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Hoai-An Trinh,Hoai Vu Anh Truong,Minh-Duc Pham,Tri Cuong Do,Hong-Hee Lee,Kyoung Kwan Ahn 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.10 No.2
Using renewable energy is becoming a new tendency for vehicular applications to reduce fossil fuel consumption and minimize greenhouse gas emissions. Well-known as an eco-friendly energy source, the proton exchange membrane fuel cell (PEMFC) is extensively used in hybrid power systems to achieve the objective of zero-emission and air protection. However, this type of fuel cell offers slow dynamics and cannot adapt to abrupt load variations when used as a primary energy source. To overcome this shortcoming, battery (BAT) and/or supercapacitor (SC) are supplemented as auxiliary sources. In this paper, an innovative energy management strategy (EMS) for a PEMFC/BAT/SC hybrid power source (HPS) is proposed to improve the accuracy of power distribution from energy sources to the load. In detail, according to different characteristics of energy sources, a frequency decoupling (FD) method is designed to determine the required currents for PEMFC, BAT, and SC based on the load power demand. Besides, an adaptive DC bus control loop is utilized to guarantee a stable DC output voltage by using the BAT. The proposed EMS is simulated in a MATLAB/Simulink environment and experimentally implemented with a real-time DSP TMS320F28379D controller board. Subsequently, a test bench of a 200 W PEMFC, 24 V–12 Ah battery, and 25 V–60 F supercapacitor is conducted for experimental validation. The obtained results show that the proposed EMS is effective to coordinate energy flows between the three used sources and enhance the fuel cell performance in a hybrid power system.
Backstepping Sliding Mode-based Model-free Control of Electro-hydraulic Systems
Hoai Vu Anh Truong,TRINH HOAI AN,안경관 사단법인 유공압건설기계학회 2022 드라이브·컨트롤 Vol.19 No.1
This paper presents a model-free system based on a framework of a backstepping sliding mode control (BSMC) with a radial basis function neural network (RBFNN) and adaptive mechanism for electro-hydraulic systems (EHSs). First, an EHS mathematical model was dedicatedly derived to understand the system behavior. Based on the system structure, BSMC was employed to satisfy the output performance. Due to the highly nonlinear characteristics and the presence of parametric uncertainties, a model-free approximator based on an RBFNN was developed to compensate for the EHS dynamics, thus addressing the difficulty in the requirement of system information. Adaptive laws based on the actor-critic neural network (ACNN) were implemented to suppress the existing error in the approximation and satisfy system qualification. The stability of the closed-loop system was theoretically proven by the Lyapunov function. To evaluate the effectiveness of the proposed algorithm, proportional-integrated-derivative (PID) and improved PID with ACNN (ACPID), which are considered two complete model-free methods, and adaptive backstepping sliding mode control, considered an ideal model-based method with the same adaptive laws, were used as two benchmark control strategies in a comparative simulation. The simulated results validated the superiority of the proposed algorithm in achieving nearly the same performance as the ideal adaptive BSMC.
Hoai Bac Nguyen,이신영,박수현,이무열,장인호,명순철 대한비뇨의학회 2013 Investigative and Clinical Urology Vol.54 No.5
Purpose: The location of acetylcholinesterase-containing nerve fibers suggests a role for acetylcholine in both contractility and secretion in the prostate gland. The colocalization of nitrergic nerves with cholinergic nerves, and the cotransmission of nitric oxide with acetylcholine in cholinergic nerves, has been demonstrated in the prostate glands of various species. Thus, we investigated the effects of acetylcholine on phenylephrine-induced contraction and the correlation between cholinergic transmission and nitric oxide synthase by using isolated prostate strips of rabbits. Materials and Methods: Isolated prostate strips were contracted with phenylephrine and then treated with cumulative concentrations of acetylcholine. Changes in acetylcholine-induced relaxation after preincubation with NG-nitroarginine methyl ester,7-nitroindazole, and aminoguanidine were measured. The effects of selective muscarinic receptor antagonists were also evaluated. Results: In the longitudinal phenylephrine-contracted strip, the cumulative application of acetylcholine (10-9 to 10-4 M) elicited a concentration-dependent relaxation effect. Acetylcholine-induced relaxation was inhibited not only by nitric oxide synthase inhibitors (10 μM L-NAME or 10 μM 7-nitroindazole) but also by 10 μM atropine and some selective muscarinic receptor antagonists (10-6 M 11-([2-[(diethylamino)methyl]-1-piperdinyl]acetyl)-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepine-6-one and 10-6M 4-diphenylacetoxy-N-methyl-piperidine). In contrast, relaxation was significantly increased by pretreatment of the strips with 10 mM L-arginine. Conclusions: Acetylcholine relaxed phenylephrine-induced contractions of isolated rabbit prostate strips. This relaxation may be mediated via both cholinergic and constitutive nitric oxide synthase with both the M2 and M3 receptors possibly playing key roles.
Neutronics design of VVER-1000 fuel assembly with burnable poison particles
Hoai-Nam Tran,Van-Khanh Hoang,Peng Hong Liem,Hung T.P. Hoang 한국원자력학회 2019 Nuclear Engineering and Technology Vol.51 No.7
This paper presents neutronics design of VVER-1000 fuel assembly using burnable poison particles (BPPs) for controlling excess reactivity and pin-wise power distribution. The advantage of using BPPs is that the thermal conductivity of BPP-dispersed fuel pin could be improved. Numerical calculations have been conducted for optimizing the BPP parameters using the MVP code and the JENDL-3.3 data library. The results show that by using Gd2O3 particles with the diameter of 60 and the packing fraction of 5%, the burnup reactivity curve and pin-wise power distribution are obtained approximately that of the reference design. To minimize power peaking factor (PPF), total BP amount has been distributed in a larger number of fuel rods. Optimization has been conducted for the number of BPP-dispersed rods, their distribution, BPP diameter and packing fraction. Two models of assembly consisting of 18 BPP-dispersed rods have been selected. The diameter of 300 and the packing fraction of 3.33% were determined so that the burnup reactivity curve is approximate that of the reference one, while the PPF can be decreased from 1.167 to 1.105 and 1.113, respectively. Application of BPPs for compensating the reduction of soluble boron content to 50% and 0% is also investigated.
Hoai Thu Dao,Quang Lam Truong,Van Tan Do,Tae-Wook Hahn 대한수의학회 2020 Journal of Veterinary Science Vol.21 No.2
Actinobacillus pleuropneumoniae (APP) causes a form of porcine pleuropneumonia that leads to significant economic losses in the swine industry worldwide. The apxIBD gene is responsible for the secretion of the ApxI and ApxII toxins and the pnp gene is responsible for the adaptation of bacteria to cold temperature and a virulence factor. The apxIBD and pnp genes were deleted successfully from APP serotype 1 and 5 by transconjugation and sucrose counter-selection. The APP1ΔapxIBDΔpnp and APP5ΔapxIBDΔpnp mutants lost hemolytic activity and could not secrete ApxI and ApxII toxins outside the bacteria because both mutants lost the ApxI- and ApxII-secreting proteins by deletion of the apxIBD gene. Besides, the growth of these mutants was defective at low temperatures resulting from the deletion of pnp. The APP1ΔapxIBDΔpnp and APP5ΔapxIBDΔpnp mutants were significantly attenuated compared with wild-type ones. However, mice vaccinated intraperitoneally with APP5ΔapxIBDΔpnp did not provide any protection when challenged with a 10-times 50% lethal dose of virulent homologous (APP5) and heterologous (APP1) bacterial strains, while mice vaccinated with APP1ΔapxIBDΔpnp offered 75% protection against a homologous challenge. The ΔapxIBDΔpnp mutants were significantly attenuated and gave different protection rate against homologous virulent wild-type APP challenging.
Hoai Thanh Truong,이만승 한국자원공학회 2017 Geosystem engineering Vol.20 No.4
To investigate the separation of Re(VII), Mo(VI), and V(V) from hydrochloric acid solution, solvent extraction with TBP was investigated. When HCl concentration was lower than 3 M, TBP could selectively extract both Re(VII) and Mo(VI), leaving V(V) in the raffinate. The extraction percentage of Re(VII) was much higher than that of Mo(VI) in 1 M HCl, while that of the two metals was similar at 2 M HCl solution. Since there was not much difference in the stripping percentage of Re(VII) and Mo(VI) from the loaded TBP using HCl, NaOH, and NH4OH solutions, it was difficult to separate the two metals by stripping. Our results indicated that it is possible to separate the three metals by solvent extraction with TBP from 1 M HCl solution.