乙烯-乙酸乙烯酯共聚物/氢化丁腈橡胶共混物的相态结构和低温性能研究

采用熔融共混法制备乙烯-乙酸乙烯酯共聚物(EVM)/氢化丁腈橡胶(HNBR)共混物,研究其硫化特性、相态结构、动态力学性能、物理性能和低温拉伸性能。结果表明:当EVM/HNBR共混比为70/30时,EVM形成连续相,HNBR形成分散相;随着HNBR用量的增大,HNBR相态由分散相向连续相转变。HNBR的加入可以提高EVM的耐低温性能,当EVM/HNBR共混比为30/70时,共混物-40℃下的低温拉断伸长率可达300%左右。差示扫描量热分析表明,随着HNBR用量的增大,共混物玻璃化温度降低。     

四壳程低温换热器的设计

换热器管程、壳程采用多程流动,可以提高流速,从而提高传热效率。通过设计实例,介绍了四壳程低温换热器的设计参数、材料选用、工作原理、结构设计、热处理要求、无损检测要求、水压试验等。     

Color changes,nitrite content,and rehydration capacity of edible bird's nest by advanced drying method

This article presents the authors’ first attempt to improve quality of edible bird’s nest through continuous and intermittent low-temperature drying (25 and 40°C) with infrared and ultraviolet C (UVC) treatments. The attributes of quality were compared in regard to quality of hot-air-dried samples at 70–90°C. Experimental results showed that a significant improvement in the quality of edible bird’s nest in terms of minimizing color changes and rehydration capacity using intermittent low-temperature drying with infrared and UVC drying profile. However, it was also found that any drying method has less significant effect on the nitrite content of edible bird’s nest.     

WATER-BORNE,LOW-TEMPERATURE CURABLE POLYACRYLATE COATINGS

A water-borne, low-temperature curable polyacrylate (PA) coating was developed by introducing crosslinkages in polymer chains with a polyfunctional comonomer. The effect was investigated of amount of comonomer on the properties of coating latex, such as mechanical properties, solvent resistance, Tg, and surface morphology of polymer. The particle size, size distribution, and the dispersion stability were also measured. Comparisons of the product were carried out with some coatings available from the market.     

The Correlation between Density and Low-Temperature Creep Property of Asphalt

The density of asphalt was measured with the pycnometer and densitometer. Creep properties of the asphalt were investigated with the bending beam rheometer at temperatures ranging from 0 ℃ to -36 ℃. The asphalt density data used to correlate with the creep properties were calculated from the regression equation of density and temperature. The asphalt sample used to determine the creep property was aged by the standard RTFOT test and the PAV test. The test results showed that the asphalt density had a linear relationship with temperature changes. The logarithm of the creep stiffness and the slope of the logarithm of the stiffness at 60 seconds all demonstrated a linear relationship with the density, and the regression coefficient of these data was around 0.99. The creep stiffness and the slope of the creep stiffness can be calculated from the asphalt density at the same temperature.     

低温氩等离子体改善PTT织物吸湿性的研究

用氩低温等离子体对PTT织物进行表面改性,以提高PTT织物的吸湿性能。在不同等离子体处理工作参数(放电功率、放电时间、工作气压)下对PTT织物吸湿性变化进行了规律性和原理分析,并探讨等离子体对PTT织物的最佳处理工艺。实验结果表明:放电时间5min、放电功率200W、气体压强50Pa的处理条件使PTT织物得到最佳的吸湿性能;PTT织物的微观表面出现了明显的凹坑和裂纹,同时强力变化较小。     

钛精矿的流态化高温碳化低温氯化生产四氯化钛

以钛精矿、碳和Cl2为原料,采用流态化的生产技术,通过气流加热碳使碳的比表面积大于20m2/g,把非多孔型无烟煤在流化床中与空气在500～600℃的高温下进行处理,直到形成多孔状,以380～400℃的低温的条件下,同样用流化床将钛精矿与碳进行100:30的混料后与氯气反应,能够实现四氯化钛(TiCl4)的制备。该方法解决了原料中CaO和MgO在床层中大量积累,并导致沟流出现,破坏流化状态,既避免沸腾氯化对原料的苛刻的要求,也解决了H2SO4法生产的废液环保问题。为解决攀枝花高钙、镁的钛资源利用提供了一个可行的途径。     

Ferroelectric SrBi 2 Nb 2 O 9 Thin Films by Aqueous Chemical Solution Deposition

SrBi 2 Nb 2 O 9 (SBN) thin films on a Pt/Ti/SiO 2 /Si substrate were prepared by aqueous chemical solution deposition. The precursor solution was synthesized by means of an 'aqueous solution-gel method', starting with stable, inexpensive and easily available inorganic salts which are dissolved in an aqueous solution of chelating or coordinating ligands (acetates and citrates). Afterwards the synthesized precursor was spin-coated. However, problems arose as a consequence of insufficient 'wetting' of the substrate surface by the aqueous solution (poor film-substrate adhesion). Instead of improving surface adhesion by the addition of a surface-wetting reagent, a new strategy was developed: prior to spin-coating the platinum surface characteristics were modified using a UV/ozone technique. In this way the precursor solution was not chemically changed. Wetting/wettability was verified by means of contact angle measurements. A uniform, three-layer thin film with a total thickness of about 200 nm was obtained after thermal treatment, as could be verified using SEM and XRD.     

发热电缆低温辐射供暖技术的应用

结合具体工程实例,阐述了发热电缆低温辐射供暖技术的应用,从该供暖方案的选择、工作机理及施工要点等几方面进行了探讨,强调了该供暖方案的施工要点,并进行了综合效益分析,最后提出了该供暖技术存在的问题,以推广该技术的应用。     

低温下用J_R曲线确定金属材料延性断裂韧度J_(IC)的研究

以石油天然气设备及机器中常用的几种中、低强度钢为代表,通过弹塑性断裂力学J积分试验,研究了在低温环境下如何用J积分阻力曲线(J_R曲线)和裂纹尖端钝化线确定金属材料低温延性断裂韧度J_(IC)值,结果表明,该方法能得到J_(IC)随温度降低而降低的规律,适合于工程应用。