Large-strain behaviour of Magneto-Rheological Elastomers tested under uniaxial compression and tension,and pure shear deformations

The large-strain behaviour of Magneto-Rheological Elastomers (MREs) is characterised experimentally under uniaxial compression, uniaxial tension and pure shear deformation, in the absence and in the presence of magnetic fields. MREs are ‘smart’ materials that can alter their properties instantaneously by the application of external stimuli. They hold great potential for use in adaptive stiffness devices. So far, the large-strain behaviour of MREs has not been well explored, and their behaviour under pure shear deformation has not been characterised. Tests on silicone rubber based isotropic and anisotropic MREs, with and without the application of an external magnetic field have been performed in this investigation. The MR effect, defined as the increase in tangent moduli, is studied versus large engineering strain. Strains were measured optically using a Digital Image Correlation (DIC) system. Relative MR effects up to 284% were found under uniaxial tension, when a magnetic field strength of 290 mT was applied with the loading direction parallel to the direction of particle alignment.     

以壳聚糖为基底的分子印迹电化学传感器研究及倍硫磷测定

研制了一种以壳聚糖修饰层为基底的倍硫磷分子印迹电化学传感器。首次利用修饰电极对探针离子的吸附富集作用提高分子印迹传感器检测的灵敏度。采用交流阻抗法和循环伏安法对传感器响应过程进行电化学表征;对洗脱、重吸附、探针富集时间等实验条件进行优化;考察了壳聚糖对“门控制效应”测量模式的增敏效应。在优化条件下,该传感器对倍硫磷的检测范围为1 ~ 10 000 pg/mL,检出限为0.35 pg/mL。该传感器已成功用于蔬菜和水果中倍硫磷的测定,其加标回收率为99.0% ~ 109%,相对标准偏差为1.9% ~ 2.9%。     

Characterisation of light emitting diodes (LEDs) for application in digital holographic microscopy for inspection of micro and nanostructured surfaces

Partial coherent light sources open up prospects for phase noise reduction in digital holographically reconstructed phase distributions by suppressing multiple reflections in the experimental setup. Thus, light emitting diodes (LEDs) are investigated for application in digital holographic microscopy. First, the spectral properties and the resulting coherence length of an LED are characterised. In addition, an analysis of dispersion effects and their influence on the hologram formation is carried out. The coherence length of LEDs in the range of a few micrometers restricts the maximum interference fringe number in off-axis holography for spatial phase shifting. Thus, the application of temporal phase-shifting-based digital holographic reconstruction techniques is compared to spatial phase-shifting-based methods. It is demonstrated that LEDs are applicable for digital holographic microscopy in connection with both spatial and temporal phase-shifting-based techniques for reduction of noise in comparison to a laser-light-based experimental setup.     

基片缺陷与磁光盘原始误码

分析了基片缺陷导致磁光盘产生原始误码的原因。首次建立了磁光读出光场与基片杂质特性的数学模型，利用数值分析方法研究了读出信号畸变、误码长度与杂质特性的关系。分析结果表明，一定大小的基片杂质是否产生误码，与杂质距记录层的距离、杂质距读写光斑的距离以及读出阈值电平等因素有关。     

Stabilization of switched linear systems with time-delay in detection of switching signal

A feedback stabilization problem for switched linear systems with time-delay in detection of switching signal is formulated. First, online state feedback controller design method for asymptotic stability and exponential stability is given. Then, offline state feedback controller design method for asymptotic stability and exponential stability is given as well.     

Some Features and Operation of Molecular Logic Elements

We show that it is feasible, in principle, to create logical photochemical elements based on intramolecular transfer and structural isomerization. The recording of an initial complex pattern in the form of one feature is realized by collecting information from all the photochemical reactive centers at different instants of time, independent of one another. It is also shown that such a logic element is capable of reacting to an indistinctly specified signal in only one manner.     

合格品链长控制图

在生产过程中不合格品率(p)很低的情况下,利用两个连续不合格品之间的合格品数(合格品链长)控制图来监督过程不合格品率能克服传统的p图所遇到的困难,为生产者提供产品质量改良的信息。本文研究两种合格品链长(CRL)控制图的制定方法,对这些控制图的效率进行了比较,并说明其实际应用。所研究的CRL控制图特别适用于自动化生产过程的100%检验的质量控制。     

光互连网络中的光学比较交换实现方法

本文提出了一种全混洗交换光互连网络中对两个数字光信号进行比较交换的新方法。用液晶光调制器和光导开关构成数字光信号交换控制单元,自动完成两列数字光信号大小的并行比较和交换     

Analysis of signal optimization problems for dielectric media

The authors have recently presented the results of the numerical implementation of a scheme for designing an incident electromagnetic plane wave which will deposit a maximum amount of energy in any selected portion of an inhomogeneous dielectric slab. This paper presents the mathematical analysis underlying this scheme for solving the signal design problem. The analysis indicates that the maximum energy is achieved by choosing the incident signal to be an appropriately normalized eigenfunction of a compact Fredholm integral operator. A numerical scheme for solving the optimization problem is discussed briefly.This research was supported by Ames Laboratory-USDOE under Contract No. W-7405-Eng-82.     

Adjustment of radiation spectrum of injection lasers by doppler-signal optical heterodyning

A procedure for changing the spectral characteristics of injection lasers by Doppler-signal optical heterodyning by changing the injection current is discussed. Results of current tuning of the radiation frequency, coherence, and other characteristics of AlGaAs-heterolasers by using the above procedure under conditions of c.w. lasing are reported. Belarusian State University, 4, F. Skorina Ave., Minsk, 220050, Belarus. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 65, No. 4, pp. 503–508, July–August, 1998.