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1.
以煤焦油的蒽油馏分为原料,通过空气氧化热聚合及蒸馏处理制备蒽油基合成沥青。正交优化实验研究结果表明,反应温度310℃、反应时间7 h、空气流量0.6 L/min条件下,可以获得软化点53℃、甲苯不溶物12.0%、喹啉不溶物0.32%、结焦值35.3%的蒽油基合成沥青。蒽油基合成沥青的红外光谱表征(FTIR)分析表明,空气氧化热聚合过程中发生了脱氢氧化缩聚反应,生成了含氧基团。对比分析蒽油和合成沥青的TG/DTG结果,合成沥青的最大失重速率与蒽油相比降低了0.83 mg/min,最大失重速率时的温度升高了53℃。  相似文献   

2.
对三乙烯四胺与甲醛合成沥青抗剥离剂进行了研究;合成的产品,可使酸性石料与沥青的粘附等级达到4 ̄5级;通过红外谱图结构分析,表明产物中存在有-C=N-R基团。  相似文献   

3.
为了定量地评价粗集料排布在室内沥青混合料成型过程中的变化规律,利用数字图像处理技术,提出一种评价沥青混合料粗集料排布的合成质心矩方法.选取常用AC20,SMA20型沥青混合料,以控制两种混合料旋转压实次数为条件制成成型试件,横向切割获取截面采集图像进行参数提取.分别计算二维累计筛余粗集料和二维分计筛余粗集料的合成质心矩.结果表明两种不同类型的沥青混合料粗集料合成质心矩随压实次数增加发生不同的变化,SMA20压实60次排布性已达到较好水平.  相似文献   

4.
目的研究玻璃纤维对排水沥青混合料路用性能的改善效果,确定玻璃纤维掺量与排水沥青混合料路用性能的规律.方法利用马歇尔试验、间接拉伸试验以及冻融劈裂试验评价排水沥青混合料的高温稳定性、中低温抗裂性以及水稳定性.结果玻璃纤维掺量为0.2%时高黏排水沥青混合料高温稳定性较好,玻璃纤维掺量为0.4%时中低温抗裂性能和水稳定性能较好.基质排水沥青混合料中玻璃纤维掺量为0.2%时高温稳定性、中低温抗裂性以及水稳定性均达到最佳.结论掺加玻璃纤维可以显著提高排水沥青混合料的路用性能.玻璃纤维掺入改性排水沥青混合料具有明显的增强效果.  相似文献   

5.
炭材料是一种重要的功能和结构材料,能否保障炭材料制品质量的关键在于使用粘结剂性能的好坏,沥青树脂粘结剂因与炭素材料有良好的亲和性而倍受国内外学者的广泛关注.以中低温煤焦油沥青为原料,多聚甲醛为交联剂,对甲苯磺酸为催化剂合成沥青树脂.考察了合成条件对沥青树脂的软化点、结焦值和β树脂等指标的影响,采用FT-IR表征了沥青树脂的合成机理.研究结果表明,中低温煤焦油沥青与多聚甲醛发生了阳离子型缩聚反应,沥青树脂的软化点在136.2~177.3℃、结焦值在27.64%~38.05%、β树脂在22.79%~41.89%可以进行调控.  相似文献   

6.
采用N-氢化牛脂基-1,3-丙撑二胺、丙烯酸甲酯和氯乙酸钠(由氢氧化钠和氯乙酸制备)为原料,合成出3种双阳离子型沥青乳化剂.通过红外光谱、核磁共振和元素分析验证了合成的双阳离子型沥青乳化剂化学结构.这3种双阳离子型沥青乳化剂对重交90号(AH-90)沥青具有良好的乳化能力,乳化沥青有良好的储存稳定性,归属于中裂型、慢裂型沥青乳化剂.中裂型沥青乳化剂适用于粘层、雾封层和无溶剂冷拌以及用于沥青再回收利用和沥青路面基层稳定的施工.慢裂型沥青乳化剂可广泛应用于稀浆封层和微表处等施工.  相似文献   

7.
以工业一级对壬基酚(简称NP)与二乙醇胺为原料合成了1种阳离子沥青乳化剂,4种两性沥青乳化剂.通过红外光谱分析验证了最终产物的结构;采用化学滴定法测定了反应产物的有效成分含量.利用合成的沥青乳化剂制备出乳化沥青,并对乳化沥青的乳化效果、储存稳定性、拌和稳定度、标准黏度、沥青含量、筛上残留物、与粗集料的裹附性等项目进行了测试.结果表明,4种沥青乳化剂的乳化效果较好,其中1种可以作为中裂型沥青乳化剂使用,另外3种可以作为慢裂型沥青乳化剂使用.  相似文献   

8.
橡胶沥青混合料SAC-13级配空隙率变化分析   总被引:1,自引:0,他引:1  
在普通沥青的多碎石沥青混凝土(SAC)设计的基础上,以空隙率为研究变量,采用固定油石比,再微调级配的方式,深入对比了SAC-13级配变化的普通沥青和橡胶沥青混合料的空隙率影响规律.结果显示:对于普通SAC-13沥青混合料,油石比每增加0.5%,空隙率减小1%~1.5%,随着9.5~13.2mm粗集料含量增多,4.75~9.5mm粗集料含量减少,混合料粗集料间隙率呈递减之势;对SAC橡胶沥青混合料,建议9.5mm以上集料用量范围限定在30%~45%之间,4.75~9.5mm集料用量范围限定在20%~40%之间,且4.75mm以上粗集料总用量应达到60%以上,2.36~4.75mm集料含量不宜高于10%,且不宜使用过多矿粉;同样目标空隙率下,SAC-13橡胶沥青混合料的粗集料掺量应略低于普通沥青混合料;SAC-13橡胶沥青混合料中当2.36~4.75mm集料含量达到8%以后,随着该档料用量的增加,空隙率增幅明显高于普通沥青混合料,需严格控制此档料含量.  相似文献   

9.
针对我国对沥青面层施工碳排放缺少适用评价方法以至于无法有效约束施工中碳排放的问题,对我国多个地区共13条在建沥青路面开展碳排放调查与检测,建立能源燃烧碳排放和沥青高温分解碳排放计算公式;提出沥青面层施工碳排放评价量化分级标准,并运用主成分分析法确定碳减排关键工序,提出相应的碳减排措施.结果表明:沥青面层施工碳排放评价达到Ⅰ级、Ⅱ级、Ⅲ级和Ⅳ级的比率分别为15%、31%、46%和8%;碳减排关键工序为集料加热、沥青加热和沥青混合料碾压,集料加热和沥青加热工序的碳排放主要受原材料加热能源类型影响,沥青混合料碾压工序的碳排放主要受沥青类型影响.  相似文献   

10.
以十八烷基二甲基叔胺、环氧氯丙烷经一步反应合成出一种新型阳离子沥青乳化剂N,N-二甲基-N-(环氧乙烷-2-亚甲基)十八烷基-1-氯化铵.确定了该反应的最佳反应条件,在最佳反应条件下反应的产率和环氧值分别为98.0%和41.8%.利用红外光谱、1H NMR和元素分析对产物结构进行了表征,利用在线红外光谱技术对该反应进行了追踪分析,检测到副产物.基于以上实验数据,提出了合理的反应机理.该乳化剂对沥青具有很好的乳化能力,制备的乳化沥青储存稳定性良好,属于中裂型沥青乳化剂.  相似文献   

11.
Ramapithecines from China: evidence from tooth dimensions   总被引:1,自引:0,他引:1  
R K Wu  C E Oxnard 《Nature》1983,306(5940):258-260
Data obtained from ramapithecine specimens found in Asia, Africa and Europe have suggested the existence of two major subgroups, Ramapithecus and Sivapithecus, with Ramapithecus having pre-human status. Recently, however, it has been proposed that the fossils all belong to a single group, Sivapithecus, which is more closely related to the apes, in particular the orang-utan. Here we analyse data from a series of similar fossils which have been found in late Miocene coalfields in Lufeng, Yunnan Province, China. These include a number of almost complete jaws and five partial skulls which are more complete than any others so far known. A statistical analysis of the overall dimensions of the large number of teeth included in these finds shows that the differences between the groups previously assigned to Ramapithecus and Sivapithecus are greater than those found between the sexes in the most sexually dimorphic of the living great apes. Within the groups the distribution is bimodal and we suggest each group contains sex subgroups.  相似文献   

12.
在镧系金属氧化物载镍催化剂上通过催化重整乙醇和乙醇水溶液可以直接转化为H2,H2的选择性达到60%,乙醇的转化率达到100%。优化催化剂及降低重整反应的温度以使水汽转化反应同时发生来降低产物气中CO的含量。该过程对于生产小型燃料电池的低成本燃料H2,以及便携燃料电池系统需要液态燃料存储的应用具有巨大的潜在价值。  相似文献   

13.
14.
The Plio-Pleistocene site of Dmanisi, Georgia, has yielded a rich fossil and archaeological record documenting an early presence of the genus Homo outside Africa. Although the craniomandibular morphology of early Homo is well known as a result of finds from Dmanisi and African localities, data about its postcranial morphology are still relatively scarce. Here we describe newly excavated postcranial material from Dmanisi comprising a partial skeleton of an adolescent individual, associated with skull D2700/D2735, and the remains from three adult individuals. This material shows that the postcranial anatomy of the Dmanisi hominins has a surprising mosaic of primitive and derived features. The primitive features include a small body size, a low encephalization quotient and absence of humeral torsion; the derived features include modern-human-like body proportions and lower limb morphology indicative of the capability for long-distance travel. Thus, the earliest known hominins to have lived outside of Africa in the temperate zones of Eurasia did not yet display the full set of derived skeletal features.  相似文献   

15.
由鸡西烟煤制备炭分子筛的研究   总被引:2,自引:0,他引:2  
以鸡西烟煤为原料综合使用炭化法和碳沉积法进行了空气分离生产富氮空气用炭分子筛的制备研究,考虑了炭化和碳沉积工艺条件对产品空气分离性能的影响。结果表明,鸡西烟煤是制备炭分子筛的优良原料。最佳工艺条件为粘结剂用量35%,升温速度为10℃/min,炭化终温为900℃,恒温时间为60min。  相似文献   

16.
Greater contribution to blood lead from water than from air   总被引:3,自引:0,他引:3  
Concern about the levels of lead in blood is widespread. There is uncertainty, however, about the relative importance of the various environmental sources. Lead in petrol is widely assumed to be one of the most important sources and air and dust have been identified as the main routes to man. Water is regarded as an important source in areas with a plumbosolvent water supply, but of little or no importance in other areas. In order to evaluate the contribution to blood lead by various environmental sources, we have conducted surveys of random samples of women in areas of Wales chosen to represent very different levels of exposure to traffic. We report here that lead in air makes a small, but significant, contribution to blood lead but there is no evidence of any contribution from dust. Although in none of the areas were high levels of lead detected in water, water emerges as an important contributor to blood lead.  相似文献   

17.
Spratling FR 《Nature》1971,233(5314):73
  相似文献   

18.
Fire from ice     
Adam D 《Nature》2002,418(6901):913-914
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19.
Cornstarch heated in the range of 230–280°C depolymerized into pyrodextrins characterized by two-component EPR signals of relatively stable free radicals. These thermally generated radicals could serve as efficient scavengers for free radicals generated from pyrodextrins with the 200 Gy dose of γ-radiation. The most efficient traps/scavengers were produced from cornstarch at 250–280°C. IR data indicated incorporation of the OH groups to the pyrodextrins. These groups most probably originated from the OH· radicals formed by the radiolysis of water. EPR spectra provided evidence for trapping free radicals generated by γ-irradiation and for their subsequent annihilation on contact with pyrodextrins. Water affected radical processes occurring in pyrodextrins caused by γ-irradiation.  相似文献   

20.
Chapman T 《Nature》2004,430(6995):113
  相似文献   

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