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近年来,我市因雷击而导致搅拌站系统瘫痪停产、影响工程进度的事件时有发生,在针对混凝土搅拌站配料秤的实际检定工作中,也常发现配料秤的称重传感器因雷击损坏而影响计量准确性。因此,对混凝土搅拌站防雷的研究具有重要意义。本文阐述了雷电对混凝土搅拌站的主要危害,分析了混凝土搅拌站常见的雷击原因及其防护措施,旨在引起生产方、安装方以及使用方对混凝土搅拌站防雷的共同重视。 相似文献
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Lu Xu Baijun Liu Mingyao Zhang Yang Bai Jinming Zhang Jiayin Song 《Polymer Engineering and Science》2020,60(6):1194-1201
A series of methacrylate-acrylonitrile-butadiene-styrene (MABS) resins was prepared using bulk polymerization. The polarity of the continuous phase and the compatibility of two phases were changed by adjusting the methyl methacrylate (MMA) content, choosing values that were close to styrene-butadiene rubber solubility value. The possibility of controlling the microstructure of the MABS resin by changing the polarity of the components and the compatibility of two phases was assessed. The dynamic mechanical analysis shows that the compatibility of two phases varies with the MMA content. The morphological analysis shows that increasing MMA contents results in a gradual decrease in the sub-inclusion structure with a network skeleton of rubber particles, and that all the particles become solid rubber when the MMA content reaches 75%. The sub-inclusion structure reappears but does not have a network skeleton when the MMA content is 90%. The impact strength and morphological analysis indicate that the solid rubber particles and the sub-inclusion structure with a network skeleton provide excellent toughness, while the sub-inclusion structure without a network skeleton does not. In contrast, the transmittance of the ABS resin first increased and then decreased with increasing MMA content. 相似文献
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Reza Soleimani Amir Hossein Saeedi Dehaghani Ali Rezai-Yazdi Seyed Abolhassan Hosseini Seyedeh Pegah Hosseini Alireza Bahadori 《化学工程与技术》2020,43(3):514-522
Solubility is one of the most indispensable physicochemical properties determining the compatibility of components of a blending system. Research has been focused on the solubility of carbon dioxide in polymers as a significant application of green chemistry. To replace costly and time-consuming experiments, a novel solubility prediction model based on a decision tree, called the stochastic gradient boosting algorithm, was proposed to predict CO2 solubility in 13 different polymers, based on 515 published experimental data lines. The results indicate that the proposed ensemble model is an effective method for predicting the CO2 solubility in various polymers, with highly satisfactory performance and high efficiency. It produces more accurate outputs than other methods such as machine learning schemes and an equation of state approach. 相似文献
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Alexandra Kodadová Zuzana Vitková Petra Herdová Anton Ťažký Jarmila Oremusová Daniel Grančai 《Drug development and industrial pharmacy》2015,41(7):1080-1088
This study deals with the formulation of natural drugs into hydrogels. For the first time, compounds from the sage essential oil were formulated into chitosan hydrogels. A sample preparation procedure for hydrophobic volatile analytes present in a hydrophilic water matrix along with an analytical method based on the gas chromatography coupled with the mass spectrometry (GC-MS) was developed and applied for the evaluation of the identity and quantity of essential oil components in the hydrogels and saline samples. The experimental results revealed that the chitosan hydrogels are suitable for the formulation of sage essential oil. The monoterpene release can be effectively controlled by both chitosan and caffeine concentration in the hydrogels. Permeation experiment, based on a hydrogel with the optimized composition [3.5% (w/w) sage essential oil, 2.0% (w/w) caffeine, 2.5% (w/w) chitosan and 0.1% (w/w) Tween-80] in donor compartment, saline solution in acceptor compartment, and semi-permeable cellophane membrane, demonstrated the useful permeation selectivity. Here, (according to lipophilicity) an enhanced permeation of the bicyclic monoterpenes with antiflogistic and antiseptic properties (eucalyptol, camphor and borneol) and, at the same time, suppressed permeation of toxic thujone (not exceeding its permitted applicable concentration) was observed. These properties highlight the pharmaceutical importance of the developed chitosan hydrogel formulating sage essential oil in the dermal applications. 相似文献
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2002年12月国务院批复了《南水北调工程总体规划》,明确中线工程分两期建设。目前,一期工程已经通水。近年来,随着社会经济的快速发展,受水区的人口、生产规模、节水水平、人们对环境的要求都发生了变化,因此有必要根据新的情况对受水区的用水需求重新预测。分析了城市化发展和城镇用水变化的新形势,依据流域、区域水资源规划成果,提出了中线二期工程受水区需调水量,并与《南水北调中线工程规划》提出的二期需调水量进行对比,以供各方参考。 相似文献
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