Multiple negative-differential-resistance (MNDR) phenomena of ametal-insulator-semiconductor-insulator-metal (MISIM)-like structurewith step-compositioned InxGa1-xAs quantum wells

In this paper, a new multiple negative-differential-resistance (MNDR) device based on a metal-insulator-semiconductor-insulator-metal (MISIM)-like structure with step-compositional In_xGa_1-x As quantum wells has been fabricated and demonstrated. The interesting MNDR phenomena are found in the current-voltage (I-V) characteristics of this device. At room temperature, the triple switching behaviours and quadruple stable operation states are obtained. In addition, the sixfold switching behaviors and a staircase-shaped I-V characteristic are observed at -105°C. A sequential carrier accumulation at InGaAs subwells and the potential lowering process are used to qualitatively explain the interesting MNDR phenomena. From the experimental results, it is shown that the studied device has good potential in multiple-valued logic applications     

On the permeation rate of copper extraction through liquid membranes

The understanding of the permeation rate of metal ions through liquid membranes is important for the design of such systems. In this paper, the permeation rates of copper ions through liquid surfactant membranes, including interfacial reaction rates and the diffusion rate of the copper ion, were analyzed using a model based on a mobilized hollow spherical globule configuration. The analysis shows that the extracting reaction is dominant at the external interface of the membrane and the stripping reaction is dominant at the internal interface; this means the reactions at both interfaces are not in equilibrium during the course of extraction. It also shows that the extraction rate, the diffusion rate and the stripping rate are not of equal value, especially at the early stage of the run.     

Effect of Particle-Size Distribution on the Microstructural Evolution in the Intermediate Stage of Sintering

The effect of particle-size distribution on microstructural evolution in the intermediate stage of sintering of powder compacts was investigated. The evolution of pore channels was dominated by particle-size distribution but independent of sintering temperature. Moreover, a powder compact with a fine particle and uniform size distribution could prolong the intermediate stage of sintering, which in turn effectively inhibited grain growth. The mechanisms of evolution and pinch off of the pore channels of the powder compact with different particle-size distributions were discussed.     

Solar Photocatalytic Degradation of Textile Dyes in TiO2 Suspended Solutions

The degradation and decolourization of direct dye (Everdirect supra turguoise blue, FBL), acidic dye (Isolan orange S-RL) and vat dye (Indanthren red FBB) have been investigated by solar/TiO2 process. The effects of solution pH, dye concentration, dosage of TiO2 and nano-size of TiO2 have been studied. The increase in initial pH (3, 5 and 11) and dye concentration decrease the removal rate. The treatment for FBB and FBL dye solutions is more efficient than that of S-RL.Under optimum conditions, the color removal is found to be almost complete for FBB and FBL while that of S-RL also reaches 95%. Langmuir adsorption isotherm and modified Langmuir-Hinshelwood kinetic model (L-H model) have been fitted to the experimental data and found to correlate the adsorption patterns as well as the kinetics of the dyes studied.     

Transport property measurements in sheared granular flows

Experiments were performed in a shear cell device under four different solid fractions. The glass spheres with a mean diameter of 3 mm were used as granular materials. The motions of the granular materials were recorded by a high-speed camera. By using image processing technology and a particle tracking method, the average and fluctuation velocities in the streamwise and the transverse directions could be successfully measured and analyzed. Three bi-directional stress gages were used to measure the normal and shear stresses along the upper boundary. The effective viscosity of the granular material flow can be calculated. By tracking the movements of particles continually, the curves of the mean-square diffusive displacements versus time were plotted and were used to determine the self-diffusion coefficients from the slopes of the curves. The fluctuations and the self-diffusion coefficients in the streamwise direction were much higher than those in the transverse direction. The fluctuations were found to increase with the solid fraction, but the diffusion coefficients were greater in a more dilute flow system.     

Accuracy and efficacy of chest radiography in the intensive care unit

264 patients with cancer of larynx, 21 female and 234 male, had a testosterone and sex hormone binding globulin (SHBG) before the treatment in serum estimated. Because of dependence of levels of hormones the group of patients was divided into three following groups: "lower than standard", "standard", "higher than standard". The correlation between these groups and sex, age, localization of tumor, organs' advances, stage of morphological malignancy and type of cancer was reported. Anomalous values of testosterone were in male group more frequently reported. Anomalous values of SHBG were similar in male and female groups, but in the female group there was a significant majority of "lower than standard" values reported. The majority of abnormal values of testosterone and SHBG was described in groups of age higher than 50 years. There were no differences in testosterone and SHBG levels in different localization of tumors in larynx. In advanced stage T3 and T4 there were more frequent lower mean values of testosterone levels and higher values of SHBG levels in comparison to T2 stages. In tumors in G1 and G2 stages of histological malignancy higher levels of SHBG and higher mean levels of testosterone. The tumors in stage G3 the hormone levels were lowers were observed. The levels of SHBG in groups of carcinoma planoepitheliale keratodes were in 66% higher than in a group of carcinoma planoepitheliale akeratodes but in both groups the levels of testosterone were nearing the same. In group of patients with larynx cancer the negative correlation between the levels of testosterone and SHBG was not observed. Higher SHBG levels were not always accompanied by lower testosterone levels.     

Deteriorating job scheduling to minimize the number of late jobs with setup times

Deteriorating jobs scheduling problems have been widely studied recently. However, research on scheduling problems with deteriorating jobs has rarely considered explicit setup times. With the current emphasis on customer service and meeting the promised delivery dates, we consider a single-machine scheduling problem to minimize the number of late jobs with deteriorating jobs and setup times in this paper. We derive some dominance properties, a lower bound, and an initial upper bound by using a heuristic algorithm to speed up the search process of the branch-and-bound algorithm. Computational experiments show that the algorithm can solve instances up to 1000 jobs in a reasonable amount of time.     

Interval optimization of rotor-bearing systems with dynamic behavior constraints using an interval genetic algorithm

A new interval optimization algorithm is presented in this paper. In engineering, most optimization algorithms focus on exact parameters and optimum objectives. However, exact parameters are not easy to be manufactured to because of manufacturing errors and expensive manufacturing cost. To account for these problems, it is necessary to estimate interval design parameters and allowable objective error. This is the first paper to propose a new interval optimization algorithm within the context of Genetic Algorithms. This new algorithm, the Interval Genetic Algorithm (IGA), can neglect interval analysis and determines the optimum interval parameters. Furthermore, it can also effectively maximize the design scope. The optimizing ability of the IGA is tested through the interval optimization of a two-dimensional function. Then the IGA is applied to rotor-bearing systems. The results show that the IGA is effective in deriving optimal interval design parameters within the allowable error when minimizing shaft weight and/or transmitted force of rotor-bearing systems.