On the estimation of pulmonary blood flow from CO2 production time series

It may be possible to estimate a nominal pulmonary blood flow (Q) during an exercise stress test via the algorithm used to estimate breath-by-breath alveolar CO2 production. Recently it has been demonstrated that by relating breath-to-breath fluctuations in alveolar CO2 production to breath-to-breath fluctuations in end-tidal CO2, an optimizing parameter related to Q can be determined that can be used to process the CO2 production fluctuations and minimize their variation. However, the reported values of Q using this procedure appear to be biased low. Using a computer simulation of gas exchange, we demonstrate that the estimate of Q is biased low when the nominal lung volume used in the alveolar gas exchange algorithm is too large. Furthermore, alveolar CO2 transport is determined by an integral of alveolar CO2 over the breath time and, thus, is a path-dependent quantity. The use of end-tidal CO2 fluctuations to approximate fluctuations in this integral contributes to an error in the estimation of Q which yields estimates that are biased low. Alternatively, the use of mean alveolar CO2 fluctuations yield more appropriate Q estimates. These results suggest practical implications for estimating effective pulmonary blood flow during an exercise stress test by using breath-to-breath estimates of mean alveolar CO2.     

A parallel implementation of the backward error propagation neural network training algorithm: experiments in event identification.

An artificial neural-network-based (ANN) event detection and alarm generation system has been developed to aid clinicians in the identification of critical events commonly occurring in the anesthesia breathing circuit. To detect breathing circuit problems, the system monitored CO2 gas concentration, gas flow, and airway pressure. Various parameters were extracted from each of these input waveforms and fed into an artificial neural network. To develop truly robust ANNs, investigators are required to train their networks on large training data sets, requiring enormous computing power. We implemented a parallel version of the backward error propagation neural network training algorithm in the widely portable parallel programming language C-Linda. A maximum speedup of 4.06 was obtained with six processors. This speedup represents a reduction in total run-time from 6.4 to 1.5 h. By reducing the total run time of the computation through parallelism, we were able to optimize many of the neural network's initial parameters. We conclude that use of the master-worker model of parallel computation is an excellent method for speeding up the backward error propagation neural network training algorithm.     

基于文丘里的湿气流量测量实验研究

对可应用于民用湿天然气流量测量的小口径文丘里管进行了实验研究。通过一台气流式雾化器用氮气把水雾化成湿气,再通过一台入口直径6mm,直径比0.567的文丘里管进行在线流量测量,获得了一定工况参数范围内不同压力、气体密度弗鲁德系数和洛克哈特-马蒂内利参数下的湿气虚高特性数据。分析了洛克哈特-马蒂内利参数、气液密度比、气体密度弗鲁德系数、韦伯数和液气体积比对湿气虚高修正系数的影响。调研了基于差压流量计的7种虚高指数修正关系式,并根据实验数据改进了R-H关系式。提出了针对小口径文丘里测量湿气的气相流量计算模型。实验结果表明,在压力0.5~2.0 MPa,气体密度弗鲁德系数1.0~8.5,洛克哈特-马蒂内利参数0~0.34, 气相体积比95%~100%范围内,该模型修正的气相流量相对误差小于士2.1%,气相均方根误差为1.2%,优于其他模型的修正结果。     

电网调控一体化运行电力设备危险点控制仿真

针对传统电力设备危险点控制方法存在检测结果不准确、控制效果较差的问题,提出一种新的电网调控一体化运行电力设备危险点控制方法。通过数据挖掘获取电网调控一体化运行电力设备危险点数据特征输入量,对电力设备危险点进行检测。依据检测的电网调控一体化运行电力设备危险点数据,通过建立自回归模型对未来危险点进行预测,根据预测模型计算令性能指标达到最优的所有控制增量,采用误差信息加权法对误差进行计算,调整控制模型,获取经校正后的电网调控一体化运行电力设备危险点控制模型,完成电网调控一体化运行电力设备危险点控制。实验结果表明,所提方法的控制效果较好,对电力设备危险点检测结果准确,与实际检测结果具有很好的拟合度,保证了电力设备的安全运行。     

矿用便携式多参数气体检测仪设计

针对现有气体检测仪只能同时检测一种气体的问题,设计了一种矿用便携式多参数气体检测仪。该检测仪采用低功耗单片机作为核心处理器,可完成实时参数(温度、CO、CH4、H2S、O2)检测、信息(气体体积分数、时间、温度、电量)液晶显示、报警数据的存储及查询、无线数据传输等功能。实际应用表明,该检测仪具有使用携带方便、测量准确、可视性好、低功耗等特点。     

煤层原生CO钻孔探测试验

当前不少研究均得出煤层赋存原生CO气体的结论,但是未考虑钻孔施工过程中产生CO后被煤体吸附的可能。为探究西北地区易自燃煤层是否存在原生CO的问题,采用原始煤层原位钻孔探测方法进行原生CO探测试验。在未受采动影响的实体煤区域沿巷帮一字排开布置3个测试钻孔,钻孔密封后采用高纯N₂置换密闭气室内气体,采用专用抽气泵抽取钻孔内气体,消除原位探测钻孔施工过程中煤体氧化产生CO对试验结果的影响。在分析煤层原生CO来源可能性及其涌出理论的基础上,探讨了密闭钻孔内气体浓度随时间变化特征,结果表明:密封后钻孔内O₂和CO体积分数随密封时间的延长而迅速降低,12 d后O₂体积分数稳定在2%以下;12 d后CO体积分数低于10^-12,气相色谱仪未检测到CO气体;钻孔内气体主要为N₂。由此推断,待测煤层中无原生CO气体。N₂环境破煤试验和煤样常温恒温氧化试验结果表明,封孔初期检出的CO气体来源于钻孔施工破煤作业。     

Application of the general linear model for smoothing gas exchange data

The precision of an interpretation of gas exchange records in progressive exercise is limited by the typical breath-to-breath variation in the data. Recently, two procedures have been proposed for minimizing the "noise" in the estimates of alveolar gas exchange time series data. One approach utilizes an estimate of pulmonary blood flow (Q) for smoothing purposes. The other approach utilizes an estimate of effective lung volume (V'L) for smoothing purposes. In this paper, we formulate the smoothing problem as a general linear model and demonstrate the concurrent estimates of both V'L and Q. Furthermore, we investigate the interaction between V'L and Q. Specifically, when a high value of lung volume is used (such as the subject's resting functional residual capacity) in the alveolar gas exchange algorithm, the estimate of Q is biased low and the result is a less effective smoothing of the data. In addition, we demonstrate how the Q estimate can be improved by utilizing more appropriate estimates of arterial carbon dioxide tension.     

Use of neural network to in situ conditioning of semiconductor plasma processing equipment

A strategy for in situ fault detection of plasma equipment is presented. This was accomplished by combining optical emission spectroscopy (OES), neural network. The OES was used to collect fault spectra, inducted by radio frequency source and bias powers. A fault detection model was constructed by training the backpropagation neural network (BPNN) on the whole OES spectrum representing a normal plasma operation. The trained BPNN model was tested on the test data generated at other powers. The test result indicates that the BPNN model was capable of detecting abnormal plasma caused by a small variation of 1% in the source power. Due to less impact on the plasma properties, the BPNN model reacted sensitively only to a relatively large variation in the bias power. The performance of the BPNN model-based monitoring scheme was further compared to that of identified radicals. Much improved sensitivity of the BPNN model over them was clearly demonstrated for the source power variation. On the other hand, certain radicals yielded much improved detection for the bias power variation. This was manifest as plasma was monitored by means of the CUSUM control chart. In consequence, monitoring BPNN model-based prediction and identified radicals simultaneously is expected to provide an improved detection of plasma processing equipment.     

ICP工艺参数对刻蚀Pyrex玻璃影响的实验研究

影响ICP刻蚀的工艺参数包括反应室压力,偏置射频功率,氩气流量比率。通过正交试验的方法,以CHF3和Ar的混合物作为反应气体,利用电感耦合等离子体技术刻蚀Pyrex玻璃。并采用回归分析方法建立了二次回归方程模型描述腐蚀速率和三个因素之间的关系。实验结果表明,氩气的流量比率（总气体流量（CHF3+Ar）是恒定的）对刻蚀速率的影响最大,影响程度的主次顺序为氩气的流量比率,反应室压力,偏置射频功率。腐蚀速率和三个因素之间的数学表达式为：腐蚀速率=532.6800+2.0556×Ar+0.0127×（偏置射频功率）-0.9641×压力-0.0655×Ar2-0.0067×Ar×（偏置射频功率）+0.0217×（偏置射频功率）×压力-0.0504×（压力）2,实验结果证明数学拟合结果良好。     

High resolution turbulence modelling of airflow in an idealised human extra-thoracic airway

Computational fluid dynamic (CFD) studies of the flow inside a modelled human extra-thoracic airway (ETA) were conducted to evaluate the performance of several turbulence models in predicting flow inside this complex geometry. Veracity of the computational models is assessed for physiologically accurate flow rates of 10, 15, and 30 l/min by comparison of numerical results with hot-wire [Johnstone A, Uddin M, Pollard A, Heenan A, Finlay WH. The flow inside an idealised form of the human extra-thoracic airway. Exp Fluids 2004;37(5):673-89] and particle image velocimetry (PIV) [Heenan AF, Matida E, Pollard A, Finlay WH. Experimental measurements and computational modelling of the flow field in an idealised extra-thoracic airway. Exp Fluids 2003;35:70-84] mean velocity data for the central sagittal plane of the ETA. Furthermore, flow features predicted by numerical models are compared to those from experimental flow-visualisation studies [Johnstone et al., 2004]. The flow in the ETA is shown to be highly three-dimensional, having strong secondary flows.     

Experimental studies on removal of carbon dioxide by aqueous ammonia fine spray

Experimental studies on carbon dioxide capture in a spray scrubber were carried out.Fine spray of aqueous ammonia was used as CO2 absorbent.Effects of different operating and design parameters on CO2 removal efficiency including concentration of aqueous ammonia,liquid flow rate,total gas flow rate,initial temperature and concentration of carbon dioxide were investigated.     

天然气管道输气站流量调节全息模式的设计

针对现有天然气输气站单路流量调节方法的不足,改进人工设定下游供气量,使供气量自动调节。以某站进行研究和试点,取某段时间内的历史供气量、压力、热值、温度、管径等参考数据,通过使用Gregg Engineering的稳态气体仿真模拟工具WinFlow,得到流量预测值,由工作人员确认预测值是否所需。确认预测值后,流量调节先根据模糊PID控制算法进行阀位调节,使阀后的供气量接近所需设定值,再进行流量微调整,以达到下游所需供气量。通过现场调试的结果发现,调压系统中加入流量调节全息模式可以有效地使下游用户所需供气量根据设定值自动调节,并且流量稳定、快速地到达预设值,提高输气效率,对调压系统有重要意义。     

The Intelligent Ventilator (INVENT) project: the role of mathematical models in translating physiological knowledge into clinical practice

This dissertation has addressed the broad hypothesis as to whether building mathematical models is useful as a tool for translating physiological knowledge into clinical practice. In doing so it describes work on the INtelligent VENTilator project (INVENT), the goal of which is to build, evaluate and integrate into clinical practice, a model-based decision support system for control of mechanical ventilation. The dissertation describes the mathematical models included in INVENT, i.e. a model of pulmonary gas exchange focusing on oxygen transport, and a model of the acid-base status of blood, interstitial fluid and tissues. These models have been validated, and applied in two other systems: ALPE, a system for measuring pulmonary gas exchange and ARTY, a system for arterialisation of the acid-base and oxygen status of peripheral venous blood. The major contributions of this work are as follows. A mathematical model has been developed which can describe pulmonary gas exchange more accurately that current clinical techniques. This model is parsimonious in that it can describe pulmonary gas exchange from measurements easily available in the clinic, along with a readily automatable variation in F(I)O(2). This technique and model have been developed into a research and commercial tool (ALPE), and evaluated both in the clinical setting and when compared to the reference multiple inert gas elimination technique (MIGET). Mathematical models have been developed of the acid- base chemistry of blood, interstitial fluid and tissues, with these models formulated using a mass-action mass-balance approach. The model of blood has been validated against literature data describing the addition and removal of CO(2), strong acid or base, and haemoglobin; and the effects of oxygenation or deoxygenation. The model has also been validated in new studies, and shown to simulate accurately and precisely the mixing of blood samples at different PCO(2) and PO(2) levels. This model of acid-base chemistry of blood has been applied in the ARTY system. ARTY has been shown to accurately and precisely calculate arterial values of acid-base and oxygen status in patients residing in the ICU, and in those with chronic lung disease. The INtelligent VENTilator (INVENT) system has been developed for optimization of mechanical ventilator settings using physiological models and utility/penalty functions, separating physiological knowledge from clinical preference. The models can be tuned to the individual patient via parameter estimation, providing patient specific advice. The INVENT team has shown prospectively that the system provides advice on F(I)O(2) which is as good as clinical practice, and retrospectively that the system provides reasonable suggestions of tidal volume, respiratory frequency and F(I)O(2). In general, this dissertation has illustrated a further example of the role of modeling in describing and understanding complex systems. The dissertation has shown that when dealing with complexity the goal of the model must be in focus if a correct balance is to be maintained between system complexity and model parameterization. The original goal of the INVENT team, i.e. to build, evaluate and integrate a DSS for control of mechanical ventilation has not as yet been completed. However, the broader hypothesis that building models generates new and interesting questions has been successfully demonstrated. The ALPE model and system has been applied in intensive care, post operative care and cardiology and is currently being evaluated in new clinical domains. ARTY has been shown to have potential benefit in eliminating the need for painful arterial punctures, and may also be useful as a screening tool. These systems illustrate the benefits of investing in models as a mechanism for translating physiological knowledge to clinical practice.     

碳化硅薄膜的ICP浅刻蚀工艺研究

选用SF6/O2 混合气体对等离子体增强化学气相淀积( PECVD)法制备的碳化硅( SiC)薄膜进行了浅槽刻蚀,并通过正交试验设计方法,研究了感应耦合等离子体( ICP)刻蚀技术中反应室压强、偏压射频( BRF)功率、O2 比例三个工艺参数对碳化硅薄膜刻蚀速率的影响及其显著性.实验结果表明:BRF功率对于刻蚀速率的影响具有高度显著性,各因素对刻蚀速率的影响程度依次为BRF功率>反应室压强>O2 比例,并讨论了所选因素对碳化硅薄膜刻蚀速率的影响机理.     

安全高效矿井监控关键技术研究

提出安全高效矿井应采用先进可靠的监控技术,实现供电、排水、通风、压风、运输、提升、瓦斯抽采等固定岗位无人值守和地面远程控制,综采、综放等采煤工作面少人作业和地面远程控制;提出供电、排水、通风、压风、运输、提升、瓦斯抽采等监控系统应具有地面远程控制功能;提出具有远程控制、报警联动、调度指挥等功能的煤矿调度指挥控制中心;提出整合计算机网络机房、程控交换机机房、调度交换机机房、监控系统机房等的数据中心;提出基于煤层瓦斯压力和瓦斯含量、综合指标、钻屑瓦斯解吸指标、复合指标、R值指标、瓦斯涌出量(根据瓦斯体积分数和风量计算)、巷道位置、微震、地音、温度等及其变化的煤与瓦斯突出预警方法;提出基于WiFi的矿用无线传输接口,以便于互通互联;提出通过分布式光纤测温预警煤炭自然发火,较通过监测CO等煤炭自然发火标志气体更直接、更及时、更可靠;提出根据运煤量实时调整输送带速度:当煤量较小时降低输送带运行速度,当煤量较大时提高输送带运行速度,以提高运输效率,减少设备磨损;提出基于光纤综合保护的供电监控系统具有防越级跳闸、地面远程整定和地面远程控制功能,提高了煤矿供电的可靠性,可实现煤矿井下机电硐室无人值守;提出具有煤岩识别与滚筒自动调高,采煤机、刮板机、液压支架3机联动,记忆割煤,地面远程、顺槽近程、手动控制和紧急停机,放顶煤量和煤矸控制,采煤机和刮板机等大型机电设备故障诊断等功能的采煤工作面监控系统。     

Au-In2O3 CO气体传感器的性能与机理研究

为了探讨氧化铟气体传感器的CO气敏性能和气敏机理,分别用化学沉淀法和浸渍法制备了未掺杂和金掺杂的氧化铟气敏材料,利用XRD和TEM对合成产物进行了表征.采用静态配气法测试了合成材料的气敏性能,利用气相色谱在线测试了CO在气敏材料表面的催化氧化产物,根据气敏性能与催化氧化结果研究了金掺杂氧化铟的气敏机理.实验结果表明:以2%质量比的金掺杂氧化铟对一氧化碳的反应有较高的灵敏度和选择性.根据金掺杂氧化铟对CO的催化氧化性能与气敏性能基本一致的结果,提出了金对氧化铟的CO增敏机理为化学增敏作用.     

云服务平台的配电终端全生命周期跟踪管理

介绍了一种以配电自动化终端产品为基础,通过RFID技术和网络云服务平台,建立了高效的数据交换通道,对产品全生命周期的所有信息进行管理与分析,使制造企业、供电公司、设备使用单位在能效、安全等方面达到整体最优,为实现电力系统的"信息流、业务流、电力流的高度融合"提供有力的信息服务.     

一种应用于隔爆试验装置中的新型自动配气系统

针对应用于隔爆试验装置中的传统配气方法存在配气速度慢、系统体积较大的问题,设计了一种基于质量流量法的自动配气系统。该系统采用质量流量控制器精确控制多种不同气体的流量,输出的多种气体经混合装置均匀混合后,由O2分析仪和H2分析仪实时监测混合气体的体积分数。测试结果表明,该配气系统配气速度快、结构简单,配制的多种气体体积分数精度能满足GB 3836.2—2010的要求。     

基于模糊控制和大数据算法模型的电力运维故障诊断设备方法

针对现有技术中对电力运维故障检测灵敏度低、诊断误差大等问题,设计了一种新型故障诊断方案。该方案将PID模糊控制计算器与大数据算法模型相结合,并采用实时布线的方法减少诊断面积,基于改进型大数据算法模型提取电力运维设备故障数据特征,对电力运维设备运行工况构建诊断网络,通过分析电力运维设备工况的功能系统完成数据诊断。为了减少诊断误差,该研究设计了一种故障诊断设备,采用集成芯片化设计和算法程序,减小体积的同时保证检测结果的准确性。实验结果表明,该研究方法故障诊断误差小,准确率最高达到98.6%。