水溶液中亚甲蓝分子聚集状态的研究

用分光光度法研究了亚甲蓝(MB)染料在水溶液中的聚集状态及其与表面活性剂的相互作用,讨论了无机盐对亚甲蓝在阴离子表面活性剂溶液中聚集状态的影响。推导了水溶液中亚甲蓝单体和二聚体的动态平衡关系式。利用计算机程序不仅求出了与作图法结果非常接近的MB单体的摩尔吸光系数和聚合平衡常数,而且求出了MB二聚体的摩尔吸光系数及相应浓度下MB单体所占的比例系数。     

最大度为7 且不含带弦5- 圈的平面图是8- 全可染的

若能用k种颜色给图的顶点和边同时进行染色使得相邻或相关联的元素(顶点或边) 染不同的色, 则称这个图是k- 全可染的. 显然, 给最大度为Δ的图进行全染色, 至少要用Δ + 1 种不同的色.本文证明最大度为7 且不含带弦5- 圈的平面图是8- 全可染的. 这一结果进一步拓广了(Δ+1)- 全可染图类.     

基于偏振衍射色散共焦的光学元件轴向间距测量

光学元件轴向间距测量对精密光学系统的定位和装调具有重要意义。针对现有色散共焦测量系统中色散物镜结构复杂、色散范围小的问题,提出基于偏振衍射色散共焦的光学元件轴向间距测量方法,将传统折射共焦镜头几百毫米的轴向尺寸和复杂的装调需求简化为数毫米的单片镜,简化了系统结构。透镜间距和厚度测量实验表明,间距测量误差为10 μm。     

Excitation of chorus-like waves by temperature anisotropy in dipole research experiment (DREX): A numerical study

Due to their significant roles in the radiation belts dynamics, chorus waves are widely investigated in observations,experiments, and simulations. In this paper, numerical studies for the generation of chorus-like waves in a launching device,dipole research experiment(DREX), are carried out by a hybrid code. The DREX plasma is generated by electron cyclotron resonance(ECR), which leads to an intrinsic temperature anisotropy of energetic electrons. Thus the whistler instability can be excited in the device. We then investigate the effects of three parameters, i.e., the cold plasma density nc, the hot plasma density nh, and the parallel thermal velocity of energetic electrons, on the generation of chorus-like waves under the DREX design parameters. It is obtained that a larger temperature anisotropy is needed to excite chorus-like waves with a high nc with other parameters fixed. Then we fix the plasma density and parallel thermal velocity, while varying the hot plasma density. It is found that with the increase of nh, the spectrum of the generated waves changes from no chorus elements, to that with several chorus elements, and then further to broad-band hiss-like waves. Besides, different structures of choruslike waves, such as rising-tone and/or falling-tone structures, can be generated at different parallel thermal velocities in the DREX parameter range.