光在按特殊准晶方式排列的媒质中的传播

简单介绍Fibonacci-class准晶(FC(n))的结构特性，利用电场理论和二阶单位模矩阵的特殊性质，研究了光在按FC(n)准晶链排列的多层介质膜中传播时的光透射性质，发现FC(2m)的透射系数具有开关性质，FC(2m+1)的透射系数具有六循环性质，它们的最大值在π(1/2±k)附近具有有趣的性质. 关键词：     

油脂降解培养基优化的遗传算法实验研究

我们运用遗传算法,首次对利用热带假丝酵母降解油脂的培养基优化问题进行了研究。通过5代实验完成了50个实验样本、6种培养基成分、64个浓度水平的优化任务。按照优化后的培养基组成,热带假丝酵母降解油脂的降解率为95．4％,比正交设计法提高了7．63％。实验结果表明：利用遗传算法可优化培养基成分含量,取得更好的效果;遗传算法是一种优于单因素试验法和正交设计法的新型、高效的培养基优化方法。     

Photonic band structures of quadrangular multiconnected networks

By means of the network equation and generalized dimensionless Floquet-Bloch theorem,this paper investigates the properties of the band number and width for quadrangular multiconnected networks (QMNs) with a different number of connected waveguide segments (NCWSs) and various matching ratio of waveguide length (MRWL).It is found that all photonic bands are wide bands when the MRWL is integer.If the integer attribute of MRWL is broken,narrow bands will be created from the wide band near the centre of band structure.For two-segment-connected networks and three-segment-connected networks,it obtains a series of formulae of the band number and width.On the other hand,it proposes a so-called concept of two-segment-connected quantum subsystem and uses it to discuss the complexity of the band structures of QMNs.Based on these formulae,one can dominate the number,width and position of photonic bands within designed frequencies by adjusting the NCWS and MRWL.There would be potential applications for designing optical switches,optical narrow-band filters,dense wavelength-division-multiplexing devices and other correlative waveguide network devices.     

Band rules for the frequency spectra of three kinds of aperiodic photonic crystals with negative refractive index materials

By means of the theory of electromagnetic wave propagation and transfer matrix method, this paper investigates the band rules for the frequency spectra of three kinds of one-dimensional (1D) aperiodic photonic crystals (PCs), generalized Fibonacci GF(p,1), GF(1,2), and Thue--Morse (TM) PCs, with negative refractive index (NRI) materials. It is found that all of these PCs can open a broad zero-? gap, TM PC possesses the largest zero-? gap, and with the increase of p, the width of the zero-? gap for GF(p,1) PC becomes smaller. This characteristic is caused by the symmetry of the system and the open position of the zero-? gap. It is found that for GF(p,1) PCs, the possible limit zero-? gaps open at lower frequencies with the increase of p, but for GF(1,2) and TM PCs, their limit zero-? gaps open at the same frequency. Additionally, for the three bottom-bands, we find the interesting perfect self-similarities of the evolution structures with the increase of generation, and obtain the corresponding subband-number formulae. Based on 11 types of evolving manners Q_i(i=1,2,....,11) one can plot out the detailed evolution structures of the three kinds of aperiodic PCs for any generation.     

ELECTRONIC ENERGY SPECTRUM STRUCTURE OF THE TWO-DIMENSIONAL FIBONACCI QUASILATTICES WITH THREE KINDS OF ATOMS AND ONE KIND OF BOND LENGTH

After establishing the method of constructing a class of two-dimensional Fibonacci quasi-lattices, by means of a decomposition-decimation method based on the renormalization-group technique, we have studied the rule. of energy spectrum splitting for the two-dimensional Fibonacci quasilattices in the framework of single-electron tight-binding on-site model. Analytic results show that there are only six kinds of clusters and the electronic energy band consists of nine subbands.     

Ni—Cr非中心对称准晶的电子性质

在单电子、紧束缚和最近邻相互作用条件下，本文利用迁移模型分析和计算了单种原子、单健长的二维十二次准晶的电子性质，包括电子能谱、积分态密度和判断电子波函数局域性的一阶矩、二阶矩、反参加比等参数。我们发现电子能谱没有正常简并，只有偶然简并，以及电子只有中间态，没有扩展态和局域态。     

傍轴光束在单轴左手介质中传输的矢量性质

研究了沿光轴入射的傍轴光束在单轴左手介质中传输的矢量性质.通过平面角谱的方法得到了横电(TE)波和横磁(TM)波在单轴左手介质中传输的严格解，并得到了傍轴近似下的矢量传输模型.利用这一模型，分析得到垂直于光轴方向不同偏振态的入射光束在单轴左手介质中同时激发横向场和低阶纵向场.如果单轴左手介质的介电常数张量在沿垂直于光轴方向上的元素不相等，同时磁导率张量在沿垂直于光轴方向上的两元素也不相等(即z方向为光轴方向，_x≠_y,μ_x≠μ_y),那么入射光束激发的横向场的分布与入射光束的初始场分布和偏振态有关，而纵向场的分布与入射光束的偏振态无关，只决定于入射光束的初始场分布. 关键词： 傍轴传输 单轴左手介质 矢量效应     

Optical transmission through basic-structural-unit superlattices

In this paper, by the transparent-component-decimation (TCD) method we obtain three kinds of new basic- components (BCs) through simplifying and decomposing the BCs of three-component Thue-Morse (3CTM) sequence. Based on these new BCs we propose a type of basic-structural-units (BSUs) and investigate the optical transmission of the one-dimensional (1D) superlattices composed of these BSUs. It is found that if the substrates of the 1D BSU superlattices are certain, the optical transmission at the central wavelength (CW) will be determined completely by the number and the type of BSUs and has nothing to do with the marshalling sequence. In particular, if the substrates are identical, the numbers of different types of BSUs are all the same and the middle two elements of BSUs constitute a cycle, then no matter whether the system is periodic, or quasiperiodic, or aperiodic, or unordered, or even random, it will be transparent at the CW. The conclusion is confirmed by the numerical results. Similar to the even layers of neighbourhood identical elements in TCD method, such a kind of optical BSU subsystem can also be decimated from the chain in the process of transmission investigation. There would be a potential application in the designing of some interesting optical devices.     

Optical and fast nondestructive identification of the ages of leaded ancient pottery

In this paper,based on the one-dimensional(1D) optical superlattice model,we calculate the average reflectivities(ARs) of leaded ancient pottery(AP) made within the last 2000 years,and find that for incident light with a suitable wavelength,the AR of the leaded AP increases monotonously with the increase in the layer number of the silvery glaze(SG) media.Based on this property,we propose an optical nondestructive method for identifying the age of leaded AP by detecting the AR.By using the exhaust algorithm and the discriminant function of variance,we obtain the optimal wavelength range of the incident light to identify the ages of the leaded AP.It is found that in the visible light band,if we choose green light with a wavelength range of 540-540.1 nm as the incident light,leaded AP made within the last 2000 years can be identified swiftly and precisely by detecting the ARs.This will be useful for designing optical instruments for the fast nondestructive identification of the ages of leaded AP.     

二维单原子斐波那契类准晶电子能谱特性研究

利用单电子、紧束缚、最近邻座模型,在重整化群的基础上,用分解-消元法分析了二维单原子斐波那契类准晶FC(n)的电子能谱分裂规律,数值计算了其电子能谱值,发现在一级近似下,该类二维准晶格中全部都只存在n×n,n×(n+1),(n+1)×(n+1)等三种原子簇分子,相应的能谱按Y_m-n-l方式分裂,得出了其电子能谱的能级数目通式,发现描述其能级数目的参量存在所谓的“斐波那契类数集合”,并且确定了该集合的前11个整数的稳定值,找出了有关斐波那契类数集合的经验公式.分析结果与数值计算值相符 关键词： 斐波那契类 准晶 电子能谱 重整化群