Advanced Materials Research Vols. 779-780

Abstract: In the present study, various quantities of Li2CO3 were added into Bi0.5(Na0.82K0.18)0.5TiO3 (abbreviated as 0.82BNT-0.18BKT) ceramics. For 0.82BNT-0.18BKT ceramics, the electromechanical coupling coefficients of the planar mode kp reaches 0.22 at the sintering of 1125 oC for 3 h. High-density samples were obtained through the addition of Li2CO3 into 0.82BNT-0.18BKT ceramics. It was found that 0.82BNT-0.18BKT with the addition of 0~0.9 wt.% Li2CO3 exhibit relatively good piezoelectric properties. For 0.82BNT-0.18BKT ceramics with the addition of 0.5 wt.% Li2CO3, the electromechanical coupling coefficients of the planar mode kp reach 0.37 at the sintering of 1125oC for 3 h. To promote the kp value, by adding low quantities of Li2CO3 is a effective method for 0.82BNT-0.18BKT solid solution ceramic.

Abstract: Poly (vinyl alcohol) (PVA)/sodium carboxymethylcellulose (Na-CMC)/nanosilicon dioxide (nanoSiO₂) films were prepared by solution casting method. The structure, properties and morphology of the films affected by nanoSiO₂ were characterized by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimeter (DSC), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and mechanical testing. With the increase of nanoSiO₂ content from 0 to 2.3 wt%, tensile strength increased from 20.98 to 34.80 MPa, while further increase of nanoSiO₂ decreased the tensile strength. FTIR spectroscopy of the films confirmed that Si-O-C bonds and hydrogen bonding were formed among PVA, Na-CMC and nanoSiO₂, which was suggested to improve the tensile strength of the films.

Abstract: Established the analytical method by using ultrasonic vibration - suspension of solid sampling graphite furnace atomic absorption spectrometry (GF-AAS) to test trace mercury in the titanium dioxide, by choosing a suitable concentration of agar solution as dispersing agent, and taking the ultrasonic oscillation technique to prepare uniform and stable titanium dioxide suspended solid solution, and finally using the solid injection sampling GF-AAS method to test trace elements of mercury.. Through the application of solid injection technique, the problem that the titanium dioxide is extremely difficult to digest and mercury volatile loss are solved and the matrix effect of the high titanium is eliminated by standard addition method as well. The paper has tested the conditions of preparation of solid suspension such as agar dispersing agent concentration, dosage, and ultrasonic vibration parameters. and titanium dioxide solid suspensions obtained by the method have the characters of uniformity, stability, mobility features, and preserve a long time. Graphite furnace testing procedures are also optimized: drying temperature 85 °C, time 30 s, by lowering the drying temperature and measures to extend the time to solve the contradiction of water evaporation and mercury volatilization; cancel the ashing step directly into the atomization stage in order to avoid mercury loss after drying. Finally, set atomic temperature 1 000 °C, for 5 s and close the purged argon flow of the internal graphite tube to ensure mercury exists as different forms such as free, particle adsorption or parcels can be effective tested. The detection limit is from 0.000 to 005% and recovery rate is from 93% to 109%, RSD <3.1%. The results of the test is correspond with that of Microwave Digestion and Inductively Coupled Plasma Mass Spectrometry method. The methods can meet the requirement of testing toxic trace elements mercury in high-grade titanium dioxide which used in medical, food, ceramics and other field.

Abstract: Through impregnation with UF and PF resin, the modification technology of Poplar was experimented and studied. The study results showed that WPG(weight percent gain) of the test-pieces impregnated with UF and PF resin had less difference. The wood vessels were scarcely filled by resin especially UF resin. Regardless of impregnating with UF or PF resin, the cell lumens near the veneer junctions are basically filled by the resin. But the most of the cell lumens depart farther from the veneer junctions were only filled by PF resin instead of UF resin.

Abstract: Oxidative degradation of ethylenediaminetetraacetic acid in aqueous solution at normal temperature and pressure by the bimetallic Fe-Cu, which was verified by ESR spectroscopy, was investigated. The results showed that the removal efficiency of EDTA, TOC and TN could be about 99%, 60% and 39% respectively after 3h reaction. The degradation products were iminodiacetate, formate and acetate. The effects of initial pH, concentration of EDTA, Cu content and Fe-Cu loading were also investigated. Significantly, the bimetallic Fe-Cu process exhibited higher reactivity than monometallic Fe⁰ process for the degradation of EDTA and it would not cause new heavy metal pollution in effluent.

Abstract: In order to solve the problem of locating defects from TKY node structure weld using for marine engineering , the article present a new approach of establishing TKY’s mathematical model to replace the traditional method of Graphic analytic method, which uses the computer to carry on the drawing. Firstly three-dimensional mathematical model of the Y-shaped tube node is made, based on what it work out the equation of the cross-sectional on different position of weld by introducing the concept of intersecting angle φ, eventually it establish the two dimensional mathematical model of cross-sectional . In the end of the article, some experimental examples show the effectiveness of the models, which testify that using computer graphics to evaluate ultrasonic pulse-echo is more effective , smaller error, higher working efficiency and reduces the impact of human factors greatly.

Abstract: The operation with a combination of three processing routes: cryomilling, hot isostatic pressing (HIPping) and hot extrusion was adopted in the present study for preparation of the bulk nanocrystalline Al 7050. The microstructure and fractography of the bulk material were observed by transmission electron microscopy (TEM) and scanning electron microscopy (SEM), respectively. Furthermore, the chemical composition, density and tensile properties of the material were also measured. Microstructural investigation showed that the grain size of the bulk nanocrystalline Al 7050 ranged from 100nm to 200nm. Numerous dispersoids with a diameter/length of ~50nm were observed on grain boundaries and inside the grains. Besides, one phase of these dispersoids existed in the bulk nanocrystalline Al 7050 was identified as Al₆(FeMn). These dispersoids dispersed within the bulk nanocrystalline Al 7050, to some extent, increased the mechanical properties and thermal stability of the material. The resulted sample exhibited ultimate strength of 412MPa with an elongation of 5.2% when tested under tensile load, which was a bit lower than that of the traditionally wrought Al 7050-T6. The present results suggested that improper selected starting powder and milling parameters resulted in the flake-like morphology of the cryomilled powder. The flake-like morphology made it difficult for the cryomilled powder to fill the can entirely and achieve a high density material, which led to the weak interface within the bulk material and in turn degraded the mechanical properties of the bulk nanocrystalline Al 7050 prepared in the present work.

Abstract: This article records the application of various types of temperature control fiber in modern clothing, which makes peoples life more comfortable.

Abstract: The SiO₂-BaO-CaO-MgO-ZnO glass-ceramic (GC) coating was prepared on the surface of the nickel based alloy GH140 by slurry spraying technique. Morphology, phase and elemental composition of the glass-ceramic before or after isothermal oxidation for 96h at 1000°C were investigated by SEM, XRD and EDX,. Results showed that the glass-ceramic was mainly composed of BaSiO₄ and MgCrO₄, and the amount of them both increased after being oxidized for 96h. Compared with bare GH140, GC/GH140 presented a pretty good antioxidant capacity. Before oxidation, white elongated crystals were homogeneously distributed in the glass phases, and a thin transitional layer had already been formed between glass-ceramic and substrate. During the oxidation process, the surface morphology of GC/GH140 became coarse, and small black Si-rich crystals appeared and well-distributed in the coating. Meanwhile, Cr and Ti in the substrate diffused to the interface, which lead to the formation of an oxide-rich interface that protected the substrate from further oxidation.