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Papers by Hoang Minh Hieu
The increasing trend towards the use of image sensors in transportation is driven both by legisla... more The increasing trend towards the use of image sensors in transportation is driven both by legislation and consumer demands for higher safety and a better-driving experience. Awareness of the environment that surrounds a vehicle can make driving and manoeuvring of the vehicle much safer for all road users. The authors present an image processing method to detect lane departure in forward-facing video specifically designed to be in accordance with proposed automotive lane departure warning standards. Our system uses a novel lane-marking segmentation algorithm in accordance with national standards for lane markings. This method does not demand the high computational requirements of inverse perspective mapping unlike methods proposed in related research. The authors present a method for lane boundary modelling based on subtractive clustering and Kalman filtering in the Hough transform domain, which is within the constraints of automotive standards. Finally, using the cameras intrinsic and extrinsic parameters, the width of the vehicle and guidelines issued by the International Organisation for Standardisation, we show how lane departure can be identified. Results are presented that verify the systems high detection rate and robustness to various background interference, lighting conditions and road environments.
Lexus Safety System+ is designed to support driver awareness, decision-making and vehicle operati... more Lexus Safety System+ is designed to support driver awareness, decision-making and vehicle operation over a wide range of speeds under certain conditions. Packaged together in an integrated system, Lexus Safety System+ features help address three key areas of accident protection: preventing or mitigating frontal collisions 3 , keeping drivers within their lane 4 and enhancing road safety during nighttime driving 5. Always drive safely, obey traffic speed limits and laws and focus on the road while driving. Lexus Safety System+ is comprised of four systems (with some variations shown as well): 1. Pre-Collision System 3 with Pedestrian Detection 6 | Left Turn Intersection Support * 2. Lane Departure Alert 4 3. Intelligent High Beams 5 4. Dynamic Radar Cruise Control 9 Lexus Safety System+ 2.0 and 2.5 include two additional features: 5. Road Sign Assist 14 † 6. Lane Tracing Assist 15 † Lexus Safety System+ 3.0 enhancements include: 7. Curve Speed Management added to Dynamic Radar Cruise Control 8. Additional Intersection Support LEXUS SAFETY SYSTEM+ ADDRESSES THREE OF THE MOST COMMON ACCIDENT TYPES Collision protection includes collision prevention. Collisions that result in injury may be caused by the delay in a driver's recognition of the situation and his or her ability to react accordingly. According to NHTSA 1 , there were almost 6.3 million reported crashes in 2015-many of which were avoidable. Lexus Safety System+ 2 is designed to help protect drivers, passengers, people in other vehicles on the road and pedestrians from harm. This system is composed of advanced active safety packages anchored by automated pre-collision warning 3 and braking. Lexus Safety System+ represents the latest milestone in our long history of creating advancements and innovations in safety that have helped prevent or mitigate crashes and protect people.
Meeting Abstracts of the Physical Society of Japan (Nihon Butsuri Gakkai koen gaiyoshu), 2010
Meeting Abstracts of the Physical Society of Japan (Nihon Butsuri Gakkai koen gaiyoshu), 2011
Advances in Natural Sciences: Nanoscience and Nanotechnology, 2016
Korean Journal of Materials Research, 2013
We present an easy method of preparing two-dimensional (2D) periodic hollow tin oxide (SnO 2) hem... more We present an easy method of preparing two-dimensional (2D) periodic hollow tin oxide (SnO 2) hemisphere array gas sensors using polystyrene (PS) spheres as a template. The structures were fabricated by the sputter deposition of thin tin (Sn) metal over an array of PS spheres on a planar substrate followed by calcination at an elevated temperature to oxidize Sn to SnO 2 while removing the PS template cores. The SnO 2 hemisphere array structures were examined by scanning electron microscopy and X-ray diffraction. The structures were calcined at various temperatures and their sensing properties were examined with varying operation temperatures and concentrations of nitric oxide (NO) gas. Their gas-sensing properties were investigated by measuring the electrical resistances in air and the target gases. The measurements were conducted at different NO concentrations and substrate temperatures. A minimum detection limit of 30 ppb, showing a sensitivity of S = 1.6, was observed for NO gas at an operation temperature of 150 o C for a sample having an Sn metal layer thickness corresponding to 30 sec sputtering time and calcined at 600 o C for 2 hr in air. We proved that high porosity in a hollow SnO 2 hemisphere structure allows easy diffusion of the target gas molecules. The results confirm that a 2D hollow SnO 2 hemisphere array structure of micronmeter sizes can be a good structural morphology for high sensitivity gas sensors.
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2015
We report a sum frequency generation (SFG) spectroscopy study of D-glucose, Dfructose and sucrose... more We report a sum frequency generation (SFG) spectroscopy study of D-glucose, Dfructose and sucrose in the C-H stretching vibration regime. Wetting effect on the SFG spectra was investigated. The SFG spectrum of D-glucose changed from that of α-Dglucose into those of α-D-glucose monohydrate by wetting. The SFG spectra showed evidence of a small change of β-D-fructopyranose into other anomers by wetting. SFG spectra of sucrose did not change by wetting. Assignments of the vibrational peaks in the SFG spectra of the three sugars in the dry and wet states were performed in the C-H stretching vibration region near 3000 cm-1 .
Springer Proceedings in Physics
... Nguyen Hoang Nghi, Nguyen Van Dung, Nguyen Huu Hoang, Tran Anh Phong, Phi Hoa Binh, Dependan... more ... Nguyen Hoang Nghi, Nguyen Van Dung, Nguyen Huu Hoang, Tran Anh Phong, Phi Hoa Binh, Dependance of giant magnetoimpedance effect of Co-based and Fe based nanocrystalline ribbons on measuring configuration, The ninth Asia Pacific physics Conference, Hanoi ...
Sensors and Actuators B: Chemical, 2014
High-performance methane gas sensors were developed from Ni 2 O 3-decorated SnO 2 semiconducting ... more High-performance methane gas sensors were developed from Ni 2 O 3-decorated SnO 2 semiconducting films. The SnO 2 film was fabricated by the sputter deposition of Sn metal followed by oxidation. Ni nanoparticles were then deposited onto the SnO 2 film by the arc discharge deposition of single-wall carbon nanotubes followed by the burning out of carbon nanotubes. The catalytic Ni nanoparticles distributed in the carbon nanotubes were oxidized to Ni 2 O 3. The surface morphology and structural properties were examined by scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The methane gas sensing properties were examined at different operation temperatures with SnO 2 thickness and Ni 2 O 3 quantity as variables. The synergetic effects induced by the Ni 2 O 3decoration including enhanced response and lowered operation temperature were observed. We also report very high sensor responses. The sensing mechanism of the hybrid sensor structure was also discussed.
Journal of Materials Chemistry C, 2013
ABSTRACT We report a heterojunction formed between single-wall carbon nanotubes (SWCNTs) and a WO... more ABSTRACT We report a heterojunction formed between single-wall carbon nanotubes (SWCNTs) and a WO3 thin film. WO3 thin films were fabricated by sputter deposition of W followed by oxidation and SWCNTs were fabricated by the arc-discharge method. The morphology of the structures was examined by scanning electron microscopy, X-ray diffraction, and Raman spectroscopy. The current–voltage characteristics of WO3 thin films, SWCNTs films, and SWCNT/WO3 heterojunctions were measured in darkness and under ultraviolet light. A rectifying heterojunction formation of p-SWCNT/n-WO3 was confirmed. The observed unconventional optoelectronic properties were analyzed, and the results were used to explain the photoconduction phenomena occurring at the heterojunction. The heterojunctions and resistors were also examined for their photodetection performance.
Nanoscale, 2013
The electrodes in photoelectrochemical cells responsible for the generation of hydrogen and oxyge... more The electrodes in photoelectrochemical cells responsible for the generation of hydrogen and oxygen by water splitting have been intensively studied because of their high photon-to-electron conversion efficiency. The morphology of nanostructures with these high-efficiency electrodes was systematically compared with the morphology of ZnO structures with vertically aligned nanorod arrays (NA), hollow hemisphere arrays (HA), urchin-like (UL) nanorod arrays, and thin films (TF). The UV-vis light absorption, photoresponse (current-voltage characteristics in the dark and under light), and photoelectrochemistry of the electrodes were measured. The highest photon-to-electron conversion efficiency of 65% at a specific UV wavelength for an electrode with a ZnO UL structure was derived from the UL morphology of high light-trapping efficiency and carrier collection efficiency. The UL morphology also produced a photon-to-electron conversion efficiency of 4.5% under a solar simulator by CdS-sensitization of the ZnO UL electrode. The value was the highest observed thus far among the ZnO-based electrodes. We demonstrated that photoresponse measurement is a practical and simple technique for the estimation of the photon-to-electron conversion efficiency of an electrode.
Journal of the Korean Physical Society, 2008
Title: Advanced Magnetic Materials Produced by Using Rapid Quenching Technology. Authors: Nghi, N... more Title: Advanced Magnetic Materials Produced by Using Rapid Quenching Technology. Authors: Nghi, Nguyen Hoang; Dung, Nguyen Van; Tung, Mai Thanh; Tinh, Nguyen Huu; Hieu, Hoang Nhat; Chien, Bui Xuan; Tam, Nguyen Thihong. ...
J. Mater. Chem., 2012
Zinc oxide (ZnO) hollow hemisphere (HS) and urchin-like (UL) structures were fabricated and exami... more Zinc oxide (ZnO) hollow hemisphere (HS) and urchin-like (UL) structures were fabricated and examined for application to a gas sensor. Films of hollow ZnO-HS arrays floating over substrates were synthesized via Zn sputtering onto the template of a polystyrene sphere ...
Journal of the Electrochemical Society, 2013
ABSTRACT Optimization of highly porous ZnO thin film electrode structures is carried out for use ... more ABSTRACT Optimization of highly porous ZnO thin film electrode structures is carried out for use in photoelectrochemical (PEC) cell. Spherical voids are formed in ZnO films using a sacrificial template of polystyrene spheres of similar to 400 nm sizes. The voids serve as light scattering centers for dramatically enhanced light absorption in the visible region of the solar spectrum, and as channels for electrolyte infiltration into the film. The UV-vis spectra reveal that light absorption at wavelength of 800 nm is enhanced to about 99%. The voids are further used as a route for the deposition of CdS nano-crystallites throughout the ZnO film. The CdS-decorated ZnO nanoparticulate structure shows a photon-to-electron conversion efficiency of 5.7% under a solar simulator. This efficiency value is the highest reported so far among ZnO-based electrodes, and is achieved by optimization of the nanostructure in the CdS-decorated ZnO films
Applied Spectroscopy, 2011
Sum frequency generation (SFG) microscopy images of cotton cellulose fibers were observed at the ... more Sum frequency generation (SFG) microscopy images of cotton cellulose fibers were observed at the infrared wavenumber of ; 2945 cm À1 and with a spatial resolution of 2 lm. Domains of different cellulose microfibril bunches were observed and they showed different second-order nonlinear responses. The intensity of the peak of the asymmetric CH 2 stretching mode at 2945 cm À1 depended strongly on the orientation of the electric fields of the incident visible and infrared light with respect to the cellulose fiber axis. The second-order nonlinear susceptibility arising from the chirality in the cellulose structure was found to be dominant. The SFG of the cross section of the cellulose fiber was relatively weak and showed a different spectrum from that measured from the side of the fiber axis.
The increasing trend towards the use of image sensors in transportation is driven both by legisla... more The increasing trend towards the use of image sensors in transportation is driven both by legislation and consumer demands for higher safety and a better-driving experience. Awareness of the environment that surrounds a vehicle can make driving and manoeuvring of the vehicle much safer for all road users. The authors present an image processing method to detect lane departure in forward-facing video specifically designed to be in accordance with proposed automotive lane departure warning standards. Our system uses a novel lane-marking segmentation algorithm in accordance with national standards for lane markings. This method does not demand the high computational requirements of inverse perspective mapping unlike methods proposed in related research. The authors present a method for lane boundary modelling based on subtractive clustering and Kalman filtering in the Hough transform domain, which is within the constraints of automotive standards. Finally, using the cameras intrinsic and extrinsic parameters, the width of the vehicle and guidelines issued by the International Organisation for Standardisation, we show how lane departure can be identified. Results are presented that verify the systems high detection rate and robustness to various background interference, lighting conditions and road environments.
Lexus Safety System+ is designed to support driver awareness, decision-making and vehicle operati... more Lexus Safety System+ is designed to support driver awareness, decision-making and vehicle operation over a wide range of speeds under certain conditions. Packaged together in an integrated system, Lexus Safety System+ features help address three key areas of accident protection: preventing or mitigating frontal collisions 3 , keeping drivers within their lane 4 and enhancing road safety during nighttime driving 5. Always drive safely, obey traffic speed limits and laws and focus on the road while driving. Lexus Safety System+ is comprised of four systems (with some variations shown as well): 1. Pre-Collision System 3 with Pedestrian Detection 6 | Left Turn Intersection Support * 2. Lane Departure Alert 4 3. Intelligent High Beams 5 4. Dynamic Radar Cruise Control 9 Lexus Safety System+ 2.0 and 2.5 include two additional features: 5. Road Sign Assist 14 † 6. Lane Tracing Assist 15 † Lexus Safety System+ 3.0 enhancements include: 7. Curve Speed Management added to Dynamic Radar Cruise Control 8. Additional Intersection Support LEXUS SAFETY SYSTEM+ ADDRESSES THREE OF THE MOST COMMON ACCIDENT TYPES Collision protection includes collision prevention. Collisions that result in injury may be caused by the delay in a driver's recognition of the situation and his or her ability to react accordingly. According to NHTSA 1 , there were almost 6.3 million reported crashes in 2015-many of which were avoidable. Lexus Safety System+ 2 is designed to help protect drivers, passengers, people in other vehicles on the road and pedestrians from harm. This system is composed of advanced active safety packages anchored by automated pre-collision warning 3 and braking. Lexus Safety System+ represents the latest milestone in our long history of creating advancements and innovations in safety that have helped prevent or mitigate crashes and protect people.
Meeting Abstracts of the Physical Society of Japan (Nihon Butsuri Gakkai koen gaiyoshu), 2010
Meeting Abstracts of the Physical Society of Japan (Nihon Butsuri Gakkai koen gaiyoshu), 2011
Advances in Natural Sciences: Nanoscience and Nanotechnology, 2016
Korean Journal of Materials Research, 2013
We present an easy method of preparing two-dimensional (2D) periodic hollow tin oxide (SnO 2) hem... more We present an easy method of preparing two-dimensional (2D) periodic hollow tin oxide (SnO 2) hemisphere array gas sensors using polystyrene (PS) spheres as a template. The structures were fabricated by the sputter deposition of thin tin (Sn) metal over an array of PS spheres on a planar substrate followed by calcination at an elevated temperature to oxidize Sn to SnO 2 while removing the PS template cores. The SnO 2 hemisphere array structures were examined by scanning electron microscopy and X-ray diffraction. The structures were calcined at various temperatures and their sensing properties were examined with varying operation temperatures and concentrations of nitric oxide (NO) gas. Their gas-sensing properties were investigated by measuring the electrical resistances in air and the target gases. The measurements were conducted at different NO concentrations and substrate temperatures. A minimum detection limit of 30 ppb, showing a sensitivity of S = 1.6, was observed for NO gas at an operation temperature of 150 o C for a sample having an Sn metal layer thickness corresponding to 30 sec sputtering time and calcined at 600 o C for 2 hr in air. We proved that high porosity in a hollow SnO 2 hemisphere structure allows easy diffusion of the target gas molecules. The results confirm that a 2D hollow SnO 2 hemisphere array structure of micronmeter sizes can be a good structural morphology for high sensitivity gas sensors.
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2015
We report a sum frequency generation (SFG) spectroscopy study of D-glucose, Dfructose and sucrose... more We report a sum frequency generation (SFG) spectroscopy study of D-glucose, Dfructose and sucrose in the C-H stretching vibration regime. Wetting effect on the SFG spectra was investigated. The SFG spectrum of D-glucose changed from that of α-Dglucose into those of α-D-glucose monohydrate by wetting. The SFG spectra showed evidence of a small change of β-D-fructopyranose into other anomers by wetting. SFG spectra of sucrose did not change by wetting. Assignments of the vibrational peaks in the SFG spectra of the three sugars in the dry and wet states were performed in the C-H stretching vibration region near 3000 cm-1 .
Springer Proceedings in Physics
... Nguyen Hoang Nghi, Nguyen Van Dung, Nguyen Huu Hoang, Tran Anh Phong, Phi Hoa Binh, Dependan... more ... Nguyen Hoang Nghi, Nguyen Van Dung, Nguyen Huu Hoang, Tran Anh Phong, Phi Hoa Binh, Dependance of giant magnetoimpedance effect of Co-based and Fe based nanocrystalline ribbons on measuring configuration, The ninth Asia Pacific physics Conference, Hanoi ...
Sensors and Actuators B: Chemical, 2014
High-performance methane gas sensors were developed from Ni 2 O 3-decorated SnO 2 semiconducting ... more High-performance methane gas sensors were developed from Ni 2 O 3-decorated SnO 2 semiconducting films. The SnO 2 film was fabricated by the sputter deposition of Sn metal followed by oxidation. Ni nanoparticles were then deposited onto the SnO 2 film by the arc discharge deposition of single-wall carbon nanotubes followed by the burning out of carbon nanotubes. The catalytic Ni nanoparticles distributed in the carbon nanotubes were oxidized to Ni 2 O 3. The surface morphology and structural properties were examined by scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The methane gas sensing properties were examined at different operation temperatures with SnO 2 thickness and Ni 2 O 3 quantity as variables. The synergetic effects induced by the Ni 2 O 3decoration including enhanced response and lowered operation temperature were observed. We also report very high sensor responses. The sensing mechanism of the hybrid sensor structure was also discussed.
Journal of Materials Chemistry C, 2013
ABSTRACT We report a heterojunction formed between single-wall carbon nanotubes (SWCNTs) and a WO... more ABSTRACT We report a heterojunction formed between single-wall carbon nanotubes (SWCNTs) and a WO3 thin film. WO3 thin films were fabricated by sputter deposition of W followed by oxidation and SWCNTs were fabricated by the arc-discharge method. The morphology of the structures was examined by scanning electron microscopy, X-ray diffraction, and Raman spectroscopy. The current–voltage characteristics of WO3 thin films, SWCNTs films, and SWCNT/WO3 heterojunctions were measured in darkness and under ultraviolet light. A rectifying heterojunction formation of p-SWCNT/n-WO3 was confirmed. The observed unconventional optoelectronic properties were analyzed, and the results were used to explain the photoconduction phenomena occurring at the heterojunction. The heterojunctions and resistors were also examined for their photodetection performance.
Nanoscale, 2013
The electrodes in photoelectrochemical cells responsible for the generation of hydrogen and oxyge... more The electrodes in photoelectrochemical cells responsible for the generation of hydrogen and oxygen by water splitting have been intensively studied because of their high photon-to-electron conversion efficiency. The morphology of nanostructures with these high-efficiency electrodes was systematically compared with the morphology of ZnO structures with vertically aligned nanorod arrays (NA), hollow hemisphere arrays (HA), urchin-like (UL) nanorod arrays, and thin films (TF). The UV-vis light absorption, photoresponse (current-voltage characteristics in the dark and under light), and photoelectrochemistry of the electrodes were measured. The highest photon-to-electron conversion efficiency of 65% at a specific UV wavelength for an electrode with a ZnO UL structure was derived from the UL morphology of high light-trapping efficiency and carrier collection efficiency. The UL morphology also produced a photon-to-electron conversion efficiency of 4.5% under a solar simulator by CdS-sensitization of the ZnO UL electrode. The value was the highest observed thus far among the ZnO-based electrodes. We demonstrated that photoresponse measurement is a practical and simple technique for the estimation of the photon-to-electron conversion efficiency of an electrode.
Journal of the Korean Physical Society, 2008
Title: Advanced Magnetic Materials Produced by Using Rapid Quenching Technology. Authors: Nghi, N... more Title: Advanced Magnetic Materials Produced by Using Rapid Quenching Technology. Authors: Nghi, Nguyen Hoang; Dung, Nguyen Van; Tung, Mai Thanh; Tinh, Nguyen Huu; Hieu, Hoang Nhat; Chien, Bui Xuan; Tam, Nguyen Thihong. ...
J. Mater. Chem., 2012
Zinc oxide (ZnO) hollow hemisphere (HS) and urchin-like (UL) structures were fabricated and exami... more Zinc oxide (ZnO) hollow hemisphere (HS) and urchin-like (UL) structures were fabricated and examined for application to a gas sensor. Films of hollow ZnO-HS arrays floating over substrates were synthesized via Zn sputtering onto the template of a polystyrene sphere ...
Journal of the Electrochemical Society, 2013
ABSTRACT Optimization of highly porous ZnO thin film electrode structures is carried out for use ... more ABSTRACT Optimization of highly porous ZnO thin film electrode structures is carried out for use in photoelectrochemical (PEC) cell. Spherical voids are formed in ZnO films using a sacrificial template of polystyrene spheres of similar to 400 nm sizes. The voids serve as light scattering centers for dramatically enhanced light absorption in the visible region of the solar spectrum, and as channels for electrolyte infiltration into the film. The UV-vis spectra reveal that light absorption at wavelength of 800 nm is enhanced to about 99%. The voids are further used as a route for the deposition of CdS nano-crystallites throughout the ZnO film. The CdS-decorated ZnO nanoparticulate structure shows a photon-to-electron conversion efficiency of 5.7% under a solar simulator. This efficiency value is the highest reported so far among ZnO-based electrodes, and is achieved by optimization of the nanostructure in the CdS-decorated ZnO films
Applied Spectroscopy, 2011
Sum frequency generation (SFG) microscopy images of cotton cellulose fibers were observed at the ... more Sum frequency generation (SFG) microscopy images of cotton cellulose fibers were observed at the infrared wavenumber of ; 2945 cm À1 and with a spatial resolution of 2 lm. Domains of different cellulose microfibril bunches were observed and they showed different second-order nonlinear responses. The intensity of the peak of the asymmetric CH 2 stretching mode at 2945 cm À1 depended strongly on the orientation of the electric fields of the incident visible and infrared light with respect to the cellulose fiber axis. The second-order nonlinear susceptibility arising from the chirality in the cellulose structure was found to be dominant. The SFG of the cross section of the cellulose fiber was relatively weak and showed a different spectrum from that measured from the side of the fiber axis.