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CO_(2)作为化学品原料的高效利用途径:与烷烃耦合反应
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作者 危长城 张雯娜 +4 位作者 杨阔 柏秀 徐舒涛 李金哲 刘中民 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 2023年第4期138-149,共12页
CO_(2)作为碳资源的规模化高附加值利用是实现其减排的重要方向.然而,由于其热力学稳定,以CO_(2)为原料高效转化为大宗化学品一直是一个巨大的挑战.工业上普遍以富氢的石脑油为原料生产相对缺氢的烯烃和芳烃产品,但其存在原料和目标产... CO_(2)作为碳资源的规模化高附加值利用是实现其减排的重要方向.然而,由于其热力学稳定,以CO_(2)为原料高效转化为大宗化学品一直是一个巨大的挑战.工业上普遍以富氢的石脑油为原料生产相对缺氢的烯烃和芳烃产品,但其存在原料和目标产品之间的碳氢不平衡问题.理论上,采用CO_(2)与富氢的烷烃耦合,可以改善二者的平衡关系,提高目标产物选择性,同时实现CO_(2)资源化利用.已有研究采用CO_(2)与烷烃反应,将CO_(2)转化为CO并减少氢气的生成,但CO_(2)的碳原子没有进入烃类产物中.本文系统研究了酸性分子筛催化的CO_(2)与烷烃耦合反应,大幅提高了芳烃选择性,证实部分CO_(2)中的碳原子直接进入了芳烃产品中.本文以H-ZSM-5为催化剂,对比研究了正丁烷、正戊烷和正己烷在He和CO_(2)气氛中的转化反应,并详细研究了反应温度、CO_(2)/n-butane比例、接触时间以及分子筛酸量等条件对耦合反应的影响.结果表明,CO_(2)的引入可大幅促进芳烃的生成,同时甲烷和乙烷等小分子烷烃的生成受到抑制.在优化反应条件下,CO_(2)/n-butane比例为0.475时,CO_(2)和n-butane转化率分别可达17.5%和100%,芳烃选择性高达80%.使用^(13)C同位素标记的CO_(2)与n-butane进行耦合反应,发现芳烃产物中含有部分13C同位素标记的碳原子,表明这部分碳原子来自CO_(2)中的碳.对耦合反应后的催化剂进行溶积碳并采用色质谱分析,发现大量甲基取代的内酯和甲基取代的环烯酮等含氧物种.同位素标记实验结果表明,这些含氧中间体由CO_(2)与烃类耦合转化生成.通过设计实验验证了反应途径,即CO_(2)与碳正离子反应得到环内酯,环内酯进一步转化为甲基环烯酮,甲基环烯酮转化为芳烃产物.提出了H-ZSM-5催化CO_(2)与烷烃耦合反应的机理,并采用密度泛函理论计算了耦合反应机理各步骤的能垒,结果验证了耦合反应机理的可行性.综上,本文提出的耦合反应为CO_(2)碳资源的大规模直接利用提供了一条有效的途径,具有广阔的应用前景. 展开更多
关键词 二氧化碳转化 轻质烷烃 芳烃 催化 分子筛
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Study on the Protective Mechanism of Acupuncture Regulating ICAM-5 mRNA Expression in Rats with Ischemic Stroke
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作者 Yating Shen Ximei Xie +4 位作者 xiu bai Hua bai Xiaofan Chang Yuanyuan Tang Qiuyu Li 《Journal of Behavioral and Brain Science》 2021年第12期313-321,共9页
<b>Objective:</b> The objective is to investigate whether acupuncture can protect brain by regulating the expression of ICAM-5 mRNA in brain tissue. <b>Methods:</b> Male SD rats were used to co... <b>Objective:</b> The objective is to investigate whether acupuncture can protect brain by regulating the expression of ICAM-5 mRNA in brain tissue. <b>Methods:</b> Male SD rats were used to construct a middle cerebral artery occlusion reperfusion injury (Middle cerebral artery occlusion, MCAO) model, and the rats were randomly divided into 4 groups, namely the normal group (group A) and the sham operation group (group B), MCAO group (group C), MCAO + acupuncture group (group D);real-time fluorescent quantitative PCR (RT-qPCR) was used to detect the expression of ICAM-5 mRNA in the brain tissue of the ischemic area, and HE staining and TUNEL were used to detect the level of neuronal apoptosis to evaluate the therapeutic effect. <b>Results:</b> Acupuncture can improve neuronal morphology and reduce neuronal apoptosis in rats with ischemic stroke. RT-qPCR: compared with group A and group B, the expression level of ICAM-5 mRNA in the brain tissues of group C and group D decreased, while compared with group C, The expression of ICAM-5 mRNA in the brain tissue of group D was significantly up-regulated (P < 0.05). There was no statistical difference between group A and group B (P > 0.05). <b>Conclusion:</b> The effectiveness of acupuncture in the treatment of ischemic stroke may achieve neuroprotection by up-regulating the expression level of ICAM-5 mRNA. 展开更多
关键词 Ischemic Stroke ACUPUNCTURE ICAM-5 mRNA Mechanism Study
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Experimental Study on the Effect of Acupuncture on ERM/PI3/Akt Signal Pathway in Rats with Ischemic Stroke
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作者 xiu bai Ximei Xie +4 位作者 Yating Shen Hua bai Yuanyuan Tang Xiaofan Chang Qiuyu Li 《Journal of Behavioral and Brain Science》 2021年第10期248-256,共9页
Objective: To observe the effect of acupuncture on the expression of ERM/PI3K/Akt signaling pathway in the brain tissue around the infarct focus of ischemic stroke model rats. Methods: According to the block randomiza... Objective: To observe the effect of acupuncture on the expression of ERM/PI3K/Akt signaling pathway in the brain tissue around the infarct focus of ischemic stroke model rats. Methods: According to the block randomization method, 80 male SD rats were divided into normal group (n = 10), sham operation group (n = 24), model group (n = 23) and acupuncture group (n = 23). The normal group was bred routinely without any intervention. In the sham operation group, only the skin was cut to find and the nerves and blood vessels were stripped and sutured. The model group and the acupuncture group were sutured to prepare the MCAO model. After the model was successfully established, acupuncture of the acupuncture group rats was given once a day, and the needles were kept for 30 minutes each time. The rats in the sham operation group and the model group only imitated capture and return, and were treated with acupuncture for 2 consecutive courses, each course was 5 days, and the two courses were rested for 2 days. After that, Western blot was used to detect ERM, changes in the concentration of PI3K and Akt proteins. Results: Compared with the normal group, the expression levels of ERM, PI3K, and Akt proteins in the sham operation group were reduced. Compared with the sham operation group, the expression levels of ERM, PI3K, and Akt proteins in the model group were significantly down-regulated. Compared with the model group, the protein expression levels of ERM, PI3K and Akt were significantly up-regulated in the acupuncture group, and the difference was statistically significant (P < 0.05). Conclusion: Acupuncture can significantly up-regulate the expression of ERM, PI3K and Akt proteins, and its effect mechanism may be related to the transduction of ERM/PI3K/Akt signaling pathway in cells. 展开更多
关键词 ACUPUNCTURE Ischemic Stroke ERM/PI3/Akt Signaling Pathway
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憨大
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作者 修白 《钟山》 2020年第3期74-90,共17页
浴室门口,地面有液体。混乱,交错。细辨,是稀释后的血迹。地砖上有物体爬过的迹象。憨大疑惑,站在门口发愣。哪来的血?他在思量,她已经过了青春期,过了在特定的日子一不小心大腿根部的血块顺着裤腿流下来的年纪。那个年纪,是女人生命力... 浴室门口,地面有液体。混乱,交错。细辨,是稀释后的血迹。地砖上有物体爬过的迹象。憨大疑惑,站在门口发愣。哪来的血?他在思量,她已经过了青春期,过了在特定的日子一不小心大腿根部的血块顺着裤腿流下来的年纪。那个年纪,是女人生命力最旺盛的时期。现在,她枯萎了,像栀子花凋谢后的花瓣,蜷缩在枝头。 展开更多
关键词 大腿根部 栀子花 青春期 思量 生命力
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