丙烯酸酯与甲基丙烯酸酯的共聚及性能研究

采用悬浮聚合法，以丙烯酸－２－乙基－己酯与甲基丙烯酸十二酯为单体，合成了共聚型高吸油性树脂。研究了共聚单体的配比、交联剂用量、引发剂用量诸因素对高吸油性树脂的性能影响。制得的树脂可以吸其自身质量的１１．８倍的煤油、１４．７倍的苯、６．５倍的泵油。     

Bandstop monolithic crystal filters having allpass response outside stopband

A dual-resonator monolithic crystal filter (MCF) is basically a narrowband bandpass filter. It is well known that a narrowband bandstop response can be obtained by connecting an inductor in parallel to an MCF element, however, it yields a lowpass response outside the stopband with a cutoff frequency about square root (2) times the stopband frequency. Ideally, outside the stopband, it should have an allpass characteristic. The author shows a simple method of designing a bandstop MCF filter having an allpass response outside the stopband by adding a series-connection inductor. The series inductor together with two capacitors provide the required highpass structure that complements the lowpass response to yield an allpass response.<>     

Influence of an external electric field on the microstructure of superplastically deformed 7475 Al

An externally applied electric field retarded strain-enhanced grain growth and promoted dynamic recrystallization during superplastic deformation of 7475 Al. Also, a more extensive dispersoid-free zone was observed in specimens deformed in the electric field, suggesting that the electric field increased the contribution of diffusion creep to superplastic deformation. The electric field promoted the coarsening of dispersoids, especially in the vicinity of the grain boundaries. Possible mechanisms for the observed effects are discussed.     

Simulation of programmable logic controller

The development and test of a PLC control program takes time, increases equipment down-time, and might damage hardware due to program errors. All of these problems can be eliminated if there is a computer simulation system for testing control programs off line. This paper presented a new method, called Direct Sequential Method, for simulating PLCs. This method resolves a ladder logic sequentially by applying a series of logic deductions. This simulation system has been implemented in C and tested successfully.     

Improved Poisson intensity estimation: denoising application using Poisson data

Recently, Timmermann and Nowak developed algorithms for estimating the means of independent Poisson random variables. The algorithms are based on a multiscale model where certain random variables are assumed to obey a beta-mixture density function. Timmermann and Nowak simplify the density estimation problem by assuming the beta parameters are known and only one mixture parameter is unknown. They use the observed data and the method of moments to estimate the unknown mixture parameter. Taking a different approach, we generate training data from the observed data and compute maximum likelihood estimates of all of the beta-mixture parameters. To assess the improved performance obtained by the proposed modification, we consider a denoising application using Poisson data.     

An investigation of bulk recycling planning for an electronics recycling facility receiving industrial returns versus residential returns

Since most end-of-life electronics equipment contain hazardous materials such as lead solder alloys or lead-impregnated glass, it is important to divert them from landfills. For end-of-life products that are not repairable and do not contain reusable parts, bulk recycling is an alternative to recover base materials. In this paper, we contrast production and recycling planning and distribution decisions, activities, and costs. We reveal that while a traditional production facility connects suppliers and customers, a recycling facility connects both "input" and "output" customers. As a result, decisions in short-term bulk recycling planning include what products to accept, what products to process and reprocess, and what products to carry in inventory. Many recyclers set prices to receive "input" based on experience. For various prices to receive "input", we use a new analytical model to investigate the sensitivity of the short-term bulk recycling planning decisions in products from two different sources: industrial returns versus residential returns. The results of the case study show that different decisions are recommended for the industrial returns versus the residential returns when the total quantity of the incoming products is equal.     

On the Cutoff Wavelength of Rectangular-Shaped Microshield Line by Edge Element Method

In this paper, the cutoff characteristic of rectangular-shaped microshield transmission line has been analysed by edge element method. Dependence of cutoff wavelengths on the thickness of metallic signal strip, dielectric constant of dielectric substrate and the width of the rectangular-shaped ground conductor are presented in tabular form. Numerical results in this paper have important values in design of rectangular-shaped microshield lines in microwave and millimeter wave integrated circuits.     

A near-optimal multiuser detector for DS-CDMA systems using semidefinite programming relaxation

A multiuser detector for direct-sequence code-division multiple-access systems based on semidefinite programming (SDP) is proposed. It is shown that maximum likelihood (ML) detection can be carried out by "relaxing" the associated integer programming problem to a dual SDP problem, which leads to a detector of polynomial complexity. Computer simulations that demonstrate that the proposed detector offers near-optimal performance with considerably reduced computational complexity compared with that of existing primal-SDP-relaxation based detectors are presented.     

A vectorial boundary element method analysis of integrated optical waveguides

In this paper, a new vectorial boundary element method is introduced and applied to the modal analysis of dielectric waveguides with piecewise homogeneous refractive indexes. The procedure, which is free of spurious modes, determines the full field distribution from the longitudinal fields at the refractive index boundaries. Singular kernels are evaluated through series solutions while the electric field discontinuity at corners is accommodated through either a grid refinement technique or a semianalytic approach. Our formalism generates propagation constants and modal field distributions for several representative refractive index profiles with far higher accuracy than standard finite-difference or finite-element procedures.