高效液相色谱法测定地塞米松及有关物质

建立了高效液相色谱法测定地塞米松及有关物质的方法。采用Kromasil 100-5 C_(18)(250 mm×4. 6 mm,5μm)色谱柱,以水和乙腈为流动相,梯度洗脱,流速1. 5 mL/min,检测波长240 nm,柱温40℃,进样量20μL。在上述色谱条件下,地塞米松与1,2-二氢物、16β-甲基环氧物和17-脱氧-21醇等杂质分离效果好,地塞米松在4～480μg/mL范围内线性关系良好,检测限为0. 32μg/mL,1,2-二氢物、16β-甲基环氧物和17-脱氧-21醇在0. 2～4. 0μg/mL范围内线性关系良好,检测限分别为0. 058,0. 063,0. 060μg/mL。方法可用于测定地塞米松及有关物质的含量。     

多体系统动力学微分／代数方程组数值方法

多体系统动力学微分／代数混合方程组又称Ｅｕｌｅｒ－ｌａｇｒａｎｇｅ方程，是近十年来动力学和计算数学领域研究的热点之一．本文介绍这两个领域中引入的传统的数值积分方法与新的理论．     

无穷远处Ⅲ型均布荷载与集中荷载作用下应变加强层连接唇形裂纹的解析解

通过对保角映射及解析延拓的应用,获得了无穷远处Ⅲ型均布荷载和集中荷载作用下,连接在唇形裂纹面上的内埋应变加强层的级数形式应力解析解．分析了材料匹配、界面连接及几何特征对界面应力的影响,研究发现对于不同的荷载形式,合理的材料匹配、连接及几何特征能够有效地减少应力集中和界面应力．     

Elastic behaviour of an edge dislocation near a sharp crack emanating from a semi-elliptical blunt crack

The interaction between an edge dislocation and a crack emanating from a semi-elliptic hole is dealt with. Utilizing the complex variable method, closed form solutions are derived for complex potentials and stress fields. The stress intensity factor at the tip of the crack and the image force acting on the edge dislocation are also calculated. The influence of the morphology of the blunt crack and the position of the edge dislocation on the shielding effect to the crack and the image force is examined in detail. The results indicate that the shielding or anti-shielding effect to the stress intensity factor increases acutely when the dislocation approaches the tip of the crack. The effect of the morphology of the blunt crack on the stress intensity factor of the crack and the image force is very significant.     

Superconductivity of bilayer titanium/indium thin film grown on SiO_2/Si(001)

Bilayer superconducting films with tunable transition temperature(Tc) are a critical ingredient to the fabrication of high-performance transition edge sensors. Commonly chosen materials include Mo/Au, Mo/Cu, Ti/Au, and Ti/Al systems. Here in this work, titanium/indium(Ti/In) bilayer superconducting films are successfully fabricated on SiO_2/Si(001)substrates by molecular beam epitaxy(MBE). The success in the epitaxial growth of indium on titanium is achieved by lowering the substrate temperature to-150?C during indium evaporation. We measure the critical temperature under a bias current of 10 μA, and obtain different superconducting transition temperatures ranging from 645 m K to 2.7 K by adjusting the thickness ratio of Ti/In. Our results demonstrate that the transition temperature decreases as the thickness ratio of Ti/In increases.     

用有限元法分析多波导耦合系统本征模的模式特性

本文应用有限元法(FEM),计算和分析了多波导耦合系统的本征模(超模)的模式特性及其变化规律,得到了强度均匀分布的基超模,克服了微扰理论计算这类问题的局限性.     

引力定律发现发展的基本特点

万有引力定律的发现,是17世纪自然科学最伟大的成果。该定律在其发现发展的过程中,体现了物理学研究的基本特点。 1 与数学密切相关 在开普勒提出了行星运动三定律,伽利略揭示了地球上物体不受阻挠时以匀速直线运动的基础上,十七八世纪许多科学家都想用力学解释天体运动的问题,想回答行星沿椭圆轨道运行的受力情况。为此,英     

Measuring Grüneisen Parameter of Lead by High Pressure-Jump Method

Using the technology of pressure jump, variations of temperature associated with pressure from 2.4 GPa to 4.6 GPa are measured for lead. The Grfuneisen parameter is calculated from the thermodynamic relation γ =（Ks/T）（aT/aP）s, in which substitution of △T/△P for aT/aP at median pressure is strictly justified. The correction of temperature change is carried out by analysing the experimental data, which makes the process more approaching to an adiabatic condition. The calculated values of △T/ △ P and γ gradually decrease with the increasing pressure. The decrease trend is consistent with the previous work. The γ values in the range of 2-3 GPa are averagely higher than the results of Ramakrishnan et al., indicating the effect of temperature correction. The improved method is promising for measurements of Grfineisen parameter to higher pressure range.     

Si-SiO_2界面的粗糙度

利用椭偏反射光谱不但验证了Si-SiO_2界面是一祖糙面,而且在恰当的模拟形貌下,把这界面粗糙层等效为若干子层,用有效介质理论处理。分别得到各自的介电特性。通过多相椭偏光反射光谱的理论计算值ψ_(cal),△_(cal)与实验值ψ_(exp),△_(exp)的比较,把粗糙的高度H及相关长度L确定,把不同条件下制备的样品的粗糙度和它们的电气性能相对比,发现两者之间的趋势十分一致。同时发现,在界面上Si的介电常数具有轻度的各向异性。     

三能级Upper-ladder型系统中的

三能级Upper-ladder型系统中,在旋波、慢变振幅近似下,求解了考虑驱动场相位扩散后的系统密度矩阵运动方程,并给出了这个三能级梯型系统稳态线性解析解.利用对密度矩阵运动方程的稳态线性解析解的数值模拟结果,研究相位扩散对无反转激光增益、色散和粒子数差的影响;利用对密度矩阵运动方程的数值模拟结果,分析相位的扩散对无反...