Semianalytic wave functions for highly rotational states of antiprotonic He

The structural and magnetic evolution in magnesium ferrite (MgFe₂O₄) caused by high-energy milling is investigated by Mössbauer spectroscopy.     

A note on the second problem of Stokes for Maxwell fluids

New exact solutions corresponding to the second problem of Stokes for Maxwell fluids have been established by means of Laplace transforms. For large times, these solutions reduce to the well-known steady-state solutions which are periodic in time and independent of the initial conditions. Furthermore, the transient solutions are in accordance with the previous solutions obtained using the Fourier sine transform. The required time to get the steady-state is determined by graphical illustrations. This time decreases if the frequency of the velocity increases. The effects of the material parameters on the decay of the transients in time are also investigated by graphs.     

A VARIATIONAL EXPECTATION-MAXIMIZATION METHOD FOR THE INVERSE BLACK BODY RADIATION PROBLEM

The inverse black body radiation problem, which is to reconstruct the area temperature distribution from the measurement of power spectrum distribution, is a well-known ill-posed problem. In this paper, a variational expectation-maximization （EM） method is developed and its convergence is studied. Numerical experiments demonstrate that the variational EM method is more efficient and accurate than the traditional methods, including the Tikhonov regularization method, the Landweber method and the conjugate gradient method.     

Topology optimization of microfluidic mixers

This paper demonstrates the application of the topology optimization method as a general and systematic approach for microfluidic mixer design. The mixing process is modeled as convection dominated transport in low Reynolds number incompressible flow. The mixer performance is maximized by altering the layout of flow/non‐flow regions subject to a constraint on the pressure drop between inlet and outlet. For a square cross‐sectioned pipe the mixing is increased by 70% compared with a straight pipe at the cost of a 2.5 fold increase in pressure drop. Another example where only the bottom profile of the channel is a design domain results in intricate herring bone patterns that confirm findings from the literature. Copyright © 2008 John Wiley & Sons, Ltd.     

嗜铅菌对水中重金属Pb~(2+)的吸附研究

研究了实验室提供的嗜铅菌对水中铅离子吸附的条件和机理.讨论了吸附时间、pH、铅离子的质量浓度和菌的质量浓度对吸附的影响.结果表明,在pH=7.0、铅离子初始质量浓度为25mg/L、离心湿菌的质量浓度为1.06g/L、吸附时间为60min时,铅离子的吸附率达96.88%;实验条件下超标25倍的含Pb~(2+)废水,可迭排放标准;Pb~(2+)的最大吸附量为150mg/g.数学模型Langmuir和Freundlich方程均能很好地描述嗜铅菌对Pb~(2+)的吸附过程.对Pb~(2+)吸附前后的红外光谱表征表明,嗜铅菌表面多糖、蛋白质的羟基峰和羰基峰均有不同程度的紫移,羟基峰、糖苷峰等峰宽略增,说明菌体吸附,主要是表面基团的作用所致.用原子力显微镜对吸附前后的嗜铅菌检测可见,吸附后菌体的弹性变小、粘性变大、部分茵体有一定的收缩,说明以表面吸附为主的吸附过程,对菌细胞的聚合度有影响,菌体内部对铅也有一定的生物积累.     

Study of adsorption processes of model drugs at supercritical conditions using partial least squares regression

The characterisation of adsorption or impregnation processes using conventional or supercritical fluid technologies becomes an increasing part of the research on drug formulations. The complexity of the relationships between these adsorption processes and the experimental variables potentially influencing them, however, makes these studies more problematic. In this paper, a chemometric approach based on nonlinear partial least squares (NL-PLS) modelling is applied to characterise the effect of the experimental variables on the supercritical impregnation process. Various adsorbent materials such as silica gel, zeolite and amberlite were investigated using the following model compounds as adsorbates: benzoic, salicylic and acetylsalicylic acids.     

广义旋转Navier-Stokes方程解的整体适定性和解析性

在α和q满足适当的条件下，当初值属于Fourier-Herz空间?_q^1-2α（R³）时，我们建立了广义3维不可压旋转Navier-Stokes方程温和解的整体适定性和解析性.作为推论，我们也给出了广义Navier-Stokes方程的相应结论.     

Capillary instability of an annular liquid jet surrounding a solid cylinder

Summary The capillary instability of an annular liquid jet surrounding a solid cylinder is presented. A general dispersion equation is derived based on the linear-perturbation technique. The instability as well as stability characteristics of that model are identified analytically and confirmed numerically. The model is unstable only to the axisymmetric perturbation whose wavelengths are longer than the circumference of the liquid jet, while it is stable to all other perturbations. The maximum temporal amplification values prevailing on such a model are fairly lower than those of the full liquid jet. The thicker the solid cylinder, whether it is regular or irregular, the larger is its stabilizing effect.

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Riassunto Si presenta l’instabilità capillare di un getto anulare di liquido che circonda un cilindro solido. Si deduce un’equazione generale di dispersione basata sulla tecnica di perturbazione lineare. Le caratteristiche d’instabilità cosí come quelle di stabilità di quel modello si identificano analiticamente e sono confermate numericamente. Il modello è instabile solo rispetto alla perturbazione assisimmetrica, le cui lunghezze d’onda sono piú lunghe della circonferenza del getto di liquido, mentre è stabile rispetto a tutte le altre perturbazioni. I valori massimi dell’amplificazione temporale che prevalgono in tale modello sono molto piú bassi di quelli del pieno flusso di liquido. Piú spesso è il cilindro solido sia esso regolare o irregolare, maggiore il suo effetto stabilizzante.

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Резюме Анализируется капиллярная неустойчивость кольцевой жидкой струи. окружающей твердьй цилиндр. Выводится общее дисперсионное уравнение. основанное на линейной пертурбационной технике. Неустойчивость, а также характеристики устойчивости в этой модели определяются аналитически и подтверждаются численно. Предложенная модель оказывается неустойчнвой только для осесимметричных возмушений, длины волн которых превышают окружность жидкой струи, и является устойчивой для всех других возмущений. Максимальные значения временного увеличения в такой модели оказываются довольно низкими. Стабилизирующий эффект увеличивается с толщиной твердого цилиндра.

     

信息化课堂教学设计--以“刚体定轴转动的角动量及角动量守恒定律”为例

遵循“学生主体、教师主导”的教育教学理念,借助信息化教学工具,合理有效地设计好每一个教学环节.采用演示、体验、探究、问题导向和分组讨论等教学手段和方法,让学生在课堂中自主发现问题、分析问题并解决问题,实现“学生做中学、教师做中教”,大大提升教学效果.