Production of Lower Olefins with Highly Dispersed Ru Catalysts Supported on Al-SBA-15 in Fischer–Tropsch Synthesis

The highly dispersed Ru catalysts supported on Al-SBA-15 with different Al/Si ratios were prepared by the “two solvent technique” and tested in Fischer–Tropsch synthesis. TEM and N₂ adsorption–desorption results illustrated that Ru crystallites were uniformly embedded inside the pore channels. XRD, hydrogen temperature programmed desorption and O₂ titration results showed that the dispersion of Ru increased with the increasing Al/Si ratio. The XPS results indicated that the interaction between Ru and the supports was a function of Ru dispersion, a stronger metal-support interaction was found in the catalyst with higher Ru dispersion. The selectivity of olefins was increased by increasing Ru dispersion. When the dispersion reached 86 %, this tendency was more pronounced and the selectivity of C₂–C₄ hydrocarbons remarkably increased to 27.0 %, with very high percentage of olefins (62.7 %).     

2-丙烯酰胺基-2-甲基丙磺酸/马来酸酐/丙烯酸甲酯共聚物阻垢特性的研究

以马来酸酐(MAH)、丙烯酸甲酯(MA)和2-丙烯酰胺基-2-甲基丙磺酸(AMPS)三种单体为原料,以过硫酸铵和次亚磷酸钠为引发剂,合成阻垢效果最佳聚丙烯酸类共聚物。并对阻垢效果最佳聚合物工作条件依赖性的实验表明:阻垢效果最佳聚合物在低投加量时阻碳酸钙垢、硫酸钙垢和磷酸钙垢的效果优异,且在p H≤9.5的情况下,阻垢性能良好。     

预拌混凝土和高性能混凝土技术的现状与发展

“九五”期间预拌混凝土的发展目标是：在全国范围内健康有序地发展预拌混凝土，年产量要从“八五”末期占全国现浇混凝土总产量比重的１０％增加到２０％。高性能混凝土是近代工程发展的需要，其性能指标应满足强度、工作性和耐久性三项基本要求，并应根据工程的特殊要求，具有某种特殊性能，目前我国已有条件在不同用途上采用。     

两性聚丙烯酰胺提高纸张强度的研究

介绍了以实验室合成的两性聚丙烯酰胺树脂（APAMR）作为造纸增强剂的作用效果和机理，实验结果表明：在麦草浆中添加0．45％的两性聚丙烯酰胺树脂，可使纸张的裂断长提高12．9％，耐破指数提高16．2％，留着率提高18．5％。     

Risk Analysis and Solution Recommendations on Uranium Supply forNuclear Power in China

The Chinese government has set ambitious goals for the development of nuclear power, which is under the risks from uranium supply shortage. The supply and demand of uranium resources both domestically and abroad is firstly analyzed in the paper. The supply can still meet the demand in the short run, but the risk of shortage may exist in the long run. Moreover, the lack of uranium resources will exist globally no matter at present or in the future. Therefore, the main factor restraining the nuclear power development in China is the short supply of uranium. Finally, recommendations are put forward such as strengthening the exploration and production of domestic uranium, cooperating with foreign enterprises in the exploration of uranium mines, building the reserves, and proactively developing the fourth generation of nuclear power technology and so on.     

雷达调平误差曲线的谐波分析

基于雷达天线座的调平误差曲线随方位转角按正弦规律变化,利用傅里叶级数对调平误差曲线进行谐波分析,提出调平误差曲线谐波分析法在调平、晃动量计算中的应用。     

电子束重熔对熔丝沉积钛合金表面组织及性能的影响

目的 通过表面重熔处理解决沉积钛合金固有组织引起的表面磨损不均及摩擦不稳定的难题,以拓宽沉积钛合金的应用领域。方法 采用电子束重熔工艺对熔丝沉积Ti6Al4V钛合金表面进行改性处理。利用体式显微镜、光学显微镜、X射线衍射仪等分析重熔前后钛合金表层的宏观形貌、显微组织及物相组成变化,运用纳米压痕仪及摩擦磨损试验机考察重熔层的表面纳米力学性能及耐磨性能,并采用三维光学轮廓仪及扫描电子显微镜观察磨损形貌特征。结果 经电子束重熔处理后,熔丝沉积钛合金沉积方向表面组织由不均匀的α+β组成的网篮组织及魏氏组织转变为均匀分布的细针状马氏体(α’)。重熔处理试样表面纳米硬度均匀,且得到明显提升,达3.8 GPa,相较于未重熔试样提高了15%以上,表现出较高的硬弹性。重熔层具有稳定的摩擦系数和较优的耐磨性,其平均摩擦系数为0.45,磨损率为3.59×10^-13 mm³/(N·m),相较于未重熔试样,分别降低了19.6%和22.1%,其磨损机理以磨粒磨损、氧化磨损及粘着磨损为主。结论 电子束重熔工艺能够有效改善熔丝沉积钛合金沉积方向的表面组织均匀性,可获得优异的...     

H形梁翼缘与端板非全熔透焊接的节点性能试验研究

对H形梁翼缘与端板分别采用全熔透焊接和非全熔透焊接的节点进行了对比试验。选择板件宽厚比、端板厚度、翼缘板与端板平面的夹角等设计参数,对24个试件进行了单调加载试验,6个试件进行了反复加载试验。试验结果表明:节点无一例发生焊缝破坏,焊缝形式对连接的最大荷载、翼缘近焊缝端应变以及滞回性能等无明显影响;在以局部屈曲为主要控制模式进行设计的轻型门式刚架中,无论对单调静力荷载还是反复荷载,H形梁翼缘与端板的连接都可采用非全熔透焊接。     

Effect of different pre-fermentation treatments on polyphenols,color, and volatile compounds of three wine varieties

Wines produced by three different grape varieties were treated with seven pre-fermentation techniques to analyze their variation in polyphenolic compounds, color parameters, and aromatic components. For polyphenolic compounds and color parameters, a better result was obtained after the grape pulp treatment, with the maximum impact observed after joint treatment with thermovinification and pectolytic enzymes, followed by thermovinification and cold soak, while pectolytic enzymes treatment alone was ineffective, resulting in almost no effect. On the contrary, the application of thermovinification and cold soak treatments before crushing the whole juice led to a dramatic decline in most indexes. For aromatic components, the joint treatment of thermovinification and pectolytic enzymes on grape pulp significantly affected its amount and type, in addition to giving the wine a mellow aroma.     

某铜矿露天转地下隔离矿柱的确定研究

露天转地下隔离矿柱的确定是露天转地下开采经常面临的重要问题,对于金属矿山地下安全生产极其重要。根据某铜矿的采矿工艺、开采深度以及工程地质条件,采用理论计算和FLAC3D有限差分法数值软件对不同厚度的隔离矿柱进行了模拟分析。结果表明,当隔离矿柱厚度为 20 m时,地下开挖导致的顶板变形较小且趋于平稳。20 m是该矿山隔离矿柱厚度的最优值,能够满足安全生产要求。该分析结果为露天转地下安全高效回采提供了理论依据和技术指导。