Low temperature selective catalytic reduction of NO by C3H6 over Ce Ox loaded on AC treated by HNO3

The activated carbons from coal were treated by HNO3(named as NAC) and used as carriers to load 7% Ce(named as Ce(0.07)/NAC) by impregnation method. The physical and chemical properties were investigated by thermogravimetric-differential thermal analysis(TG-DTA), Brunauer-Emmett-Teller(BET), X-ray diffraction(XRD), X-ray photoelectron spectra(XPS), scanning electron microscopy(SEM) and NH3-temperature programmed desorption(NH3-TPD) and NO-temperature programmed desorption techniques. The catalytic activities of Ce(0.07)/NAC were evaluated for the low temperature selective catalytic reduction(SCR) of NO with C3H6 using temperature-programmed reaction(TP-reaction) in NO, C3H6, O2 and N2 as a balance. The results showed that the specific surface area of Ce(0.07)/NAC was 850.8 m2/g and less than NAC, but Ce oxides could be dispersed highly on the activated carbons. Ce oxides could change acid sites and NO adsorption as well as oxygen-containing functional groups of activated carbons, and Ce4+ and Ce3+ coexisted in catalysts. The conversion of NO with C3H6 achieved 70% at 280 °C over Ce(0.07)/NAC, but with the increase of O2 concentration, heat accumulation and nonselective combustion were exacerbated, which could cause surface ashing and roughness, resulting in a sharp decrease of catalytic activities. The optimum O2 concentration used in the reaction system was 3% and achieved the high conversion of NO and the widest temperature window. The conversion of NO was closely related to the NO concentrations and [NO]/[C3H6] ratios, and the stoichiometric number was just close to 2:1, but the presence of H2 O could affect the denitration efficiency of catalyst.     

动物源副产物胶原蛋白肽的制备及其在食品工业中的应用研究进展

在动物加工过程中会产生大量的副产品和废弃物,这些产品中富含生物活性蛋白质,可以通过化学处理或酶水解等方式转化为具有特殊生理功能的胶原蛋白肽。胶原蛋白具有一定的营养价值,但由于其分子质量较大,难以被人体消化吸收。而胶原蛋白肽分子质量较小,更容易被人体消化吸收,并且发现动物源副产物胶原蛋白肽具有许多特殊的生理功能,因此将胶原蛋白肽作为新型食品原材料成为近些年来的研究热点之一。本文综述动物源副产物胶原蛋白肽制备方式的优缺点,及胶原蛋白肽在人体中的消化吸收,同时介绍胶原蛋白肽在食品加工中的应用,为将来开发胶原蛋白肽新产品提供新思路。     

海水和矿物掺合料对硫铝酸盐水泥砂浆性能的影响

本文研究了不同拌和水以及海水拌和时粉煤灰和硅灰掺量对硫铝酸盐水泥(SAC)砂浆力学性能和表观孔隙率以及净浆凝结时间、化学收缩、孔溶液pH值和氯离子结合能力等的影响,并通过XRD、SEM和EDS分析水泥水化产物和微观结构。结果表明,海水能加快SAC早期水化并提高其早期强度,但后期强度和淡水拌和时无明显差别。粉煤灰和硅灰均会延长SAC凝结时间,对早期抗压强度不利,而掺加质量分数为5.0%和7.5%的硅灰能提高SAC砂浆28 d抗压强度。硅灰掺量增加时会提高用水量和表观孔隙率,降低流动性,使水泥化学收缩增大,降低净浆pH值且减少氯离子结合量;粉煤灰能够提高砂浆流动性,减少水泥化学收缩,但掺量越大对SAC砂浆抗压强度和抗折强度越不利,掺质量分数为10%的粉煤灰可小幅提高氯离子结合量且减小表观孔隙率。     

粉煤灰掺量对海水海砂高性能混凝土性能的影响

通过宏观力学性能、化学收缩、pH值、氯离子浓度等测试和SEM、XRD等微观表征研究粉煤灰掺量对海水海砂高性能混凝土性能的影响。结果表明:为维系钢筋钝化膜稳定,高温蒸养时粉煤灰掺量不宜大于30%(质量分数,下同),标养时粉煤灰掺量不宜大于50%;海水海砂高性能混凝土中游离Cl^-浓度随养护时间波动,前期先升高后骤降,后期缓慢增加,标养条件下Cl^-浓度明显低于高温蒸养条件下;海水海砂高性能混凝土具有早强性,其强度随粉煤灰掺量增加大致呈下降趋势,高温蒸养可明显提高混凝土抗折、抗压强度;粉煤灰掺量越多,残留的未水化颗粒越多,高温蒸养可有效改善混凝土微观结构,提高致密性;粉煤灰掺量过多或过少均会增加硅酸盐水泥体系的化学收缩,粉煤灰掺量为30%和40%时混凝土化学收缩值较小。     

融合模糊德尔菲法与结构方程模型的水冷机箱用户体验满意度研究

为提高产品设计的满意度,衡量产品评价因素对设计的重要性,准确获取用户需求,提升用户体验,提出模糊德尔菲法(Fuzzy Delphi Method, FDM)与结构方程模型(Structural Equation Model, SEM)相结合的评价方法;基于FDM筛选计算机水冷机箱评价指标因素,建立层级评价指标模型,并基于SEM提出假设,创建水冷机箱的用户满意度评价模型,得出标准化回归系数,分析各潜变量对用户满意度的影响,提出设计方案的改进意见。研究表明：该方法可减少设计评价中指标量化的主观性,帮助设计人员确定指标因素的优先级,明确设计重点,提升用户满意度,为产品设计方案的评选提供参考。     

电子对抗情报工作平战转换研究

电子对抗情报工作平战转换是电子对抗情报工作从平时状态转入战时状态的过程。分析了电子对抗情报工作平战转换问题产生的根本原因,以及面临的主要困难,并有针对性地提出了几点改进措施。