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61.
李剑敏  陈志红 《应用化工》2006,35(6):407-409
制备了一种含Zn2+、Mn2+、N i2+三系离子的LC-1磷化液,通过硫酸铜点滴、氯化钠浸蚀、SEM等手段对磷化膜进行了测试,测定了磷化温度、磷化时间对膜层耐蚀性的影响。结果表明,在磷化温度大于65℃,磷化时间大于10 m in的条件下,所形成的磷化膜结晶均匀、致密、黑褐色,耐蚀性良好。LC-1三系磷化液可适用于大批量钢铁工件的磷化生产。  相似文献   
62.
利用差示扫描量热仪研究了丙烯酸接枝线形低密度聚乙烯(PE-LLD-g-AA)的热学行为,结果表明,与纯线形低密度聚乙烯(PE—LLD)相比,PE-LLD-g-AA的熔融温度(Tm)略有增加,结晶温度(Tc)增加大约4℃,熔融焓(AHm)随AA含量的增加而降低。还利用差示扫描量热仪研究了PE—LLD和PE—LLD-g—AA的等温结晶动力学,用扫描电子显微镜观察了PE—LLD-g—AA等温结晶形态。结果表明,PE-LLD-g-AA的结晶速率大于纯PE—LLD的,随着接枝率的增加,PE-LLD的球晶半径减小,接枝到PE—LLD分子链上的AA分子起到了成核剂的作用。  相似文献   
63.
In order to supplement the literature data on VLE, isobaric bubble temperature data were collected for the binary systems phenol-i-amyl alcohol and phenol-n-amyl alcohol over the entire composition range by indirect method using a standard Swietoslawski type ebulliometer. The measurements were made at three sub-atmospheric pressures. The experimental t-x data were correlated with both equation of state method and gamma-phi methods. In the former approach, the Soave equation of state is used, whereas in the latter case Wilson, NRTL and UNIQUAC equations are used.  相似文献   
64.
The bioreactor system to interesterify edible oils and fats at an ultra-micro aqueous phase of 100 ppm and less was investigated. The adsorption of lecithin, together with lipase onto a carrier, was effective for conducting the interesterifying reaction efficiently for oils and fats in micro aqueous phase. To improve the handling properties of palm oil at rather low temperature, palm oil was blended with canola or soybean oil, and then these blended oils were modified by enzymatic selective interesterification in a solvent-free, ultra-micro aqueous bioreactor system with an immobilized lipase that had 1,3-positional specificity. The effects of enzymatic interesterification were confirmed by triglyceride determination, by solid fat content profiles and by cloud point profiles, which were also compared to products of chemical interesterification. The improvement in the fluidity of blended oils with canola oil by the enzymatic reaction was bigger than with soybean oil, and chemical interesterification had no effects on the fluidity of blended oils.  相似文献   
65.
电子陶瓷和器件的低温共烧技术   总被引:1,自引:0,他引:1  
较系统地介绍了电子器件用低温共烧陶瓷(low temperature cofired ceramics,LTCCs)材料,探讨了其工艺中的若干问题。电子器件用低温共烧陶瓷材料包括:玻璃/陶瓷复合材料、结晶化玻璃、晶化玻璃/陶瓷复合材料以及液相烧结陶瓷,其中典型的和最为常用的LTCCs为玻璃/陶瓷(特别是氧化铝)复合材料。正在研究的一些陶瓷介质材料中,Bi基介质材料引起了人们的关注。玻璃/陶瓷复合材料的制备工艺中,应当着重关注和加深了解玻璃的流动性和结晶性、玻璃的起泡、玻璃和陶瓷颗粒间的反应、共烧材料的匹配等问题,从优选材料配方和优化工艺着手,从而获得优质可靠的材质和器件。  相似文献   
66.
Gérald Guérin 《Polymer》2003,44(24):7477-7484
The bonding of polystyrene (PS) surfaces below Tg was investigated by two different fracture tests: the lap-shear joint method and the cantilever beam method. Adhesion energy values obtained by the two methods are in agreement and develop with (time)1/2, at temperatures as low as Tg−16 °C. Even if the double cantilever method is the most common test found in the literature for adhesions above Tg, for low adhesion values, below Tg, the lap-shear joint geometry is more appropriate. Moreover, when the glass transition temperature is used as a reference temperature, polydisperse and monodisperse PS adhesion energy curves are superposable, suggesting that the auto-adhesion is not significantly favored by the presence of numerous chain ends at the surface (due to the low molecular weight chains provided by the polydisperse PS).  相似文献   
67.
试验温度和停放时间对胶料加工性能的影响   总被引:1,自引:0,他引:1       下载免费PDF全文
丁萍萍 《轮胎工业》2004,24(8):497-499
研究试验温度和停放时间对胶料加工性能的影响。结果表明,试验温度对胶料的门尼粘度、门尼焦烧时间和硫化特性均有一定影响。门尼粘度测定的试验温度选择100℃;门尼焦烧时间测定的试验温度一般选120℃,SBR胶料可提高至130℃左右,以缩短试验时间;硫化特性测定的试验温度一般选185℃。试验前模腔达到规定温度后再保持15min,以使转子与模腔温度一致。胶料停放时间应控制在2h左右。  相似文献   
68.
Temperature programmed reduction (TPR) and oxidation (TPO) are used extensively in catalyst characterisation. In this paper, we examine the use of TPR/TPO cycles for the characterisation of a range of molybdates and single oxides. In particular we observe that the first cycle differs from that of subsequent analyses, even when the maximum temperature is limited to that used in the catalytic reaction. The effect is independent of heating rates and cooling atmospheres and has been demonstrated using different bed configurations. This observation has significance when these oxides are used in periodic flow reactors that involve many cyclical reduction/oxidation.  相似文献   
69.
High pressure microdilatometer experiments were performed on a subbituminous (Wyodak) and a bituminous (Illinois no. 6) coal in helium and hydrogen atmospheres with and without added tetralin. Wyodak coal samples showed no swelling but contractions ranging between 24 and 40 vol% upon heating at 20 and 100 °C min− 1 under helium or hydrogen pressures between 150 and 1000 psig (˜1.0–6.9 MPa). Under the same conditions, Illinois no. 6 coals displayed contractions (25–60 vol%) prior to swelling up to 117 vol%. Upon tetralin addition (at 35–190 wt% of the coal), Wyodak coal samples did not swell but showed an increasing contraction with increasing helium or hydrogen pressure due to a slight softening and fusion of the coal particles. In contrast, addition of tetralin at much lower concentrations (5–35 wt%) had a marked effect on the contraction and swelling behaviour of Illinois no. 6. A maximum swelling of 200 vol% was obtained at a tetralin addition of 30 wt%. The increased swelling results from more extensive softening and fusion of coal particles in the presence of tetralin. Both coals showed a decreasing char yield with increasing tetralin concentration. The substantially lower extent of interaction observed between Wyodak coal samples and tetralin compared to Illinois no. 6 coal can be attributed to the differences in pore structure and/or chemical constitution of the two coal samples. Examination of the resultant solids by optical microscopy revealed the microstructural changes produced by thermal treatment in dilatometer experiments.  相似文献   
70.
Joseph Berger 《Polymer》1984,25(11):1629-1632
New light-sensitive polymers were prepared by modification of four different elastomers with 4-(N-dimethylmaleimido)-benzenesulphenyl chloride (DMI-BSCI). Polydienes modified by DMI-BSCI form block copolymers. These polymers show a strong increase of the glass transition temperature Tg whereby the Tg increase of modified poly(octenamer) is much smaller. Higher modified polydienes have two Tg. Modified poly(octenamers) show a melting temperature dependence Tm on the content of trans double bonds which is characteristic of statistical copolymers. The ratio of rate constants with which trans- and cis-structures in poly(octenamer) are occupied by DMI-BSCI, is
ktranskcis = 0.34
  相似文献   
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