well as a decrease in the rate of melt feed and in the band motion velocity increase the thermal instability. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 82, No. 1, pp. 106–113, January–February, 2009.     

哀怨--汉乐府民歌的主旋律

从游子离人、弱女弃妇、贫困百姓的悲苦命运和哀怨之歌入手,分析了经久不衰的两汉乐府民歌的魅力在于继承和发扬了《诗经》现实主义的优良传统,广泛而又真实地扫描了两汉时期的黑暗政治和社会现实。