Abstract: This study involved the preparation and characterization of polyethylene glycol (PEG)/ polyacrylamide (PAM) composite as solid-solid phase change materials (PCM). In this study, the polyethylene glycol / polyacrylamide composites as solid-solid phase change material was prepared, and the phase change behavior and crystalline morphology of the phase change materials were investigated using differential scanning calorimeter (DSC) , wide-angle X-ray diffraction (WAXD). Results indicated that the composite remained solid when the weight percentage of PEG was less than 60%. The PEG/PAM composite that exhibited solid-solid phase change behavior can be used as a new kind of phase change material for the shortage of thermal energy and temperature control.
Abstract: The method of ultrasoft pseudopotential within the generalized gradient approximation has been employed to study the elastic constants and electronic structure of (Al,Si)3Sc precipitate with L12 structure in Al-base alloys. Based on the calculated results, the elastic properties of (Al,Si)3Sc precipitate were investigated. The Young’s and shear modulus of the polycrystals for (Al,Si)3Sc precipitate were calculated using Voigt-Reuss-Hill averaging scheme. The calculated results of elastic properties showed that the (Al,Si)3Sc precipitate has a strengthening effect in the Al matrix, owing to the larger shear modulus differences between (Al,Si)3Sc and Al matrix. The calculated results also showed that (Al,Si)3Sc precipitate is brittle in nature.
Abstract: Poly(arylene ether nitriles) (PEN) nanocomposites containing various functionalized multi-walled carbon nanotubes (MWCNTs) were prepared through solution-casting method. The as-prepared PEN nanocomoposites were investigated by parallel-plate rheometer, aiming at examining the effect of surface functionalizaion on the dispersion of MWCNTs by using viscoelastic properties. The results of linear viscoelasticy indicated that the 4-aminophenoxyphthalonitrile-grafted MWCNTs (MWCNTs-CN) presented better dispersion in PEN matrix than purified and carboxylic MWCNTs because of the corresponding composite showed the lowest rheological percolation threshold, which was further confirmed by morphological observation. Both the dispersion state and the surface functionalization of MWCNTs are very important to the rheological behaviors of PEN matrix.
Abstract: Microfibril angle (MFA) was determined at each growth ring from disks at breast height (1.3 m) from four scots pine (Pinus sylvestris) trees grown in northeastern China. Significant variation in microfibril angle was observed among growth rings. MFA at breast height showed a decreasing trend from pith to bark for each tree. The modified logistic model with nonlinear mixed-effects was used for modeling earlywood MFA. The NLME procedure in S-Plus is used to fit the mixed-effects models for the MFA data. The results showed that logistic model with two random parameters and could significantly improve the model performance. The CS, AR(1), MA(1), and ARMA(1,1) correlation structures were incorporated into mixed-effects models. The mixed model with the AR(1), MA(1), and ARMA(1,1) correlation structures improved model performance (P<0.0001).
Abstract: The scintillation response of Lu1.8Y0.2SiO5:Ce (LYSO:Ce) and LaCl3:Ce scintillators were compared under g-ray excitation using photomultiplier tube (PMT) readout. For 662 keV g-rays (137Cs source), energy resolution of 4.5±0.2% obtained for LaCl3:Ce coupled to XP5200B PMT is much better than that of 8.2±0.4% for LYSO:Ce. The non-proportionality of the light yield and energy resolution versus g-ray energy were measured and the intrinsic resolution of the crystals was calculated. Special attention was devoted to the correlation between intrinsic resolution and non-proportional response of scintillators.
Abstract: The scintillation response of Lu0.7Y0.3AP:Ce and Bi4Ge3O12 scintillation crystals have been compared using photomultiplier tube readout for photon energies ranging from 22.1 to 1274.5 keV. Lu0.7Y0.3AP:Ce showed a light yield non-proportionality of about 20% upon lowering energy from 1,274.5 to 22.1 keV, which is better than that of about 39% obtained for Bi4Ge3O12. Lu0.7Y0.3AP:Ce showed the light yield of 13,400 ph/MeV and energy resolution of about 8 % for 662 keV gamma rays from a 137Cs source. The photofraction of Bi4Ge3O12 is better than that of Lu0.7Y0.3AP:Ce. The intrinsic resolution of the crystals versus energy of gamma rays has been determined after correcting the measured energy resolution for photomultiplier tube statistics.
Abstract: To discuss the surface characteristics and friction properties of PTFE yarn, the longitudinal structure and cross section were analyzed, it were investigated that the influence on friction coefficient of running speed, guide material and initial tension on ring spinning for producing PTFE film yarn. The results show that the longitudinal section of PTFE yarn was regular cylinder, the cross section was polygon, the yarn surface was very smooth, not easy to absorb dust, PTFE yarn had very good self-cleaning function. The friction coefficient of PTFE yarn was decreased at first with the increase of running speed but increased later, and the friction coefficient of PTFE yarn was reduced with the increase of initial pressure. The friction coefficient between PTFE yarn and plastic was very small, it can be said that plastic was the best guide material for ring spinning of PTFE yarn. Introduction
Abstract: Design the formula of UV waterless offset ink, through changing the content of padding, different ink samples that with different rheological properties were made. Proof with the IGT printability tester, and the printing qualities of inks were tested. The influence of rheological properties on the printing quality of ink was analysis. The results show that the rheological properties influence the printing quality directly. The higher the viscosity of ink is, the bigger the thixotropy is, and the smaller the fluidity is. The solid density, gloss, ink-transfer rates and dot gain of the printed matter decrease with the increase of ink’s yield value.
Abstract: Prepolymer and monomer which are the main components of the UV ink have significant influence on the performance. By changing the proportion of prepolymer and monomer to make the different kinds of UV offset ink samples, the samples’ flow curve, yield stress, curing rate, glossiness, emulsification ratio, solid density and ink transfer rate were tested. And the effects of the proportion of prepolymer and monomer on the performance of UV offset ink were studied. The results show that with the decrease of prepolymer, the viscosity, yield stress and glossiness of the ink were reduce, and the curing rates were more or less the same. The emulsification ratio, solid density and ink transfer rate increased with the decrease of prepolymer.
Abstract: A high dose of electron irradiation generates amorphous zones with critical vacancy concentrations in the pyrographite. The degree of disorder “” of amorphization of Graphite, natural graphite, pyrographite and polycrystal pyrographite are analyzed as a function of time “t”, and the amorphization kinetics under different voltages inside the HVTEM.