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Nguyen Van Hung,Bui Thi Minh Nguyet,Nguyen Huu Nghi,Nguyen Minh Luon,Nguyen Ngoc Bich,Le Van Thanh Son,Nguyen Trung Kien,Dao Ngoc Nhiem,Nguyen Thanh Tuoi,Dinh Quang Khieu 대한환경공학회 2024 Environmental Engineering Research Vol.29 No.4
In the present work, ZnO/g-C₃N₄/biochar was prepared, and it was used for visible-light driven photocatalytic degradation of some colorants (methylene blue, rhodamine B, methyl orange) and some antibiotics (doxycycline, ciprofloxacin, amoxicilline). Biochar was prepared by pyrolysing Phragmites australis biomass. The ZnO/g-C₃N₄/biochar composite was synthesized with the alkaline hydrolysis method. The obtained materials were characterized by X-ray diffraction, scanning electron microscopy, transition electron microscopy, energy dispersive X-ray/elemental mapping, ultraviolet-visible-diffuse reflectance spectroscopy, photoluminescence spectroscopy, nitrogen adsorption/desorption isotherms and X-ray photoelectron spectroscopy. The results show that ZnO nanoparticles with a large surface area are highly dispersed on the g-C₃N₄ particle surface and biochar. The composite exhibits superior photocatalytic degradation ability toward doxycycline, a broad-spectrum antibiotic of the tetracycline compared with individual components (ZnO or g-C₃N₄) and satisfies stability after six treatment cycles. The kinetics and degradation mechanisms of doxycyline were also addressed. In addition, the present catalyst also exhibits the photocatalytic degradation of methylene blue, rhodamine B, methyl orange, ciprofloxacin and amoxicillin in visible-light regions.
Fabrication of Planar Waveguide Chip for Splitting or Combining an Infrared Light Beam
Nguyen Thanh Binh,Nguyen Tat Thanh,Duong Thanh Trung,Nguyen Thanh Huong,Le Quoc Minh 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.52 No.5
Based on hybrid materials of polymethamethyl acrylat, silica and zirconia (ASZ)/Titania (AST), some planar structures of optical power splitter/combiner type 1×N channels were designed and simulated for making masks by using computer software. Splitter chips were then fabricated by using the thin-film sol-gel technique and their structure was formed by using a direct photo-patterning method with UV light and a mask. A conformation of the waveguide was tested with an Alpha-Step IQ system. The waveguide properties of the splitter were measured with a 1550 nm laser source. The experimental results show that the light was transmitted through the chip with a total output efficiency of around 6% and was separated uniformly at the output channels. Based on hybrid materials of polymethamethyl acrylat, silica and zirconia (ASZ)/Titania (AST), some planar structures of optical power splitter/combiner type 1×N channels were designed and simulated for making masks by using computer software. Splitter chips were then fabricated by using the thin-film sol-gel technique and their structure was formed by using a direct photo-patterning method with UV light and a mask. A conformation of the waveguide was tested with an Alpha-Step IQ system. The waveguide properties of the splitter were measured with a 1550 nm laser source. The experimental results show that the light was transmitted through the chip with a total output efficiency of around 6% and was separated uniformly at the output channels.
A Phosphate Starvation-Inducible Ribonuclease of Bacillus licheniformis
( Thanh Trung Nguyen ),( Minh Hung Nguyen ),( Huy Thuan Nguyen ),( Hoang Anh Nguyen ),( Thi Hoi Le ),( Thomas Schweder ),( Britta Jurgen ) 한국미생물 · 생명공학회 2016 Journal of microbiology and biotechnology Vol.26 No.8
The BLi03719 protein of Bacillus licheniformis DSM13 belongs to the most abundant extracellular proteins under phosphate starvation conditions. In this study, the function of this phosphate starvation inducible protein was determined. An amino-acid sequence analysis of the BLi03719-encoding gene showed a high similarity with genes encoding the barnase of Bacillus amyloliquefaciens FZB42 and binase-like RNase of Bacillus pumilus SARF-032. The comparison of the control strain and a BLi03719-deficient strain revealed a strongly reduced extracellular ribonuclease activity of the mutant. Furthermore, this knockout mutant exhibited delayed growth with yeast RNA as an alternative phosphate and carbon source. These results suggest that BLi03719 is an extracellular ribonuclease expressed in B. licheniformis under phosphate starvation conditions. Finally, a BLi03719 mutant showed an advantageous effect on the overexpression of the heterologous amyE gene under phosphate-limited growth conditions.
Does conventional freezing affect sperm DNA fragmentation?
Le, Minh Tam,Nguyen, Thai Thanh Thi,Nguyen, Tung Thanh,Nguyen, Trung Van,Nguyen, Tam An Thi,Nguyen, Quoc Huy Vu,Cao, Thanh Ngoc The Korean Society for Reproductive Medicine 2019 Clinical and Experimental Reproductive Medicine Vol.46 No.2
Objective: Sperm cryopreservation has been widely used in assisted reproductive technology, as it offers great potential for the treatment of some types of male infertility. However, cryopreservation may result in changes in membrane lipid composition and acrosome status, as well as reductions in sperm motility and viability. This study aimed to evaluate sperm DNA fragmentation damage caused by conventional freezing using the sperm chromatin dispersion test. Methods: In total, 120 fresh human semen samples were frozen by conventional methods, using SpermFreeze Solution as a cryoprotectant. Routine semen analysis and a Halosperm test (using the Halosperm kit) were performed on each sample before freezing and after thawing. Semen parameters and sperm DNA fragmentation were compared between these groups. Results: There was a significant decrease in sperm progressive motility, viability, and normal morphology after conventional freezing (32.78%, 79.58%, and 3.87% vs. 16%, 55.99%, and 2.55%, respectively). The sperm head, midpiece, and tail defect rate increased slightly after freezing. Furthermore, the DNA fragmentation index (DFI) was significantly higher after thawing than before freezing (19.21% prior to freezing vs. 22.23% after thawing). Significant increases in the DFI after cryopreservation were observed in samples with both normal and abnormal motility and morphology, as well as in those with normal viability. Conclusion: Conventional freezing seems to damage some sperm parameters, in particular causing a reduction in sperm DNA integrity.
Trajectory analyses of uncontrolled circular parachutes in random spatial wind fields
Thanh Dong Pham,Anh Tuan Nguyen,Vu Dan Thanh Le,Trung Kien Nguyen 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.8
The present paper explores the trajectories of two uncontrolled circular parachute models which differ in size and mass in random spatial wind fields. The wind velocity components were generated through three-dimensional inverse fast Fourier transforms; and the correlations of the simulation data compared with the theoretical functions to confirm the accuracy of the wind model. The parachute systems are modelled as six-degrees-of-freedom rigid bodies, on which the aerodynamic forces and moments are applied. The dynamics model was validated before being used to study the drop trajectories of the parachute systems in spatial wind fields. Analyzing the drop trajectories and the impact point dispersion characteristics of the two parachute systems, the paper shows that the smaller one oscillates at a higher frequency and is affected more strongly by the wind. While descending at low altitude, there could be resonance between the dynamics of the larger parachute model and the wind turbulence. Moreover, it is found that the use of simplified vertical wind profiles, which include only the variation of the wind velocity against the altitude, may cause significant error in the simulation results.
Identification of a Pneumatic Actuator using Non-linear Black-Box Model
Nguyen Thanh Trung,Dinh Quang Truong,Kyoung Kwan Ahn 제어로봇시스템학회 2011 제어로봇시스템학회 국제학술대회 논문집 Vol.2011 No.10
A pneumatic actuator is a device that is capable of converting energy from a pressurized gas into motion. While motion can be created through other means, such as a hydraulic or electric motor, pneumatic actuators are safer, cheaper, and cleaner. Therefore, pneumatic actuators have been used widely in the field of industry automation. However, the compressibility of air and the inherent non-linearity of pneumatic actuators cause challenges in controlling accurately position of pneumatic actuators. This paper presents an accurate non-linear back-box model (NBBM) for identifying the dynamic behavior of pneumatic actuators. Once the optimized NBBM of the pneumatic actuator is obtained, it can give a generation of an effective solution for designing a position controller of that. Here, the NBBM is a multi-player perceptron neural network (MLPNN), whose parameters are optimized by using the Lervenberg-Marquardt Back Propagation (LMBP) algorithm. For the model verification, a pneumatic actuator was set up to investigate the dynamics of it as well as to generate the training data. Next, the advanced NBBM for the pneumatic actuator is performed with suitable inputs to estimate the cylinder piston displacement. Finally, the NBBM ability is evaluated by a comparison of the estimated and real pneumatic actuator performance.
Trung Tran,Loc Thi My Nguyen,Thanh Thi Nghiem,Hien Thi Thu Le,Cuong Huu Nguyen,Thuy Phuong La,Trung Tien Nguyen,Hang Thi-Thu Nguyen 한국과학학술지편집인협의회 2019 Science Editing Vol.6 No.2
This study aimed at elucidating the present situation of scholarly journals published in Vietnam according to the minimum criteria to be indexed in the ASEAN Citation Index (ACI) and Scopus, with the goal of suggesting development strategies for scholarly journals in Vietnam. From the 387 journals accredited by the Vietnamese State Council for Professorship, 13 education journals were arbitrarily selected, and their compliance with the five minimum criteria for the ACI (peer review, timeliness, abstracts in English, references in Roman script, and a website in English) and the six minimum criteria for Scopus (peer review, timeline, abstracts in English, references in Roman characters, Electronic International Standard Serial Number [ISSN], and publication ethics) were assessed. Two of the 13 journals were eligible to be indexed in the ACI, while none fulfilled the minimum criteria to be indexed in Scopus. An urgent task for the editors of those journals is to establish an informative journal homepage in English that provides basic information on the journal. Then, an Electronic ISSN can be obtained from the ISSN International Center. Furthermore, the following steps are suggested for journal promotion: establishment of appropriate editorial policies and publication ethics procedures, improvement of research integrity, enhancement of the journals’ reputation in the international scientific community, and improvement of the online publishing system by adopting a journal manuscript management system. To achieve those goals, financial support from the Vietnamese government will be invaluable.
Trung Thanh Nguyen,Van-Tuan Tran,Minh-Thai Le 한국정밀공학회 2022 International Journal of Precision Engineering and Vol.23 No.7
This work addresses a process parameter-based optimization of the electrical discharge drilling (EDD) of the hole to decrease the specific drilling energy (SDE), the dilation of the hole (DH), and the tapper ratio (TR). The input parameters are the applied current (AC), pulse on time (TON), pulse off time (TOFF), discharge voltage (VO), gap voltage adjustor (GAP), capacitance parallel connection (CAP), and servo sensitivity selection (SV). The adaptive neuro based-fuzzy inference system (ANFIS)-based models were proposed to render the relations between the process parameters and EDD performances. The weights between multi-responses are determined using the entropy method. The optimum factors were obtained by the neighborhood cultivation genetic algorithm (NCGA). The findings revealed that the proposed ANFIS models employing gaussmf membership function may help to minimize the predictive error. The optimal values of the AC, TON, TOFF, VO, GAP, CAP, and SV are 5 A, 60 μs, 50 μs, 60 V, 6, 7, and 7, respectively. The SDE, DH, and TR are reduced by 10.13%, 34.46%, and 11.63%, respectively, as compared to initial values. Moreover, a hybrid approach using the ANFIS model, entropy method, and NCGA is a prominent technique for modeling and optimizing different EDD processes.