A notch filter for 140 GHz microwave radiation

The construction of a notch-filter for 140 GHz with very low passband insertion loss is described. It is based on a single-mode rectangular waveguide and cylindrical cavities matched to it. The typical transmission characteristic is also presented.     

A New Method for Rotation and Brightness Invariant Pattern Recognition Based on Modified Multiple Circular Harmonic Expansions

A new method for rotation and brightness invariant pattern recognition was proposed by applying multiple circular harmonic expansions to the joint transform correlator. The amplitudes of the multiple orders of circular harmonic expansions made from a detecting image were synthetically modified to respond to the same auto-correlation peaks. These modified circular harmonic expansions were arranged in the input plane as reference patterns together with an arbitrary target pattern, and the correlation signals between them were calculated in the subtracted joint transform correlator. The fraction of the correlation-peak intensities between the target and the references were extracted as a new discrimination parameter. This new parameter performs pattern recognition under rotation and brightness invariance with good discriminability. Its high discriminability has been proved in computer simulations using the face image patterns of many individuals.     

Production and characterization of refractive index gratings in high-birefringence fibre optics

In this work, we report production and modelling of both Bragg gratings and rocking filters in high birefringence fibre optics. Bragg gratings are produced by UV (257.0 nm) external interferometric exposition of a frequency-doubled Ar⁺ ion laser, whereas for rocking filters formation the visible Ar⁺ ion laser lines in 488.0 and 514.5 nm are used in an internal method. The spectral characteristics due to the birefringence properties are studied through numerical methods and experimental techniques. The spectral responsivity of the structures under temperature changes and stress application is presented.     

Electronegativity scheme for reactions involving radical addition to vinyl monomers

The concept of the apparent electronegativity of a reaction site has been introduced. This has been used to develop a new scheme for calculating the relative rate constants of addition of radicals with different structures to vinyl monomers. The parameters of the scheme are given for 40 reagents. The results of a comparison of calculated and literature rate constants of addition are presented.Institute of Nonaqueous Solution Chemistry, Russian Academy of Sciences, 150003 Ivanovo. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 10, pp. 2238–2245, October, 1992.     

Differential density matrix overlap: an index for assessment of electron correlation in atoms and molecules

Summary A new index, called the differential density matrix overlap (DDMO), is proposed for assessment of the electron correlation effects in atoms and molecules. DDMO can be easily calculated as the negative value of the correlation energy derivative with respect to the relative position of the occupied and virtual orbitals. DDMO is transparent to physical interpretation. It can serve as a tool for analyzing the accuracy of approximate electron correlation methods and the validity of the Hartree-Fock wavefunction as the zeroth-order approximation. The properties of DDMO are discussed using test calculations on 11 atoms and molecules as an example.     

Pairwise Correlations in a Multicomponent Anisotropic Liquid

We investigate a multicomponent anisotropic liquid system. The first spatial moment of the direct correlation function is taken into account to obtain asymptotic expressions for the pairwise correlation functions. In this approximation, we obtain the pairwise correlation functions that describe the system behavior not only in the critical-state neighborhood but also in the noncritical domain. We show that the critical parameters for the anisotropic system differ from those for the isotropic system.     

UV protection filters by dielectric multilayer thin films on Glass BK-7 and Infrasil 301

The increasing use of Ultraviolet (UV) light in medicine, industrial environments, for cosmetic use, and even in consumer products necessitates that greater attention be paid to the potential hazards of this type of electromagnetic radiation. To avoid any adverse effects of exposure to this type of radiation, four suitable protection filters were produced to block three UV bands (UVA, UVB, and UVC). The design structure of the required dielectric multilayer filters was done by optical thin film technology using the absorbing property of UV radiation for the substrates and dielectric materials. The computer analyses of the multilayer filter formulas were prepared using Macleod Software for the production processes. The deposition technique was achieved on optical substrates (Glass BK-7 and Infrasil 301) by dielectric material combinations including Titanium dioxide (Ti₂O₃), Hafnium dioxide (HfO₂), and Lima (mixture of oxides SiO₂/Al₂O₃); deposition being achieved using an electron beam gun. The output results of the theoretical and experimental transmittance values for spectral band from 200 nm to 800 nm were discussed in four processes. To analyze the suitability for use in ‘real world’ applications, the test pieces were subjected to the durability tests (adhesion, abrasion resistance, and humidity) according to Military Standard MIL-C-675C and MIL-C-48497A.     

Micromagnetic analysis of transition noise for high-density perpendicular recording

In this paper, specific issues related to high-density perpendicular magnetic recording processes, such as transition noise properties and cross-track correlation lengths, were investigated with the help of micromagnetic analysis. The effects of media parameters were taken into consideration, including intergranular exchange coupling, and exchange distribution, irregular grain shapes, magnetization saturation distribution, and anisotropy distribution. The micromagnetic simulation results showed that the effect of anisotropy distribution on transition noise is more significant than magnetization saturation distribution, and it is crucial to reduce this effect to achieve a high signal-to-noise ratio. Additionally, a new method to further estimate the partial erasure threshold was proposed to approximate the partial erasure effects, and the relation between the microtrack jitter and total track jitter was investigated.     

相关系数与相关性度量

研究了度量相关性的两个主要工具:线性相关系数和尾部相关系数.线性相关系数反映了变量间的线性相关性,这对于一般的椭圆型分布是合适的.但如果随机变量具有不对称的尾部变化特征时,要用尾部相关系数描述它们之间的相关性.通过相关函数C opu la,对沪深股市的尾部相关系数进行了定量分析.结果表明:沪深股市具有较强的相关性.     

关于Noetherian环上拓扑滤子交换性的一个注记

Let R be a ring with identity,and R-fil denote the set of all left topolo-gizing filters on R.In this paper,we give a sufficient condition for the commutativityof R-fil under the hypothesis of left Noetherianness,as well as some examples.