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聚丙烯纤维共辐射接枝苯乙烯-二乙烯苯的研究 被引量:13
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作者 邓琼 曾庆轩 +1 位作者 冯长根 周绍箕 《辐射研究与辐射工艺学报》 CAS CSCD 北大核心 2004年第5期276-280,共5页
以Coγ射线为辐射源,研究了聚丙烯(PP)纤维共辐射接枝苯乙烯?二乙烯苯反应中的影响因素。结60果表明,当单体浓度为20%—25%,吸收剂量>15kGy时,自由基利用率高,产生的共聚物少,导入率高。接枝反应前纤维在接枝液中的溶胀时间大于7h以... 以Coγ射线为辐射源,研究了聚丙烯(PP)纤维共辐射接枝苯乙烯?二乙烯苯反应中的影响因素。结60果表明,当单体浓度为20%—25%,吸收剂量>15kGy时,自由基利用率高,产生的共聚物少,导入率高。接枝反应前纤维在接枝液中的溶胀时间大于7h以上,可避免扩散效应对反应的影响,提高导入率。当溶剂以溶胀作用为主导作用时,可促进接枝反应的进行。同时保持一定的接枝反应后效应时间,可提高导入率。通过研究,得到了接枝反应的最佳工艺条件,制备出导入率在200%—280%且机械强度很好的产品,为工业化生产离子交换纤维提供了良好的中间产品。 展开更多
关键词 聚丙烯(PP)纤维 苯乙烯-二乙烯苯 辐射接枝 导入率
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聚丙烯腈纤维接枝丙烯酰胺亲水改性的研究 被引量:12
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作者 陈志军 黄年华 柳浩 《武汉纺织大学学报》 2013年第6期32-36,共5页
采用化学接枝法以丙烯酰胺(AM)为接枝单体、过氧化苯甲酰(BPO)为引发剂、三烯丙基异三聚氰酸酯(TAIC)为交联剂、丙酮和去离子水为溶剂,对聚丙烯腈(PAN)纤维进行了接枝亲水改性。用傅立叶红外光谱仪(FTIR)和热重分析仪(TGA)等技术手段对... 采用化学接枝法以丙烯酰胺(AM)为接枝单体、过氧化苯甲酰(BPO)为引发剂、三烯丙基异三聚氰酸酯(TAIC)为交联剂、丙酮和去离子水为溶剂,对聚丙烯腈(PAN)纤维进行了接枝亲水改性。用傅立叶红外光谱仪(FTIR)和热重分析仪(TGA)等技术手段对接枝样品进行了表征,研究了原料配比和反应条件对导入率的影响。结果表明,PAN纤维上接枝了AM,适宜的溶液配比为AM 0.8 mol/L、BPO 3×10-3mol/L、TAIC 1 vol%,在85℃恒温水浴中反应2 h,可得到导入率为127.9%的接枝纤维,接枝改性后的纤维亲水性得到提高,断裂强度和断裂伸长率均有下降,纤维分解温度和高温下的热稳定性得到提高。 展开更多
关键词 聚丙烯腈 亲水性 丙烯酰胺 化学接枝 导入率
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等离子体法制备强碱性离子交换纤维
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作者 张道武 刘廷岳 《北京服装学院学报(自然科学版)》 CAS 北大核心 2009年第4期14-19,共6页
通过等离子体引发苯乙烯单体与腈纶无纺布接枝聚合,对接枝产物进行氯甲基化和胺化反应制备了强碱性离子交换纤维,研究了处理功率、压强、时间对腈纶无纺布接枝苯乙烯的影响.结果表明:等离子体法接枝效果较为明显,在功率为100 W,压强为30... 通过等离子体引发苯乙烯单体与腈纶无纺布接枝聚合,对接枝产物进行氯甲基化和胺化反应制备了强碱性离子交换纤维,研究了处理功率、压强、时间对腈纶无纺布接枝苯乙烯的影响.结果表明:等离子体法接枝效果较为明显,在功率为100 W,压强为30 Pa,时间为4 min条件下可达到最佳接枝效果,导入率为20%左右;经氯甲基化和胺化后可得到交换容量为1.40 mmol/L左右的产物. 展开更多
关键词 等离子体 接枝 导入率 离子交换纤维
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Defective recovery of QT dispersion following transcatheter aortic valve implantation: frequency, predictors and prognosis 被引量:1
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作者 Rutger-Jan Nuis Gokhan Turgut +7 位作者 Robert M van der Boon Nicolas M van Mieghem Sjoerd T Nauta Patrick W Serruys Ron T van Domburg Giulio Zuchelli Luc Jordaens Peter P de Jaegere 《Journal of Geriatric Cardiology》 SCIE CAS CSCD 2015年第5期482-488,共7页
Background Corrected QT dispersion (cQTD) has been correlated with non-uniform ventricular repolarisation and increased mortality. In patients with aortic stenosis, cQTD has been shown improved after surgical valve ... Background Corrected QT dispersion (cQTD) has been correlated with non-uniform ventricular repolarisation and increased mortality. In patients with aortic stenosis, cQTD has been shown improved after surgical valve replacement, but the effects of transcatheter aortic valve implantation (TAVI) are unknown. Therefore, we sought to explore the frequency, predictors and prognostic effects of defective cQTD recovery at 6 months after TAVI. Methods A total of 222 patients underwent TAVI with the Medtronic-CoreValve System between November 2005 and January 2012. Patients who were on class Ⅰ or Ⅲ antiarrhythmics or on chronic haemodialysis or who developed atrial fibrillation, a new bundle branch block or became pacemaker dependent after TAVI were excluded. As a result, pre-, post- and follow-up ECG (median: 6 months) analysis was available in 45 eligible patients. Defective cQTD recovery was defined as any progression beyond the baseline cQTD at 6 months. Results In the 45 patients, the mean cQTD was 47 ± 23 ms at baseline, 45 ±17 ms immediately after TAVI and 40 ± 16 ms at 6 months (15% reduction, P = 0.049). Compared to baseline, cQTD at 6 months was improved in 60% of the patients whereas defective cQTD recovery was present in 40%. cQTD increase immediately after TAVI was an independent predictor of defective cQTD recovery at 6 months (per 10 ms increase; OR: 1.89, 95% CI: 1.15-3.12). By univariable analysis, defective cQTD recovery was associated with late mortality (HR: 1.52, 95% CI: 1.05-2.17). Conclusions Despite a gradual reduction ofcQTD after TAVI, 40% of the patients had defective recovery at 6 months which was associated with late mortality. More detailed ECG analysis after TAVI may help to avoid late death. 展开更多
关键词 Aortic stenosis Conduction abnormalities Left bundle branch block PREDICTORS QT dispersion Transcatheter aortic valve implantation
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Transcatheter aortic valve implantation in very elderly patients: immediate results and medium term follow-up 被引量:1
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作者 Isaac Pascual Antonio J Mu oz-García +9 位作者 Diego López-Otero Pablo Avanzas Manuel F Jimenez-Navarro Belén Cid-Alvarez Raquel del Valle Juan H Alonso-Briales Raimundo Ocaranza-Sanchez José M Hemández Ramiro Trillo-Nouche César Morís 《Journal of Geriatric Cardiology》 SCIE CAS CSCD 2015年第4期340-345,共6页
Objective To evaluate immediate transcatheter aortic valve implantation (TAVI) results and medium-term follow-up in very elderly pa- tients with severe and symptomatic aortic stenosis (AS). Methods This multicente... Objective To evaluate immediate transcatheter aortic valve implantation (TAVI) results and medium-term follow-up in very elderly pa- tients with severe and symptomatic aortic stenosis (AS). Methods This multicenter, observational and prospective study was carried out in three hospitals. We included consecutive very elderly (〉 85 years) patients with severe AS treated by TAVI. The primary endpoint was to evaluate death rotes from any cause at two years. Results The study included 160 consecutive patients with a mean age of 87 ± 2.1 years (range from 85 to 94 years) and a mean logistic EuroSCORE of 18.8% ± 11.2% with 57 (35.6%) patients scoring 〉 20%. Procedural success rate was 97.5%, with 25 (15.6%) patients experiencing acute complications with major bleeding (the most frequent). Global mortality rate during hospitalization was 8.8% (n = 14) and 30-day mortality rate was 10% (n = 16). Median follow up period was 252.24± 232.17 days. During the follow-up period, 28 (17.5%) patients died (17 of them due to cardiac causes). The estimated two year overall and cardiac survival rates using the Kaplan-Meier method were 71% and 86.4%, respectively. Cox proportional hazard regression showed that the variable EuroSCORE ≥ 20 was the unique vari- able associated with overall mortality. Conclusions TAVI is safe and effective in a selected population of very elderly patients. Our findings support the adoption of this new procedure in this complex group of patients. 展开更多
关键词 Aortic stenosis High surgical risk Transcatheter aortic valve Very elderly patients
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A centenarian transcatheter aortic valve implantation case
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作者 Abdullah Nabi Aslan Huseyin Ayhan +1 位作者 Elcin Ozdemir Engin Bozkurt 《Journal of Geriatric Cardiology》 SCIE CAS CSCD 2016年第10期869-871,共3页
Aortic stenosis (AS) has become a leading cause of morbidity and mortality among a growing population of older adults. The number of elderly patients with severe symptomatic AS requiring aortic valve replacement has... Aortic stenosis (AS) has become a leading cause of morbidity and mortality among a growing population of older adults. The number of elderly patients with severe symptomatic AS requiring aortic valve replacement has been significantly increasing in recent years. 展开更多
关键词 Aortic stenosis The aged Transcatheter aortic valve implantation
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