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Results 421-430 of 698 (Search time: 0.001 seconds).
  • Authors: Vu, Le Huy; Le, Thi Huyen Linh; Nguyen, Dinh Dzung;  Advisor: -;  Co-Author: - (2021)

    Parallel robots are being applied popular in industry. They usually have many closed-loop kinematic structures, therefore their movement equations have the form of redundant coordinates and are complex. In most cases, parameters of dynamic model of the parallel robots required to be known exactly for control problem using the control laws such as PD, PID, CTC. This study is going to see in which the conditions of the Rostock Delta parallel robot should be used well with the PD control law. The movement equations of Rostock Delta robot in the form of differential equation system with redundant generalized coordinates is used to establish the PD control law. The stableness of the control law is also proved. Tracking control of a specific Rostock Delta robot is then simulated to see wh...

  • Authors: Minh-Hoang Nguyen;  Advisor: -;  Co-Author: - (2021)

    Urban humans and biodiversity-related concepts are interacting with each other in many negative and positive ways. The biodiversity provides a wide array of provision and cultural-ecological services to urban residents, but it is being overexploited to the point of crisis. The crisis is largely driven by the expanding illegal wildlife trade in developing countries with a high urbanization rate and biodiversity level like Vietnam. While supply-side measures are ineffective in reducing biodiversity loss, researchers have suggested demand-side measures as supplements, such as social marketing campaigns and law enforcement in urban areas. Moreover, urban residents are also potential visitors to urban public parks and national parks, which helps generate finance for biodiversity preserva...

  • Authors: Nguyen Thanh Vinh; Tran Van Dang; Bui Thi Hang; Anh-Tuan Le; Nguyen Tri Tuan; Le Khanh Vinh; Nguyen Van Quy;  Advisor: -;  Co-Author: - (2021)

    The sensing material plays a very important role in determining the sensing properties of a gas sensor. In order to synthesise the sensing material, the precursors have a large effect on the properties of the sensing material. In this study, three types of γ-Fe2O3 nanoparticles were prepared with different ferric ion concentrations of [Fe3+] and [Fe2+] as precursors, by a typical facile chemical precipitation process and a following annealing treatment. A mass-type gas sensor was fabricated by using a quartz crystal microbalance (QCM) coated with various γ-Fe2O3 nanoparticles. The morphology, crystallisation, and gas adsorption characteristics of the γ-Fe2O3 nanoparticles were investigated. The effect of ferric ion concentrations of [Fe3+] and [Fe2+] on sensing properties is discuss...

  • Authors: Minhhuy Le;  Advisor: Van Su Luong; Khoa Dang Nguyen; Jinyi Lee;  Co-Author: - (2021)

    Detection of corrosion at rivet sites in a multilayer structure of an aircraft is an essential task to ensure the flight safety of an aircraft. It is challenging to detect the corrosion due to the influence on the signal of the rivet and the multiple fastened layers in the structure. In this letter, an electromagnetic testing method is used in conjunction with principal component analysis (PCA) to detect corrosion around fasteners. Multiple Hall sensors were used for efficient measurement of the magnetic field distribution at the rivet sites. The features of the scanned magnetic image were automatically extracted by the PCA in orthogonal subspaces. The proposed method shows potential results of features extraction and corrosion signal extraction for further development of electromag...

  • Authors: Minh Cuong, Duong; Hong Trang, Nguyen; Mai, Duong;  Advisor: -;  Co-Author: - (2022)

    Vaccine hesitancy is a major threat to COVID-19 vaccination programs. This study aimed to examine the public attitudes towards COVID-19 vaccines, the variance of these attitudes, and associated determinants within a large COVID-19 outbreak in Vietnam.

  • Authors: Quoc, Thai Cao; Quan, Hoang Vuong; Hiep, Hung Pham; ; Dinh, Hai Luong; Manh, Toan Ho; Anh, Duc Hoang; Minh, Trang Do;  Advisor: -;  Co-Author: - (2021)

    The mental health of university students is not only a predominant topic for psychology and education researchers but also a source of interest for policymakers and various stakeholders. Although there has been a lot of research on higher education students’ mental health, we have little understanding on the mental health of international students (MHIS). Despite their distinctive characteristics compared to native students, the mental health issues of international students only started receiving attention very recently. So far, the literature on this topic lacks a comprehensive overview of its sub-topic and trending issues. By using bibliometric analysis, this research aims to fulfil this gap and provide a review of the extant literature about MHIS. Specifically, this study aims t...

  • Authors: Van Tan, Tran; Jeonghyo, Kim; Sangjin, Oh; Ki-Jae Jeong; Jaebeom, Lee;  Advisor: -;  Co-Author: - (2022)

    There are usually trade-offs between maximizing the color saturation and brightness and minimizing the angle-dependent effect in structural colors. Here, a magnetic field-induced assembly for the rapid formation of scalable, uniform amorphous photonic arrays (APAs) featuring unique structural colors is demonstrated. The magnetic field plays a fundamental role in photonic film formation, making this assembly technology versatile for developing structural color patterns on arbitrary substrates. The synergistic combination of surface plasmonic resonance of the Ag core and broadband light absorption of high refractive index (RI) Fe3O4 shell in hybrid magnetoplasmonic nanoparticles (MagPlas NPs) enables breaking the trade-offs to produce brilliant, noniridescent structural colors with hi...

  • Authors: Kenny, Kuchta; Kosuke, Aritake; Yoshihiro, Urade;  Advisor: -;  Co-Author: - (2022)

    The objective of this review is to evaluate the anti-dementia activities of saffron and its combination with Kampo medicine. The Kampo formula Kamiuntanto composed of 13 crude drugs is well known for its anti-dementia activity. A significant increase in choline acetyltransferase activity and mRNA levels were observed. Polygala radix was identified as the most essential component drug in Kamiuntanto, probably due to the saponins, tenuifolin, and sinapinic acid. Ginseng was also identified as an essential Kamiuntanto component in terms of its synergistic functions with Polygala radix. Saffron, which was recommended in the Bencao Gangmu for memory and dementia, and is used as an anti-spasmodic, anti-catarrhal, and sedative herbal drug. Saffron and its major constituent, crocin were sho...

  • Authors: Vinh, V.Le; Dinh, Thi Hinh;  Advisor: -;  Co-Author: - (2022)

    The molecular dynamics simulations have been carried out to investigate the mechanical behaviors of amorphous silicon nitride under the uniaxial tensile deformation. The amorphous silicon nitride was obtained by the cooling process. The network structure of the sample consists of SiNx (x = 3, 4 and 5) units and NSiy (y = 2, 3 and 4) linkages. The stress-strain curve of the sample exhibits the elastic and plastic deformation. The Si-N bond lengths are stretched out in the elastic region and the plastic region I. They are shrunk to the initial state in the plastic region II due to the appearance of the large clusters which contain the overlapping big simplexes with the RS ≥ 2.4 Å. These big simplexes tend to appear at the shear transformation zones in the elastic region. These shear t...