共查询到20条相似文献,搜索用时 125 毫秒
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沈英 《精细化工原料及中间体》2014,(3)
正本发明涉及一种氢溴酸普拉格雷醋酸化合物的合成方法。以普拉格雷为中间体,将普拉格雷和水混合搅拌,得悬浊液,然后与氢溴酸和醋酸反应,加入有机溶剂,析出固体,干燥,即得,或者,以氢溴酸普拉格雷为中间体,将氢溴酸普拉格雷和水混合搅拌,得悬浊液,然后和醋酸反应,加入有机溶剂,析出固体,干燥,即得。本发明采用水作为溶剂,更加环保,节能,而且本发明步骤简单,得到的产物纯度高,生产成本低,可工业化生产。公开号:CN103450219A 相似文献
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晚清以来碑学大兴,大篆名家辈出,吴昌硕结体长方,左低右高,取斜势,陶博吾书自石鼓,自得天成,放逸随意,破石鼓文之匀雅,变而奇崛峭拔。大篆取向多样,吸引着学人为之研究,近人罗振玉、丁辅之、董作宾诸人均在此处取得了可贵的成就,张云龙先生所书的大篆有独到之处,《石鼓文》之外,兼擅《散氏盘》、《毛公鼎》、琅邪刻石等,于秦砖汉瓦自有天机处,别开新境。大篆是以形为上,云龙先生取钟鼎之浑圆,玉筋之婉通,或取诏版之方折,不拘泥于原形勾画。其大篆的线条自成一相,方圆错落有致,章法布白高妙,静中有动,动中有静,字距参差有致,行距疏宕有韵,别具生机。 相似文献
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改革开放以来,我国橡胶工业的发展速度是前所未有的,其间有许多成功的经验,特别是入世后,在上世纪末全行业整体亏损的不利情况下,大家认识一致,认真对待,风雨同舟,趋利避害,经受住了考验,不仅行业经济全面复苏,而且取得新的发展。当前,全行业面对的是新一轮的竞争,而且更为激烈 相似文献
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以硫酸氢钠为催化剂,乙酸与乙醇为原料合成了乙酸乙酯,讨论了酸醇物质的量比、催化剂用量、反应时间、带水剂等因素对酯化率的影响,确定了最佳工艺条件为:以0.2mol乙醇为基准,酸醇物质的量比为1.5∶1,催化剂用量为1.5g,反应时间为2h,带水剂环己烷为10mL,乙酸乙酯的酯化率为85.2%.该催化剂具有催化效果好,使用量少,酯化率高,能够重复使用,环境污染小,腐蚀性小,价格低廉易得等特点,是一种很有发展前景的催化剂. 相似文献
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《中国耐火材料》2015,(1):72-74
<正>Sinosteel Luoyang Institute of Refractories Research Co.,Ltd.(LIRR)is a science and technology enterprise affiliated to Sinosteel Corporation,China.LIRR,established in 1963,is the only large integrated research institute and the center of technology,science,information and services in refractories industry.Its business scope covers refractory products,testing equipment,processing tools,project design,consultation and turnkey,domestic and foreign trade,products quality inspection,information service,etc. 相似文献
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《聚氨酯》2014,(7)
<正>一、市场行情简述本月行情:本月AA市场窄幅整理,月初,海力公布挂牌,受到上游原料纯苯强势走势影响,上调500元/吨,对外执行11,500元/吨,贸易商心态得到提振,纷纷上调报盘,刺激下游接货,但端午节后归市下游惯性观望,交投有限,中旬时期,随着下游进入传统行业淡季,需求明显萎缩,贸易商报盘坚挺,但实则成交重心暗降,随着明稳暗降操作,场内低价货源陆续增多,下游采购谨慎,临近月末,上游原料纯苯挂牌上调300元/吨,强势震荡影响市场操作积极性,海力又公布了6月结算价格,对外执行11,500元/吨,提振持货商心态,但实盘成交寥寥,下游需求跟进滞缓。上游原料: 相似文献
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硫磺别名硫、胶体硫、硫黄块,外观为淡黄色脆性结晶或粉末,有特殊臭味.分子量为32.06,蒸汽压是0.13 kPa,闪点为207℃,熔点为119℃,沸点为444.6℃,比重、熔点及其在二硫化碳中的溶解度均因晶体不同而异,工业硫磺呈黄色或淡黄色,有块状、粉状、粒状或片状等.块状硫磺为淡黄色块状结晶体,粉末为淡黄色粉末,能溶于二硫化碳、四氯化碳和苯,不溶于水. 相似文献
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H. Woltman 《Color research and application》1982,7(3):247-251
A half-century ago retroreflective glass buttons were formally approved to improve the nighttime visibility of highway signs. The development of flexible retroreflective sheetings dates from the late 1930s, and these unique materials permitted the uniform color coding of warning, regulatory, and informational signs. Color coding has contributed to more rapid comprehension and the transmission of fairly complex information. The success of the signing system at night depends on sign brightness, size, and on the natural background against which the driver must see the sign. Research on signing materials is providing improved brightness, while greater understanding of our dependence on the nighttime environment is leading to attempts at characterizing this important variable. The subsequent adjustment of sign luminance will provide traffic signs that more satisfactorily match driver needs. 相似文献
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Anna Cherepanova Evgeniy Savel'ev Leila Alieva Irina Kuznetsova Valentin Sapunov 《Journal of the American Oil Chemists' Society》2020,97(11):1265-1272
The current work has shown the potentials for the aerobic oxidation of fatty acid methyl ester (FAME) of vegetable oils in the production of polyvinylchloride (PVC) plasticizers with the exclusion of other reagents. The reaction mixtures contain epoxidized derivatives of FAME, and esters, with the quantity of the ester groups being higher than in the initial raw material. It was established that the increase in the additional ester groups resulting from the “aerobic” Baeyer-Villiger (BV) reaction has a significantly positive influence on the plasticizing ability of the oxidized FAME mixtures for PVC when compared to the formation of epoxide compounds. The development of the technology for the production of PVC plasticizers proposed in this investigation provides an opportunity for resolving some of the environmental issues normally associated with the use of phthalate-based plasticizers. 相似文献
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Composites based on PVC were compounded with 5% of montmorillonite and 10% of PMMA. Two types of reinforcement were studied, which included a purified sodium montmorillonite and a montmorillonite organically modified with an alkylammonium chloride. The composites were compounded with a Gelimat type thermokinetic mixer and were ejected at a maximum temperature of 180°C. The organically modified montmorillonite discolored the PVC, result which was interpreted as a sign of chemical degradation caused by the alkylammonium modifier. The composite made with 5% of purified montmorillonite and 10 of % PMMA displayed the best overall properties. The most important improvement was obtained on flexural strain at break (0.097–0.175 mm/mm) and maximum flexural strength (62–76 MPa). The HDT increased by up to 8°C. Dynamic mechanical analysis showed that 10% of PMMA in PVC moved the tan δ peak to temperatures 5–6°C higher. The PMMA was completely miscible in PVC and played an important role in the montmorillonite dispersion, as observed by XRD and SEM analysis. It also contributed to the overall increase in properties of PVC/PMMA/montmorillonite composites. J. VINYL ADDIT. TECHNOL., 13:91–97, 2007. © 2007 Society of Plastics Engineers. 相似文献
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Mixtures of a series of polymethacrylates and polyacrylates with PVC were prepared by solvent casting from methyl ethyl ketone. Some mixtures were also prepared by mechanical mixing and in situ polymerization (polymerization of vinyl chloride monomer in the presence of the other polymer). The mixtures were assessed for compatibility by dynamic mechanical measurements and optical clarity. It was found that all polymethacrylates from poly(methyl methacrylate) to poly(n-hexyl methacrylate) were compatible with PVC as were poly(n-propyl acrylate) and poly(n-butyl acrylate). Higher chain polyacrylates are incompatible. Poly(methyl acrylate) and poly(ethyl acrylate) appear incompatible with PVC when mixtures are prepared by solvent casting, but compatible when prepared by in situ polymerization, and mechanical mixtures show some sign of compatibility. It seems possible that in this case the solvent interferes with the compatibility. Mixtures of PVC with poly(n-hexyl methacrylate), poly(n-butyl acrylate) and poly(n-propyl acrylate) phase separate when heated in the region between 100°C and 160°C indicating the existence of a lower critical solution temperature. 相似文献
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桥梁伸缩缝过渡区混凝土性能的优劣不仅对桥梁伸缩缝结构服役性能有着重要的影响,且对行车安全有着直接的影响.首先简要介绍了公路桥梁伸缩缝过渡区混凝土病害的产生机理.然后综合评述了国内外近年来有关公路桥梁伸缩缝过渡区混凝土修复结构和修复材料等最新研究应用成果.最后根据功能/结构一体化设计理念,建立了一种基于功能梯度组合结构设计的超高韧性混凝土快速修复技术,并探讨了其在实际工程中的应用.工程实践表明:这种基于功能梯度组合结构设计的新型快速修复技术实施效果良好,具有广阔的推广应用前景. 相似文献
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Jim Romeo 《Plastics Engineering》2018,74(8):22-27
“One day your car may speed along an electric super‐highway, its speed and steering automatically controlled by electronic devices embedded in the road. Highways will be made safe—by electricity! No traffic jams … no collisions … no driver fatigue.” 相似文献
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我国路面标线涂料的现状与展望 总被引:1,自引:0,他引:1
本文论述了我国路面标线涂料的发展现状,对比国外近年来的发展,阐述了我国路面标线涂料在质量、产量及应用技术等方面存在的差距,旨在唤起我国标线涂料生产及应用部门,尽快地适应公路建设的需要。 相似文献
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重交通道路石油沥青是一种以原油为原料,经过各种工艺生产的适用于修建重交通道路的石油产品.产品适用于修建高速公路、一级公路和城市快速路、主干路等重交通量道路,也适用于其它各等级公路、城市道路、机场路面等. 相似文献