蓝宝石的紫外-可见光谱及其致色机理分析

蓝宝石的紫外-可见吸收光谱和能谱分析结果表明,蓝宝石从粉红色→紫色→蓝色→绿色→黄绿色→黄色,其Fe3+的浓度相对Fe2+-Ti4+离子对浓度由低至高变化;浅蓝色到深蓝色蓝宝石中的Fe和Ti均有所增加;褐色蓝宝石含有相对较多的Fe和Cr;Mn可能与蓝宝石的紫色有成因联系。热处理蓝色蓝宝石和辐照黄色蓝宝石在450,375,387nm处的吸收较未处理的弱,辐照黄色蓝宝石在405nm处有吸收带。

Coupling effects of influence factors on probability of corrosion initiation time of reinforced concrete

The coupling model of major influence factors such state affecting the chloride diffusion process in concrete is as environmental relative humidity, load-induced crack and stress discussed. The probability distributions of the critical chloride concentration Cc, the chloride diffusion coefficient D, and the surface chloride concentration Cs were determined based on the collected natural exposure data. And the estimation of probability of corrosion initiation considering the coupling effects of influence factors is presented. It is found that the relative humidity and curing time are the most effective factors affecting the probability of corrosion initiation before and after 10 years of exposure time. At the same exposure time, the influence of load-induced crack and stress state on the probability of corrosion initiation is obvious, in which the effect of crack is the most one

Reliability-based service life prediction of existing concrete structures under marine environment

Chloride-induced corrosion of the reinforcement is considered as one of the major mechanisms resulting in the reduction of structural resistance of reinforced concrete structural elements located in marine and other aggressive environments. A study of reinforced concrete structures located at the Fangcheng dock in the Beibu Gulf port, China, was present. The result from field survey indicates that the concrete cover depth and chloride diffusion coefficient fit best normal distribution and lognormal distribution, respectively. The service life of structure is about 55 a, while initiation time is 45 a. Sensitivity analysis indicates that the most influential factor of the structure service life prediction is concrete cover, followed by diffusion coefficient, diffusion decay index, critical chloride concentration, surface chloride concentration, current density and localized pitting corrosion. Finally, the effects of diffusion decay index and critical chloride concentration on structure service life prediction are discussed.

Effects of Ionic Concentrations on Survival and Growth in Polyculture of Litopenaeus vannamei with Oreochromis niloticus in Low Salinity Water

A study comparative of rearing of the Pacific white shrimp （Litopenaeus vannamei） with the Nile tilapia （Oreochromis niloticus） in three earthen ponds （5,600 m^2） with the salinity ranged from 0.5-1.2 ppt and three treatment ponds with salinity of 2-4 ppt by adding brine water into the ponds. Postlarvae 12 （PL12） of L. vannamei were stocked at density of 9 PL/m^2 and after one week the Nile tilapia fingerlings were stocked at density of I fish/m^2. Only pelleted feed were given to the fish during the 196-day rearing period. Shrimps were partially harvested by sieve net at day 80 and 120, and five days later PLI2 were stocked at the rate of 3 PL/m^2. After final harvesting at day 196, the production, body weight and survival from the treatment group were significantly higher （P 〈 0.05） than those of the control group. While the fish production body weight and survival rate from both groups were not significant differences （P 〉 0.051）. The ionic concentration of six major ions （CI, SO42, Ca^2＋, Na^＋, Mg^2＋ and K^＋）, salinity and hardness in the treatment ponds were significantly higher than those of the control ponds （P 〈 0.05）. Moreover, the ionic profiles of the treatment ponds were similar to seawater at the salinity of 2 ppt while only 1 ppt in the control ponds. Results from the study indicated that in order to achieve good growth and survival rate of L. vannamei, brine water should be added into grow-out ponds prior to stocking and during the rearing： period to obtain and maintain the salinity not less than 2 ppt.

Formation of Polyethersulfone Film with Regular Microporous Structure by Water Vapor Induced Phase Separation

Polyethersulfone(PES)film with regular microporous structure was formed using dichloromethane as the solvent via water vapor induced phase separation(VIPS).The effects of solution concentration,atmospheric humidity and temperature,as well as molecular weight of PES on the surface morphology of the polymer film were investigated.The surface morphology characterized by SEM showed that the pore size reduced as the solution concentration increased.There was an optimum range of relative humidity for the formation of regular pore structure, which was from 60%to 90%at concentration of 20 g·L-1 and 20°C.With the atmospheric temperature varied from 20 to 30°C,the pore became larger and the space between pores increased.The pore size in the PES film with low molecular weight was smaller than that with high molecular weight.

Measurement of the association constants through micro-Raman spectra of supersaturated lithium perchlorate droplets

High quality micro-Raman spectra of the LiClO4 droplet with mass of nanogram scale were obtained at various concentrations from dilute to supersaturated state. From component band analysis of the v1-ClO4^- band, four peaks at 933.3, 936.8, 942.1 and 950.7 cm^-1 were identified and assigned to free solvated perchlorate anion, solvent-shared ion pair, contact ion pair and com- plex ion aggregates, respectively. As expected, the signature of free solvated CIO4 ion was observed to decrease in intensity with the increase in concentration. The intensity of the signature from solvent-shared ion pair was observed to rise with in- crease in concentration from 1.8 mol/kg to 5.0 mol/kg before decreasing as the concentration was further increased to 5.6 mol/kg. Signatures of contact ion pair and of complex ion aggregates were shown to increase as the concentration was enhanced. Based upon the Eigen mechanism, we show that three association equilibria can be used to describe the transfor- mations between free solvated perchlorate anion, solvent-shared ion pair, contact ion pair and complex ion aggregates. The overall association constant, K, and the stepwise association constants Ki （i = 1 to 3） in the Eigen mechanism were determined separately with values of 0.025 ± 0.003, 0.023 ± 0.002, 0.068 ± 0.033 and 0.686 ± 0.174. Based on these constants, the electronic performance can be reasonably predicted by the optimum choice of electrolyte concentrations.