Implementation of a novel two-attractor grid multi-scroll chaotic system

This paper proposed a method of generating two attractors in a novel grid multi-scroll chaotic system.Based on a newly generated three-dimensional system,a two-attractor grid multi-scroll attractor system can be generated by adding two triangular waves and a sign function.Some basic dynamical properties,such as equilibrium points,bifurcations,and phase diagrams,were studied.Furthermore,the system was experimentally confirmed by an electronic circuit.The circuit simulation results and numerical simulation results verified the feasibility of this method.     

使用AlN/GaN超晶格势垒层生长高Al组分AlGaN/GaN HEMT结构

在蓝宝石衬底上生长了以AlN/GaN超晶格准AlGaN合金作为势垒的HEMT结构材料,并与传统AlGaN合金势垒样品进行了对比.在高Al组分(≥40%)情况下,超晶格势垒样品的表面形貌明显改进,电学性能特别是2DEG面电子浓度也有所改进.对超晶格势垒生长参数进行了初步优化,使得HEMT结构薄层电阻进一步降低,最后获得了251 Ω/□的薄层电阻. 关键词： AlGaN/GaN 结构 AlN/GaN超晶格 二维电子气 高电子迁移率晶体管     

Absorption Enhancement of Ultrathin Crystalline Silicon Solar Cells with Dielectric Si_3N_4 Nanostructures

A design of ultrathin crystalline silicon solar cell with Si3 N4 circular truncated cone holes(CTCs) arrays on the top is proposed. In this article, we perform an optical simulation of the structure. The finite-difference time-domain method is used to calculate the optical absorption of different periods, radius of top and bottom circles and depth of Si3 N4 CTCs. The short-circuit current density generated by the optimized cells(30.17 mA/cm~2) is 32.44% more than the value gained by control group(with flat Si3 N4). Then adding a layer of back silver to allow us to better analyze optical absorption. Later, we simulate the optimization of the same configuration of different silicon thicknesses andfind that our structure does enhance the light absorption. This work uses a combined path towards achieving higher photocurrent ultrathin crystalline silicon solar cells by constructing the texture of anti-reflection coating.     

Study of top and bottom contact resistance in one organic field-effect transistor

This paper reports that the organic field-effect transistors with hybrid contact geometry were fabricated, in which the top electrodes and the bottom electrodes were combined in parallel resistances within one transistor. With the facility of the novel structure, the difference of contact resistance between the top contact geometry and the bottom contact geometry was studied. The hybrid contact devices showed similar characteristics with the top contact configuration devices, which provide helpful evidence on the lower contact resistance of the top contact configuration device. The origin of the different contact resistance between the top contact device and the bottom contact device was discussed.     

线性调频信号激励过阻尼双稳系统的随机共振现象研究

线性调频信号是工程中常见的一种信号, 由于其为非周期信号, 无法以频域信噪比作为衡量其是否产生随机共振的测量手段, 故鲜有文献研究以线性调频信号为激励信号的随机共振现象. 本文利用线性调频信号在最优分数阶Fourier变换域上的能量聚集性, 首次提出以最优分数阶Fourier变换域上定义的信噪比作为测量手段, 研究了线性调频信号叠加高斯白噪声激励过阻尼双稳系统的随机共振现象, 且发现了以线性调频信号为激励信号时产生的新现象, 即随着信号频率的增大, 随机共振将逐渐减弱, 并给出了合理的解释.仿真的结果与理论分析一致, 验证了本文所提出方法的有效性. 关键词： 线性调频信号 分数阶Fourier变换 随机共振     

Representation of the category of tangles by Kontsevich's iterated integral

Applying Kontsevich's iterated integral for tangles, we get an isotopy invariant of tangles. We give a method to compute the integral of a tangle combinatorially from modified integrals of some simple tangles. We localize the integral by moving the end points of the tangle to an extreme configuration, and modify the integral so that it is convergent. By using a similar technique, we generalize Kontsevich's invariant to a framed tangle.     

汽包锅炉炉内局部结渣实时诊断研究

研究了汽包锅炉炉膛内局部结渣的故障诊断问题.选取膜式水冷壁背火侧三个温度点──鳍端温度、鳍根温度和管外壁中点温度──作为炉内局部结渣故障特征参数,使用灰渣层热阻反映炉内水冷壁局部结渣程度,运用径向基函数网络建立起描述故障特征参数和局部结渣程度之间高度非线性映射关系的故障诊断模型.实例分析表明:该方法诊断结果准确,无需布置昂贵的热流计,是一种有效的诊断炉内局部结渣的故障诊断方法.     

基于飞秒激光写制波导的PPKTP晶体倍频实验研究

在PPKTP晶体上进行了飞秒激光刻写波导的实验研究,优化了c-切PPKTP晶体中写制二型波导的工艺参数.当波导长度为10mm,宽度为14.5μm,准相位匹配波长为1064nm时,实现了单模传输.利用该波导对调QNd:YAG激光进行了准相位匹配倍频实验,实现的二次谐波转换效率为39.8%.     

Studies on the electrochemiluminescent behavior of luminol on indium tin oxide (ITO) glass

The electrochemiluminescence (ECL) of luminol on indium tin oxide (ITO) glass was high even under a low potential around 0.4-0.5 V, which was quite different from other electrodes such as platinum. ITO nanoparticles were synthesized and used in the research on ITO glass in the ECL process. A static interaction between ITO and luminol is confirmed from UV-vis and fluorescence spectra. Then the ECL enhancement can be supposed to originate from the adsorption of luminol on ITO, which facilitated luminol’s oxidization to the excited state, giving out ECL. On the other hand, ITO can catalyze the generation of reactive oxygen species (ROSs), similar to some other nanomaterials, which also favored the ECL enhancement of luminol.     

Self-sum- and -difference-frequency mixing in GdAl(3)(BO(3))(4):Nd(3+) for generation of tunable ultraviolet and infrared radiation

We exploited Nd(3+) laser emission at 1061.9 nm ((4)F(3/2)?(4)I(11/2) channel) in a self-chi((2)) active GdAl(3)(BO(3))(4):Nd(3+) laser crystal. UV radiation was obtained from a 1.8% yield from self-sum-frequency mixing: 1/pump + 1/1061.9 = 1/UV, during pumping in the Nd(3+) (4)G(5/2)-(2)G(7/2) levels near 588 nm. The UV tunability had a range of 378-382 nm. We have demonstrated, for the first time to our knowledge, generation of coherent IR radiation from a self-difference-frequency mixing laser: 1/pump - 1/1061.9 = 1/IR. We got a 0.5% yield and tunability in the 1305-1365-nm range.