大粒径透水性沥青混合料水稳定性能对比研究

针对不同沥青用量的大粒径透水性沥青混合料(LSPM-30)进行了常规的浸水马歇尔试验、真空饱水马歇尔试验及冻融劈裂试验,结果表明:存在一个最佳的沥青用量,该沥青用量使得LSPM-30沥青混合料的残留稳定度和残留强度比达到最大值;浸水马歇尔试验和冻融劈裂试验对于评价LSPM-30沥青混合料的水稳定性有一定局限性.采用汉堡车辙试验对比分析了LSPM-30,OGFC-16,SMA-13,AC-251这4种沥青混合料的水稳定性,结果表明:LSPM-30,OGFC-16,SMA-13这些骨架嵌挤型的沥青混合料有较好的水稳定性;汉堡车辙试验较适于用来评价LSPM-30的水稳定性.     

骨架密实型沥青混合料集料的分形特征

为了分析和利用骨架密实型沥青混合料集料分形特征,基于分形几何的基本理论,推导出了集料的质量分布分形几何模型,并以SMA-16混合料为例,探讨了集料分维值(D)的最小计算粒径;结合SMA-16混合料体积参数的测试结果,研究了分形维数与体积参数的关系.结果表明:对于SMA-16混合料,分维值的最小计算粒径为0.6 mm;规范级配范围对应的分维值为2.355～2.457;分维值越大,混合料级配越细;分维值与空隙率、矿料间隙率、沥青饱和度等混合料体积参数有很好的线性相关性.     

Global phase behavior of imidazolium ionic liquids and compressed 1,1,1,2‐tetrafluoroethane (R‐134a)

Novel processes involving ionic liquids with refrigerant gases have recently been developed. Here, the complete global phase behavior has been measured for the refrigerant gas, 1,1,1,2‐tetrafluoroethane (R‐134a) and 1‐n‐alkyl‐3‐methyl‐imidazolium ionic liquids with the anions hexafluorophosphate [PF₆], tetrafluoroborate [BF₄] and bis(trifluoromethylsulfonyl)imide [Tf₂N] from ～0°C to 105°C and to 33 MPa. All of the systems studied were Type V from the classification scheme of Scott‐van Konynenburg with regions of vapor‐liquid equilibrium, miscible/critical regions, vapor‐liquid‐liquid equilibrium, and upper and lower critical endpoints (UCEP and LCEP). The effect of the alkyl chain length has been investigated, for ethyl‐([EMIm]), n‐butyl‐([BMIm]), and n‐hexyl‐([HMIm]). With increasing chain length, the temperature of the lower critical end points increases and pressure at the mixture critical points decrease. With a common cation, the temperature of the LCEP increased and the mixture critical point pressures decreased in the order of [BF₄], [PF₆], and [Tf₂N]. © 2008 American Institute of Chemical Engineers AIChE J, 2009     

Electrooxidation of methanol and 2-propanol mixtures at platinum single crystal electrodes

In the present work the electrooxidation of methanol, 2-propanol and different mixtures of both alcohols has been studied on the three platinum basal planes in three different electrolytes (H₂SO₄, HClO₄ and NaOH). The results indicate that, like in the case of both individual alcohols, the electrooxidation of the mixture is a structure sensitive reaction and that Pt(1 1 1) leads to higher current densities for some mixture compositions as compared to what could be expected from the contribution of the individual compounds. The effect of the methanol concentration in the mixture points out that 2-propanol is the main reacting fuel at the Pt(1 1 1) surface. Interestingly, the addition of methanol clearly has a positive effect on 2-propanol oxidation. For a specific mixture composition, while results from cyclic voltammetry indicate a modest twofold increase in current density, chronoamperometric results after 10 min experiment show a nearly 200 times higher current density. IR experiments have been performed to gain information about the enhancement mechanism. Nevertheless, we have found that both methanol and 2-propanol seem to follow the same mechanism as they follow in the absence of the other alcohol, and therefore the enhancement could be probably related to a competitive adsorption for the active surface sites.     

Resolving the unresolved complex mixture in motor oils using high-performance liquid chromatography followed by comprehensive two-dimensional gas chromatography

High-performance liquid chromatography (HPLC) followed by comprehensive two-dimensional gas chromatography (GC×GC) was used for detailed group-type characterization of hydrocarbons present in motor oils. With conventional GC, motor oil is not well separated due to its complexity, resulting in a “hump” in the chromatogram: the unresolved complex mixture (UCM). With HPLC-GC×GC, motor oil hydrocarbons can be quantitatively separated into four major groups: alkanes, cycloalkanes, alkenes and aromatics. Each group can be further separated and divided by ring number or carbon number. Three selected motor oil samples were characterized by HPLC-GC×GC including two conventional motor oils and a synthetic motor oil. Using a proprietary silver-modified HPLC column, the aromatic components in motor oils were baseline separated from the aliphatic UCM and were then further separated by GC×GC based on their aromatic ring numbers. Accordingly, the aliphatic components were separated by GC×GC based on their saturated ring numbers. This paper illustrates the capabilities of HPLC-GC×GC for reliable and detailed quantitative group-type characterization of hydrocarbons present in motor oils.     

沥青混合料渗透性试验分析

通过对渗透性试验结果的分析,论证了沥青混合料的渗透性对沥青路面水损害的影响,并从渗透性的角度,提出加强沥青混合料抗水损害性能的方法。     

高性能混凝土干燥收缩规律研究

收缩是非荷载作用下引起混凝土裂缝最常见的因素。水泥混凝土收缩是因内部水分迁移和水化消耗水分,其收缩率与水分损失率不是直接线性关系。对高性能混凝土的试验方法、配合比及其收缩特性进行研究,并提出了收缩模型。     

混合杀菌剂对两种橡胶叶斑病的联合作用研究

采用交叉滤纸条法,对橡胶炭疽病和棒孢霉叶斑病菌进行杀菌剂混用联合毒力研究。结果表明,9种杀菌剂共14个不同的混用组合中,大多数混用表现为相加作用;嘧菌酯和百菌清、抑霉唑和百菌清、溴菌腈和百菌清、腈菌唑与代森锰锌4个组合表现增效作用;而抑霉唑和代森锰锌的混用则表现出明显的拮抗作用。根据对抑菌带的分析,咪鲜胺对两种病菌的抑菌效果均为最高,其次是腈菌唑、抑霉唑和溴菌腈。     

改造传统高浓度制浆工艺的生产实践

阐述了15万t/a传统高浓度制浆工艺改造用神华煤生产水煤浆所采取的工艺技术、改造内容、运行结果等。改造后连续稳定的生产实践证明,神华煤制水煤浆工艺技术是完全可行的,并为中国传统水煤浆工艺的发展提供了一个方向。     

硅藻精土改性沥青混合料的应用机理和经济性

通过对硅藻精土结构及物理化学特征的分析,探讨了硅藻精土增强沥青混合料高、低温和水稳定性能的机理,同时对其工程应用的经济性进行了分析,为硅藻精土作为新型改性剂的推广应用提供了理论依据和经济性参考。