Li2O-B2O3-P2O5系统非晶态混合骨架效应的NMR研究

用核磁共振对非晶态中B³⁺离子的微观结构进行了测定,结合Raman光谱的研究,对Li₂O-B₂O₃-P₂O₅系统非晶态的性能(电导率、密度等)在P₂O₅/B₂O₃比约等于1时产生极值的原因从理论上作了阐明。     

脉冲激光偏振方向对氮分子高次谐波的影响——基于含时密度泛函理论的模拟

采用含时密度泛函方法,结合赝势模型和电子交换相关作用的广义梯度近似,模拟了氮分子在超强飞秒激光脉冲作用下的高次谐波产生现象,并研究了激光脉冲偏振方向对氮分子高次谐波的影响.结果表明氮分子的高次谐波谱具有典型原子谐波谱的特征;谐波谱强度随着θ(激光偏振方向与分子轴向夹角)的增大而减小.这与J.Itatanl在Nature上报道的实验结果基本一致.     

Preparation and Mechanical Properties of Fe3Al Nanostructured Intermetallics

Nanostructured Fe₃Al intermetallic compounds were produced by using hydrogen arc plasma method. The transmission electron microscopy experiments showed that the average particle size of the as-synthesized was about 40-nm. The change in hardness of Fe₃Al nanostructured intermetallic compounds with annealing temperatures was observed and evaluated.     

s波超导体绝缘层dx2-y2波超导体结的直流Josephson电流

在s波超导体绝缘层dx2-y2波超导体结(sId)中,考虑到结界面粗糙散射,运用BogoliubovdeGennes(BdG)方程和FurusakiTsukada(FT)电流公式,计算超导结中的准粒子传输系数和直流Josephson电流.结果表明:sId超导结的直流Josephson电流随温度以及结两侧的相位差变化的关系曲线强烈地依赖于d波超导体的晶轴方位;结界面的粗糙散射对Josephson电流有抑制作用 关键词： s/I/d超导结 dx2-y2波超导体 直流Josephson电流     

Searching for a counterfeit coin with b-balance

We consider the classical problem of searching for a heavier coin in a set of n coins, n-1 of which have the same weight. The weighing device is b-balance which is the generalization of two-arms balance. The minimum numbers of weighings are determined exactly for worst-case sequential algorithm, average-case sequential algorithm, worst-case predetermined algorithm, average-case predetermined algorithm.We also investigate the above search model with additional constraint: each weighing is only allowed to use the coins that are still in doubt. We present a worst-case optimal sequential algorithm and an average-case optimal sequential algorithm requiring the minimum numbers of weighings.     

NEW ALTERNATING DIRECTION FINITE ELEMENT SCHEME FOR NONLINEAR PARABOLIC EQUATION

A new alternating direction (AD) finite element (FE) scheme for 3-dimensional nonlinear parabolic equation and parabolic integro-differential equation is studied. By using AD, the 3-dimensional problem is reduced to a family of single space variable problems, calculation work is simplified; by using FE, high accuracy is kept; by using various techniques for priori estimate for differential equations such as inductive hypothesis reasoning, the difficulty arising from the nonlinearity is treated. For both FE and ADFE schemes, the convergence properties are rigorously demonstrated, the optimal H1-and L2-norm space estimates and the 0((△t)2) estimate for time variable are obtained.     

Rheological and diffusion properties of a dextran-con A polymer in the presence of Insulin and Magnesium

Previous work carried out in our laboratories has focused on the formation and investigation of a dextran and concanavalin A (con A) based gel, which has the ability to alter its conformational structure in the presence and absence of free and terminal glucoses such that a gel–sol phase transition occurs. Here we report the diffusion and rheological investigations in to the effects of the addition of insulin and varyingconcentrations of magnesium chloride hexahydrate (Mg₂Cl₂6H₂O) at 20 and 37 °C. Rheological examination of glucose-sensitive (dextran-con A) gels were conducted using a cone and plate viscometer used in continual rotation and oscillatory modes. The results are interpreted in terms of the structure of the gel network and suggest rheological assessment provides an effective method of assessing the properties of gel systems. The subsequent testing of such formulations in in-vitro diffusion experiments revealed a reduction in the rate of diffusivity in the insulin marker, poly R-478 dye. The performance of this self-regulating drug delivery system has been examined and the addition of insulin and magnesium chloride may alter the way in which the gel operates as a drug delivery device and in the delivery of insulin. This may have implications for other ligands.     

校准电表的一种方法

利用电位差计的高精度，设计出合理的实验电路对C31型电表进行校准，使得电表的准确度等级得以提高。     

变In组分沟道的MM-HEMT材料电子输运特性研究

在变缓冲层高迁移率晶体管（MM_HEMT）器件中，二维电子气的输运性质对器件性能起着决定作用.通过低温下二维电子气横向电阻的量子振荡现象，结合变温度的Hall测量，系统研究了不同In组分沟道MM_HEMT器件中子带电子迁移率和浓度随温度的变化关系.结果表明，沟道中In组分为0.65的样品，材料电学性能最好，In组分高于0.65的样品，严重的晶格失配将产生位错，引起迁移率下降，大大影响材料和器件的性能. 关键词： 变缓冲层高迁移率晶体管 Shubnikov_de Hass 振荡