Advanced Materials Research Vols. 989-994

Abstract: A series of Tb³⁺-doped Li₂SrSiO₄:Tb³⁺ phosphors were prepared by high temperature solid state reaction. The morphology and the thermal stability of Li₂SrSiO₄:Tb³⁺ phosphors were discussed by SEM and PL measurements, respectively. The results showed that the morphology of Li₂SrSiO₄:Tb³⁺ was changed from flower-like to rod-like with increasing Tb³⁺-doped content. Moreover, the emission intensity measured at 350 ⁰C almost maintain with constant compared with that measured at room temperature. The results showed that Li₂SrSiO₄:Tb³⁺ phosphor might be a potential phosphor for white light-emitting diodes.

Abstract: The natural halloysite as the main raw material, removing the kaolinite, the quartz, feldspar and other impurities through purification. The purified halloysite was roasting activation pretreatment, in order to enhance surface porosity and reaction activity, and then was made of halloysite composite by modifying through the use of silane coupling agent. The samples were characterized by XRD、FESEM、BET、FT-IR and other chemical analysis method. The weight percentage of CO₂ which were adsorbed by the modified halloysite increased from 3.13% to 13.92%.

Abstract: Used electrochemical tests and the natural atmospheric exposure experiment to study initial atmospheric corrosion of 2cr13 steel in Guiyang city . Measured impedance spectrum curves and polarization curves of experimental steel in the local rain medium.Weight method measured the corrosion rate. The results showed that the exposure period of 0 to 60 days, with longer time, the corrosion current increased firstly then decreased, and the corrosion current decreased after the firstly increased. Impedance spectra showed that passivation process was controlled by the electrochemical reaction. Measured the corrosion rate of 0.000280 ~ 0.000280 mm/a, which belongs to the corrosion level 2 - very corrosion resistance.

Abstract: Flax fiber moisture, permeability, with good wearability. But the flax fiber dyeing performance is poor, light color , there will be color difference, dyeing unequal phenomenon . Through the analysis of the performance of flax fiber dyeing , tells the story of flax fiber dyeing difficulties. This paper introduces the urea, bulking agent, sodium hydroxide, ultrasonic, rare earth and other methods to improve the dyeing properties of flax fiber.

Abstract: There are significant regional differences of the heavy metals contents in urban soils in China. The heavy metals contents in urban soils of the eastern, central and western regions are quite different, and the pollution of capital cities and prefecture-level cities are different. The study about spatial variability, time differences, pollution levels and environmental risks of heavy metals from China's urban soil show that the heavy metal contents in Chinese cities are over the soil background value in China, especially the contents of Cd and Pb , which were 91.37 times and 41.91 times to the Chinese soil background value. And the content of Ni l is only 1.59 times to the Chinese soil background value.There are also obvious differences among different functional areas the city. Meanwhile, the metal content of urban soils change with the length of time of urban development. Nemero comprehensive pollution index of China's urban soil heavy metal was 45.404, which is heavily polluted. The potential ecological risk index of China's urban soil heavy metal is 71.56, which is high potential ecological risk. Different levels of urban pollution with development degrees cause the different environmental risks.

Abstract: Mixing chlorine is one of the ways to ensure the theory and practical steel bars corrosion rate closer when mixing concrete for laboratory electrochemical accelerated corrosion and appropriate chloride dosage should guarantee the steel bars are in the critical corrosion state when we start to accelerated corrosion. By comparing the specimens’ experimental compressive strength, chloride-permeation resistance, corrosion potential measured by the half-cell potential method and polarization potential curves measured by the linear polarization potential method with different Nacl dosage, we get the appropriate Nacl dosage is nearly 1.90%, namely cl^- content is about 1.15%.

Abstract: The layered LiNi0.4Co0.2Mn0.4O2was synthesized by co-precipitation method using carbonate sodium as precipitant. The microscopic structural features and morphologies of as-prepared cathode materials were investigated using X-ray diffraction (XRD) and scanning electron microscopy (SEM). And then, the charge-discharge measurements were carried out to determine the electrochemical properties in a voltage range of 2.5-4.6 V. The results show that the pH value in the process of co-precipitation reaction plays a greater part on the electrochemical properties than feed rate does. The cathode materials prepared at higher pH value illustrate better electrochemical properties in the voltage range of 2.5-4.6 V, which can be attributed to a less cation mixing in the cathode material as well as the smaller primary particles and the smaller second particles.

Abstract: The UV-Visible absorption spectroscopy was performed to study the SrTiO3 (STO) single crystals implanted with the fluences of 1.5×10¹⁵ and 1.875×10¹⁶ Ar⁺/cm². The two absorption peaks at 425 and 742 nm were recorded for the low-fluence implanted samples, while the additional peak at 520 nm was measured only for the high-fluence implanted samples. Through the evolution of the absorption peak with the annealing temperature, the 425, 520, and 742 nm peaks are attributed to the isolated oxygen vacancies, oxygen bivacancies, and oxygen interstitials, respectively. The thermal evolution of absorption spectra reveals that the STO lattice defects have poor thermal stability and disappear completely after 400°C annealing treatment.

Abstract: Using 3.5 G PAMAM as a stabilizing agent, Au nanoparticles have been prepared by reducing HAuCl₄ with microwave irradiation. The influence of microwave irradiation at the same ratio of 3.5 G PAMAM to HAuCl₄ for the different time and at the different ratio of 3.5 G PAMAM to HAuCl₄ for the same time on Au nanoparticles ́size and shape has been studied. Au nanoparticles were characterized by UV-vis spectra and TEM. At the same ratio of 3.5 G PAMAM to HAuCl₄, the microwave irradiation time has a little influence on the Au nanoparticles ́size and shape, meanwhile more dispersed Au nanoparticles were obtained with the appropriate increase of reactive time. At the same irradiation time, bigger and more aggregative Au nanoparticles were acquired as the ratio of 3.5 G PAMAM to HAuCl₄ was decreased.

Abstract: In this paper, critical temperature of phase transformation and continuous cooling transformation (CCT) curve of S87B were determined by hot uniaxial compression tests. At several of cooling speed, the microstructures were studied. The results indicate that the critical temperature of phase transformation become lower with cooling speed increasing, the min interlamellar spacing of pearlite was 0.125μm when the cooling speed was 4°C/s, the best cooling speed of phase transformation area was during (3-4)°C/s..