The broad class of explosives includes nitro aromatics as well as challenging aliphatic nitro-organics whose detection is important from counter-terrorism and national security perspectives.Here we report a turn-on fl...The broad class of explosives includes nitro aromatics as well as challenging aliphatic nitro-organics whose detection is important from counter-terrorism and national security perspectives.Here we report a turn-on fluorescent sensor array based on aggregation-induced emission(AIE)fluorophores as receptors.To achieve a good sensing system with fast response,good sensitivity and low detection limit,three receptors with abundant chemical diversities for target analytes were synthesized.The turn-on response of the individual receptor showed highly variable and cross-reactive analyte-dependent changes in fluorescence.The excellent ability to identify a variety of explosives,especially the challenging aliphatic nitro-organics(2,3-dimethyl-2,3-dinitrobutane(DMNB),1,3,5-trinitro-1,3,5-triazinane(RDX),cyclotetramethylene tetranitramine(HMX)and entaerythritol tetranitrate(PETN)),was demonstrated in qualitative and quantitative analyses with 100%accuracy.The fluorescence signal amplification in the presence of explosives allows for application of these receptors in a sensor microarray suitable for high-throughput screening.These results suggested that the cross-reactive sensor array based on AIE fluorophores could find a wide range of applications for sensing various analytes or complex mixtures.展开更多
Omnidirectional imaging sensors have been used in more and more applications when a very large field of view is required.In this paper,we investigate the unwrapping,epipolar geometry and stereo rectification issues fo...Omnidirectional imaging sensors have been used in more and more applications when a very large field of view is required.In this paper,we investigate the unwrapping,epipolar geometry and stereo rectification issues for omnidirectional vision when the particular mirror model and the camera parameters are unknown in priori.First,the omnidirectional camera is calibrated under the Taylor model,and the parameters related to this model are obtained.In order to make the classical computer vision algorithms of conventional perspective cameras applicable,the ring omnidirectional image is unwrapped into two kinds of panoramas:cylinder and cuboid.Then the epipolar geometry of arbitrary camera configuration is analyzed and the essential matrix is deduced with its properties being indicated for ring images.After that,a simple stereo rectification method based on the essential matrix and the conformal mapping is proposed.Simulations and real data experimental results illustrate that our methods are effective for the omnidirectional camera under the constraint of a single view point.展开更多
We demonstrate a pH sensor based on ultrasensitive nanosize Schottky junctions formed within bottom-up grown dopant-flee arrays of assembled silicon nanowires. A new measurement concept relying on a continuous gate sw...We demonstrate a pH sensor based on ultrasensitive nanosize Schottky junctions formed within bottom-up grown dopant-flee arrays of assembled silicon nanowires. A new measurement concept relying on a continuous gate sweep is presented, which allows the straightforward determination of the point of maximum sensitivity of the device and allows sensing experiments to be performed in the optimum regime. Integration of devices into a portable fluidic system and an electrode isolation strategy affords a stable environment and enables long time robust FET sensing measurements in a liquid environment to be carried out. Investigations of the physical and chemical sensitivity of our devices at different pH values and a comparison with theoretical limits are also discussed. We believe that such a combination of nanofabrication and engineering advances makes this Schottky barrier-powered silicon nanowire lab-on-a-chip platform suitable for efficient biodetection and even for more complex biochemical analysis.展开更多
基金the National Natural Science Foundation of China(50873051,205333050)National High Technology Research and Development Program of China(2007AA03Z307)Transregional Project(TRR61)
文摘The broad class of explosives includes nitro aromatics as well as challenging aliphatic nitro-organics whose detection is important from counter-terrorism and national security perspectives.Here we report a turn-on fluorescent sensor array based on aggregation-induced emission(AIE)fluorophores as receptors.To achieve a good sensing system with fast response,good sensitivity and low detection limit,three receptors with abundant chemical diversities for target analytes were synthesized.The turn-on response of the individual receptor showed highly variable and cross-reactive analyte-dependent changes in fluorescence.The excellent ability to identify a variety of explosives,especially the challenging aliphatic nitro-organics(2,3-dimethyl-2,3-dinitrobutane(DMNB),1,3,5-trinitro-1,3,5-triazinane(RDX),cyclotetramethylene tetranitramine(HMX)and entaerythritol tetranitrate(PETN)),was demonstrated in qualitative and quantitative analyses with 100%accuracy.The fluorescence signal amplification in the presence of explosives allows for application of these receptors in a sensor microarray suitable for high-throughput screening.These results suggested that the cross-reactive sensor array based on AIE fluorophores could find a wide range of applications for sensing various analytes or complex mixtures.
基金supported by the National Natural Science Foundation of China (Nos.60502006,60534070 and 90820306)the Science and Technology Plan of Zhejiang Province,China (No.2007C21007)
文摘Omnidirectional imaging sensors have been used in more and more applications when a very large field of view is required.In this paper,we investigate the unwrapping,epipolar geometry and stereo rectification issues for omnidirectional vision when the particular mirror model and the camera parameters are unknown in priori.First,the omnidirectional camera is calibrated under the Taylor model,and the parameters related to this model are obtained.In order to make the classical computer vision algorithms of conventional perspective cameras applicable,the ring omnidirectional image is unwrapped into two kinds of panoramas:cylinder and cuboid.Then the epipolar geometry of arbitrary camera configuration is analyzed and the essential matrix is deduced with its properties being indicated for ring images.After that,a simple stereo rectification method based on the essential matrix and the conformal mapping is proposed.Simulations and real data experimental results illustrate that our methods are effective for the omnidirectional camera under the constraint of a single view point.
文摘We demonstrate a pH sensor based on ultrasensitive nanosize Schottky junctions formed within bottom-up grown dopant-flee arrays of assembled silicon nanowires. A new measurement concept relying on a continuous gate sweep is presented, which allows the straightforward determination of the point of maximum sensitivity of the device and allows sensing experiments to be performed in the optimum regime. Integration of devices into a portable fluidic system and an electrode isolation strategy affords a stable environment and enables long time robust FET sensing measurements in a liquid environment to be carried out. Investigations of the physical and chemical sensitivity of our devices at different pH values and a comparison with theoretical limits are also discussed. We believe that such a combination of nanofabrication and engineering advances makes this Schottky barrier-powered silicon nanowire lab-on-a-chip platform suitable for efficient biodetection and even for more complex biochemical analysis.
