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早强型聚羧酸系减水剂对基准水泥早期水化的影响研究 被引量:4
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作者 黄伟 周佳敏 +4 位作者 衷从浩 麻秀星 方云辉 柯余良 韦建刚 《硅酸盐通报》 CAS 北大核心 2022年第4期1211-1221,共11页
探究早强型聚羧酸系减水剂(ES-PCE)对水泥水化的作用机制,有助于ES-PCE的研发设计与推广应用。本文通过对水泥水化进程、溶解速率、水化产物生长、凝结时间与抗压强度进行表征,分析了ES-PCE与普通聚羧酸系减水剂(PCE)对基准水泥早期水... 探究早强型聚羧酸系减水剂(ES-PCE)对水泥水化的作用机制,有助于ES-PCE的研发设计与推广应用。本文通过对水泥水化进程、溶解速率、水化产物生长、凝结时间与抗压强度进行表征,分析了ES-PCE与普通聚羧酸系减水剂(PCE)对基准水泥早期水化的影响机理。结果表明:PCE与ES-PCE均会降低水泥悬浮液的溶解速率;PCE的掺入延缓了水泥水化的诱导期与加速期,降低了水化放热量;而ES-PCE仅略微延迟了水泥水化的诱导期,但缩短了加速期,水化放热量基本不变。与基准水泥相比,ES-PCE分别提早了水泥初凝时间10 min和终凝时间85 min。ES-PCE的掺入提高了水泥早期和后期强度,掺0.2%(质量分数)ES-PCE的水泥7 d抗压强度较基准组提高了14%,而同掺量的PCE强度提高仅为前者的一半。PCE与ES-PCE的掺入释放了水泥颗粒团状絮凝结构中的水分,有利于水泥水化,但二者对水化的影响截然相反;PCE分子结构中大量的羧基络合了溶液中的Ca^(2+),抑制了水泥颗粒表面晶核的形成,起到了一定的缓凝作用;然而,ES-PCE分子结构中羧基含量较低,Ca^(2+)的络合作用较弱,缓凝效果并不明显,在体系中有效水分增多的情况下,反而促进水泥的水化,起到了早强效果。水灰比为0.4的水泥砂浆中,ES-PCE的掺量适宜控制在0.3%以下,在保证减水率的同时,对水泥早期和后期强度均起到一定的增强作用。 展开更多
关键词 早强型聚羧酸系减水剂 水化 电导率 水化产物生长 凝结时间 抗压强度
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The Influence of the "Terroir" Concerning the Quantity and Quality of Grapes Yield at White Grapevine Varieties Growing in the lasi Vineyard
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作者 Liliana Rotaru Vasile Stoleru Feodor Filipov Mihai Mustea Gabriela Petrea 《Journal of Life Sciences》 2011年第8期646-653,共8页
Abstract: Romania is famous of the potential of his vineyard, winemaking is a traditional occupation, in fact it can be said that there are many areas that can provide a vineyard product. Moreover, typicity and authe... Abstract: Romania is famous of the potential of his vineyard, winemaking is a traditional occupation, in fact it can be said that there are many areas that can provide a vineyard product. Moreover, typicity and authenticity of a wine are defining conditions under conditions of fierce intemational competition to guarantee success of wine. There were concerns for determining areas with designation of origin from a vineyard that will produce quality wines, but the purpose of this study is to delimit the level of a vineyard small area that can ensure the achievement of a certain type of wine, a quality required by consumers. The research was made during 2006-2008 and revealed that the production of quality grapes and are influenced by different factors such as genetic, environmental and technological acting in complex. This is a first attempt to study characterize the concept of "terroir", as applied in the Copou vineyard from lasi county and provides information on the behavior of two varieties of grapes for wine: Feteasca Regala and Muscat Ottonel. Depending on the purpose, observations and calculations have found the influence of soil characteristics on several biochemical parameters and productive at varieties of Feteasca Regala and Muscat Ottonel (soluble carbohydrate content, total acidity, the average yield of grapes) for the purpose of knowledge than a more detailed wine center in northeast of Romania. The results of this study can be used to determine with precision small areas crop at the parcel that will produce quality wines. 展开更多
关键词 IASI TERROIR VARIETIES behaviour interactions.
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