期刊文献+
共找到2篇文章
< 1 >
每页显示 20 50 100
SATURATION DIVING WITH HELIOX TO 350 METERS OBSERVATION ON HEARING THRESHOLD, BRAINSTEM EVOKED RESPONSE AND ACOUSTIC IMPEDANCE 被引量:1
1
作者 汪磊 姜伟 +1 位作者 龚锦涵 郑向阳 《Chinese Medical Journal》 SCIE CAS CSCD 1994年第12期56-60,共5页
Four divers were compressed to 350 m to observe changes in hearing threshold, brainstem evoked response and acoustic impedance. The divers experienced no tinnitus, impairment of bearing, earache daring compression. Ex... Four divers were compressed to 350 m to observe changes in hearing threshold, brainstem evoked response and acoustic impedance. The divers experienced no tinnitus, impairment of bearing, earache daring compression. Examination showed that the threshold of tower frequency range of hearing was elevated because of the masking effect of the noise in the hyperbaric chamber. Changes in waveform and latency of brainstem evoked response were due to changes in sound wave transmission affected by the chamber pressure and a poor ratio of signal to noise in the hyperbaric environment with heliox. All these changes were transient After leaving the chamber, the hearing threshold and brainstem evoked response returned to normal. Besides, there were no changes in tympanogram, acoustic compliance and stapedius reflex before and after diving. This indicated the designed speed of compression and decompression in the experiment caused no damage to the divers' acoustic system, and the functions of their Eustachain tubes, middle and inner ears were normal during the diving test 展开更多
关键词 In BRAINSTEM EVOKED RESPONSE AND ACOUSTIC IMPEDANCE SATURATION DIVING WITH HELIOX TO 350 METERS observation ON HEARING threshold
原文传递
Effective model based fault detection scheme for rudder servo system
2
作者 徐巧宁 周华 +2 位作者 喻峰 魏兴乔 杨华勇 《Journal of Central South University》 SCIE EI CAS 2014年第11期4172-4183,共12页
The inherent nonlinearities of the rudder servo system(RSS) and the unknown external disturbances bring great challenges to the practical application of fault detection technology. Modeling of whole rudder system is a... The inherent nonlinearities of the rudder servo system(RSS) and the unknown external disturbances bring great challenges to the practical application of fault detection technology. Modeling of whole rudder system is a challenging and difficult task. Quite often, models are too inaccurate, especially in transient stages. In model based fault detection, these inaccuracies might cause wrong actions. An effective approach, which combines nonlinear unknown input observer(NUIO) with an adaptive threshold, is proposed. NUIO can estimate the states of RSS asymptotically without any knowledge of external disturbance. An adaptive threshold is used for decision making which helps to reduce the influence of model uncertainty. Actuator and sensor faults that occur in RSS are considered both by simulation and experimental tests. The observer performance, robustness and fault detection capability are verified. Simulation and experimental results show that the proposed fault detection scheme is efficient and can be used for on-line fault detection. 展开更多
关键词 rudder servo system fault detection nonlinear unknown input observer adaptive threshold
下载PDF
上一页 1 下一页 到第
使用帮助 返回顶部