Applied Mechanics and Materials Vols. 80-81

Abstract: The properties of polymeric components made by hot embossing are obviously affected by the geometry of the mold such as the duty ratio, the aspect ratio, width to thickness ratio and the mold cavity position. This paper focuses on numerical simulations with isothermal embossing conditions in order to observe the stress distribution and the stress concentration of the polymeric patterns. The simulation results show that stress concentration in the PMMA resist accumulates at the contact corner between the mold and the polymer, and the location of the stress distribution is mainly on the profile of the replicated patterns. Small duty ratio will result in high stress concentration at the corner of the replicated components. The stress concentration also increases rapidly while the aspect ratio of the mold increases. The thicker the polymer is, the more difficult the adequate flow of the polymer becomes, and the stress concentration rises up. A stress barrier can be used in the mold in order to reduce the stress concentration in the middle of the replicated polymeric patterns.

Abstract: In this paper, a new concept of combination degree (CBD) is proposed. And the CBD between nylon and insert in the pipe wrench is investigated using ANSYS .Then studied the effects of factors on the CBD, such as load, elastic modulus, friction coefficient and behavior of contact surface between the nylon and the steel insert. The results indicate that as the load increases from500Nm to1500Nm, the CBD declines from4.92mm-1 to 1.23mm-1, which presents the combinative characteristics become worse. However, with the elastic modulus and the friction coefficient increases respectively, the CBD also increases. When the elastic modulus is 8000MPa, its CBD goes up to1.78mm-1. As the friction coefficient ranges from 0.1 to 0.5,the CBD increases from1.56mm-1 to 2.32mm-1.In addition, different behaviors of contact surface between the nylon and the insert have different effects on the CBD. When such behavior of contact surface is bonded, its CBD is the highest, 3.31mm-1, but when such behavior of contact surface is standard which means that if the separation between the nylon and the insert occurs, the normal pressure equals zero. And its CBD is the lowest, 1.78 mm-1.

Abstract: In order to study the morphology and catalytic oxidation performance of LaMnO3 nanoparticles after A or B site doping , the sol-gel methods is applied, the La1-xSrxMnO3 and LaCuxMn1-xO3（x=0.1, 0.2, 0.3, 0.4, 0.5) nanoparticles are prepared. The diameter of particles and morphology-distribution of naniparticles with different doping amounts are analyzed by X-ray diffraction (XRD), scan electric microscope (SEM) and related software. With the framework of the experiment, the average diameter of particles is between 16-21nm with better chemical homogeneity and have higher surface area. At the same time, the catalytic oxidation of nanoparticle under different doping amounts is also studied. Tests results show that nanoparticle has excellent catalytic oxidation performance, and with the increase of doping amount, the catalytic activity of the particle increase first and decrease afterwards with the increase of A or B site doping amount, the best performance presents at X=0.2 of A or B doping concentration. The effect of lattice deformation arising from the dopants, which leads to the decrease of the catalytic performance, can not be ignored at higher doping concentration anymore. Under the same doping amounts, the catalytic performance of B-site doped is better than A-site.

Abstract: How to used non-EU-banned insoluble azo dyes to prepare a new-type colour-display anti-counterfeiting paper(ACP) is investigated in this paper. The ACP will display red spots when it is wiped with alcohol. Through studying its mainly affecting facts ,including the dosage of Naphthol AS-BO ,dosage of Chromophore Red-B, the Chromophore's pH value and the drying temperature etc.,the best optimize technological conditions are obtained of insoluble azo dyes' color-displaying on the paper for the purpose of anti-counterfeiting. After the red spot are displayed in the paper,the chromatic aberration and physical properties of the paper are detected. The results showed that the paper made by adding Chromophore Red-B and Naphthol AS-BO had a very good anti-counterfeiting effect, while its physical properties had only changed a little.

Abstract: The magnitude and dynamic response of the third-order optical nonlinearity of a 1,3-bis(2,4,6-trihydroxy-phenyl)squaraine was measured by femtosecond degenerate four-wave mixing (DFWM) technique at 800 nm. Ultrafast optical response has been observed and the magnitude of the second-order hyperpolarizability of the studied squaraine was measured as large as 3.8 ×10-31 esu. The large optical nonlinearities of the squaraine can be attributed to their rigid and intramolecular charge transfer structure, and the instantaneous NLO response of squaraine is mainly contributed from the electron delocalization.

Abstract: The investigation into the cushioning properties of multi-layer corrugated boards is a hotspot issue in the packaging field. People one after another investigate into the compressive properties based on experiments. As far as authors' knowledge is concerned, no theoretical research on compressive constitutive relation for multi-layer corrugated boards has ever been reported in literature. Therefore, we investigated into the compressive properties of multi-layer corrugated boards and analyzed their compressive breakage mechanism. The compression curve of multi-layer corrugated boards presents the three sections of linear elasticity, sub-buckling going with local collapse and densification. We constructed the compressive constitutive equation by a subsection function. The equation is standardized by the solid modulus Es of corrugated sandwich materials. Focusing on the structure characteristics, it can express the compression resistance and cushioning properties in the same curve for different basis materials. Comparison between the theory and experiments shows that a good consistency is achieved between theoretical and experimental stress-strain curves. By means of the compressive constitutive equation, the compression resistance and cushioning properties can be evaluated without more experiments, which facilitates the optimization of the structure of the corrugated sandwich structure and the optimized design of the cushioning package.

Abstract: Directly using cheap D,L-lactic acid (D,L-LA) and glucose (Glu) as starting materials, biodegradable material poly(D,L-lactic acid-co-Glucose) [P(D,L-LA-co-Glu)] was synthesized via melt polycondensation. When n(Glu) : n(D,L-LA) = 1:200, the appropriate synthetic condition is that: after 120 °C prepolymerization for 5 h, 160 °C melt polymerization catalyzed by w(SnCl2) = 0.5% for 5 h. P(D,L-LA-co-Glu) with different molar feed ratios were synthesized and characterized with [η], FTIR, 1H NMR, GPC and XRD. The Tg of all copolymer P(D,L-LA-co-Glu) was lower than that of homopolymer polylactic acid directly synthesized via melt polycondensation. The copolymers with Mw from 2,100 Da to 5,100 Da could meet the demand of drug delivery carrier material.

Abstract: Warping deformation is an important indicator to evaluate the performance of thin-wall Plastic. In this paper, using the CAE（computer aided engineering）technology and DOE（Design of experiment）in the thin-wall injection molding field, take a box-shaped thin-wall plastic parts for example, using the moldflow software to simulation analyze of the process parameters of injection molding. By analyzing the causes of plastic parts’ warpage, learn the holding pressure is a leading role in warping. Optimization of process parameters under the guidance of the orthogonal test, it can reduce the warpage of plastic parts effectively.

Abstract: The objective of this article is to provide an insight into a new composite bonding system of Cement/emulsified-Asphalt/Epoxy resin (CAE) for steel box girder bridge pavement. The effect of epoxy resin on emulsified asphalt mixtures added with cement has been investigated in laboratory. Besides the mechanical properties of mixtures using CAE binders, the microscopic feature of CAE binders also have been measured. The results of mechanical tests indicate good performances for pavement, especially rutting deformation at high temperature and adhesive strength with steel blocks. Then, microscopic images show some interesting microscopic feature, which could be related to the development of performances.

Abstract: In this article, some common defects, which are caused by material properties, and the mechanism of the defects occur are introduced. Author introduces how these defects are treated in conventional process, meanwhile, points out the disadvantages of the process. For the disadvantages, several special processes are introduced, including gas-assisted injection molding, rapid variotherm injection molding and hot runner technology, and their mechanism and advantages.