Natural gas (NG) is one of the most important sources of energy for industrial and domestic consumption in the present era because it is cheap and free from sulfur impurities. Therefore, accurate and precise measureme...Natural gas (NG) is one of the most important sources of energy for industrial and domestic consumption in the present era because it is cheap and free from sulfur impurities. Therefore, accurate and precise measurement of its composition is of fundamental importance for trade reasons. To improve the quality of NG gas measurements, certified reference materials (CRMs) should be used for calibration of measuring equipment in order to ensure the traceability of the measurement results to the SI units. For the traceability purpose, a multicomponent natural gas mixture was prepared gravimetrically as a reference material according to ISO 6142 from pure helium, hydrogen, n-pentane, i-pentane, n-butane, i-butane, propane, ethane, hexane, methane and nitrogen. The preparation was done in two dilution steps in 5 L aluminum cylinders. The calculated mole fractions and associated uncertainties of natural gas components were verified by a dual GC-FID/TCD system in accordance with ISO 6143 calibrated by a series of primary gas mixtures (CRMs) produced by an NMI. The results obtained by gravimetry and by GC measurements have been checked for compatibility as required by ISO 6142 and were found in very good agreement. Details of the preparation and calculation of the mole fractions and uncertainties of all gas components are explained in this article.展开更多
目的探讨格拉斯哥昏迷评分（Glasgow Coma Scale,GCS）及美国国立卫生院神经功能缺损评分（National Institutes of Health Stroke Scale,NIHSS）对基底动脉尖综合征（top of the basilar syndrome,TOBS）转归的预测价值。方法从南京卒...目的探讨格拉斯哥昏迷评分（Glasgow Coma Scale,GCS）及美国国立卫生院神经功能缺损评分（National Institutes of Health Stroke Scale,NIHSS）对基底动脉尖综合征（top of the basilar syndrome,TOBS）转归的预测价值。方法从南京卒中注册系统中筛选出符合基底动脉尖综合征诊断的64例患者,根据卒中后30d改良Rankin量表评分（modified Rankin Scale,mRS）分为好转组（0-3分）和不良转归组（4-6分）,对两组入院时GCS、NIHSS评分进行回顾性分析。结果不良转归组中GCS分值低于好转组（P〈0.01）;NIHSS分值均高于好转组（P=0.011）。经Logistic回归校正年龄、性别及治疗方式3个因素后,GCS评分OR值0.301（95%CI0.167-0.542）;NIHSS评分OR值1.436（95%CI1.147-1.796）,二者均为独立预测因素。ROC曲线分析显示,以GCS分值10分作为预测TOBS预后的界点,其灵敏度87.9%,特异度83.9%;以NIHSS分值14分作为界点,灵敏度63.6%,特异度77.4%。结论GCS、NIHSS均是基底动脉尖综合征转归重要的预测指标;GCS≤10分、NIHSS≥14分对于基底动脉尖综合征患者不良转归均有重要的预测价值,GCS预测效价高于NIHSS。展开更多
文摘Natural gas (NG) is one of the most important sources of energy for industrial and domestic consumption in the present era because it is cheap and free from sulfur impurities. Therefore, accurate and precise measurement of its composition is of fundamental importance for trade reasons. To improve the quality of NG gas measurements, certified reference materials (CRMs) should be used for calibration of measuring equipment in order to ensure the traceability of the measurement results to the SI units. For the traceability purpose, a multicomponent natural gas mixture was prepared gravimetrically as a reference material according to ISO 6142 from pure helium, hydrogen, n-pentane, i-pentane, n-butane, i-butane, propane, ethane, hexane, methane and nitrogen. The preparation was done in two dilution steps in 5 L aluminum cylinders. The calculated mole fractions and associated uncertainties of natural gas components were verified by a dual GC-FID/TCD system in accordance with ISO 6143 calibrated by a series of primary gas mixtures (CRMs) produced by an NMI. The results obtained by gravimetry and by GC measurements have been checked for compatibility as required by ISO 6142 and were found in very good agreement. Details of the preparation and calculation of the mole fractions and uncertainties of all gas components are explained in this article.
文摘目的探讨格拉斯哥昏迷评分（Glasgow Coma Scale,GCS）及美国国立卫生院神经功能缺损评分（National Institutes of Health Stroke Scale,NIHSS）对基底动脉尖综合征（top of the basilar syndrome,TOBS）转归的预测价值。方法从南京卒中注册系统中筛选出符合基底动脉尖综合征诊断的64例患者,根据卒中后30d改良Rankin量表评分（modified Rankin Scale,mRS）分为好转组（0-3分）和不良转归组（4-6分）,对两组入院时GCS、NIHSS评分进行回顾性分析。结果不良转归组中GCS分值低于好转组（P〈0.01）;NIHSS分值均高于好转组（P=0.011）。经Logistic回归校正年龄、性别及治疗方式3个因素后,GCS评分OR值0.301（95%CI0.167-0.542）;NIHSS评分OR值1.436（95%CI1.147-1.796）,二者均为独立预测因素。ROC曲线分析显示,以GCS分值10分作为预测TOBS预后的界点,其灵敏度87.9%,特异度83.9%;以NIHSS分值14分作为界点,灵敏度63.6%,特异度77.4%。结论GCS、NIHSS均是基底动脉尖综合征转归重要的预测指标;GCS≤10分、NIHSS≥14分对于基底动脉尖综合征患者不良转归均有重要的预测价值,GCS预测效价高于NIHSS。
