Nanoparticles,or particles in size of 1-100 nm,are extensively used in the world in different applications.For instance,single-walled carbon nanotubes(SWCNTs) are commonly used in consumer products,such as biosensors,...Nanoparticles,or particles in size of 1-100 nm,are extensively used in the world in different applications.For instance,single-walled carbon nanotubes(SWCNTs) are commonly used in consumer products,such as biosensors,drug and vaccine delivery transporters,and novel biomaterials.Although nanoparticles do not cause safety concerns to consumers who use nanoparticle-containing products,these small particles are potentially harmful for workers who produce them in factories or in cases of discharge to aquatic ecosystems.SWCNTs do not have a natural analogue,so the effects on health of their disposal remain largely unknown.In this study,we evaluated the effects of SWCNTs on a population of the green microalga Chromochloris zofingiensis and the profile and production of pigments and fatty acids.The alga was incubated with SWCNTs for 6 days in 0(control),40,80,160,or 320 mg/L concentrations.SWCNTs showed both positive and negative effects on the growth of C.zofingiensis,with a biomass enhancement at low levels(40-160 mg/L) but inhibition at high levels(320 mg/L).By contrast,a decreased accumulation of fatty acids and pigments of C.zofingiensis was observed over the range of the tested concentrations.These results indicate that the markers on the inhibitive toxicity of SWCNTs are increasingly sensitive in the following order:biomass and fatty acids < primary carotenoids < chlorophylls < secondary carotenoids.C.zofingiensis is a suitable microalga for evaluating the ecotoxicological hazards of SWCNTs,especially in terms of pigmentation response.展开更多
Walkers improve self-reliability. We examined the effectiveness of a newly developed wheeled walking frame for use by physically handicapped persons. Unstable gaits in walker users were analyzed by tri-axial accelerom...Walkers improve self-reliability. We examined the effectiveness of a newly developed wheeled walking frame for use by physically handicapped persons. Unstable gaits in walker users were analyzed by tri-axial accelerometers and a motion capture system. Several markers were placed on subjects' backs and legs. Subjects were requested to walk around a test course at a comfortable speed, while their motion was recorded by two high-speed video cameras. The activities performed on the test course comprised standing, normal walking, fast walking, and walking over a barrier. Any accidental falls were also recorded. We established the characteristic rules of gait motion using a walker. Furthermore, we demonstrated that gait characteristics are more conveniently extracted from acceleration sensors than from motion capture systems, since the sensors can be affixed to subjects for self-monitoring and goal achievements. The methods employing acceleration sensors are considered suitable for determining the average gait motions of elderly persons living in nursing homes, and can be used to evaluate walking motion before and aider rehabilitation.展开更多
An invasive electrical resistance tomographic sensor was proposed for production logging in vertical oil well.The sensor consists of 24 electrodes that are fixed to the logging tool,which can move in the pipeline to a...An invasive electrical resistance tomographic sensor was proposed for production logging in vertical oil well.The sensor consists of 24 electrodes that are fixed to the logging tool,which can move in the pipeline to acquire data on the conductivity distribution of oil/water mixture flow at different depths.A sensitivity-based algorithm was introduced to reconstruct the cross-sectional images.Analysis on the sensitivity of the sensor to the distribution of oil/water mixture flow was carried out to optimize the position of the imaging cross-section.The imaging results obtained using various boundary conditions at the pipe wall and the logging tool were compared.Eight typical models with various conductivity distributions were created and the measurement data were obtained by solving the forward problem of the sensor system.Image reconstruction was then implemented by using the simulation data for each model.Comparisons between the models and the reconstructed images show that the number and spatial distribution of the oil bubbles can be clearly identified.展开更多
In ground-based astronomy, images of objects in outer space are acquired via ground-based tele- scopes. However, the imaging system is generally interfered by atmospheric turbulence and hence images so acquired are bl...In ground-based astronomy, images of objects in outer space are acquired via ground-based tele- scopes. However, the imaging system is generally interfered by atmospheric turbulence and hence images so acquired are blurred with unknown point spread function (PSF). To restore the observed images, aberration of the wavefront at the telescope's aperture, i.e., the phase, is utilized to derive the PSF. However, the phase is not readily available. Instead, its gradients can be collected by wavefront sensors. Thus the usual approach is to use regularization methods to reconstruct high-resolution phase gradients and then use them to recover the phase in high accuracy. Here, we develop a model that reconstructs the phase directly. The proposed model uses the tight frame regularization and it can be solved efficiently by the Douglas-Rachford alternating direction method of multipliers whose convergence has been well established. Numerical results illustrate that our new model is efficient and gives more accurate estimation for the PSF.展开更多
Fiber optic sensors have a set of properties that make them very attractive in biomechanics. However, they remain unknown to many who work in the field. Some possible causes are scarce information, few research groups...Fiber optic sensors have a set of properties that make them very attractive in biomechanics. However, they remain unknown to many who work in the field. Some possible causes are scarce information, few research groups using them in a routine basis, and even fewer companies offering turnkey and affordable solutions. Nevertheless, as optical fibers revolutionize the way of carrying data in telecommunications, a similar trend is detectable in the world of sensing. The present review aims to describe the most relevant contributions of fiber sensing in biomechanics since their introduction, from 1960s to the present, focusing on intensity-based configurations. An effort has been made to identify key researchers, research and development (R&D) groups and main applications.展开更多
基金Supported by the National Natural Science Foundation of China(No.50904051)the Science and Technology Planning Project of Yantai,China(No.2010247)the Open Fund of Shandong Oriental Ocean Sci-Tech Co.,Ltd.(No.200803)
文摘Nanoparticles,or particles in size of 1-100 nm,are extensively used in the world in different applications.For instance,single-walled carbon nanotubes(SWCNTs) are commonly used in consumer products,such as biosensors,drug and vaccine delivery transporters,and novel biomaterials.Although nanoparticles do not cause safety concerns to consumers who use nanoparticle-containing products,these small particles are potentially harmful for workers who produce them in factories or in cases of discharge to aquatic ecosystems.SWCNTs do not have a natural analogue,so the effects on health of their disposal remain largely unknown.In this study,we evaluated the effects of SWCNTs on a population of the green microalga Chromochloris zofingiensis and the profile and production of pigments and fatty acids.The alga was incubated with SWCNTs for 6 days in 0(control),40,80,160,or 320 mg/L concentrations.SWCNTs showed both positive and negative effects on the growth of C.zofingiensis,with a biomass enhancement at low levels(40-160 mg/L) but inhibition at high levels(320 mg/L).By contrast,a decreased accumulation of fatty acids and pigments of C.zofingiensis was observed over the range of the tested concentrations.These results indicate that the markers on the inhibitive toxicity of SWCNTs are increasingly sensitive in the following order:biomass and fatty acids < primary carotenoids < chlorophylls < secondary carotenoids.C.zofingiensis is a suitable microalga for evaluating the ecotoxicological hazards of SWCNTs,especially in terms of pigmentation response.
文摘Walkers improve self-reliability. We examined the effectiveness of a newly developed wheeled walking frame for use by physically handicapped persons. Unstable gaits in walker users were analyzed by tri-axial accelerometers and a motion capture system. Several markers were placed on subjects' backs and legs. Subjects were requested to walk around a test course at a comfortable speed, while their motion was recorded by two high-speed video cameras. The activities performed on the test course comprised standing, normal walking, fast walking, and walking over a barrier. Any accidental falls were also recorded. We established the characteristic rules of gait motion using a walker. Furthermore, we demonstrated that gait characteristics are more conveniently extracted from acceleration sensors than from motion capture systems, since the sensors can be affixed to subjects for self-monitoring and goal achievements. The methods employing acceleration sensors are considered suitable for determining the average gait motions of elderly persons living in nursing homes, and can be used to evaluate walking motion before and aider rehabilitation.
基金Supported by the National Natural Science Foundation of China (61001135)the Fundamental Research Funds for the Central Universities (YWF-11-03-Q-072)
文摘An invasive electrical resistance tomographic sensor was proposed for production logging in vertical oil well.The sensor consists of 24 electrodes that are fixed to the logging tool,which can move in the pipeline to acquire data on the conductivity distribution of oil/water mixture flow at different depths.A sensitivity-based algorithm was introduced to reconstruct the cross-sectional images.Analysis on the sensitivity of the sensor to the distribution of oil/water mixture flow was carried out to optimize the position of the imaging cross-section.The imaging results obtained using various boundary conditions at the pipe wall and the logging tool were compared.Eight typical models with various conductivity distributions were created and the measurement data were obtained by solving the forward problem of the sensor system.Image reconstruction was then implemented by using the simulation data for each model.Comparisons between the models and the reconstructed images show that the number and spatial distribution of the oil bubbles can be clearly identified.
基金supported by Hong Kong Research Grants Council(HKRGC)(Grant Nos.CUHK400412 and HKBU203311)CUHK Direct Allocation Grant(Grant No.4053007)+1 种基金CUHK Focused Investment Scheme(Grant No.1902036)National Natural Science Foundation of China(Grant No.11301055)
文摘In ground-based astronomy, images of objects in outer space are acquired via ground-based tele- scopes. However, the imaging system is generally interfered by atmospheric turbulence and hence images so acquired are blurred with unknown point spread function (PSF). To restore the observed images, aberration of the wavefront at the telescope's aperture, i.e., the phase, is utilized to derive the PSF. However, the phase is not readily available. Instead, its gradients can be collected by wavefront sensors. Thus the usual approach is to use regularization methods to reconstruct high-resolution phase gradients and then use them to recover the phase in high accuracy. Here, we develop a model that reconstructs the phase directly. The proposed model uses the tight frame regularization and it can be solved efficiently by the Douglas-Rachford alternating direction method of multipliers whose convergence has been well established. Numerical results illustrate that our new model is efficient and gives more accurate estimation for the PSF.
文摘Fiber optic sensors have a set of properties that make them very attractive in biomechanics. However, they remain unknown to many who work in the field. Some possible causes are scarce information, few research groups using them in a routine basis, and even fewer companies offering turnkey and affordable solutions. Nevertheless, as optical fibers revolutionize the way of carrying data in telecommunications, a similar trend is detectable in the world of sensing. The present review aims to describe the most relevant contributions of fiber sensing in biomechanics since their introduction, from 1960s to the present, focusing on intensity-based configurations. An effort has been made to identify key researchers, research and development (R&D) groups and main applications.