混合冷凝器的计算

介绍混合冷凝器的计算方法并详细计算示例。     

A Comparative Evaluation of Disposable Humidifiers

The performance of four hygroscopic condenser humidifiers (HCH) and two conventional heat and moisture exchangers (HME), all commercially available, have been evaluated in laboratory tests. A clinical study was also made in order to confirm the test results. It was found that the new generation of heat and moisture exchangers, which have hygroscopic properties, are superior to conventional HME units. When dry inspired gases are used, the HCH units, but not the HME units, deliver a moisture level that is comparable to what is produced in the upper trachea during normal breathing the nose. Our clinical experience as well as the extensive body of literature on humidification requirements support the conclusion that in most cases they can be recommended to be used for extended time periods even with dry gases. The humidification efficiency decreases with increasing tidal volume for all units. However, the best units can be used up to tidal volumes of 1000-1500 ml. The dead space of these units varies from 90 ml to 100 ml and the resistances are only about 50 Pa at 0.5 l/s. The weight is in the range 18-40 g. One of the best HCH devices also has distinct antimicrobial properties. The others are found at least not to promote organism growth. This feature added to others such as safety and simplicity in use make an HCH device an attractive alternative to conventional humidification techniques.     

冷凝器和蒸发器在制冷系统中的作用与保养

冷凝器和蒸发器是制冷系统中重要组成部件，它们的工作状态直接影响着系统的制冷效果，作者从它们的工作原理上分析产生故障的原因及解决的方法，并对如何维护保养好冷凝器和蒸发器作了详细的阐述。     

改装EcoScreen冷凝器收集机械通气患者呼出气冷凝液的研究

目的探讨设计改装EcoScreen冷凝器收集机械通气患者呼出气冷凝液(EBC)的可行性。方法①体外模拟肺测试:改装EcoScreen冷凝器与模拟肺连接,在干燥呼吸机管道不连接湿化器、连接不加温湿化器、连接加温湿化器三种不同连接状态下机械通气60min,观察气道压和潮气量(VT)的变化,并测量收集冷凝液量。②人体测试:10例患者在干燥呼吸机管道不连接湿化器状态下进行机械通气20min,观察气道压、VT、呼吸频率及心率、血压、SpO2的变化。并测量收集冷凝液量。结果①体外模拟肺测试发现,干燥呼吸机管道不连接湿化器机械通气60min可收集冷凝液2.2mL,期间气道压、VT无明显增高,冷凝器收集管腔无阻塞;连接不加温湿化器,机械通气中VT下降伴气道压升高,50min时被迫中止测试,发现冷凝器收集管腔被冷凝物质明显堵塞,收集冷凝液5mL;连接加温湿化器机械通气60min,收集冷凝液10.5mL,期间气道压轻度升高,VT轻度下降。②人体测试显示,干燥呼吸机管道不连接湿化器,直接与呼吸机相连,机械通气20min可收集冷凝液2mL,收集过程中气道压、VT、呼吸频率及心率、血压和SpO2无显著变化。结论改装EcoScreen冷凝器可用于收集机械通气患者的EBC。为获得检测所需的足量EBC标本,并防止EBC被稀释和气道阻塞,建议脱离湿化器,收集时间20min,同时加强呼吸机和临床监护。     

复杂性热性惊厥儿童视频脑电图及头颅神经影像学特点分析

目的：探讨复杂性热性惊厥(complex febrile seizures, CFS)患儿的视频脑电图及神经影像学特点。方法：选取50例CFS患儿(观察组),并以同期住院的单纯性热性惊厥(simple febrile seizures, SFS)患儿为对照组,对其临床特征、视频脑电图及神经影像学检查结果进行比较。结果：(1)观察组发病前有神经系统异常8例,发作后有神经系统异常表现5例,热性惊厥家族史15例。(2)观察组中视频脑电图(electroence-phalogram, EEG)异常32例,对照组EEG异常14例;观察组32例异常EEG中,痫样放电占28.0%,显著高于对照组(5.0%)。观察组随访1年后,EEG异常者中继发癫痫2例(6.25%)。(3)观察组行头颅CT检查8例(16.0%),头颅磁共振成像(magnetic resonance imaging, MRI)检查42例(84.0%),共发现异常20例(40.0%),显著高于对照组(10.0%)。CT和MRI图像异常率分别为 12.5%和 59.5%,差异有统计学意义。结论：CFS儿童EEG及神经影像学(尤其MRI)异常率高,易发生脑损伤及继发癫痫。在CFS的诊治过程中,有必要个体化选择适合患儿自身的EEG及影像学检查方法,从而有利于临床的早期诊断、早期治疗,有利于长期评估随访。     

钛冷凝器失效原因分析及国产化关键技术研究

分析了扬子石化公司PTA生产装置中氧化工段钛冷凝器的失效原因，通过断裂换热管的新口分析确定了钛管失效类型为疲劳断裂，根据列管振动分析计算结果，证实了钛冷凝器在运行过程中确实会产生振动，从而引起钛管疲劳失效。据此，提出了消除振动及改进冷凝器结构的措施，并就国产化制造中的关键技术开展试验与分析研究。     

均匀生物组织的介电常数的测量的一种简易方法

本文介绍了应用平行板电容器测量均匀生物组织的复介电常数的方法和原理     

The Hygroscopic Condenser Humidifier A new device for general use in anaesthesia and intensive care

The design and performance of the Hygroscopic Condenser Humidifier (HCH) are described. In principle the HCH consists of two parts, a conventional Heat-Moisture-Exchanger (HME) and a hygroscopic unit. The hygroscopic action is shown to improve the water retention efficiency of the device by about a factor of two as compared with optimal HME designs. As a result, humidification levels corresponding to around 80% relative humidity at 37 degrees C are obtained in the trachea and this is also achieved when completely dry gases are delivered to the patient. The unit can therefore be used for all procedures in anaesthesia and in intensive care.     

机械通气患者呼出气冷凝液收集的临床安全性和可行性

目的 研究机械通气患者呼出气冷凝液(exhaled breath condensate,EBC)收集技术的临床安全性和可行性.方法 28例机械通气患者采用改装EcoScreen冷凝器进行93次EBC收集.观察收集前、收集中和收集后三个阶段的呼吸监护和生命体征监护参数的变化.测量EBC收集量并检测其中一氧化氮(NO)和8-异前列烷(8-isoPG)的水平.结果 ①机械通气患者在EBC收集前与收集后的呼吸监护和生命体征监护参数的差异无统计学意义.②在EBC收集过程中,PSV模式下VT、f和VM下降；A/C-PC模式下VT、f和VM下降,Pmean升高；A/C-VC模式下VT下降,PIP升高；其变化幅度均小于10％;HR、MAP和SpO2无明显变化.③收集期间VT无进行性下降.④VM为(10.68±4.24) L/min,30 min内的EBC收集量为(4.70±1.48) ml.EBC收集量与VM相关(r=0.482,P＜0.01).⑤机械通气患者EBC中NO和8-isoPG可以检出.结论 使用改装Ecoscreen冷凝器对机械通气患者进行EBC采集具有临床安全性和可行性.为减少风险,建议预先评估病情,更换干燥管道,适当提高VT设置,限制收集时间小于30 min.     

PTA装置塔顶冷凝器U型316L换热管腐蚀失效分析

通过设备现场勘查、气密性试验、内窥镜观察、机械性能试验、管材化学分析、腐蚀产物EDAX能谱分析、金相检验等对PTA装置脱水塔塔顶冷凝器U型换热管腐蚀泄漏失效原因进行了分析。换热管在含溴醋酸环境、欠合理的工艺结构及排布等综合作用下发生点蚀穿孔、均匀腐蚀及机械冲刷腐蚀,同时提出了相应的对策措施。