The paper takes a new campus project site of Shanxi university town for example, tests the influence of dynamic com- paction vibration and vibration isolation effect of isolation trench on this ground, and compares th...The paper takes a new campus project site of Shanxi university town for example, tests the influence of dynamic com- paction vibration and vibration isolation effect of isolation trench on this ground, and compares the influences of the dynamic compaction vibration on surrounding buildings with isolation trench and without it. Furthermore, the attenuation law of dy- namic compaction vibration in fill foundation of the loess area under different tamping energy and how to determine safe distance of dynamic compaction construction are studied. And then the quantitative relationship between acceleration and vibration source in new campus project site is presented. We derive the evaluation method that dynamic compaction construction affects adjacent buildings by contrasting with the existing standards and norms. The monitoring results show that isolation trench makes the amplitude attenuation of the horizontal velocity of dynamic compaction vibration reach above 75%, and the safe dis- tance be 30 m under the tamping energy of 6 000 kN · m. Therefore, isolation trench is better for vibration reduction under dynamic compaction construction.展开更多
Sensor localization is crucial for the configuration and applications of wireless sensor network (WSN). A novel distributed localization algorithm, MDS-DC was proposed for wireless sensor network based on multidimensi...Sensor localization is crucial for the configuration and applications of wireless sensor network (WSN). A novel distributed localization algorithm, MDS-DC was proposed for wireless sensor network based on multidimensional scaling (MDS) and the shortest path distance correction. In MDS-DC, several local positioning regions with reasonable distribution were firstly constructed by an adaptive search algorithm, which ensures the mergence between the local relative maps of the adjacent local position regions and can reduce the number of common nodes in the network. Then, based on the relationships between the estimated distances and actual distances of anchors, the distance estimation vectors of sensors around anchors were corrected in each local positioning region. During the computations of the local relative coordinates, an iterative process, which is the combination of classical MDS algorithm and SMACOF algorithm, was applied. Finally, the global relative positions or absolute positions of sensors were obtained through merging the relative maps of all local positioning regions. Simulation results show that MDS-DC has better performances in positioning precision, energy efficiency and robustness to range error, which can meet the requirements of applications for sensor localization in WSN.展开更多
Wire ropes,employed extensively in coal mine hoists and transportation systems are subject to damage due to wear,corrosion and fatigue.The extent of damage and the carrying capacity of ropes are closely related to the...Wire ropes,employed extensively in coal mine hoists and transportation systems are subject to damage due to wear,corrosion and fatigue.The extent of damage and the carrying capacity of ropes are closely related to the sense of safety by staff and equipments.Magnetic flux leakage detection method(MFL),as an effective method,is these days widely used in detection of broken strands of wire ropes.In order to improve the accuracy of detection of flaws in wire ropes by magnetic flux leakage(MFL),the effect of the distance between a sensor and the surface of a wire rope(i.e.,lift-off) on detection by magnetic flux leakage was in-vestigated.An analysis of the main principles for the choice of lift-off is described by us and a new method that improves the structure of the detector is proposed from the point of view of the design of a magnetic circuit,to restrain the impact of fluctuations of sensor lift-off.The effect of this kind of method is validated by simulation and computation.The results show that the detection sensitivity is markedly increased by this method.Furthermore,the signal-to-noise ratio(SNR) can be increased by over 28%.This method will lend itself to offer reliable scientific information to optimize the structure of excitation devices and improve the accuracy of MFL detection.展开更多
Dynamic detection based on optics sensors and ranging radars is a new method to detect the luminous intensity of flight aid lights. The optics sensors can get the illumination information of each light, the ranging ra...Dynamic detection based on optics sensors and ranging radars is a new method to detect the luminous intensity of flight aid lights. The optics sensors can get the illumination information of each light, the ranging radar gets the distance information, and then data amalgamation technology is used to compute the luminous intensity of each light. A method to modify the errors of this dynamic detection system is presented. It avoids the accumulation error and measurement carrier’s excursion error by using peak value detection based on optics sensors to estimate the accurate position of each light, then to modify the lights’ lengthways distance information and transverse position information. The performance of the detection and ranging system is validated by some experiments and shown in pictures.展开更多
Kenya's tourism business stagnated from 1991 to 2003 and only registered small but steady grew from 2004. One of the sectors that recorded poor performance as a result of the slow growth of tourism is the hotel busin...Kenya's tourism business stagnated from 1991 to 2003 and only registered small but steady grew from 2004. One of the sectors that recorded poor performance as a result of the slow growth of tourism is the hotel business. Despite this slack, stakeholders in Kenya have not tried to assess the extent to which the quality of this sector may impact on destination preference. The ultimate purpose of this research was to establish the quality gap between the expected and the perceived hotel product/service quality from both the perspective of the tourists and the hotel operators in Kenya. It was motivated by the need to create parameters that can elavate the competitiveness of Kenya's tourism using the hotel product/service quality offer. Descriptive quantitative research design was used to establish the secondary objectives and to assess two propositions set for the study. A sample of 211 tourists and 19 hotel operators in two major tourist provinces of Kenya was used to obtain information regarding normative and perceptive hotel product/service quality. Kenya's only destination marketing organisation, Kenya Tourist Board (KTB) marketers were also surveyed to provide insight on Kenya's destination position with regard to the motivation of tourists to visit Kenya. The study established that although the attractions which make tourists come to Kenya are the unique wildlife safari, beach tourism and the natural scenery, hotel product quality and hospitality plays a vital role in motivating tourists to choose Kenya as the destination to visit. However, this study found out that while the tourists and hotel operators agree on the normative hotel product quality level, there is a significant gap between the normative quality and the perceptual quality registered by tourists who used hotel services. The study established that hotel operators only recognize quality regulatory institutions with statutory and legal authority to incriminate facilities that do not comply with laid down operational requirements such as Hotels and Restaurants Authority and the Local Authority Public Health Department. The study has proposed an integrated framework that may be utilized to build a superior national hotel product/service quality so that the economic potential of tourism is maximized in Kenya.展开更多
The equivalent two-port network model of a middle range wireless power transfer(WPT) system was presented based on strongly coupled multiple resonators. The key parameters of the WPT system include self-inductance, re...The equivalent two-port network model of a middle range wireless power transfer(WPT) system was presented based on strongly coupled multiple resonators. The key parameters of the WPT system include self-inductance, resistance, parasitic capacitance, mutual inductance and S-parameters of coils & resonators were analyzed. The impedance matching method was used to optimize load power and transmission efficiency of the multi-resonator WPT system, and the impedance matching method was realized through adjusting the distances between the coils and resonators. Experiments show that the impedance matching method can effectively improve load power and transmission efficiency for middle range wireless power transfer systems with multiple resonators, at distances up to 3 times the coil radius with efficiency more than 70% and load power also close to 3.5 W.展开更多
In this paper, we compare the quantum operation sensitivity for different distance measures. We find that, among all usual distance measures, Bures fidelity is more sensitive to quantum operation than others. This may...In this paper, we compare the quantum operation sensitivity for different distance measures. We find that, among all usual distance measures, Bures fidelity is more sensitive to quantum operation than others. This may explain in some sense why fidelity is so useful in quantum information theory.展开更多
Underwater Acoustic Sensor Network(UASN) has attracted significant attention because of its great influence on ocean exploration and monitoring. On account of the unique characteristics of underwater environment, loca...Underwater Acoustic Sensor Network(UASN) has attracted significant attention because of its great influence on ocean exploration and monitoring. On account of the unique characteristics of underwater environment, localization, as one of the fundamental tasks in UASNs, is a more challenging work than in terrestrial sensor networks. A survey of the ranging algorithms and the network architectures varied with different applications in UASNs is provided in this paper. Algorithms used to estimate the coordinates of the UASNs nodes are classified into two categories: rangebased and range-free. In addition, we analyze the architectures of UASNs based on different applications, and compare their performances from the aspects of communication cost, accuracy, coverage and so on. Open research issues which would affect the accuracy of localization are also discussed, including MAC protocols, sound speed and time synchronization.展开更多
The conception of "advanced radar" is introduced and lint forward, while it is proved that the weakpoints of interference can still be employed. Meanwhile, the paper expounds the principle how Over-The-Horizon Radar...The conception of "advanced radar" is introduced and lint forward, while it is proved that the weakpoints of interference can still be employed. Meanwhile, the paper expounds the principle how Over-The-Horizon Radar(OTHR) works, and derives the OTHR interference equation. By listing the OTHR examples, it analyzes and calculates the equivalent power of the OTHR and the sensitivity of the receiver to build up a block diagram how the interferencer is structured. Hence, the effective area is achieved, and OTHR can be intereferenced effectively with not so high equivalent power.展开更多
Objective To explore the relationship between the receptor temperature and moxibustion distance of mild moxibustion, and provide evidence for clinical moxibustion distance. Methods Mild moxibustion was carried out for...Objective To explore the relationship between the receptor temperature and moxibustion distance of mild moxibustion, and provide evidence for clinical moxibustion distance. Methods Mild moxibustion was carried out for 15min by adopting moxibustion shelf, and the moxibustion ash was shook off automatically for once every 3 min. The distance between moxa stick and temperature sensor was set as 2 cm, 3 cm, 4 cm and 5 cm, respectively, by ruler. The temperature was recorded for once every 2 s with photothermal detection system for moxibustion combustion to form a temperature profile. The initial temperature, maximum temperature and average temperature were observed, and the experimental data were analyzed via SPSS18.0 statistical software. Results The initial receptor temperature was (25.33±0.29) ℃ when the moxibustion distance was 2 cm, (25.29±0.05) ℃ when the moxibustion distance was 3 cm, (25.43±0.17) ℃ when the moxibustion distance was 4cm, and (25.16±0.22) ℃ when the moxibustion distance was 5 cm, respectively. The maximum temperature was (74.96±1.20) ℃ when the moxibustion distance was 2 cm, (51.70±0.74) ℃ when the moxibustion distance was 3 cm, (49.33±0.40) ℃ when the moxibustion distance was 4 cm, and (42.50±0.26) ℃ when the moxibustion distance was 5 cm, respectively. The average temperature was (62.40±7.84) ℃-(62.68±7.58) ℃ when the moxibustion distance was 2 cm, (44.77±3.31) ℃-(45.11±3.21) ℃ when the moxibustion distance was 3 cm, (42.72+3.86) ℃-(43.12±3.54) ℃ when the moxibust-ion distance was 4 cm, and (38.45±1.67) ℃-(38.50±1.63) ℃ when the moxibustion distance was 5 cm, respectively. The temperature curve showed that the fluctuation range was the maximum when the moxibustion distance was 2 cm, larger when the moxibustion distance was 3 cm, smaller when the moxibustion distance was 4 cm, and minimum when the moxibustion distance was 5 cmo There was no significant difference in the initial temperature of mild moxibustion at different distances, however, the maximum temperature, average temperature and the fluctuation range of temperature curve were closely related to the moxibustion distance. Conclusion The nearer the distance is, the higher the maximum temperature and average temperature as well as the larger the fluctuation range will be, and the farther the distance is, the lower the maximum temperature and average temperature as well as the smaller the fluctuation range will be. Accordin8 to preliminary analysis, the temperature will be the most suitable when the moxibust-ion distance is 3 cm-4 cm.展开更多
In this paper,the force-distance curves have been employed to investigate the force sensing properties of the probe-type microforce sensors.In the preliminary studies,two kinds of probe-type microforce sensors have be...In this paper,the force-distance curves have been employed to investigate the force sensing properties of the probe-type microforce sensors.In the preliminary studies,two kinds of probe-type microforce sensors have been used to load the objects with dry and wetted surfaces.One is a developed piezoresistive cantilever force sensor with sensitivity of 35 μN/V and the other an atomic force microscope(AFM) cantilever beam probe with sensitivity of 10.4 nN/V.The force outputs corresponding to the regimes of approaching,indenting,and loading are obtained,and the properties of the stability in the approaching regime of the sensors,local mechanical behavior of the tested objects in the indenting regime,and the force sensing of the global samples are analyzed.Experimental results of this analysis are also presented.展开更多
The ventilators have been vividly called "the lungs of mine". The rotating blades are the core parts of a ventilator, they can influence the safety and reliability of the ventilator. This paper will use the tip-timi...The ventilators have been vividly called "the lungs of mine". The rotating blades are the core parts of a ventilator, they can influence the safety and reliability of the ventilator. This paper will use the tip-timing method based on the fiber Bragg grating magnetically coupling sensor to study and analyze the ventilator blade vibration, in order to realize long-distance and non-contact real-time online safety monitoring of blade vibration. Compared with the electronic sensorand fiber intensity reflective sensor, the fiber grating coupling magnetic sensor has such advantages as explosion-proof, working at harsh environment with humid air, dust and greasy dirt, capable of achieving long-distance signal transmission, and joining easily with other fiber Bragg grating sensors to form a network in order to achieve multi-parameter distributed online monitoring.展开更多
The underwater heat exhausting source can cause the thermal difference of the surrounding and surface water.In this paper,the thermal character caused by the underwater heat exhausting source is studied by numerical s...The underwater heat exhausting source can cause the thermal difference of the surrounding and surface water.In this paper,the thermal character caused by the underwater heat exhausting source is studied by numerical simulation and experiment.The results show that the thermal floating distance is related with the sailing velocity of the underwater target.The higher the velocity is,the longer the hot wake is,and the broader the hot scope is.The relative distance of the thermal floating spot is almost in a logarithmic law with the velocity.The experimental results are accordant with the numerical simulation,and the obvious hot wake can be observed by the moving underwater heat exhausting source testing with temperature sensors and infrared camera.展开更多
基金Project of National Natural Science Fund for the Youth,China(No.51208473)The Key Project for Science and Technology of Shanxi,China(No.20130313010-3)
文摘The paper takes a new campus project site of Shanxi university town for example, tests the influence of dynamic com- paction vibration and vibration isolation effect of isolation trench on this ground, and compares the influences of the dynamic compaction vibration on surrounding buildings with isolation trench and without it. Furthermore, the attenuation law of dy- namic compaction vibration in fill foundation of the loess area under different tamping energy and how to determine safe distance of dynamic compaction construction are studied. And then the quantitative relationship between acceleration and vibration source in new campus project site is presented. We derive the evaluation method that dynamic compaction construction affects adjacent buildings by contrasting with the existing standards and norms. The monitoring results show that isolation trench makes the amplitude attenuation of the horizontal velocity of dynamic compaction vibration reach above 75%, and the safe dis- tance be 30 m under the tamping energy of 6 000 kN · m. Therefore, isolation trench is better for vibration reduction under dynamic compaction construction.
基金Supported by National Natural Science Foundation of China (No60702037)Research Fund for the Doctoral Program of Higher Education of China (No20070056129)Natural Science Foundation of Tianjin (No09JCYBJC00800)
文摘Sensor localization is crucial for the configuration and applications of wireless sensor network (WSN). A novel distributed localization algorithm, MDS-DC was proposed for wireless sensor network based on multidimensional scaling (MDS) and the shortest path distance correction. In MDS-DC, several local positioning regions with reasonable distribution were firstly constructed by an adaptive search algorithm, which ensures the mergence between the local relative maps of the adjacent local position regions and can reduce the number of common nodes in the network. Then, based on the relationships between the estimated distances and actual distances of anchors, the distance estimation vectors of sensors around anchors were corrected in each local positioning region. During the computations of the local relative coordinates, an iterative process, which is the combination of classical MDS algorithm and SMACOF algorithm, was applied. Finally, the global relative positions or absolute positions of sensors were obtained through merging the relative maps of all local positioning regions. Simulation results show that MDS-DC has better performances in positioning precision, energy efficiency and robustness to range error, which can meet the requirements of applications for sensor localization in WSN.
文摘Wire ropes,employed extensively in coal mine hoists and transportation systems are subject to damage due to wear,corrosion and fatigue.The extent of damage and the carrying capacity of ropes are closely related to the sense of safety by staff and equipments.Magnetic flux leakage detection method(MFL),as an effective method,is these days widely used in detection of broken strands of wire ropes.In order to improve the accuracy of detection of flaws in wire ropes by magnetic flux leakage(MFL),the effect of the distance between a sensor and the surface of a wire rope(i.e.,lift-off) on detection by magnetic flux leakage was in-vestigated.An analysis of the main principles for the choice of lift-off is described by us and a new method that improves the structure of the detector is proposed from the point of view of the design of a magnetic circuit,to restrain the impact of fluctuations of sensor lift-off.The effect of this kind of method is validated by simulation and computation.The results show that the detection sensitivity is markedly increased by this method.Furthermore,the signal-to-noise ratio(SNR) can be increased by over 28%.This method will lend itself to offer reliable scientific information to optimize the structure of excitation devices and improve the accuracy of MFL detection.
基金Science and Technology Development Project Item of Tianjin(06YFGZGX00800)Science and Technology Item of CAAC(MY0517416)
文摘Dynamic detection based on optics sensors and ranging radars is a new method to detect the luminous intensity of flight aid lights. The optics sensors can get the illumination information of each light, the ranging radar gets the distance information, and then data amalgamation technology is used to compute the luminous intensity of each light. A method to modify the errors of this dynamic detection system is presented. It avoids the accumulation error and measurement carrier’s excursion error by using peak value detection based on optics sensors to estimate the accurate position of each light, then to modify the lights’ lengthways distance information and transverse position information. The performance of the detection and ranging system is validated by some experiments and shown in pictures.
文摘Kenya's tourism business stagnated from 1991 to 2003 and only registered small but steady grew from 2004. One of the sectors that recorded poor performance as a result of the slow growth of tourism is the hotel business. Despite this slack, stakeholders in Kenya have not tried to assess the extent to which the quality of this sector may impact on destination preference. The ultimate purpose of this research was to establish the quality gap between the expected and the perceived hotel product/service quality from both the perspective of the tourists and the hotel operators in Kenya. It was motivated by the need to create parameters that can elavate the competitiveness of Kenya's tourism using the hotel product/service quality offer. Descriptive quantitative research design was used to establish the secondary objectives and to assess two propositions set for the study. A sample of 211 tourists and 19 hotel operators in two major tourist provinces of Kenya was used to obtain information regarding normative and perceptive hotel product/service quality. Kenya's only destination marketing organisation, Kenya Tourist Board (KTB) marketers were also surveyed to provide insight on Kenya's destination position with regard to the motivation of tourists to visit Kenya. The study established that although the attractions which make tourists come to Kenya are the unique wildlife safari, beach tourism and the natural scenery, hotel product quality and hospitality plays a vital role in motivating tourists to choose Kenya as the destination to visit. However, this study found out that while the tourists and hotel operators agree on the normative hotel product quality level, there is a significant gap between the normative quality and the perceptual quality registered by tourists who used hotel services. The study established that hotel operators only recognize quality regulatory institutions with statutory and legal authority to incriminate facilities that do not comply with laid down operational requirements such as Hotels and Restaurants Authority and the Local Authority Public Health Department. The study has proposed an integrated framework that may be utilized to build a superior national hotel product/service quality so that the economic potential of tourism is maximized in Kenya.
基金Project(61104088)supported by the National Natural Science Foundation of ChinaProject(12C0741)supported by Scientific Research Fund of Hunan Provincial Education Department,China
文摘The equivalent two-port network model of a middle range wireless power transfer(WPT) system was presented based on strongly coupled multiple resonators. The key parameters of the WPT system include self-inductance, resistance, parasitic capacitance, mutual inductance and S-parameters of coils & resonators were analyzed. The impedance matching method was used to optimize load power and transmission efficiency of the multi-resonator WPT system, and the impedance matching method was realized through adjusting the distances between the coils and resonators. Experiments show that the impedance matching method can effectively improve load power and transmission efficiency for middle range wireless power transfer systems with multiple resonators, at distances up to 3 times the coil radius with efficiency more than 70% and load power also close to 3.5 W.
基金Supported by National Natural Science Foundation of China under Grant No. 10901103the New Teacher Foundation of Ministry of Education of China under Grant No. 20070248087Supported by a Grant of Science and Technology Commission of Shanghai Municipality (STCSM No. 09XD1402500)
文摘In this paper, we compare the quantum operation sensitivity for different distance measures. We find that, among all usual distance measures, Bures fidelity is more sensitive to quantum operation than others. This may explain in some sense why fidelity is so useful in quantum information theory.
基金supported by National Natural Science Foundation of China under Grants 61001067,61371093and 61172105Natural Science Foundation of Zhejiang Prov.China under Grants LY13D060001
文摘Underwater Acoustic Sensor Network(UASN) has attracted significant attention because of its great influence on ocean exploration and monitoring. On account of the unique characteristics of underwater environment, localization, as one of the fundamental tasks in UASNs, is a more challenging work than in terrestrial sensor networks. A survey of the ranging algorithms and the network architectures varied with different applications in UASNs is provided in this paper. Algorithms used to estimate the coordinates of the UASNs nodes are classified into two categories: rangebased and range-free. In addition, we analyze the architectures of UASNs based on different applications, and compare their performances from the aspects of communication cost, accuracy, coverage and so on. Open research issues which would affect the accuracy of localization are also discussed, including MAC protocols, sound speed and time synchronization.
文摘The conception of "advanced radar" is introduced and lint forward, while it is proved that the weakpoints of interference can still be employed. Meanwhile, the paper expounds the principle how Over-The-Horizon Radar(OTHR) works, and derives the OTHR interference equation. By listing the OTHR examples, it analyzes and calculates the equivalent power of the OTHR and the sensitivity of the receiver to build up a block diagram how the interferencer is structured. Hence, the effective area is achieved, and OTHR can be intereferenced effectively with not so high equivalent power.
基金Supported by National Basic Research Program of China:2015CB554502Research Study and Innovative Experimental Planning Project of Hunan Province Undergraduates:NO221+2 种基金Doctor Scientific Research Fund Project of Hunan University of Chinese Medicine:9982-1001-014Popularizing Project of State Administration of Traditional Chinese Medicine of ChinaProject of China Postdoctoral Science Foundation:2015M580689
文摘Objective To explore the relationship between the receptor temperature and moxibustion distance of mild moxibustion, and provide evidence for clinical moxibustion distance. Methods Mild moxibustion was carried out for 15min by adopting moxibustion shelf, and the moxibustion ash was shook off automatically for once every 3 min. The distance between moxa stick and temperature sensor was set as 2 cm, 3 cm, 4 cm and 5 cm, respectively, by ruler. The temperature was recorded for once every 2 s with photothermal detection system for moxibustion combustion to form a temperature profile. The initial temperature, maximum temperature and average temperature were observed, and the experimental data were analyzed via SPSS18.0 statistical software. Results The initial receptor temperature was (25.33±0.29) ℃ when the moxibustion distance was 2 cm, (25.29±0.05) ℃ when the moxibustion distance was 3 cm, (25.43±0.17) ℃ when the moxibustion distance was 4cm, and (25.16±0.22) ℃ when the moxibustion distance was 5 cm, respectively. The maximum temperature was (74.96±1.20) ℃ when the moxibustion distance was 2 cm, (51.70±0.74) ℃ when the moxibustion distance was 3 cm, (49.33±0.40) ℃ when the moxibustion distance was 4 cm, and (42.50±0.26) ℃ when the moxibustion distance was 5 cm, respectively. The average temperature was (62.40±7.84) ℃-(62.68±7.58) ℃ when the moxibustion distance was 2 cm, (44.77±3.31) ℃-(45.11±3.21) ℃ when the moxibustion distance was 3 cm, (42.72+3.86) ℃-(43.12±3.54) ℃ when the moxibust-ion distance was 4 cm, and (38.45±1.67) ℃-(38.50±1.63) ℃ when the moxibustion distance was 5 cm, respectively. The temperature curve showed that the fluctuation range was the maximum when the moxibustion distance was 2 cm, larger when the moxibustion distance was 3 cm, smaller when the moxibustion distance was 4 cm, and minimum when the moxibustion distance was 5 cmo There was no significant difference in the initial temperature of mild moxibustion at different distances, however, the maximum temperature, average temperature and the fluctuation range of temperature curve were closely related to the moxibustion distance. Conclusion The nearer the distance is, the higher the maximum temperature and average temperature as well as the larger the fluctuation range will be, and the farther the distance is, the lower the maximum temperature and average temperature as well as the smaller the fluctuation range will be. Accordin8 to preliminary analysis, the temperature will be the most suitable when the moxibust-ion distance is 3 cm-4 cm.
基金supported by the National Natural Science Foundation of China (Grant Nos 10972113 and 10732080)the National Basic Research Program of China (Grant Nos 2007CB936803 and 2010CB631005)SRFDP (Grant No 20070003053)
文摘In this paper,the force-distance curves have been employed to investigate the force sensing properties of the probe-type microforce sensors.In the preliminary studies,two kinds of probe-type microforce sensors have been used to load the objects with dry and wetted surfaces.One is a developed piezoresistive cantilever force sensor with sensitivity of 35 μN/V and the other an atomic force microscope(AFM) cantilever beam probe with sensitivity of 10.4 nN/V.The force outputs corresponding to the regimes of approaching,indenting,and loading are obtained,and the properties of the stability in the approaching regime of the sensors,local mechanical behavior of the tested objects in the indenting regime,and the force sensing of the global samples are analyzed.Experimental results of this analysis are also presented.
文摘The ventilators have been vividly called "the lungs of mine". The rotating blades are the core parts of a ventilator, they can influence the safety and reliability of the ventilator. This paper will use the tip-timing method based on the fiber Bragg grating magnetically coupling sensor to study and analyze the ventilator blade vibration, in order to realize long-distance and non-contact real-time online safety monitoring of blade vibration. Compared with the electronic sensorand fiber intensity reflective sensor, the fiber grating coupling magnetic sensor has such advantages as explosion-proof, working at harsh environment with humid air, dust and greasy dirt, capable of achieving long-distance signal transmission, and joining easily with other fiber Bragg grating sensors to form a network in order to achieve multi-parameter distributed online monitoring.
基金supported by Key Laboratory for National Defence of Underwater Observing and Control Technology fund number 9140c2603100805
文摘The underwater heat exhausting source can cause the thermal difference of the surrounding and surface water.In this paper,the thermal character caused by the underwater heat exhausting source is studied by numerical simulation and experiment.The results show that the thermal floating distance is related with the sailing velocity of the underwater target.The higher the velocity is,the longer the hot wake is,and the broader the hot scope is.The relative distance of the thermal floating spot is almost in a logarithmic law with the velocity.The experimental results are accordant with the numerical simulation,and the obvious hot wake can be observed by the moving underwater heat exhausting source testing with temperature sensors and infrared camera.