比较了两个声学特征对区分阻塞性睡眠呼吸暂停低通气综合症(OSAHS)患者不同鼾声信号的性能。如何寻找能够反映上气道阻塞程度的声学特征对于医生和工程师去共同开发能够指导精确手术的"非侵入式"OSAHS诊断检测设备有重要意义...比较了两个声学特征对区分阻塞性睡眠呼吸暂停低通气综合症(OSAHS)患者不同鼾声信号的性能。如何寻找能够反映上气道阻塞程度的声学特征对于医生和工程师去共同开发能够指导精确手术的"非侵入式"OSAHS诊断检测设备有重要意义。波峰因子(crest factor)和800 Hz功率比(power ratio 800)被分别进行了比较,我们发现,对于区分两个不同上气道阻塞程度时产生的鼾声信号,即低通气和正常呼吸时,power ratio 800有比crest factor更好的性能。展开更多
A new bipolar junction field-effect transistor (BJFET) was described. The theoretical analysis and computer simulation of BJFET obstructive characteristic are achieved. The gate bias voltage affects the BJFET obstruct...A new bipolar junction field-effect transistor (BJFET) was described. The theoretical analysis and computer simulation of BJFET obstructive characteristic are achieved. The gate bias voltage affects the BJFET obstructive voltage greatly. The BJFET obstructive characteristic is relevant to structure parameters of channel width W and channel length L. The decrease-bias-voltage operation can weaken the device obstructive characteristic. The forward turn in device forward obstructive region can also affect the BJFET obstructive characteristic. BJFET has a good high temperature obstructive characteristic and can be applying to high temperature status as high voltage switch devices.展开更多
Existed evidences show that airborne transmission of human respiratory droplets may be related with the spread of some infectious disease, such as severe acute respiratory syndrome （SARS） and H1N1 pandemic. Non-phar...Existed evidences show that airborne transmission of human respiratory droplets may be related with the spread of some infectious disease, such as severe acute respiratory syndrome （SARS） and H1N1 pandemic. Non-pharmaceutical approaches, including ventilation system and personal protection, are believed to have certain positive effects on the reduction of co-occupant＇s inhalation. This work then aims to numerically study the performances of mouth covering on co-occupant＇s exposure under mixing ventilation （MV）, under-floor air distribution （UFAD） and displacement ventilation （DV） system, using drift-flux model. Desk partition, as one generally employed arrangement in plan office, is also investigated under MV. The dispersion of 1, 5 and 10 grn droplet residuals are numerically calculated and CO2 is used to represent tracer gas. The results show that using mouth covering by the infected person can reduce the co-occupant＇s inhalation greatly by interrupting direct spread of the expelled droplets, and best performance can be achieved under DV since the coughed air is mainly confined in the microenvironment of the infected person. The researches under MV show that the two interventions, mouth covering and desk partition, achieve almost the sarae inhalation for fine droplets while the inhalation of the co-occupant is lower when using mouth covering for large droplets.展开更多
文摘比较了两个声学特征对区分阻塞性睡眠呼吸暂停低通气综合症(OSAHS)患者不同鼾声信号的性能。如何寻找能够反映上气道阻塞程度的声学特征对于医生和工程师去共同开发能够指导精确手术的"非侵入式"OSAHS诊断检测设备有重要意义。波峰因子(crest factor)和800 Hz功率比(power ratio 800)被分别进行了比较,我们发现,对于区分两个不同上气道阻塞程度时产生的鼾声信号,即低通气和正常呼吸时,power ratio 800有比crest factor更好的性能。
文摘A new bipolar junction field-effect transistor (BJFET) was described. The theoretical analysis and computer simulation of BJFET obstructive characteristic are achieved. The gate bias voltage affects the BJFET obstructive voltage greatly. The BJFET obstructive characteristic is relevant to structure parameters of channel width W and channel length L. The decrease-bias-voltage operation can weaken the device obstructive characteristic. The forward turn in device forward obstructive region can also affect the BJFET obstructive characteristic. BJFET has a good high temperature obstructive characteristic and can be applying to high temperature status as high voltage switch devices.
基金funded by Research Grant Committee of the Hong Kong SAR government (RGC No. PolyU5265/08E)
文摘Existed evidences show that airborne transmission of human respiratory droplets may be related with the spread of some infectious disease, such as severe acute respiratory syndrome （SARS） and H1N1 pandemic. Non-pharmaceutical approaches, including ventilation system and personal protection, are believed to have certain positive effects on the reduction of co-occupant＇s inhalation. This work then aims to numerically study the performances of mouth covering on co-occupant＇s exposure under mixing ventilation （MV）, under-floor air distribution （UFAD） and displacement ventilation （DV） system, using drift-flux model. Desk partition, as one generally employed arrangement in plan office, is also investigated under MV. The dispersion of 1, 5 and 10 grn droplet residuals are numerically calculated and CO2 is used to represent tracer gas. The results show that using mouth covering by the infected person can reduce the co-occupant＇s inhalation greatly by interrupting direct spread of the expelled droplets, and best performance can be achieved under DV since the coughed air is mainly confined in the microenvironment of the infected person. The researches under MV show that the two interventions, mouth covering and desk partition, achieve almost the sarae inhalation for fine droplets while the inhalation of the co-occupant is lower when using mouth covering for large droplets.
