新型环氧灌封胶的研究

通过环氧树脂、增韧剂、固化剂及固化促进剂的筛选 ,完成了一种在 130℃下、剪切强度大于 10MPa、不开裂、韧性好的环氧树脂灌封胶的研制工作 ,同时介绍了该灌封胶的主要性能指标     

Effect of cobalt promoter on Co–Mo–K/C catalysts used for mixed alcohol synthesis

The structures of sulfided Co–Mo–K/C catalysts were studied by means of X-ray diffraction (XRD), laser Raman spectra (LRS), and X-ray absorption fine structure (XAFS). Activities for alcohol synthesis via CO hydrogenation were used to characterize the catalytic performance of these catalysts. On the activated carbon support, molybdenum is mainly present as MoS₂ species which shrinks with the cobalt loading, while cobalt is mainly present in the form of “Co–Mo–S” phase at the low Co loading and partly in a Co₉S₈-like structure at higher Co loading. The catalysts exhibit outstanding performance for higher alcohol synthesis due to the addition of the promotion of cobalt. The activity for alcohol formation is optimized at a Co/Mo atomic ratio of 0.5. Co species operate as a synergistic system, rather than independently from the MoS₂ phase.     

Impact of adhesive ingredients on adhesion between rubber and brass-plated steel wire in tire

Proficiency on underlying mechanism of rubber-metal adhesion has been increased significantly in the last few decades. Researchers have investigated the effect of various ingredients, such as hexamethoxymethyl melamine, resorcinol, cobalt stearate, and silica, on rubber-metal interface. The role of each ingredient on rubber-metal interfacial adhesion is still a subject of scrutiny. In this article, a typical belt skim compound of truck radial tire is selected and the effect of each adhesive ingredient on adhesion strength is explored. Out of these ingredients, the effect of cobalt stearate is found noteworthy. It has improved adhesion strength by 12% (without aging) and by 11% (humid-aged), respectively, over control compound. For detailed understanding of the effect of cobalt stearate on adhesion, scanning electron microscopy and energy dispersive spectroscopy are utilized to ascertain the rubber coverage and distribution of elements. X-ray photoelectron spectroscopy results helped us to understand the impact of Cu_XS layer depth on rubber-metal adhesion. The depth profile of the Cu_XS layer was found to be one of the dominant factors of rubber-metal adhesion retention. Thus, this study has made an attempt to find the impact of different adhesive ingredients on the formation of Cu_XS layer depth at rubber-metal interface and establish a correlation with adhesion strength simultaneously.     

稀土石膏常压酸化法制备硫酸钙晶须的研究

以含稀土的石膏为原料运用常压酸化法合成硫酸钙晶须,探讨了不同工艺条件对生成的硫酸钙晶须形貌的影响,同时还考察了晶型助长剂的种类和晶型助长剂的含量对硫酸钙晶须生长的影响,利用SEM和XRD分别对硫酸钙晶须的表面形貌、物相特征做了表征分析。实验得到制备硫酸钙晶须的最佳的反应条件：稀土石膏质量浓度为0.22 g/mL、反应时间为25 min、盐酸浓度为2.8 mol/L、反应温度为70 ℃、陈化时间为4 h,在此条件下合成的硫酸钙晶须平均长度为61 μm,平均长径比为30.5;通过对比实验选出了CuCl₂作为促进硫酸钙晶须生长的助长剂,在添加5%（质量分数）的CuCl₂的情况下可使硫酸钙晶须长径比从30.5增至41,长度从61 μm增至81 μm。     

GAP型交联改性双基推进剂黏合剂的力学性能

将GAP与异氰酸酯预聚后引入双基推进剂黏合剂中,研究了固化剂种类、R值、固化催化剂二月桂酸二丁基锡(T12)的含量和增塑比对黏合剂的交联网络结构参数RNB值和力学性能的影响。结果表明,随着R值以及(T12)含量的增大,黏合剂的RNB值增大。在与NC中活性-OH交联反应时,TDI的反应活性比IPDI的高。GAP-TDI/NC/NG胶片的最大抗拉强度和断裂延伸率分别可达1.09MPa和202.12%,Tg最低为-42.66℃。     

Lower Temperature Cultures Enlarge the Effects of Vitreoscilla Hemoglobin Expression on Recombinant Pichia pastoris

An heterologous expression of Vitreoscilla hemoglobin (VHb) for improving cell growth and recombinant protein production has been successfully demonstrated in various hosts, including Pichia pastoris. Lower temperature cultures can enhance target protein production in some studies of P. pastoris. In this study, the strategy of combining heterologous VHb expression and lower temperature cultures in P. pastoris showed that final cell density and viability of VHb⁺ strain at 23 °C were higher than that at 30 °C. In addition, the effects of VHb expression on recombinant β-galactosidase production and oxygen uptake rate were also higher at 23 °C than at 30 °C. Consequently, lower temperature cultures can enlarge VHb effectiveness on cell performance of P. pastoris. This is because VHb activity obtained at 23 °C cultures was twofold higher than that at 30 °C cultures, due to a different heme production. This strategy makes P. pastoris an excellent expression host particularly suitable for increasing the yields of the low-stability and aggregation-prone recombinant proteins.     

CO气相偶联合成草酸二甲酯催化剂的研制

考察助剂、制备方法和还原介质对CO气相偶联合成草酸二甲酯催化剂性能的影响。结果表明,以贵金属Pd为活性组分,非贵金属C为助剂,以α-Al_2O_3为载体,采用分步等体积浸渍法制备的催化剂,在水合肼还原后,具有良好的反应活性和稳定性。在反应温度130℃,空速3 000 h^(-1)时,产物中草酸二甲酯含量90%以上,时空收率平均可达813 g·(L·h)^(-1)。催化剂PC-3反应500 h后,物理性能和反应活性变化不大。     

SrO助催化剂对Fe1-xO基熔铁氨合成催化剂性能的影响

采用高温熔融法制备了不同SrO含量的Fe_{1- x} O基氨合成催化剂。在类似工业条件下（15MPa、30000h^-1）使用固定床反应器对催化剂进行了氨合成（氮的催化加氢）活性评价,并采用X射线能谱仪（EDS）、程序升温还原（H₂-TPR）、N₂程序升温脱附（N₂-TPD）、X射线粉末衍射（XRD）对样品进行表征。结果表明,随着SrO含量的增加,催化剂的活性先增加后降低,呈现出火山型活性变化趋势。当SrO质量分数为0.4%时,催化剂活性最高。SrO存在表面偏析现象,且SrO的添加并没有促进或明显抑制催化剂的还原。少量SrO的添加降低了N₂的解离活化能或降低了NH _x 物种的稳定性,提高了催化剂的活性;SrO含量进一步增加,覆盖了表面部分活性位,消耗了体相的重要结构助催化剂Al,降低了催化剂的活性和耐热性能。     

Advances in Infrared Spectroscopy of Catalytic Solid–Liquid Interfaces: The Case of Selective Alcohol Oxidation

Progress in the use of ATR-IR spectroscopy to improve the understanding of liquid-phase heterogeneous catalytic reactions is illustrated using the example of the oxidation of benzyl alcohol over Pd/Al₂O₃ and Bi–Pd/Al₂O₃. The in situ studies performed in both batch and continuous reactor cells provide rich information on the reaction pathway and important facets of the mechanism, such as the nature of active Pd sites and the effect of the Bi-promoter. The combination of CO site blocking prior to reaction and isotopic labeling suggests that alcohol dehydrogenation occurs uniformly over Pd nanoparticles, but only selected sites may allow desorption of the product benzaldehyde thus providing the required selectivity. Promotion of Pd/Al₂O₃ using bismuth produces infrared spectra free of adsorbed CO. This information demonstrates that Bi is deposited on selected adsorption sites (terraces rather than defects) and simultaneously confirms that open terraces favor product decomposition. Experiments performed in the continuous reactor cell using different catalyst film thickness show that reactions can be studied under kinetic or mass transfer limited conditions depending on catalyst film thickness. This allowed to study the alcohol oxidation under conditions of oxygen diffusion limitation, which are preferably applied in praxis in order to prevent catalyst deactivation by over-oxidation.