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Results 21-30 of 144 (Search time: 0.001 seconds).
  • Authors: Tran, Diem Hong;  Advisor: Tran, Hau Thi; Le, Uyen Phuong; Vu, Xuan Dang; Trinh, Thi Bich Ngoc; Do, Hoang Dang Khoa; Than, Van Thai; Bui, Le Minh; Vu, Van Van; Nguyen, Thi Lan; Phung, Huong Thi Thu; Le, Van Phan;  Co-Author: - (2021)

    African swine fever (ASF) is a highly infectious viral disease with high mortality. The most recent ASF outbreak in Vietnam began in 2019, posing a threat to spread to the neighbouring Asian countries. Without a commercial vaccine or efficient chemotherapeutics, rapid diagnosis and necessary biosecurity procedures are required to control the disease. While the diagnostic method of ASF recommended by the World Organization of Animal Health is real-time PCR, the ideal diagnosis procedure including master mix setup, template extraction and a high-cost qPCR equipment for many samples being tested simultaneously is not portable. In this study, a colorimetric loop-mediated isothermal amplification (LAMP) assay was modified and evaluated for ASF virus detection using crude serum samples co...

  • Authors: Nguyen, Trung Kien;  Advisor: Hoang, Tuan Hai;  Co-Author: - (2021)

    Using bio-based fuels in diesel engines is an effective solution to reduce the generation of toxic components in the exhaust gas. One of them, alcohol, is the potential fuel to reduce emissions and dependence on fossil fuels. So, this study is aimed to investigate the effects of ethanol port injection timing and delivery rate on the combustion characteristic of a heavy-duty V-12 diesel engine when ethanol substitution percentage is 30% to reach the original diesel quantity at full load. The combustion characteristic analysis indicates that the variation in cylinder gas pressure and temperature decreases when retarded ethanol injection timing and decreased ethanol delivery rate, the engine works more smoothly due to the maximum rate of pressure rise decreases. However, the changes ar...

  • Authors: Vu Le Huy; Nguyen Dinh Dzung;  Advisor: -;  Co-Author: - (2021)

    Since parallel robots are the multibody systems with closed-loop structures, their movement equations usually are in the complex form of redundant coordinates and their dynamics parameters are usually uncertain. The aim of this paper is to improve the control quality for the parallel robot by applying RBF neutron network. Firstly, the movement equations of Rostock Delta robot are established as differential–algebraic systems of equations with redundant generalized coordinates. Then, the stableness of the control method based on sliding mode control law using neural network is proved. Finally, the error in tracking control of a specific Rostock Delta robot is simulated by using this method.

  • Authors: Xiong Yang; Xue-Jing Xing; Yi-Fan Liu; Chun-Hong Mu; Hao Van Bui; Zhong-Wei Zhang; Simeon Agathopoulos; Xin Xu; Liang-Jun Yin;  Advisor: -;  Co-Author: - (2021)

    Nitride red phosphors of Sr2Si5N8:Eu2+ are synthesized in mild conditions and exhibit excellent luminescence properties; yet, the occurrence of thermal degradation results in a decrease of their luminous intensity and quantum efficiency at the high working temperature of wLED. This work shows that Sr2Si5N8:Eu2+ phosphors, prepared by a high-temperature solid-state reaction, undergo severe thermal degradation at high temperatures, not only in air atmosphere, but even in highly pure N2 gas. In order to shed light on the degradation mechanism, the materials obtained after heat-treatment at various temperatures up to 600 °C were thoroughly characterized at the investigated temperatures with the aid of several experimental techniques, such as in-situ HRTEM, along with XPS, luminescence s...

  • Authors: Vo, Van Nhan;  Advisor: Chakchai, So-In; Tran, Hung; Tran, Duc-Dung; Tung Pham Huu;  Co-Author: - (2021)

    In this article, we consider the information leakage and outage probabilities of a multiple-input single-output (MISO) energy-harvesting (EH) Internet of Things (IoT) system in which a multiantenna ground base station (GBS) transmits messages to legitimate IoT destinations (LIDs) with the help of IoT relays (IRs) using non-orthogonal multiple access (NOMA) in the presence of a malicious jammer (MJ) and eavesdroppers (EAVs). The communication protocol is separated into two phases. In the EH phase, the IRs harvest energy from a power beacon (PB). In the information transmission (IT) phase, the communication process is further divided into two subphases: 1) The GBS broadcasts signals to the IRs using NOMA. Simultaneously, the MJ sends interfering signals to attack the IRs while the EAV...

  • Authors: Truong V. Vu;  Advisor: -;  Co-Author: - (2021)

    A compound droplet solidifying on a cold curved surface in a gaseous environment is numerically studied by an axisymmetric three-phase front tracking method. The compound droplet containing an inner core of gas is initially assumed to be part of a sphere, and the curved surface is maintained at temperature below the solidification point of the shell liquid. The effects of the radius of the cold surface, volume change (in terms of the solid-to-liquid density ratio ρsl), supercooling degree (in terms of the Stefan number St), growth angle ϕgr and shell liquid thickness on the solidified droplet shape, the solidification rate and the solidification times are under consideration. Volume expansion (ρsl < 1.0) induces an apex, and volume shrinkage (ρsl > 1.0) results in a cavity on top of...

  • Authors: Tran Khoa Dang; Nguyen Tang Son; Nguyen Thi Lanh; Phan Hong Phuoc; Nguyen Ngoc Viet; Le Viet Thong; Chu Manh Hung; Nguyen Van Duy; Nguyen Duc Hoa; Nguyen Van Hieu;  Advisor: -;  Co-Author: - (2021)

    External and internal heterojunctions of reduced graphene oxide (rGO) and ZnO nanofibers (NFs) are developed for ultrasensitive H2S sensing. The gas response of both heterojunctions is significantly higher than that of bare ZnO NFs. The internal heterojun

  • Authors: Dung Do Thi Thuy;  Advisor: Vu, Thi Ngoc Minh; Nguyen, Xuan Truong; Pham, Van Huan; Vuong-Pham Hung; Nguyen, Duy-Hung; Bui, Thi Hoan; Tu Le Manh; Hoang, Nhu Van;  Co-Author: - (2021)

    This work presents a novel multifunctional material synthesized by hydroxyapatite/ β-tricalcium phosphate (HA/β-TCP) doped with Er-Yb-Mo ions (using hydrothermal method) and its characterization, showing a peculiar property of green dual-mode emissions (up and down-conversions). It was found that the obtained material exhibits an intense green emission (510–560 nm) both via up-conversion (excited by 975 nm) and down-conversion (excited by 379 nm), which depend on the Mo6+ contents. Particularly, compared with the free-Mo6+ sample, the green emission intensities of the samples doped with 5% Mo6+ mol are 50 and 35 times higher for UC and DC emissions, respectively. Furthermore, the temperature sensing property of the HA/β-TCP: Er-Yb-Mo composite is investigated by fluorescence intensi...

  • Authors: Anh D. Phan; Nguyen K. Ngan; Nam B. Le; Le T. M. Thanh;  Advisor: -;  Co-Author: - (2021)

    Physical properties of the pressure-induced activation volume and dynamic decoupling of ternidazole, glycerol, and probucol by the elastically collective nonlinear Langevin equation theory is theoretically investigated. Based on the predicted temperature dependence of activated relaxation under various compressions, the activation volume is determined to characterize effects of pressure on molecular dynamics of materials. It is found that the decoupling of the structural relaxation time of compressed systems from their bulk uncompressed value is governed by the power-law rule. The decoupling exponent exponentially grows with pressure below 2 GPa. The decoupling exponent and activation volume are intercorrelated and have a connection with the differential activation free energy. Rela...