We propose a novel and efficient multi-functional optical fiber sensor system based on a dense wavelength division multiplexer(DWDM).This system consists of an optical fiber temperature sensor, an optical fiber strain...We propose a novel and efficient multi-functional optical fiber sensor system based on a dense wavelength division multiplexer(DWDM).This system consists of an optical fiber temperature sensor, an optical fiber strain sensor, and a 48-channel DWDM.This system can monitor temperature and strain changes at the same time.The ranges of these two sensors are from-20℃ to 100℃ and from-1000 με to 2000 με, respectively.The sensitivities of the temperature sensor and strain sensor are 0.03572 nm/℃ and 0.03808 nm/N, respectively.With the aid of a broadband source and spectrometer,different kinds and ranges of parameters in the environment can be monitored by using suitable sensors.展开更多
Passenger ride comfort has become a focus of attention in rail transportation equipment design,manufacture and later operation to meet people’s demand for travel quality.However,comfort is a very subjective concept,w...Passenger ride comfort has become a focus of attention in rail transportation equipment design,manufacture and later operation to meet people’s demand for travel quality.However,comfort is a very subjective concept,which is difficult to quantify and evaluate directly,and can be affected by various factors,leading to the corresponding technologies for ride comfort improvement becoming diverse.In this paper,recent research on the assessment method and improvement measures of railway passenger ride comfort is reviewed.The main types of ride comfort are summarized first according to the sources of discomfort,including static comfort,vibration comfort,noise comfort,aural pressure comfort,thermal comfort and visual comfort.The current assessment methods of ride comfort are introduced from the aspects of environmental parameters and human parameters based on the nature of evaluation indicators.Finally,the improvement technologies for each type of ride comfort are presented.展开更多
Discomfort caused by long-term sitting decreases the passenger experience and may lead to musculoskeletal diseases, and this hasbecome one of the main problems for passengers of high-speed railways. However, the comfo...Discomfort caused by long-term sitting decreases the passenger experience and may lead to musculoskeletal diseases, and this hasbecome one of the main problems for passengers of high-speed railways. However, the comfort degradation mechanism during longtermsitting in high-speed railways is still unknown. This study aimed to reveal passengers’ sitting comfort degradation mechanismin high-speed railways. By carrying out long-term sitting tests on high-speed trains running on the Shanghai-Kunming line, the dynamicinterface pressure and subjective comfort including overall and regional comfort of seven participants were obtained.Machinelearning models and statistical analysis methods were combined for data analysis to reveal the effect of regional comfort and thecontribution of sitting duration during the process of sitting comfort degradation. The results show that overall comfort is most significantlyinfluenced by the comfort of the shoulders, waist and buttocks. The seats play different roles before and after 20 minutesduring long-term sitting and there is a lag between the fatigue occurring and being offset. Therefore, the structure of seats affectsoverall comfort by affecting important regional comfort, and a long-term sitting test is necessary for accurate seat assessment. Thecomfort degradation mechanism can be used to define standards for long-term sitting comfort or provide guidance for seat evaluation,and the design and evaluation plan mentioned in this article for second-class seats can be applied to other cases with limitedaccommodating space.展开更多
基金Project supported by the National Key Research and Development Program of China(Grant No.2016YFB0402504)the National Natural Science Foundation of China(Grant Nos.61875069 and 61575076)+1 种基金Hong Kong Scholars Program,China(Grant No.XJ2016026)the Science and Technology Development Plan of Jilin Province,China(Grant Nos.20190302010GX and 20160520091JH)
文摘We propose a novel and efficient multi-functional optical fiber sensor system based on a dense wavelength division multiplexer(DWDM).This system consists of an optical fiber temperature sensor, an optical fiber strain sensor, and a 48-channel DWDM.This system can monitor temperature and strain changes at the same time.The ranges of these two sensors are from-20℃ to 100℃ and from-1000 με to 2000 με, respectively.The sensitivities of the temperature sensor and strain sensor are 0.03572 nm/℃ and 0.03808 nm/N, respectively.With the aid of a broadband source and spectrometer,different kinds and ranges of parameters in the environment can be monitored by using suitable sensors.
基金the National Natural Science Foun-dation of China(Grant No.52075553)the Hunan Science Foun-dation for Distinguished Young Scholars of China(Grant No.2021JJ10059)the School Enterprise Cooperation Program of Cen-tral South University(Grant No.2021XQLH097).
文摘Passenger ride comfort has become a focus of attention in rail transportation equipment design,manufacture and later operation to meet people’s demand for travel quality.However,comfort is a very subjective concept,which is difficult to quantify and evaluate directly,and can be affected by various factors,leading to the corresponding technologies for ride comfort improvement becoming diverse.In this paper,recent research on the assessment method and improvement measures of railway passenger ride comfort is reviewed.The main types of ride comfort are summarized first according to the sources of discomfort,including static comfort,vibration comfort,noise comfort,aural pressure comfort,thermal comfort and visual comfort.The current assessment methods of ride comfort are introduced from the aspects of environmental parameters and human parameters based on the nature of evaluation indicators.Finally,the improvement technologies for each type of ride comfort are presented.
基金the National Natural Science Foundation of China(Grant No.52075553)the Hunan Science Foundation for Distinguished Young Scholars of China(Grant No.2021JJ10059)the School Enterprise Cooperation Program of Central South University(Grant No.2021XQLH011).
文摘Discomfort caused by long-term sitting decreases the passenger experience and may lead to musculoskeletal diseases, and this hasbecome one of the main problems for passengers of high-speed railways. However, the comfort degradation mechanism during longtermsitting in high-speed railways is still unknown. This study aimed to reveal passengers’ sitting comfort degradation mechanismin high-speed railways. By carrying out long-term sitting tests on high-speed trains running on the Shanghai-Kunming line, the dynamicinterface pressure and subjective comfort including overall and regional comfort of seven participants were obtained.Machinelearning models and statistical analysis methods were combined for data analysis to reveal the effect of regional comfort and thecontribution of sitting duration during the process of sitting comfort degradation. The results show that overall comfort is most significantlyinfluenced by the comfort of the shoulders, waist and buttocks. The seats play different roles before and after 20 minutesduring long-term sitting and there is a lag between the fatigue occurring and being offset. Therefore, the structure of seats affectsoverall comfort by affecting important regional comfort, and a long-term sitting test is necessary for accurate seat assessment. Thecomfort degradation mechanism can be used to define standards for long-term sitting comfort or provide guidance for seat evaluation,and the design and evaluation plan mentioned in this article for second-class seats can be applied to other cases with limitedaccommodating space.