A web camera based multi-camera convergent close-range photogrammetric system is developed to obtain the neonates＇ head and facial morphology. The data will then be used to develop a secure and good-fitting eye-patch...A web camera based multi-camera convergent close-range photogrammetric system is developed to obtain the neonates＇ head and facial morphology. The data will then be used to develop a secure and good-fitting eye-patch protector for neonates, particularly whoa they are exposed to bright lights such as phototherapy light. Measurements obtained by the system are evaluated and validated against data obtained from optical scanning. Results show that the photogrammetric system meets the requirements of measuring accuracy and safety for neonate in the neonatal units.展开更多
Exhaust gas temperature is an important factor in NOx, THC and PM emissions of engines. Especially 2D temperature and concentration distribution plays an important role for the engine efficiency. A thermocouple is int...Exhaust gas temperature is an important factor in NOx, THC and PM emissions of engines. Especially 2D temperature and concentration distribution plays an important role for the engine efficiency. A thermocouple is intrinsically a point temperature measurement method and noncontact 2D temperature distribution cannot be attained by thermocouples. Recently, as a measurement technique with high sensitivity and high response, laser diagnostics has been developed and applied to the actual engine combustions. With these engineering developments, transient phenomena such as start-ups and load changes in engines have been gradually elucidated in various conditions. In this study, the theoretical and experimental research has been conducted in order to develop the noncontact and fast response 2D temperature and concentration distribution measurement method. The method is based on a Computed Tomography （CT） method using absorption spectra of water vapor at 1388 nm. It has been demonstrated that the method has been successfully applied to engine exhausts to measure 2D temperature distributions.展开更多
It is well known that optical tomography can accurately and quantitatively reconstruct the refractive index field of a transparent medium and display the three dimensional image of other physical quantities relevant t...It is well known that optical tomography can accurately and quantitatively reconstruct the refractive index field of a transparent medium and display the three dimensional image of other physical quantities relevant to temperature or density. In this paper, a new multidirectional holographic interferometric system is built, and two kinds of image reconstruction algorithms are introduced and an automatic image processing system of interferogram is designed. A three dimentsional asymmetric gas flow field above a combustor is expertmentally investigated with holographic interferometry. The reconstructed temperatures are similar to those measured with a thermocouple.展开更多
The undisturbed ground temperatures are important for design of the ground heat exchangers in ground source heat pump （GSHP） systems. In this paper, the undisturbed ground temperatures measured in two different me...The undisturbed ground temperatures are important for design of the ground heat exchangers in ground source heat pump （GSHP） systems. In this paper, the undisturbed ground temperatures measured in two different methods are presented. The investigation was carried out in two cases. The temperature measured with the direct method is assumed to give the correct undisturbed ground temperature profile. The temperature measured with indirect method overestimates the undisturbed ground temperature by 2.1℃ and 1.7~C. This difference is mainly caused by the circulation pump and ambient air to the fluid. Therefore, the results that are decreased about 2℃ as compared with the indirect measured are recommended to estimate the undisturbed ground temperature in situ measuring. A smaller pump or deeper borehole or mild weather would result in a more correct temperature. Because the undisturbed ground temperature is affected by many factors. Whether or not these conclusions are correct to other areas, this would need further investigation.展开更多
Three kinds of methods for processing the data of the multi-wavelength pyrometer are presented in this paper and are named curve auto-search method, curve auto-regression method and neural network method. Tbe experime...Three kinds of methods for processing the data of the multi-wavelength pyrometer are presented in this paper and are named curve auto-search method, curve auto-regression method and neural network method. Tbe experimental results indicate that the calculated temperature and the spectral emissivity compared with the true target temperature and spectral emissivity have significant deviation using the curve auto-search and the curve auto-regression methods. However, the calculated temperature and the spectral emissivity with higher accuracy can be obtained using the neural network method.展开更多
A sapphire fiber thermal probe with Cr^3＋ ion-doped end was grown using the laser heated pedestal method. The fluorescence thermal probe offers advantages of compact structure, high performance and the ability to sus...A sapphire fiber thermal probe with Cr^3＋ ion-doped end was grown using the laser heated pedestal method. The fluorescence thermal probe offers advantages of compact structure, high performance and the ability to sustain high temperature from the room temperature to 450℃. Based on the fast fourier transform （FFT）, the fluorescence lifetime is obtained from the tangent function of the phase angle of the first non-zeroth item of FFT result. Compared with other traditional fitting methods, our method has advantages such as fast speed, high accuracy and being free from the influence of the base signal. The standard deviation of FFT method is about half of that method. In addition, since the FFT method is immunity to analysis can be skipped. of the Prony method and close to the one of the Marquardt the background noise of the signal, the background noise展开更多
The tomography technique is commonly used for the reconstruction of holographic interferometry. However, the current reconstruction method doesn’t consider the measurement errors which are non-avoidable in the measur...The tomography technique is commonly used for the reconstruction of holographic interferometry. However, the current reconstruction method doesn’t consider the measurement errors which are non-avoidable in the measurement and will degrade the reconstruction quality. The factors affecting the reconstruction quality are analyzed and the distribution law of the reconstruction error with experimental errors is discussed. Finally, a method to improve the reconstruction quality—the Kalman filter method is presented.展开更多
Directly measuring the oxidative heat release intensity at low temperatures is difficult at present.We developed a new method based on heat conduction theory that directly measures heat release intensity of loose coal...Directly measuring the oxidative heat release intensity at low temperatures is difficult at present.We developed a new method based on heat conduction theory that directly measures heat release intensity of loose coal at low temperatures.Using this method, we calculated the oxidative heat release intensity of differently sized loose coals by comparing the temperature rise of the coal in nitrogen or an air environment.The results show that oxidation heat release intensity of Shenhua coal sized 0～15 mm is 0.001～0.03 W/m3 at 30～90 °C and increases with increasing temperature.The heat release intensity at a given temperature is larger for smaller sized coal.The temperature effect on heat release intensity is muted as the coal size increases.At lower temperature the change in heat release intensity as a function of size becomes smaller.These results show that the test system is usable for practical applications and is easy to operate and is capable of measuring mass samples.展开更多
基金Earmarked Research Grant (Hong Kong)(No.POLYU 5299/04E)
文摘A web camera based multi-camera convergent close-range photogrammetric system is developed to obtain the neonates＇ head and facial morphology. The data will then be used to develop a secure and good-fitting eye-patch protector for neonates, particularly whoa they are exposed to bright lights such as phototherapy light. Measurements obtained by the system are evaluated and validated against data obtained from optical scanning. Results show that the photogrammetric system meets the requirements of measuring accuracy and safety for neonate in the neonatal units.
文摘Exhaust gas temperature is an important factor in NOx, THC and PM emissions of engines. Especially 2D temperature and concentration distribution plays an important role for the engine efficiency. A thermocouple is intrinsically a point temperature measurement method and noncontact 2D temperature distribution cannot be attained by thermocouples. Recently, as a measurement technique with high sensitivity and high response, laser diagnostics has been developed and applied to the actual engine combustions. With these engineering developments, transient phenomena such as start-ups and load changes in engines have been gradually elucidated in various conditions. In this study, the theoretical and experimental research has been conducted in order to develop the noncontact and fast response 2D temperature and concentration distribution measurement method. The method is based on a Computed Tomography （CT） method using absorption spectra of water vapor at 1388 nm. It has been demonstrated that the method has been successfully applied to engine exhausts to measure 2D temperature distributions.
文摘It is well known that optical tomography can accurately and quantitatively reconstruct the refractive index field of a transparent medium and display the three dimensional image of other physical quantities relevant to temperature or density. In this paper, a new multidirectional holographic interferometric system is built, and two kinds of image reconstruction algorithms are introduced and an automatic image processing system of interferogram is designed. A three dimentsional asymmetric gas flow field above a combustor is expertmentally investigated with holographic interferometry. The reconstructed temperatures are similar to those measured with a thermocouple.
文摘The undisturbed ground temperatures are important for design of the ground heat exchangers in ground source heat pump （GSHP） systems. In this paper, the undisturbed ground temperatures measured in two different methods are presented. The investigation was carried out in two cases. The temperature measured with the direct method is assumed to give the correct undisturbed ground temperature profile. The temperature measured with indirect method overestimates the undisturbed ground temperature by 2.1℃ and 1.7~C. This difference is mainly caused by the circulation pump and ambient air to the fluid. Therefore, the results that are decreased about 2℃ as compared with the indirect measured are recommended to estimate the undisturbed ground temperature in situ measuring. A smaller pump or deeper borehole or mild weather would result in a more correct temperature. Because the undisturbed ground temperature is affected by many factors. Whether or not these conclusions are correct to other areas, this would need further investigation.
基金Sponsored by the National Natural Science Foundation of China(Grant No. 60377037)the Scientific Research Foundation of Harbin Institute of Technol-ogy (Grant No. HIT. 2002. 18)the Spaceflight Support Foundation.
文摘Three kinds of methods for processing the data of the multi-wavelength pyrometer are presented in this paper and are named curve auto-search method, curve auto-regression method and neural network method. Tbe experimental results indicate that the calculated temperature and the spectral emissivity compared with the true target temperature and spectral emissivity have significant deviation using the curve auto-search and the curve auto-regression methods. However, the calculated temperature and the spectral emissivity with higher accuracy can be obtained using the neural network method.
基金the Natural Science Research Foundation of Education Bureau of Hebei Province, China (Grant No.2001265)
文摘A sapphire fiber thermal probe with Cr^3＋ ion-doped end was grown using the laser heated pedestal method. The fluorescence thermal probe offers advantages of compact structure, high performance and the ability to sustain high temperature from the room temperature to 450℃. Based on the fast fourier transform （FFT）, the fluorescence lifetime is obtained from the tangent function of the phase angle of the first non-zeroth item of FFT result. Compared with other traditional fitting methods, our method has advantages such as fast speed, high accuracy and being free from the influence of the base signal. The standard deviation of FFT method is about half of that method. In addition, since the FFT method is immunity to analysis can be skipped. of the Prony method and close to the one of the Marquardt the background noise of the signal, the background noise
基金KeyProgramofScienceandTechnologyofMinistryofEducation China
文摘The tomography technique is commonly used for the reconstruction of holographic interferometry. However, the current reconstruction method doesn’t consider the measurement errors which are non-avoidable in the measurement and will degrade the reconstruction quality. The factors affecting the reconstruction quality are analyzed and the distribution law of the reconstruction error with experimental errors is discussed. Finally, a method to improve the reconstruction quality—the Kalman filter method is presented.
基金Projects 50474067 supported by the National Natural Science Foundation of China2007KF11 by the State Key Laboratory of Coal Resources and Safety Mining
文摘Directly measuring the oxidative heat release intensity at low temperatures is difficult at present.We developed a new method based on heat conduction theory that directly measures heat release intensity of loose coal at low temperatures.Using this method, we calculated the oxidative heat release intensity of differently sized loose coals by comparing the temperature rise of the coal in nitrogen or an air environment.The results show that oxidation heat release intensity of Shenhua coal sized 0～15 mm is 0.001～0.03 W/m3 at 30～90 °C and increases with increasing temperature.The heat release intensity at a given temperature is larger for smaller sized coal.The temperature effect on heat release intensity is muted as the coal size increases.At lower temperature the change in heat release intensity as a function of size becomes smaller.These results show that the test system is usable for practical applications and is easy to operate and is capable of measuring mass samples.
