Advanced Materials Research Vol. 1028

Abstract: In this paper, a novel low molecular weight poly (γ-glutamic acid) hydrogels were prepared by chemical method, and their preparation conditions such as poly (γ-glutamic acid) and crosslinker concentration, pH and temperature were studied. When poly (γ-glutamic acid) solution was 18%, pH 4.0, poly (γ-glutamic acid) was crosslinked to yield high water hydrogel with specific water content of 1328 times their dry volume depending on the preparation conditions.

Abstract: A series of silicon (VI) porphyrins compounds with varying meso substitutions Si (TPP)Cl₂ (where X=5,10,15,20-tetraphenylporphyrin), Si (TFP)Cl₂ (X=5,10,15,20-tetrafluorenylporphyrin), Si (TQP)Cl₂(X=5‚10‚15‚20-tetra (2,3,6,7-tetrahydro-1H,5H-benzo [ij] puinolizine) porphyrin),Si (TMP)Cl₂(X=5,10,15,20-tetra (N,N-dimethylphenyl) porphyrin) have been investigated using density functional theory (DFT) to assess the influence of ruffled conformation on the electronic structures, frontier molecular orbital, charge carrier transport, electronic spectra. The electronic structures reveal that all these Si porphyrins display visible ruffling distortion, as the dihedral angle Cα₂-N₂-N₄-Cα₄ are ca. 30 ̊. And calculations confirm that ruffed distortion result in higher LUMO energies, lower EA values than corresponding planed Zn porphyrins, especial for similar λ_hole and λ_electron values. These calculations suggest that the ruffled conformation bring about better charge injection and transport, which would broaden the application of distorted porphyrin in several different fields.

Abstract: Pd-Ag-Sn-In-Zn alloy was subjected to isothermal aging treatments at 400°C, 500°C, and 650°C. Age-hardening behaviour and related microstructure changes of the aged alloy were studied by means of hardness test, X-ray diffraction (XRD), scanning electron microscopic (SEM) and energy dispersive spectrometer (EDS). The results indicate that the hardness of the alloy reaches a highest value of 348Hv after aging at 650°C for 20min. Further increasing the aging time leads to softening. The hardening of the alloy at early stage of the age-hardening at 650°C is ascribed to the formation of lamellar (α₁ + β) precipitates along the grain boundaries of α matrix. The softening of the alloy occurred by further increasing aging time is caused by the coarsening of the precipitates.

Abstract: Ring-spun cotton yarn and rotor-spun yarn with hard twist factor were manufactured. It shows that yarn breaking strength varies slightly with twist factor, either ring-spun yarn or rotor-spun yarn. Twist factor has little effect on yarn breaking elongation. Yarn number has effect on yarn hairiness for ring-spun yarn and rotor-spun yarn. Coarser yarn has more hairiness than fine yarn. Ring-spun yarn hairiness is higher than rotor-spun yarn. Twist factor has some effect on coarse yarn uniformity while it affects fine yarn uniformity slightly. Ring-spun yarn has higher strength than rotor-spun yarn. Rotor-spun yarn has less elongation and less hairiness than ring-spun yarn and its uniformity is better.

Abstract: In this paper, the standard test method of fabric shielding effectiveness was simply introduced in order to understand systematically the influence of fabric structure of stainless steel fiber on the shielding effectiveness. The different fabrics were woven using of stainless steel monofilament cotton yarn, stainless steel multifilament cotton yarn and stainless steel fiber cotton yarn. Then shielding effectiveness of these fabrics was measured. Results show that spacing between the stainless steel filaments has a great influence on the shielding effectiveness. The shielding effectiveness of fabric will reduce in a certain range when distance of stainless steel filaments is lengthened. Then shielding effectiveness of blended fabric will increase with increasing of the content of stainless steel fiber. The shielding effectiveness of duplex stainless steel filament fabrics is much better than unidirectional stainless steel filament fabric. Under the same testing condition the shielding effectiveness is different between stainless steel monofilament blended fabric and stainless steel multifilament blended fabric. The structure of stainless steel blended yarn has a great effect on shielding effectiveness of shielding fabric, the shielding effectiveness of stainless steel fiber blended fabric is better than the stainless steel filament blended fabric because the content of stainless steel fiber is difference between two kinds of yarn structure.

Abstract: The diffusion behaviors of Fe adatom on Fe nanoparticles with three different sizes have been explored by molecular dynamics (MD) simulation. The activation energies and pre-exponential factors are extracted from the Arrhenius relation. The MD simulation shows that the hopping, exchange and direct/indirect crossing mechanisms contribute to the diffusion of Fe adatom on Fe nanoparticles and the diffusion behaviors do not show a significant nanosize effect.

Abstract: The migration behaviors of Fe adatom on Fe nanoparticles have been explored by the nudged elastic band (NEB) method. We take nanoparticle consisting of 2465 atoms as an example to illustrate the energy barriers and the migration pathways of Fe adatom on Fe nanoparticle. For the adatom at the three typical kinds of locations, the hopping mechanism is more favorable with the lowest barriers and the exchange mechanism requires relatively higher energies. For the single adatom far away from the interface region, a single adatom on each nanoparticle facet follows a migration behavior similar to that on a bcc surface. In the interface region, there is a competition between the direct crossing mechanism and the indirect crossing mechanism. In addition, the locations have obvious influences on the migration behaviors of the adatom and the effects are to some extent restricted by the migration mechanism.

Abstract: This work is focused on the preparation and properties of ternary fatty acid eutectic mixtures/ expanded graphite form-stable phase change materials (PCMs). Based on the theoretical calculation of the mass ratio and ternary eutectic melting temperature, the ternary eutectic mixture of capric acid (CA), lauric acid (LA) and palmitic acid (PA) was prepared firstly, which is for the sake of decreasing the phase transformation temperature. Thermal characteristics such as melting temperature and latent heat of fusion of these developed eutectics measured by using Differential Scanning Calorimetry (DSC) technique, which also showed that the eutectic mixture was composed by CA, LA and PA in the mass ratio of 59.7:30.1:10.02. Then the CA–LA–PA was absorbed in expanded graphite (EG), which acts as a supporting material, the optimum mass ratio of CA–LA–PA to EG is 17:1. The CA–LA–PA/EG composites were characterized by the scanning electronic microscope (SEM), differential scanning calorimeter (DSC). The SEM observations showed that the CA–LA–PA was adsorbed into the porous structure of EG, instead of any chemical action. The DSC results indicated that the phase change temperature and latent heat of the CA–LA–PA and CA–LA–PA/EG were 19.92 °Cand 19.48 °C, and 135.49 J/g and 130.73 J/g respectively. The thermal conductivity of CA–LA–PA /EG composite PCM was improved by the high thermal conductivity of the EG. Thermal cycling test showed that the CA–LA–PA/EG composite had a good thermal reliability. All results indicated that CA–LA–PA/EG composite PCM has a proper melting temperature and latent heat for building energy conservation.

Abstract: This article through to the mainstream of six kind of strings on the market through instrument to proceed comparison test. The experimental results show that between domestic and foreign badminton lines, there is an obvious gap on elasticity, wear resistance, shock resistance, resistance to fracture. After comprehensive the above several factors comparison,the overall price ratio is lower and difficult to meet the needs of the professional athletes. Suggestions: in our country's sports industry, strengthen the badminton equipment research and development investment, policy support, strengthen the construction of material research team and precision instrument hardware research and development, etc.