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凝固浴温度对纤维素中空纤维膜结构及气体渗透分离性能影响研究 被引量:3
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作者 毛智明 介兴明 +4 位作者 曹义鸣 刘丹丹 刘建辉 周美青 袁权 《高分子学报》 SCIE CAS CSCD 北大核心 2011年第4期395-401,共7页
利用新型溶解工艺,在不同的凝固浴温度(0~60℃)下制备了纤维素中空纤维膜,考察了凝固浴温度对纤维素中空纤维膜结晶结构、机械性能和气体渗透分离性能的影响.扫描电镜表征表明凝固浴温度的升高使得纤维素中空纤维膜更加疏松,并且内侧... 利用新型溶解工艺,在不同的凝固浴温度(0~60℃)下制备了纤维素中空纤维膜,考察了凝固浴温度对纤维素中空纤维膜结晶结构、机械性能和气体渗透分离性能的影响.扫描电镜表征表明凝固浴温度的升高使得纤维素中空纤维膜更加疏松,并且内侧的指状孔变大变多;膜的机械性能随凝固浴温度的升高而变差;XRD谱图显示凝固浴温度对纤维素中空纤维膜的结晶度没有明显影响.气体渗透分离性能测试结果表明,随着凝固浴温度的升高,干态纤维素中空纤维膜气体渗透速率增加明显,表现出"Knudson扩散"控制行为;与干态纤维素膜相比,加湿状态下的纤维素中空纤维膜气体渗透性能都有大幅度的下降,而且较低凝固浴温度下制备的纤维素中空纤维膜M-1(0℃)、M-2(20℃)气体渗透通过膜的机理由原来干膜的Knudson扩散过渡到湿膜的溶解扩散,CO2取代H2成为在膜内扩散速度最快的气体.在较高的凝胶浴温度下(40℃、60℃),由于所制备的膜结构过于疏松,对几种气体没有表现出"溶解选择性". 展开更多
关键词 纤维素中空纤维膜 凝固浴 气体分离 knudson扩散 溶解扩散
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Evaluation of Spirometry for Medical Clearance in Occupations Requiring Respirator Usage
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作者 Ushang Desai Giffe T. Johnson +1 位作者 James D. McCluskey Raymond D. Harbison 《Occupational Diseases and Environmental Medicine》 2017年第3期67-77,共11页
Medical certification of workers for respirator use is an important activity of occupational medicine health professionals. Spirometry is a diagnostic tool to evaluate respiratory distress/insufficiency that may affec... Medical certification of workers for respirator use is an important activity of occupational medicine health professionals. Spirometry is a diagnostic tool to evaluate respiratory distress/insufficiency that may affect respirator use. The pulmonary function data of 337 subjects from different occupations that required medical evaluation to wear a respirator were analyzed to determine the effect of using various spirometric equations on respirator fitness outcomes. Of 337 subjects who were cleared for respiratory use by medical questionnaires for respirator compliance, 14 (4.15%) failed to pass respirator compliance by NFPA criteria and 5 (1.48%) failed to pass respirator compliance measures by ATS criteria. We compared the use of different spirometric equations to evaluate these measures, and it was determined that the Crapo equation cleared more workers for respirator use as compared to the Knudson and NHANES III equations. As some workers were able to qualify for respirator use based on questionnaire alone but failed respirator clearance after pulmonary function testing, it is recommended that spirometry is used to evaluate clearance for all workers who will use a respirator in the workplace. As well, using different spirometric equations can affect the outcome on passing or failing clearance for respirator use, and this should be considered in a respiratory medical certification program. 展开更多
关键词 SPIROMETRY NHANES III Crapo knudson RESPIRATORY Protection PROGRAM
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