Papers by Nguyen Duc Hung
Vietnam Journal of Science and Technology
Surface electrochemically plated with nickel and highly inert particles provides useful applicati... more Surface electrochemically plated with nickel and highly inert particles provides useful applications: Ni–CeO2 as chemical catalysts, high hardness Ni–CBN (cubic boron nitride) as grinding tools, among others. The plating’s inert particles – 100 mm in size – on nickel surface need to be tightly adherent and evenly dispersed; it is therefore necessary to determine and control the coating layer’s thickness corresponding to the inert particles’ size by parameters like electrical current density and time. With 40–60 nm CeO2 particle size, Ni plating thickness is 12 mm. With 60–100 mm CBN particles, Ni plating thickness is up to 60 mm. Weight and plating thickness were determined by the weight method and Faraday's law. The difference between the two methods showed the presence of inert functional particles on composite coating. EDX method and SEM image also showed the alignment as well as the distribution of particles on the coating surface. Catalytic ability of Ni–CeO2 coating and ab...
Vietnam Journal of Science and Technology
Electrochemical plasma is formed by an electrochemical reaction with a high voltage direct curren... more Electrochemical plasma is formed by an electrochemical reaction with a high voltage direct current (DC) in a non-electrolyte solution such as distilled water to create a gaseous state on the electrodes. Under conditions of high voltage, strong electric field and suitable temperature rise due to the Joule-Lenz effect, an electrochemical plasma will appear and be noted by the glow on the electrode as well as the characteristic amperage of the reaction rate leading to a rapid increase in the electrochemical reaction. Plasma reactions produce substances with strong chemical reactivity such as H2, H2O2, or OH* free radicals, etc. in the aquatic environment. Electrochemical plasma formation can be controlled by technological parameters such as voltage, the distance between electrodes, conductivity, and the metallic nature of electrodes, etc. Using electrochemical plasma, it is possible to treat pollutants harmful to the aquatic environment such as 2,4-D; 2,4,5-T, and ammonia. In the proce...
TNU Journal of Science and Technology
Curcumin là hợp chất polyphenol màu vàng cam được tìm thấy trong phần thân củ của cây nghệ (Curcu... more Curcumin là hợp chất polyphenol màu vàng cam được tìm thấy trong phần thân củ của cây nghệ (Curcuma longa), được sử dụng như một vị thuốc trong y học cổ truyền do có hoạt tính sinh học mạnh như kháng viêm, kháng khuẩn, kháng oxy hóa và kháng tế bào ung thư. Tuy nhiên, các hoạt tính sinh học của curcumin bị giới hạn bởi đặc tính ít tan trong nước, tốc độ phân hủy cao và dễ bị quang hóa. Trong các nghiên cứu trước, nang micro curcumin đã được bào chế bằng phương pháp tạo gel ion và sự giải phóng curcumin đã được đánh giá trong môi trường giả lập dạ dày PBS pH = 1,2 và ruột non PBS pH = 7,4. Trong nghiên cứu này, quá trình giải phóng curcumin từ nang micro S0, S3, S8, S15 đã được thực hiện trong môi trường dạ dày giả lập (pH = 1,2) có bổ sung chất hòa tan hoạt động bề mặt TPGS nồng độ 3 g/L trong thời gian từ 1 đến 420 phút. Qua kết quả đánh giá động lực học giải phóng curcumin bằng các mô hình động học bao gồm mô hình bậc không, mô hình bậc một, mô hình Higuchi, mô hình Hixson-Crowell...
VNU Journal of Science: Mathematics - Physics
In this study, we synthesized K3AlF6:Mn4+ phosphor by co-precipitation method. The crystal struct... more In this study, we synthesized K3AlF6:Mn4+ phosphor by co-precipitation method. The crystal structure and photoluminescence properties were investigated. By surface modification of K3AlF6:Mn4+ using K3AlF6, the moisture resistance performances of the phosphor can be significantly improved. It was found that the luminescence performance of K3AlF6:Mn4+@K3AlF6, which was dispersed in water for 2 h, is unchanged but the uncoated sample reduces dramatically. White light emitting diodes (WLEDs) based on the phosphor combined with commercial YAG:Ce3+ coated on a blue LED showed significantly improved of performance with color correlated temperature (CCT) from 5307 K down to 3528 K and color rendering index (CRI) from 64 up to 87. The results exhibit the potential for the application of K3AlF6:Mn4+@K3AlF6 as a red phosphor in warm WLEDs.
International Journal of Cancer Management, 2020
Background: Central nervous system (CNS) lymphoma presents as the dense infiltration of tumor cel... more Background: Central nervous system (CNS) lymphoma presents as the dense infiltration of tumor cells in the perivascular space and blood-brain barrier disruption, on histopathological examination. The Ki-67 expression has been significantly correlated with tumor proliferation and is considered to be a prognostic factor. Objectives: This study aimed at analyzing the correlations among the apparent diffusion coefficient (ADC), the relative cerebral blood volume (rCBV), and the Ki-67 proliferation index in CNS lymphoma. Methods: From August 2019 to March 2020, 26 patients (14 men and 12 women) who underwent biopsy or surgery and were histologically confirmed as CNS lymphoma were included in this retrospective study. Diffusion and perfusion acquisitions were performed in 26 and 10 examinations, respectively. The Ki-67 proliferation index was available for all cases. Results: The mean tADC, rADC, and rCBV values were 0.61 ± 0.12 × 10-3 mm2/s, 0.73 ± 0.14, and 1.1 ± 0.32, respectively. Neg...
La Clinica terapeutica, 2020
BACKGROUND Abdominal solid organ trauma accounts for 86.9% of all blunt abdominal trauma cases, a... more BACKGROUND Abdominal solid organ trauma accounts for 86.9% of all blunt abdominal trauma cases, among which 5%-25% of cases are associated with arterial injuries. Aim: In this study, we aimed to determine the characteristics and diagnostic functions of computed tomography (CT) scans during the diagnosis of arterial injuries, including active extravasation, pseudoaneurysm, and arteriovenous fistula associated with solid organ trauma compared with digital subtraction angiography (DSA). METHODS From July 2019 to March 2020, a retrospective study was performed on 44 patients who presented with clinical manifestations of blunt abdominal injury and CT diagnosis of arterial injuries due to solid organ trauma, including active extravasation, pseudoaneurysm, and arteriovenous fistula, and later underwent DSA at Vietduc Hospital, in Hanoi, Vietnam. The features of arterial lesions on CT scan was described. Value of CT scan for the diagnosis of arterial injuries was analyzed compared to the DS...
Archives of Applied Science Research, 2009
This paper describes the character of the reduction of TNR by ZVI in anaerobic conditions and the... more This paper describes the character of the reduction of TNR by ZVI in anaerobic conditions and the oxidative reaction of amine reso rcine in the system of ZVI-EDTA-O2. The products of TNR by ZVI in anaerobic conditions were amine resorcine compounds. These compounds tend to be easier to oxidize by the free radical OHgenerated in the system of ZVI-EDTA-O2. HPLC and Chemical Oxygen Demand analysis (COD) were used to monitor the efficiency of reactions. The ex periments have suggested that the removal of TNR from groundwater should be implemented by a two step process. The first step is reduction of TNR by ZVI to form amine resorcine. The second step is oxidation of amine resorcine in system consisting o f ZVI-EDTA-O2. From the obtained results a model for TNR contaminated groundwater treatment has been suggested and tested.
IEEE Access, 2020
This paper proposes the models to solve the optimal generator dispatching problem in an islanded ... more This paper proposes the models to solve the optimal generator dispatching problem in an islanded Micro grid with different uncertainties in the constraint and in the objective coefficient. The optimal problem with interval in the power balance constraint is considered as a linear parametric optimization problem, focusing on optimal solutions based on the lower and upper ends of this interval. When the coefficients of cost per power unit caused by load shedding are imprecise and expressed as intervals, the proposed model will be based on the two ends of interval and the problem is converted to a two-objective problem. With uncertainties in both constraint and objective coefficient, the problem will be treated as a four-objective one, considering the lower and upper ends of all intervals. All models are expressed in the linear forms and the linearization is carried out by Max-Affine method. To solve this multi-objective problem, the Bellman-Zadeh approach and Particle Swarm Optimization (PSO) algorithm are applied. The rationality of the proposed models is confirmed in the case study with one low voltage Micro Grid.
Tạp chí Phẫu thuật Tim mạch và Lồng ngực Việt Nam, 2020
Đặt vấn đề: Ứng dụng những lợi ích của nội soi trong phẫu thuật tim hở tại Việt Nam còn rất mới, ... more Đặt vấn đề: Ứng dụng những lợi ích của nội soi trong phẫu thuật tim hở tại Việt Nam còn rất mới, chưa có công trình nào trong nước công bố về lĩnh vực này. Nghiên cứu được tiến hành nhằm tổng kết những kinh nghiệm ban đầu và đánh giá kết quả sớm của phương pháp phẫu thuật tim hở ít xâm lấn với nội soi hỗ trợ tại trung tâm tim mạch bệnh viện E.Đối tượng và phương pháp nghiên cứu: Nghiên cứu mô tả, tiến cứu, do cùng một nhóm phẫu thuật. Từ tháng 5/2013 đến tháng 3/2014 tổng số 63 bệnh nhân được phẫu thuật: đóng thông liên nhĩ, thay van hai lá, sửa van hai lá, sửa toàn bộ thông sàn nhĩ thất bán phần, lấy u nhầy nhĩ trái, bắc cầu chủ vành, cắt màng ngăn nhĩ trái, sửa hẹp van động mạch phổi.Kết quả: Thành công trên 60 bệnh nhân. 2 bệnh nhân phải mở rộng đường mở ngực,1 trường hợp chuyển mở xương ức do chảy máu từ động mạch liên thất sau, 1 bệnh nhân chảy máu sau mổ phải mở lại đường mở ngực lấy máu cục màng phổi; không có tử vong bệnh viện.Kết luận: phương pháp an toàn, khả thi, có thể t...
Vietnam Journal of Chemistry, 2019
Copper-silver bimetallic nanoparticles (NPs) can be prepared by electrochemical high voltage DC u... more Copper-silver bimetallic nanoparticles (NPs) can be prepared by electrochemical high voltage DC using silver and copper anodes in double distilled water. Bimetallic nano formation of Cu-Ag-NPs were performed by dissolving the Ag anode in anodic dissolved Cu solution or in the Cu NPs solution. The dependence of the DC current and the amount of electricity on the time show the reaction with a 200 mm electrode gap with formation of electronic plasma. The product obtained at 5 kV had the same characteristics as AgNPs with UV-Vis spectrum: 420 nm, particle size distribution was mainly in small areas of 100 nm, zeta potential had value up to-80.6 mV as well as the good ability to kill bacteria.
Vietnam Journal of Chemistry, 2018
Silver nanoparticles (AgNPs) were prepared by DC high voltage electrochemical method using a silv... more Silver nanoparticles (AgNPs) were prepared by DC high voltage electrochemical method using a silver anode. The results showed that, for all prepared samples, depending on the size and shape of their nanoparticles, a well-defined UV-Vis peak in aqueous solution induced by the surface Plasmon property of AgNPs was observed at wavelength values in the range of 400-450 nm. Based on the linear dependence between AgNPs concentration and UV-Vis absorbance up to 200 ppm with the R value of 0.9989, the concentration of AgNPs can be derived quantitatively. Thus, this study introduced a simple quantitative method to determine the concentration of silver nanoparticles directly, instead of the total ionic silver that other chemical, biological or physical methods usually provided.
Vietnam Journal of Science and Technology, 2019
Silver nanoparticles (AgPNs) were prepared by high-voltage electrochemical methods using silver a... more Silver nanoparticles (AgPNs) were prepared by high-voltage electrochemical methods using silver anode to produce silver ions and hydrogen gas at the cathode from electrolysis of distilled water as solvents. The electrolyte solution resulting from the AgPNs product obtained does not contain ions of the electrolyte solution such as conventional chemical or electrochemical methods. Silver anode dissolution process will provide Ag+ and disperse it into distilled water. The process of generating H2 from the electrolysis of H2O disperses into distilled water and escapes upward towards the anode due to the arrangement of the electrolytic vaporizer vertically above the anode and the cathode below. Ag+ and H2's encounter in the aqueous solution will take the oxidation-reduction reaction to form AgPNs. Due to the high-voltage DC electrolytic processes that generate gas on the electrodes, both high-voltage and high magnetic fields, as well as high water-distillation resistance, will increa...
Vietnam Journal of Science and Technology, 2019
Nano silver was known as a bactericidal agent for almost all bacterial species and has been... more Nano silver was known as a bactericidal agent for almost all bacterial species and has been intensively investigated over the world to apply for disinfection in different fields of human activities and environmental protection. Specifically, genital exudate media contain numerous dangerous bacteria such as Neisseria gonorrhoeae, Enterococcus faecalis, Staphylococcus aureus, Candida albicans etc. which as a rule are drug-resistant with respect to antibiotics. This research presents the results of the application of nanosilver in replacing antibiotics in elimination of the above mentioned microorganisms by using low nanosilver concentrations of about 0.01 mg/cm2 immobilized on non-woven fabric. The experimental data showed that nanosilver-impregnated fabric samples at a concentration 0.01 mg/cm2 gave antibacterial rings of 10 mm, 9 mm and 8 mm, respectively, for N. gonorrhoeae, Candida albicans + E.coli and Candida albicans + E.coli + S. aureus.
Future Internet, 2016
Climate and weather realizations are essential inputs for simulating crop growth and yields to an... more Climate and weather realizations are essential inputs for simulating crop growth and yields to analyze the risks associated with future conditions. To simplify the procedure of generating weather realizations and make them available over the Internet, we implemented novel mechanisms for providing weather generators as web services, as well as a mechanism for sharing identical weather realizations given a climatological information. A web service for preparing long-term climate data was implemented based on an international standard, Sensor Observation Service (SOS). The weather generator services, which are the core components of the framework, analyze climatological data, and can take seasonal climate forecasts as inputs for generating weather realizations. The generated weather realizations are encoded in a standard format, which are ready for use to crop modeling. All outputs are generated in SOS standard, which broadens the extent of data sharing and interoperability with other sectoral applications, e.g., water resources management. These services facilitate the development of other applications requiring input weather realizations, as these can be obtained easily by just calling the service. The workload of analysts related to data preparation and handling of legacy weather generator programs can be reduced. The architectural design and implementation presented here can be used as a prototype for constructing further services on top of an interoperable sensor network system.
International Journal of Fuzzy Logic and Intelligent Systems, 2013
LED lighting control system using unidirectional DMX512 (digital multiplex with 512 pieces of inf... more LED lighting control system using unidirectional DMX512 (digital multiplex with 512 pieces of information)) protocol has been the most popular. Nowadays, the user's consumption has been upgrading to the more intelligent system but the upgrading process does not affect the existing infrastructure. There were many researches use the additional communication for the feedback communication way such as WiFi, Controller Area Network (CAN), Power Line Communication (PLC), etc but all researches had inherent disadvantages that created the independent feedback with the existing DMX512 system. Our paper represents the novel method that uses the remote device management (RDM) protocol to associate the additional feedback with existent DMX512 infrastructure in the one system. The data in DMX512 frame sending to the DMX512 client is split and repacked to become the RDM packet. This RDM packet is transferred to the RDM monitor console and the response RDM packet is converted to the DMX512 frame for control DMX512 client devices. This is the closed loop control model which uses the bidirectional convertibility between RDM packet and DMX512 frame. The proposed method not only upgrades the feedback control function for the old DMX512 system without changing the existent infrastructure, but also solves compatible problems between new RDM devices and old DMX512 devices and gives the low cost solution for extending DMX512 universe.
International Journal of Control, Automation and Systems, 2010
In this paper, a new tracking controller that integrates a kinematic controller (KC) with an inte... more In this paper, a new tracking controller that integrates a kinematic controller (KC) with an integral sliding mode dynamic controller (ISMC) is designed for an omnidirectional mobile platform (OMP) to track a desired trajectory at a desired velocity. First, a posture tracking error vector is defined, and a kinematic controller (KC) is chosen to make the posture tracking error vector
Physical Review E, 2010
We introduce a model of media with the cubic attractive nonlinearity concentrated along a single ... more We introduce a model of media with the cubic attractive nonlinearity concentrated along a single or double stripe in the two-dimensional (2D) plane. The model can be realized in terms of nonlinear optics (in the spatial and temporal domains alike) and BEC. In recent works, it was concluded that search for stable 2D solitons in models with a spatially localized self-attractive nonlinearity is a challenging problem. We make use of the variational approximation (VA) and numerical methods to investigate conditions for the existence and stability of solitons in the present setting. The result crucially depends on the transverse shape of the stripe: while the rectangular profile supports stable 2D solitons, its smooth Gaussian-shaped counterpart makes all the solitons unstable. The double stripe with the rectangular profile admit stable solitons of three distinct types: symmetric and asymmetric ones with a single peak, and double-peak symmetric solitons. The shape and stability of single-peak solitons of either type are accurately predicted by the VA. Collisions between stable solitons are briefly considered too, by means of direct simulations. Depending on the relative velocity we observe excitation, decay or catastrophic self focusing.
Journal of Applied Physics, 1993
An investigation of the electrical and microstructural characteristics of the Ti contact on silic... more An investigation of the electrical and microstructural characteristics of the Ti contact on silicon has been carried out. The presence of As in Ti/n+-Si samples was found to retard the formation of polycrystalline silicide (p-silicide) compared with that in Ti/p+-Si samples with BF2+ implantation. Amorphous interlayers (a-interlayers) were found to be present in both Ti/n-Si and Ti/p-Si samples annealed at temperatures of and lower than 450 °C. Although the Schottky barrier heights (SBH’s) vary for about 0.05–0.08 eV for samples annealed over a temperature range from room temperature to 900 °C, SBH’s at the a-interlayer/n-Si and a-interlayer/p-Si were measured to be about 0.52–0.54 and 0.59–0.57 eV, respectively. The specific contact resistance (ρc) in the Ti/n+-Si system was measured to be the lowest with a value of 1.4×10−7 Ω cm2 when the a interlayer is present. In Ti/p+-Si system, the minimum ρc is about 3×10−7 Ω cm2. The variation in contact resistance with annealing temperatur...
Uploads
Papers by Nguyen Duc Hung