With different structural forms of ventilation pipes have various attenuation effects on incident shock waves while meeting ventilation requirements.The attenuation mechanism and the propagation law of shock waves in ...With different structural forms of ventilation pipes have various attenuation effects on incident shock waves while meeting ventilation requirements.The attenuation mechanism and the propagation law of shock waves in ventilation pipes of different structures are investigated by experiments and numerical simulations.Furthermore,for the same structure,the effects of peak pressure and positive pressure time on the attenuation rate are discussed.It is found that the attenuation rate increases with the incident shock wave pressure,and the shock wave attenuation rate tends to reach its limiting value k for the same structure and reasonably short positive pressure time.Under the same conditions,the attenuation rate is calculated using the pressure of the shock wave as follows:diffusion chamber pipe,branch pipe and selfconsumption pipe;the attenuation rate per unit volume is calculated as follows:self-consumption pipe,branch pipe and diffusion chamber pipe.In addition,an easy method is provided to calculate the attenuation rate of the shock wave in single and multi-stage ventilation pipes.Corresponding parameters are provided for various structures,and the margin of error between the formulae and experimental results is within 10%,which is significant for engineering applications.展开更多
To explore the spatial-temporal evolution law of rock mass temperature in high geothermal roadway during mechar^ical ventilation, a series of experiments were conducted based on the physical simulation test system of ...To explore the spatial-temporal evolution law of rock mass temperature in high geothermal roadway during mechar^ical ventilation, a series of experiments were conducted based on the physical simulation test system of thermal and humid environment in high geothermal roadway, which is a method independently developed by China University of Mining and Technology. The results indicate that during ventilation, the disturbed region of the temperature extends gradually from shallow area to deep area in the surrounding rock mass of the roadway. Meanwhile, the temperature increases as the exponential function from shallow area to deep, with steady decrease of the temperature gradient and heat flux. As the ventilation proceeds, the relationship between dimensionless temperature and dimensionless time approximately meets Hill function.展开更多
目的探索近10年重症监护病房(intensive care unit,ICU)机械通气患者撤机相关研究现状、热点及未来发展趋势,为开展相关研究和临床实践提供建议。方法计算机检索Web of Science数据库和中国知网数据库中关于ICU机械通气患者撤机的相关文...目的探索近10年重症监护病房(intensive care unit,ICU)机械通气患者撤机相关研究现状、热点及未来发展趋势,为开展相关研究和临床实践提供建议。方法计算机检索Web of Science数据库和中国知网数据库中关于ICU机械通气患者撤机的相关文献,检索时间为2013年1月1日至2024年8月15日,采用CiteSpace 6.2.R4对检索结果进行分析。结果经筛选共纳入ICU机械通气患者撤机相关文献5323篇,其中:中文1191篇,英文4132篇。ICU机械通气患者撤机相关研究的文献发文量呈上升趋势,研究热点聚焦在机械通气撤机的影响因素、撤机指征评估、困难撤机与撤机失败等方面。结论ICU机械通气患者撤机领域研究呈现快速发展态势。建议相关研究者运用案例报告、机器学习研究方法,重点围绕机械通气撤机相关指标进行机械通气撤机研究的探索,构建机械通气撤机的流程和方案。展开更多
目的调查呼吸重症监护室(respiratory intensive care unit,RICU)机械通气患者代理决策者决策冲突发生并分析其影响因素。方法采用便利抽样法,选取2024年6-12月陆军军医大学第二附属医院101名RICU的机械通气患者代理决策者为调查对象。...目的调查呼吸重症监护室(respiratory intensive care unit,RICU)机械通气患者代理决策者决策冲突发生并分析其影响因素。方法采用便利抽样法,选取2024年6-12月陆军军医大学第二附属医院101名RICU的机械通气患者代理决策者为调查对象。采用一般资料表、决策准备度量表、决策冲突量表进行问卷调查;采用单因素分析、Pearson相关性分析和多元线性回归对影响因素进行分析。结果RICU机械通气患者代理决策者决策准备度总分为(64.14±22.35)分;RICU机械通气患者代理决策者决策冲突总分为(35.18±26.47)分,决策冲突发生率为69.31%。单因素分析显示,是否清楚患者预后、与患者的关系、是否知道患者关于治疗的想法、对机械通气相关信息的了解程度差异有统计学意义(P<0.05);Pearson相关性分析显示,决策准备度与决策冲突及其3个维度均呈显著负相关关系(P<0.001);多元线性回归分析结果显示,对机械通气相关信息的了解程度、决策准备度为RICU机械通气患者代理决策者决策冲突的影响因素(P<0.001)。结论RICU机械通气患者代理决策者决策冲突水平较高,且代理决策者决策冲突水平与其机械通气相关信息了解程度和决策准备度呈显著负相关。展开更多
文摘With different structural forms of ventilation pipes have various attenuation effects on incident shock waves while meeting ventilation requirements.The attenuation mechanism and the propagation law of shock waves in ventilation pipes of different structures are investigated by experiments and numerical simulations.Furthermore,for the same structure,the effects of peak pressure and positive pressure time on the attenuation rate are discussed.It is found that the attenuation rate increases with the incident shock wave pressure,and the shock wave attenuation rate tends to reach its limiting value k for the same structure and reasonably short positive pressure time.Under the same conditions,the attenuation rate is calculated using the pressure of the shock wave as follows:diffusion chamber pipe,branch pipe and selfconsumption pipe;the attenuation rate per unit volume is calculated as follows:self-consumption pipe,branch pipe and diffusion chamber pipe.In addition,an easy method is provided to calculate the attenuation rate of the shock wave in single and multi-stage ventilation pipes.Corresponding parameters are provided for various structures,and the margin of error between the formulae and experimental results is within 10%,which is significant for engineering applications.
基金Project(2014-6121)supported by Fundamental Research Funds for the Central Universities,ChinaProject(51504236)supported by the National Natural Science Foundation of ChinaProject supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions,China
文摘To explore the spatial-temporal evolution law of rock mass temperature in high geothermal roadway during mechar^ical ventilation, a series of experiments were conducted based on the physical simulation test system of thermal and humid environment in high geothermal roadway, which is a method independently developed by China University of Mining and Technology. The results indicate that during ventilation, the disturbed region of the temperature extends gradually from shallow area to deep area in the surrounding rock mass of the roadway. Meanwhile, the temperature increases as the exponential function from shallow area to deep, with steady decrease of the temperature gradient and heat flux. As the ventilation proceeds, the relationship between dimensionless temperature and dimensionless time approximately meets Hill function.
文摘目的探索近10年重症监护病房(intensive care unit,ICU)机械通气患者撤机相关研究现状、热点及未来发展趋势,为开展相关研究和临床实践提供建议。方法计算机检索Web of Science数据库和中国知网数据库中关于ICU机械通气患者撤机的相关文献,检索时间为2013年1月1日至2024年8月15日,采用CiteSpace 6.2.R4对检索结果进行分析。结果经筛选共纳入ICU机械通气患者撤机相关文献5323篇,其中:中文1191篇,英文4132篇。ICU机械通气患者撤机相关研究的文献发文量呈上升趋势,研究热点聚焦在机械通气撤机的影响因素、撤机指征评估、困难撤机与撤机失败等方面。结论ICU机械通气患者撤机领域研究呈现快速发展态势。建议相关研究者运用案例报告、机器学习研究方法,重点围绕机械通气撤机相关指标进行机械通气撤机研究的探索,构建机械通气撤机的流程和方案。
文摘目的调查呼吸重症监护室(respiratory intensive care unit,RICU)机械通气患者代理决策者决策冲突发生并分析其影响因素。方法采用便利抽样法,选取2024年6-12月陆军军医大学第二附属医院101名RICU的机械通气患者代理决策者为调查对象。采用一般资料表、决策准备度量表、决策冲突量表进行问卷调查;采用单因素分析、Pearson相关性分析和多元线性回归对影响因素进行分析。结果RICU机械通气患者代理决策者决策准备度总分为(64.14±22.35)分;RICU机械通气患者代理决策者决策冲突总分为(35.18±26.47)分,决策冲突发生率为69.31%。单因素分析显示,是否清楚患者预后、与患者的关系、是否知道患者关于治疗的想法、对机械通气相关信息的了解程度差异有统计学意义(P<0.05);Pearson相关性分析显示,决策准备度与决策冲突及其3个维度均呈显著负相关关系(P<0.001);多元线性回归分析结果显示,对机械通气相关信息的了解程度、决策准备度为RICU机械通气患者代理决策者决策冲突的影响因素(P<0.001)。结论RICU机械通气患者代理决策者决策冲突水平较高,且代理决策者决策冲突水平与其机械通气相关信息了解程度和决策准备度呈显著负相关。
