Noninvasive determination of cardiac output in patients with severe airflow limitation

The noninvasive measurement of cardiac output (Q) by the Indirect Fick CO2-rebreathing technique requires mixed venous P CO2 (P CO2) to be determined by the rebreathing maneuver, and Pa CO2 to be estimated from end-tidal P CO2 (PET CO2). Previous work has suggested that although P CO2 can be determined, Pa CO2 cannot be accurately estimated in patients with significant airflow limitation. Nineteen patients with cystic fibrosis who had severe airflow limitation (%FEV1, 29.3 +/- 7.12 SD) were studied during steady-state exercise at 50% of their measured maximal work capacity. Estimated Pa CO2 was slightly lower than Pa CO2 measured from blood samples obtained from an indwelling arterial catheter (measured: 45.2 +/- 4.92; estimate: 42.7 +/- 5.68 mm Hg). To calculate arterial blood content, the values derived from Pa CO2, pH, hemoglobin (Hb), and O2 saturation were compared with those derived from PET CO2 and O2 saturation, where (1) pH was assumed to be 7.40 and Hb was measured, and (2) pH was assumed to be 7.40 and Hb was assumed to be 15 g/dl (measured mean pH, 7.34; Hb, 14.4 g/dl). No difference in arterial CO2 content was seen between the three methods (measured: 47.53 +/- 5.17; estimate 1: 49.57 +/- 6.58; estimate 2: 49.12 +/- 6.61 ml/100 ml). As pH and Hb can also affect mixed venous CO2 content, the effect on Q was also assessed. Both estimates fit closely with measured Q (r2=0.77 and 0.76), with intercepts not different from zero and slopes not different from 1, and coefficients of variation of 13.5 and 14.6%. When viewed with regard to the confidence intervals for Q as a function of O2 consumption, Q was altered to a minor extent. We conclude that the use of PET CO2 to estimate Pa CO2 can give reasonable values for Q determined noninvasively in patients with severe airflow limitation.     

煤粉性状对残炭颗粒微结构及其燃烧特性的影响

本文研究了不同粒主工的烟煤和无烟煤经高温气流燃烧后残炭颗粒的形态及孔隙结构，对其燃烧方式和燃尽特性进行了讨论，并比较了两种煤的差别。结果表明，由镜质组形成的残炭表面和内部同时燃烧，并比较了两种煤的差别。结果表明，由镜质组形成的球残炭表面和内部时燃烧，容易燃尽；由惰性组形成的不规则残炭以外部反应为主，较难燃尽，同无烟煤相比，烟煤残炭孔隙多，燃烧剧列，且孔穴内部燃烧所占比重更大。     

NUMERICAL STUDY ON QUASI- STEADY FLOW OF NONNEWTONIAN FLUID IN SUCK-ROD PUMP

This paper presents a numerical method for simulation of the flow and thecalculated results of the quasi-steady axisymmetrical flow field and pressure distribution on valveball with power-law model for Non-Newtonian fluid in suck-rod pump.We believe the methodcan provide a foundation for further research and improvement of the design of suck-rod pump.     

铈离子引发壳聚糖与MMA接枝共聚的研究

在乙酸水溶液中，以铈盐为氧化还原引发剂，在氮气存在下，壳聚糖与ＭＭＡ可发生接枝共聚反应。接枝百分比及均聚物百分含量依赖于反应温度、时间和引发剂的浓度，但不依赖于单体的浓度。表观活化能为７４．４ｋＪ／ｍｏｌ。接枝物不溶于壳聚糖的溶剂，在丙酮中发生溶胀现象。     

液相对流对固液界面稳定性的影响

以模型合金丁二腈－乙醇的强制性晶体生长为基础，利用自行研制的液相对流驱动装置，详细考查了液相自然对流及强迫对流作用下，模型合金平界面失稳的动态生长过程，证实了液相的流动加快了液相温度与浓度分布的均匀化，从而增强了液／固界面的稳定性。并且随流动速度的增加，界面稳定性提高。     

Intermodulation analysis of the collector-up InGaAs/InAlAs/InP HBTusing Volterra series

The intermodulation (IM) distortion of the collector-up InGaAs/InAlAs/InP heterojunction bipolar transistor (HBT) is analyzed using Volterra-series theory. A T-equivalent circuit is used for this analysis. The contribution and interaction of four nonlinear elements: base-emitter resistance, base-emitter capacitance, base-collector capacitance, and common base-current gain are analyzed. For the particular device under investigation, it is found that the cancellation effect is not significant and the base-emitter resistance nonlinearity dominates the third-order IM     

注水站微机数据采集与控制系统

用工控机组成了油田注水站数据采集系统．给出了系统的组成及测量方法，并讨论了系统的可靠性等问题．     

卫星包装箱的随机隔振优化分析

用钢丝绳隔振器将卫星包装箱支承在运输车上,将卫星与车辆简化为二自由度体系,优化分析了在随机路面上行驶时使包装箱响应最小之隔振参数,对实测得到的钢丝绳减振器的非线性迟滞性能作了描述,提出了统计线性化分析的方法。     

热塑性聚氨酯增韧改性聚甲醛的研究

本文对ＰＯＭ／ＴＰＰＵ／Ｚ－３共混体系进行了研究，结果表明，增容剂Ｚ－３可控制共混体系中分散相的颗粒尺寸及分布，起着聚集剂的作用。随着ＴＰＰＵ用量的增加，共混合金的结晶度和拉伸强度增降低，缺口冲击强度出现峰值，ＭＩ下降，当ＰＯＭ／ＴＰＰＵ／Ｚ－３＝１００／７／０．４９时，共混合金的缺口冲击强度达到最大值。