Applied Mechanics and Materials Vol. 468

Abstract: A novel photochromic diarylethene bearing a pyrimidine unit as one aryl moiety has been synthesized. The compound exhibited remarkable photochromism, changing from colorless to violet after irradiation with UV light. When irradiated with UV light, the compound exhibited a relatively strong fluorescence switch along with the photochromism from open-ring isomer to closed-ring isomer. Using this diarylethene as optical storage was performed successfully.

Abstract: An unsymmetrical photochromic diarylethene was synthesized and its photochromism and fluorescent properties were investigated in detail. The compound exhibited remarkable photochromism, changing from colorless to violet after irradiation with 297 nm UV light, in which absorption maxima were observed at 535 nm in hexane and at 541 nm in PMMA amorphous films, respectively. The fluorescence intensity of diarylethene 1o decreased upon irradiation with 297 nm UV light, in which fluorescence peaks were observed at 448 nm in hexane and at 426 nm in PMMA amorphous films, respectively. And the modulation efficiency were 12% and 75% in both hexane and PMMA films.

Abstract: A novel photochromic diarylethene based on pyrimidine moiety was synthesized. Its properties, including photochromism and fluorescence were investigated in detail. The compound exhibited remarkable photochromism, changing from colorless to red after irradiation with UV light. The fluorescence had a remarkable initial increase with subsequent dramatic decrease with increasing concentration. The results indicated that the pyrimidine moiety played a very important role during the process of photochromic reaction for the diarylethene derivative.

Abstract: A new symmetrical photochromic diarylethene which is called 1,2-bis (2, 5-dimethyl-4-dromine-3-thienyl) perfluorocyclopentene (1o) was synthesized, and its photochromic reactivity, fluorescent were also investigated. The results showed that it exhibited excellent photochromism, changing from colorless to pink after irradiation with UV light in solution. When the concentration arrived at 2 × 10^-5 mol·L^-1, the fluorescence intensity of the diarylethene reached the maximum. Furthermore, the fluorescence intensity of the photochromic diarylethene 1o declined remarkably, when irradiation with UV light. Using this diarylethene 1o as optical storage and fluorescence switches was performed successfully.

Abstract: This paper firstly introduces the basic principle of PUSHOVER analysis and general steps of analysis. And then use the actual construction example to illustrate its application. This paper aims to evaluate the anti-seismic property through setting the parameters, building the data model and establishing the PUSHOVER conditions, and then do the static elastoplastic analysis. When the anti-seismic property of the building can not meet the necessary standard, the strengthening is needed. What is more, this paper employs the steel plate for reinforcement since its advantages.

Abstract: Global warming is becoming a serious problem nowadays. The emissions of greenhouse gas from vessels draw great attentions. As a significant research part of vessel seakeeping performance, resistance capability exert pretty effect on energy consuming. A Wigley ship model is set as the object to compute constraint and free model in calm water and head waves on resistance and hydrodynamic potential coefficients by STAR-CCM. Differences are discussed between both models. Effects on calculation of hydrostatic resistance ignoring trim and heave are revealed .Wave added resistance of free model is computed and compared at different amplitudes and wavelengths. How trim and heave matter the computed results are discussed. So does how wavelength and amplitudes influence total resistance is considered.

Abstract: Current researches of material engineering give little investigations on the construction impacts of soil consolidation material property. Based on the Shanghai tunneling case, the excavation mechanics analyses for shield tunnels are conducted considering soil consolidation material property using 3D (three-dimensional) finite element numerical simulation method. The longitudinal deformation behaviors for existing tunnel after the completion of shield tunnel excavation are obtained under several typical cases of soil consolidation, including one month later, one year later, and ten years later. It is shown that the consolidation material property has a significant post-construction time effects on the vertical displacements of existing tunnels. The stringent stipulations on controlling the deformation for buried structures and strengthened monitoring measures are necessary and substantial for reducing potential service risks according to the post-construction state.

Abstract: The frequency response functions (FRFs) are frequently used to identify dynamic properties of the mechanical joints. However, the ill-posed problems of the system are caused by the contamination of measurement noise even if it is processed by reduction technique. In order to solve this problem, put the noised FRFs into identification equations to theoretical derivation, explained the degree of influence on the identified results by noised FRFs in theory. In order to make the identified results represent real properties of the joints, an improved FRFs method was developed based on subtraction term frequency selection, in which the measured data were processed could get high degree of anti-noise frequency before parameters identification. This method avoids the occurrence of ill-posed problems. The results of simulation show that the proposed method can solve the ill-posed problems, thus significantly improve the accuracy of identification.

Abstract: Abstract: The simulation model of zoom nozzle was established in this article.The numerical simulation of flow field in the zoom nozzle was completed with the Fluent software and based on orthogonal experimental method the structure size optimization of the nozzle was completed too.The results showed that the cavitation phenomenon is easy to form near the transition area of the cylindrical section and expansion section of the nozzle.Using orthogonal experimental method,we can achieve structure size optimization of the nozzle from reducing cavitation rate and increase the distance that emergence point of maximum cavitation rate with the cylindrical section of nozzle.

Abstract: This paper presents a digital control system for swinging arc narrow gap MAG welding based on double single-chip microcomputers. The control system utilizes a single-chip microcomputer to set and display welding process parameters, and then uses another single-chip microcomputer to realize the control functions that are necessary for the swing arc process, in which the two single-chip microcomputers can exchange data through asynchronous serial communication circuit. Experimental results show that the control system works stably and reliably with strong anti-interference capabilities, and can completely satisfy the requirements of swinging arc narrow gap welding process.