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In order to analyze the optical properties of different dyeing invisible curtain after long time insolation in xenon arc lamp which stimulated realistic sunlight conditions. Four different light color dyeing (yellow,blue,purple,and peach )Tricot Invisible Curtains were selected. The color and the optical properties,including the light transmittance and reflectance of the technical face and back side of samples in the ultraviolet and visible band, were tested and analyzed.The results showed that the color of all samples had different degree of fading after insolation, the anti-ultraviolet and transmittance properties were improved. The light-admitting and privacy-keeping functions of samples can keep stable after long time insolation and yellow sample keep the best performance of anti-peep properties.

A novel approach to the schedulability analysis is presented in this paper for timing constraint Petri nets, which have wide applications in the workflow management, software engineering, reliability engineering, and so on. The analysis can be conducted in two phases: finding firing sequences and timing constraint analysis, among which the first one is to find the transition sequences that transform the initial marking to a certain marking by using incidence matrix in the underlying Petri net, and the second one is to verify whether the reachable marking found in the first step is reachable with the timing constraints. The proposed method is able to pinpoint out non-schedulable transitions and adjust the timing constraints to make all the transitions schedulable within complex task sequences, while meeting the needs of the managers to schedule the tasks.

Since the individuals’ reproduction and existing probability can be greatly improved by introducing evolution rule into cellular automata algorithm, this paper presents a new niche cellular genetic algorithm by involving cellular automata evolution rule and introducing niche technique. The results of simulation experiments on some well-known complex benchmarking problems reveal that this algorithm outperforms the basic cellular genetic algorithms (cGAs) and cGAs with evolution rule in terms of diversity, convergence, global optimization and stability.

This paper presents a crowding niche cellular genetic algorithm (referred to NCGA) aiming at solving the problems of local convergence and non-uniform population distribution in traditional genetic algorithm. The selecting operation in traditional genetic algorithm is improved by bringing in the concept of neighbors of cellular genetic algorithm, and the population distribution is greatly enhanced by introducing crowding niche mechanism, which betters the ability of global searching and helps to avoid the population local convergence. Meanwhile, the paper describes the crowding niche cellular genetic algorithm in details and compares it with simple genetic algorithm （SGA） and simple niche genetic algorithm （NGA）; the comparison results reveal that, NCGA outperforms the other two algorithms in terms of convergence rate and population diversity.

In this paper, numerical simulation was carried out for the tube bundle of a float-head heat exchanger with concentration on the effects of tube stiffness and tubesheet thickness on the thermal stress of the tubes and tubesheet. It is found that decreasing the tube stiffness by using corrugated tubes can reduce the axial thermal stress at the tubes and, thus, decrease the possibility of strength failure of the connection between the tubes and tubesheet. Decreasing the tubesheet thickness can reduce the thermal stress at the tubesheet, which is meaningful for the heat exchangers with large temperature difference between the shell-side fluid and tube-side fluid and under small pressures.

In this paper, double embedded elliptical cracks in a weld of pressure vessels under tension was taken into consideration, and stress intensity factors at the crack tip were calculated with the emphasis on the interaction between cracks. It is found that when the distance between the double embedded elliptical cracks is larger than the major semi-axis of the ellipse, influence between the cracks can be neglected. Unlike the single embedded crack, owing to the crack interactions, the point with maximum stress intensity factor is not always at the end of the minor axis of the ellipse, it may swift to the end of major axis, especially when the ellipse is close to a circle.

In this paper, numerical simulation was carried out for the tube bundle of a slurry oil steam generator with concentration on the thermal stresses at the tubesheet with or without a welding clad on the tubesheet surface. It is found that as having a larger heat expansion coefficient, thermal expansion of the welding clad is constrained and most areas are in compressive state. But the tensile stresses in the clad are also notable especially at the interface and could break the clad if added by the tensile stresses produced by pressure loadings. Presence of the welding clad causes significant tensile stresses in the base tubesheet. It is possible that the maximum tensile stress comprised by the thermal tensile stress and pressure induced tensile stress will exceed the tensile strength of the material and cause initiation of cracks in the tubesheet.

In this paper, numerical simulation for hydraulic expanding connection of tube to tubesheet was performed. Residual contact preesure on the contact surface between tube and tubesheet as well as residual expansion stress in the tubesheet were investigated. It is seen the distribution of residual contact pressure is not uniform. Instead, near the two tubesheet surfaces, there are two tightness bands on which the residual contact pressure is high. Based on the fact that residual expansion stress could be a driving force for the tubesheet cracking, it is suggested that the expansion pressure should not be too large but enough to completely form the tightness bands on the contact surface. With this criterion, expansion pressures for typical tube materals and size are given.