This dissertation aims at providing steady sensing for the shape detection of colonoscopes. The research especially deals with the key techniques of fiber bragg grating (FBG) large curvature sensor and sensor net, int...This dissertation aims at providing steady sensing for the shape detection of colonoscopes. The research especially deals with the key techniques of fiber bragg grating (FBG) large curvature sensor and sensor net, integrates the techniques of mechatronics and computer graphics, and develops real time FBG shape sensing system and incremental shape sensing system for colonoscopies.展开更多
In this paper, an efficient thermal analysis method is presented for large scale compound semiconductor integrated circuits based on a heterojunction bipolar transistor with considering the change of thermal conductiv...In this paper, an efficient thermal analysis method is presented for large scale compound semiconductor integrated circuits based on a heterojunction bipolar transistor with considering the change of thermal conductivity with temperature.The influence caused by the thermal conductivity can be equivalent to the increment of the local temperature surrounding the individual device. The junction temperature for each device can be efficiently calculated by the combination of the semianalytic temperature distribution function and the iteration of local temperature with high accuracy, providing a temperature distribution for a full chip. Applying this method to the InP frequency divider chip and the GaAs analog to digital converter chip, the computational results well agree with the results from the simulator COMSOL and the infrared thermal imager respectively. The proposed method can also be applied to thermal analysis in various kinds of semiconductor integrated circuits.展开更多
A high sensitive long period fiber grating（LPFG） sensor for the detection of nitrite is proposed, which is realized by coating multiple poly（sodium 4-styrensulfonate）（PSS） and poly（diallyldimethylammonium） chl...A high sensitive long period fiber grating（LPFG） sensor for the detection of nitrite is proposed, which is realized by coating multiple poly（sodium 4-styrensulfonate）（PSS） and poly（diallyldimethylammonium） chloride （PDDA） layers on the fiber grating surface. The sensitivity of this LPFG sensor is maximum when the number of assembled layers is 70. Under this condition, a nitrite concentration of 3×10^-3 mol/L, which is lower than the National Food Additive Standard, 4.2×10^-3 mol/L, can be distinguished. The sensitivity is further increased by 30% when nitrite was determined in the sucrose solution with a concentration of 65%, which provides a new solution for the best refraction index approaching matched index of the fiber cladding. Compared with chemical methods, this nitrite detection technology offers some advantages, such as high accuracy, non toxicity, high speed, low cost, without chemical reagent, and is suitable for foodstuff security detection.展开更多
The micro-cantilever beam with a twin long period optic fiber grating sensitive to the strain and the vibration is designed to use as the sensor head.The micro-displacement of wavelength caused by strain or vibration ...The micro-cantilever beam with a twin long period optic fiber grating sensitive to the strain and the vibration is designed to use as the sensor head.The micro-displacement of wavelength caused by strain or vibration is amplified in the system.Special cladding material is used to eliminate the interference brougth about the temperature.The designing structure is enabled to detect the micro-information.展开更多
The bonded distributed feedback（DFB） fiber laser（FL） acoustic emission sensor and the intensity response of the DFB-FL to external acoustic emissions are investigated. The dynamic sensitivity of the DFB-FL is cali...The bonded distributed feedback（DFB） fiber laser（FL） acoustic emission sensor and the intensity response of the DFB-FL to external acoustic emissions are investigated. The dynamic sensitivity of the DFB-FL is calibrated by a referenced piezoelectric receiver. In the DFB-FL we used here, the minimum detectable signal is2 × 10^（-6）m∕s at 5 kHz. Using wavelet packet technology, the collected signals are analyzed, which confirms that an intensity-modulated DFB-FL sensor can be used to detect acoustic emission signals.展开更多
The multi-crack damages modal of simple supported beam has been build, at the vibrating status, the multi-damage detecting method of simple supported beam measured by fiber Bragg grating strain sensing array has been ...The multi-crack damages modal of simple supported beam has been build, at the vibrating status, the multi-damage detecting method of simple supported beam measured by fiber Bragg grating strain sensing array has been studied. From 0 hz to 200 hz, using exciter vibrating simple supported beam, with different damages, resonant frequency of simple supported beam has changed. So, when the damage appears in simple supported beam, the local rigidity will decrease, the resonant frequency of simple supported beam will be affected, the damage status of simple supported beam have been determined by this. The experimental result indicates that the resonant frequency of simple supported beam has changed when there is no damage, one damage, two damages, three damages on simple supported beam. According to this, the fiber Bragg grating strain sensing array can detect multi-crack damage of simple supported beam under vibrating status.展开更多
The measuring method of structure damage during vibrating has been developed by applying simple supported beam as object of study, fiber Bragg grating strain sensing array as the measuring method, and wavelet package ...The measuring method of structure damage during vibrating has been developed by applying simple supported beam as object of study, fiber Bragg grating strain sensing array as the measuring method, and wavelet package analysis as signal extracting tools. The damage data of simple supported beam at vibrating state has been collected. The damage characteristic indexes have been extracted based on analyzing and handling the damage data with wavelet analysis. The experiment shows that fiber Bragg grating strain sensing array can sensitively measure the experimental data of simple supported beam at vibrating state. The fiber Bragg grating strain sensing array measuring is a new method in dynamic measurement.展开更多
文摘This dissertation aims at providing steady sensing for the shape detection of colonoscopes. The research especially deals with the key techniques of fiber bragg grating (FBG) large curvature sensor and sensor net, integrates the techniques of mechatronics and computer graphics, and develops real time FBG shape sensing system and incremental shape sensing system for colonoscopies.
基金Project supported by the Advance Research Foundation of China(Grant No.9140Axxx501)the National Defense Advance Research Project,China(Grant No.3151xxxx301)+1 种基金the Frontier Innovation Program,China(Grant No.48xx4)the 111 Project,China(Grant No.B12026)
文摘In this paper, an efficient thermal analysis method is presented for large scale compound semiconductor integrated circuits based on a heterojunction bipolar transistor with considering the change of thermal conductivity with temperature.The influence caused by the thermal conductivity can be equivalent to the increment of the local temperature surrounding the individual device. The junction temperature for each device can be efficiently calculated by the combination of the semianalytic temperature distribution function and the iteration of local temperature with high accuracy, providing a temperature distribution for a full chip. Applying this method to the InP frequency divider chip and the GaAs analog to digital converter chip, the computational results well agree with the results from the simulator COMSOL and the infrared thermal imager respectively. The proposed method can also be applied to thermal analysis in various kinds of semiconductor integrated circuits.
基金Supported by the National Natural Science Foundation of China(Nos.60707016 and 60807030)
文摘A high sensitive long period fiber grating（LPFG） sensor for the detection of nitrite is proposed, which is realized by coating multiple poly（sodium 4-styrensulfonate）（PSS） and poly（diallyldimethylammonium） chloride （PDDA） layers on the fiber grating surface. The sensitivity of this LPFG sensor is maximum when the number of assembled layers is 70. Under this condition, a nitrite concentration of 3×10^-3 mol/L, which is lower than the National Food Additive Standard, 4.2×10^-3 mol/L, can be distinguished. The sensitivity is further increased by 30% when nitrite was determined in the sucrose solution with a concentration of 65%, which provides a new solution for the best refraction index approaching matched index of the fiber cladding. Compared with chemical methods, this nitrite detection technology offers some advantages, such as high accuracy, non toxicity, high speed, low cost, without chemical reagent, and is suitable for foodstuff security detection.
文摘The micro-cantilever beam with a twin long period optic fiber grating sensitive to the strain and the vibration is designed to use as the sensor head.The micro-displacement of wavelength caused by strain or vibration is amplified in the system.Special cladding material is used to eliminate the interference brougth about the temperature.The designing structure is enabled to detect the micro-information.
基金supported by the National 863 Program of China(No.2014AA093406)the Youth Innovation Promotion Association of CAS(No.2016106)+1 种基金the Project of Observation Instrument Development for Integrated Geophysical Field of China Mainland(No.Y201606)the Key Project of Hebei Educational Committee(No.BJ2016048)
文摘The bonded distributed feedback（DFB） fiber laser（FL） acoustic emission sensor and the intensity response of the DFB-FL to external acoustic emissions are investigated. The dynamic sensitivity of the DFB-FL is calibrated by a referenced piezoelectric receiver. In the DFB-FL we used here, the minimum detectable signal is2 × 10^（-6）m∕s at 5 kHz. Using wavelet packet technology, the collected signals are analyzed, which confirms that an intensity-modulated DFB-FL sensor can be used to detect acoustic emission signals.
文摘The multi-crack damages modal of simple supported beam has been build, at the vibrating status, the multi-damage detecting method of simple supported beam measured by fiber Bragg grating strain sensing array has been studied. From 0 hz to 200 hz, using exciter vibrating simple supported beam, with different damages, resonant frequency of simple supported beam has changed. So, when the damage appears in simple supported beam, the local rigidity will decrease, the resonant frequency of simple supported beam will be affected, the damage status of simple supported beam have been determined by this. The experimental result indicates that the resonant frequency of simple supported beam has changed when there is no damage, one damage, two damages, three damages on simple supported beam. According to this, the fiber Bragg grating strain sensing array can detect multi-crack damage of simple supported beam under vibrating status.
文摘The measuring method of structure damage during vibrating has been developed by applying simple supported beam as object of study, fiber Bragg grating strain sensing array as the measuring method, and wavelet package analysis as signal extracting tools. The damage data of simple supported beam at vibrating state has been collected. The damage characteristic indexes have been extracted based on analyzing and handling the damage data with wavelet analysis. The experiment shows that fiber Bragg grating strain sensing array can sensitively measure the experimental data of simple supported beam at vibrating state. The fiber Bragg grating strain sensing array measuring is a new method in dynamic measurement.
