有势力和规范对称性

介绍了有势力的一般性质,针对一般非惯性系中的惯性力引入其矢势和标势,并分析了其中的规范对称性与电磁学的形式类比.     

二醇基硅胶毛细管整体柱的制备与应用

综合应用溶胶-凝胶、分子修饰和环氧基在柱水解技术,制备了二醇基硅胶毛细管整体柱。考察了乙腈流动相对环氧基和二醇基整体柱保留行为的影响,评价了二醇基硅胶整体柱的色谱性能。结果表明,水解前的环氧基整体柱主要表现为疏水作用机理,水解后生成的二醇基硅胶整体柱固定相表面亲水性增强,表现为典型的亲水作用机理,多环芳烃非极性化合物保留因子的对数值降低,甲苯、N,N-二甲基甲酰胺、硫脲在6min内实现基线分离,柱效分别为90000,94000,99000塔板数/m,7种极性麻醉镇痛药得到较好分离。     

The simulation of ultrasonic beams with a Gaussian beam equivalent point source model

Point Sources and Gaussian beams are used frequently as fundamental building blocks for developing ultrasonic beam models. Both these models have different weaknesses that limit their effectiveness. Here, we will show that one can develop a Gaussian Beam Equivalent Point Source （GBEPS） model that removes those weaknesses and combines the accuracy and versatility of the point source models with much of the speed and well-behaved nature of Gaussian beam models. We will demonstrate the efficiency and versatility of this new GBEPS model in simulating the beams generated from ultrasonic phased arrays, using as few as one Gaussian beam per element of the array. A single element GBEPS model will be shown to be as accurate as a point source model even when substantial beam focusing or steering is present in the array or where the array beam is transmitted through an interface. At the same time the GBEPS model will be shown to be several orders of magnitude faster than the point source model.     

Normal mode wave-number estimation using horizontal synthetic aperture array

A moving synthetic aperture processing with high resolution spectral analysis method was provided to estimate the mode wave-number of acoustics in shallow water waveg- uide, and to overcome the problem of short aperture. First, large aperture synthetic array is created by a moving of short horizontal array, then a MUSIC processing is applied to the estimation of normal mode wave-number. The simulated and sea trial results indicate that the problem of short aperture can be resolved by using of synthetic aperture processing, and the accuracy of estimation in normal mode wave-number could be improved by varying the array depth when it is being towed away from the source.     

Noise Shielding Using Acoustic Metamaterials

We exploit theoretically a class of rectangular cylindrical devices for noise shielding by using acoustic metamateriais. The function of noise shielding is justified by both the far-field and near-field full-wave simulations based on the finite element method. The enlargement of equivalent acoustic scattering cross sections is revealed to be the physical mechanism for this function. This work makes it possible to design a window with both noise shielding and air flow.     

Four-Electron Quantum Ring in a Magnetic Field

We study a quantum ring （QR） with four electrons in a perpendicular external magnetic field B by exact diagonalization. The low-lying spectra of the QR as a function orb are obtained. A phase diagram is presented indicating that the angular momentum and the spin of the ground state of the QR may jump when B and/or the radius of the QR vary, and a corresponding analysis is performed. By plotting the density functions of the QR, the ground-state configuration is found to be a regular quadrangle. Furthermore, the features of the ground-state persistent current are revealed.     

最大似然法在HL-2A汤姆逊散射中的初步应用

介绍了一种处理HL-2A汤姆逊散射原始实验数据的新方法--最大似然法。该方法用数理统计的手段,通过使理论推导出的数据与实际采集到的散射数据最大可能的一致,得到了较准确的等离子体电子温度T_e和密度n_e。将计算所得的结果与现在汤姆逊散射系统所用的比值法得到的结果相比较,验证了该方法的可适用性,并能够克服比值法的一些缺陷。     

跨音速轴流风扇转子叶顶泄漏流的数值研究

采用数值模拟方法研究了不同间隙,不同流量工况下叶顶泄漏流非定常流动特征,发现在研究的三个间隙中,只有当间隙大于或等于设计间隙时,流动才会出现非定常性.随着流量的减小,泄漏涡轨迹前移,当泄漏涡轨迹到达相邻叶片压力面时,影响压力面压力分布,打破流场静态平衡,引起叶顶流场及激波位置、强度发生非定常波动.     

电磁场中带电粒子在非对易相空间的能级

非对易空间效应是出现在弦的尺度下的一种物理效应。 首先扼要介绍了非对易相空间中的量子力学代数、 Moyal Weyl乘法和广义Bopp变换, 然后讨论了电磁场中带电粒子的Hamiltonian算符, 最后给出了其在非对易相空间中的能级情况。     

LIPS技术探测CH4/空气火焰中的OH自由基

论述了激光诱导偏振光谱技术的基本原理,实验方法及其对燃烧场的测量结果.利用光谱扫描方法获得了A2∑ -X2Ⅱ(0,0)跃迁带系列吸收谱线及P1(2)谱线的线型轮廓.测量了CH4/空气预混火焰不同化学配比、不同空间位置OH自由基的相对分布.实验中通过设计精密旋转调节装置有效提高了信噪比.