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Applications of Magnetite Nanoparticles for Water Treatment and for DNA and Cell Separation
Nguyen Hoang Hai,Nguyen Chau,Nguyen Hoang Luong,Nguyen Thi Van Anh,Phan Tuan Nghia 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.3
Magnetic nanoparticles with a diameter of 15 nm prepared by using the coprecipitation method have been applied to enforce the sedimentation of the solid waste, to adsorb the arsenic ions in water, to increase the DNA concentration by using a magnetic eld for the electrochemical DNA sensor and to separate the helper CD4+ T cells to determine the number of the cells in blood. A combination of magnetic nanoparticles and alum makes the solid waste in water under a magnetic field aggregate a dozen times faster than under the gravity alone. A concentration of 0.1 mg/l of arsenic in water was reduced to a value lower than the permissible concentration of 0.01 mg/l after few minutes of stirring. The particles functionalized with 3-aminopropyl triethoxysilane were used to enrich the DNA of the Herpes virus, which extended the sensitivity of an electrochemical sensor down to a concentration lower than nM/l. The particles coated with fluorescent-labeled antiCD4 antibody were used to count the helper CD4+ T cells. The fluorescence signals of the particle/cell system were two times stronger than those of the uorescence antiCD4 cell system. This can be used for the treatment of an HIV-infected patient with a simple fluorescent microscope. Magnetic nanoparticles with a diameter of 15 nm prepared by using the coprecipitation method have been applied to enforce the sedimentation of the solid waste, to adsorb the arsenic ions in water, to increase the DNA concentration by using a magnetic eld for the electrochemical DNA sensor and to separate the helper CD4+ T cells to determine the number of the cells in blood. A combination of magnetic nanoparticles and alum makes the solid waste in water under a magnetic field aggregate a dozen times faster than under the gravity alone. A concentration of 0.1 mg/l of arsenic in water was reduced to a value lower than the permissible concentration of 0.01 mg/l after few minutes of stirring. The particles functionalized with 3-aminopropyl triethoxysilane were used to enrich the DNA of the Herpes virus, which extended the sensitivity of an electrochemical sensor down to a concentration lower than nM/l. The particles coated with fluorescent-labeled antiCD4 antibody were used to count the helper CD4+ T cells. The fluorescence signals of the particle/cell system were two times stronger than those of the uorescence antiCD4 cell system. This can be used for the treatment of an HIV-infected patient with a simple fluorescent microscope.
Nguyen Huu Nghia,Nguyen Thi Nguyen,Phan Trong Binh,Le Thi May,Tong Tran Huy,Pham Thai Giang,Sophie St-Hilaire,Phan Thi Van 한국수산과학회 2022 Fisheries and Aquatic Sciences Vol.25 No.8
This study assessed the effects of oxygen and ozone nanobubbles on gill morphology, weight gain, and mortality of Pacific white shrimp (Penaeus vannamei), as well as the level of Vibrio parahaemolyticus and water quality of shrimp culture tanks under lab conditions. Two experiments were carried out with oxygen macrobubble, ozone macrobubble, oxygen nanobubble, ozone nanobubble, and control treatments (air-stone macrobubble). Experiments were done in triplicate in 100 L tanks with 15‰ saline water, and 20 shrimp per tank. Tanks in Experiment 1 were not inoculated with bacteria; tanks in Experiment 2 were inoculated with V. parahaemolyticus at a concentration of 106 CFU/mL. The results revealed that short treatments with ozone nanobubbles had minimal impact on shrimp gills, mortality, and growth rates, reduced V. parahaemolyticus concentration in water compared to the other groups, and improve water quality. These laboratory results indicate that ozone nanobubble treatment may be useful for controlling V. parahaemolyticus. More work is needed to find the best protocol to apply the technology on a commercial scale.
Preparing cuprous oxide nanomaterials by electrochemical method for non-enzymatic glucose biosensor
Nguyen, Thu-Thuy,Huy, Bui The,Hwang, Seo-Young,Vuong, Nguyen Minh,Pham, Quoc-Thai,Nghia, Nguyen Ngoc,Kirtland, Aaron,Lee, Yong-Ill IOP 2018 Nanotechnology Vol.29 No.20
<P>Cuprous oxide (Cu<SUB>2</SUB>O) nanostructure has been synthesized using an electrochemical method with a two-electrode system. Cu foils were used as electrodes and NH<SUB>2</SUB>(OH) was utilized as the reducing agent. The effects of pH and applied voltages on the morphology of the product were investigated. The morphology and optical properties of Cu<SUB>2</SUB>O particles were characterized using scanning electron microscopy, x-ray diffraction, and diffuse reflectance spectra. The synthesized Cu<SUB>2</SUB>O nanostructures that formed in the vicinity of the anode at 2 V and pH?=?11 showed high uniform distribution, small size, and good electrochemical sensing. These Cu<SUB>2</SUB>O nanoparticles were coated on an Indium tin oxide substrate and applied to detect non-enzyme glucose as excellent biosensors. The non-enzyme glucose biosensors exhibited good performance with high response, good selectivity, wide linear detection range, and a low detection limit at 0.4 <I>μ</I>M. Synthesized Cu<SUB>2</SUB>O nanostructures are potential materials for a non-enzyme glucose biosensor.</P>
Real-time Multiple Pedestrians Tracking for Embedded Smart Visual Systems
Nguyen, Van Ngoc Nghia,Nguyen, Thanh Binh,Chung, Sun-Tae Korea Multimedia Society 2019 멀티미디어학회논문지 Vol.22 No.2
Even though so much progresses have been achieved in Multiple Object Tracking (MOT), most of reported MOT methods are not still satisfactory for commercial embedded products like Pan-Tilt-Zoom (PTZ) camera. In this paper, we propose a real-time multiple pedestrians tracking method for embedded environments. First, we design a new light weight convolutional neural network(CNN)-based pedestrian detector, which is constructed to detect even small size pedestrians, as well. For further saving of processing time, the designed detector is applied for every other frame, and Kalman filter is employed to predict pedestrians' positions in frames where the designed CNN-based detector is not applied. The pose orientation information is incorporated to enhance object association for tracking pedestrians without further computational cost. Through experiments on Nvidia's embedded computing board, Jetson TX2, it is verified that the designed pedestrian detector detects even small size pedestrians fast and well, compared to many state-of-the-art detectors, and that the proposed tracking method can track pedestrians in real-time and show accuracy performance comparably to performances of many state-of-the-art tracking methods, which do not target for operation in embedded systems.
Warping stresses of a rectangular single leaf flexure under torsion
Nghia Huu Nguyen,Ji-Soo Kim,이동연 국제구조공학회 2016 Structural Engineering and Mechanics, An Int'l Jou Vol.59 No.3
We describe a stress analysis of a single leaf flexure under torsion in which the warping effect is considered. The theoretical equations for the warping normal stress (xx) and shear stresses (xz and xy) are derived by applying the warping function of a rectangular cross-sectional beam and the twist angle equation that includes the warping torsion. The results are compared with those of the non-warping case and are verified using finite element analysis (FEA). A sensitivity analysis over the length, width, and thickness is performed and verified via FEA. The results show that the errors between the theory of warping stress results and the FEA results are lower than 4%. This indicates that the proposed theoretical stress analysis with warping is accurate in the torsion analysis of a single leaf flexure.
Real Time Control of an Induction Motor Using IMC Approach
Nghia, Duong Hoai,Nho, Nguyen Van,Bac, Nguyen Xuan,Lee, Hong-Hee The Korean Institute of Power Electronics 2009 JOURNAL OF POWER ELECTRONICS Vol.9 No.3
The paper presents a method for controlling induction motors using a nonlinear internal model control (IMC) approach. The process model and the inverse model are developed in the rotor flux coordinate. The main advantage of the proposed method is that it easily specifies the performance (steady state error, transient response, etc.) and the robustness of the controller by means of the IMC filters. Simulation results illustrate the effectiveness of the proposed method. Results on a real time system show that the control system has good performance and robustness against changes in motor parameters (rotor and stator resistances, rotor and stator inductances, rotor inertia).
Displacement Analysis of a Single-Bent Leaf Flexure under Transverse Load
Nghia Huu Nguyen,임병덕,이동연 한국정밀공학회 2015 International Journal of Precision Engineering and Vol. No.
We report a displacement analysis of a single-bent leaf flexure under transverse loading. Euler-Bernoulli, Timoshenko, and third-orderbeam theories, and the partially restrained warping effect, are considered. Castigliano’s theorem is used to derive theoreticalexpressions of deflection under transverse loading. A sensitivity analysis is performed, and all of the results are verified using finiteelement analysis (FEA). The results show that the theoretical equations with third-order beam theory and a warping restraint factorof K=0.5 are in a good agreement with the FEA results, within a maximum 4% error. These results indicate that the accuracy of thedisplacement analysis of the single-bent flexure under transverse loading depends on both the transverse shear deformation and thepartially restrained warping effect.
Torsional analysis of a single-bent leaf flexure
Nghia Huu Nguyen,임병덕,이동연 국제구조공학회 2015 Structural Engineering and Mechanics, An Int'l Jou Vol.54 No.1
We present a torsion analysis of single-bent leaf flexure that is partially restrained, subject to a torsional load. The theoretical equations for the torsional angle are derived using Castigliano’s theorem. These equations consider the partially restrained warping, and are verified using finite element analysis (FEA). A sensitivity analysis over the length, width, and thickness is performed and verified via FEA. The results show that the errors between the theory result and the FEA result are lower than 6%. This indicates that the proposed theoretical torsional analysis with partially restrained warping is sufficiently accurate.