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Research objectives: this study aims to clarify the role of knowledge in social development, and open knowledge management in higher education. Research Methods: The authors mainly use theoretical research methods. Research through documents: retrospective, summarizing, systematizing theories from domestic and foreign studies, selected documents closely related to the task of knowledge research, knowledge management, thereby, act as a scientific basis for further studies to propose appropriate measures for higher education in Vietnam in the digital transformation period in education. Research results: the study shows the role of knowledge in the process of social development. In addition, the study points out the importance of open knowledge management to the training process in universities.

The objective of the research: (1) Assessing the process of students’ forming pedagogical professionalism at Hanoi National University of Education (HNUE), Vietnam; (2) find effective solutions aiming at improving the quality of pedagogical professionalism education for students of this University, to meet the requirements of social innovation as well as upgrade the standards in teacher training. Research Methodology: We surveyed to collect information on the current status of pedagogical professionalism education for students of the Faculty of Psychology and Pedagogy in HNUE, Vietnam. Students: 95 male students, 108 female students and 18 lecturers in the Faculty of Psychology and Pedagogy in HNUE. Research results: Solutions proposed by the research team for implementation at HNUE.

The sun provides a plentiful and inexpensive source of carbon-neutral energy that has yet to be fully utilized. This is a major driving force behind the development of organic photovoltaic (OPV) materials and devices, which are expected to offer benefits such as low cost, flexibility, and widespread availability. For the photovoltaic performance enhancement of the inverted ZnO-nanorods (NR)/organic hybrid solar cells with poly(3-exylthiophene):(6,6)-phenyl-C61-butyric-acid-methylester (P3HT:PCBM) and poly (3,4-ethylenedioxythiophene):poly (styrenesulfonate) (PEDOT:PSS) active layers, gold nanoparticles (Au-NPs) were introduced into the interface between indium-thin-oxide cathode layer and ZnO cathode buffer layer, and the efficiency improvement was observed. It's worth noting that adding Au NPs had both a positive and negative impact on device performance. Au NPs were shown to be advantageous to localized surface plasmon resonance (LSPs) in the coupling of dispersed light from ZnO NRs in order to extend the light's path length in the absorbing medium. Although the light absorption in the active layer could be enhanced, Au NPs might also act as recombination centers within the active layer. To avoid this adverse effect, Au NPs are covered by the ZnO seeded layer to prevent Au NPs from direct contact with the active layer. The dominant surface plasmonic effect of Au NPs increased the photoelectric conversion efficiency from 2.4% to 3.8%.

White spot syndrome virus (WSSV) is a double stranded DNA virus that causes WSS diseases for many crustaceans including the Penaeidae family shrimp. In this study, standard DNA for detection and quantification of WSSV by real-time polymerase chain reaction (qPCR) method was created. A specific gene fragment of 126 bp from WSSV genome was successfully amplified by PCR and cloned into pGEM-T vector. qPCR calibration curves using the created recombinant pGEM vector harboring 126 bp gene fragment as the standard DNA at concentrations of 3x102 to 3x108 copies/mL showed to have good linear regression with an efficiency of 99.1%, correlation coefficient R2 of 0.998 and the slope of -3.344. The recombinant vector was also used as a positive standard for detection and quantification of WSSV in a number of WSSV-infected shrimp samples and the values ranging from 3.69x103 copies/mL to 1.25x108 copies/mL WSSV were found in the collected samples.

According to the theory of active education and Mathematics teaching in secondary schools, there are five steps designed for geometrical knowledge and four stages for the process of applying the examined circumstances. The research objective aims to evaluate the effectiveness and feasibility of the suggestion focused on the process of constructing and manipulating situations in teaching Geometry. The research method uses the case study in the specific teaching process, which was conducted with 24 teachers who have taught Mathematics at secondary schools over three months from August 2019 to October 2019; and 30 secondary school students between May 2020 and July 2020. Finally, the result shows that all teachers agree that the design and application process is appropriate and effective for their lesson. In terms of the student's aspect, the case study reveals that the application of various steps in the process is beneficial for improving geometric deductive and spatial estimation, as well as using theoretical knowledge in the practical situation. Based on the research, this paper will clarify some solutions related to the way to design processes and utilize them in some Geometry content in secondary schools in Vietnam.

Molybdenum disulfide (MoS2) is a promising alternative for the anode of Li-ion batteries because of its high theoretical capacity and layered structure for rapid ion transport. However, the issues ...

In mathematics instruction, mathematical models are one of the powerful tools for promoting effective learning. However, it must be used properly. Teachers need to use mathematical models as part of their teaching methods. STEAM education represents a paradigm shift from a traditional education based on standardized test scores to modern ideas that focus on the valuation of learning process. In essence, we allow our students to be wrong, try many ideas, listen to alternative ideas and create a knowledge base that can be applied to real life. In this paper, the researcher studied the application of modeling in STEAM education projects.

The objective of the study to evaluate the effectiveness of lectures designed and applied integrated teaching methods for geometry in grade 9. We conducted research with 10 teachers and 154 students in both experimental and control classes (Grade 9). The tools used include: integrated lesson plans that are selected for the topic (circle) and taught in a period of 3 weeks. Firstly, we designed integrated teaching case studies through two examples, followed by a specific example that will guide teachers to integrate Mathematics in Grade 9. To evaluate research results, we used a carefully designed Rubric to evaluate the teacher's Math teaching process; SPSS version 20 software helps us compare students' Math learning results between experimental and control classes. We have found that there is a significant increase in students' Math performance in terms of how they perceive knowledge, apply knowledge to solve life situations, narrow the gap between math and life situations, increase motivation and increase student flexibility in problem solving.

The paper presents experimental results and structural analysis of reinforced concrete (RC) columns made of recycled aggregate concrete (RAC) and natural aggregate concrete (NAC) under concentric compressive load. The ratio of recycled aggregates in mixture (i.e, replacement ratio, r in %) was 0, 50, and 100% by mass, where r = 0% corresponding to NAC. The load and deformation curves including cracking load, ultimate load, crack width, and compressive strain of the tested columns, were analyzed to determine the effects of replacement ratio of recycled aggregate on the behaviors of square column structures. The results show that the increase of r reduced the load-carrying capacity of RC columns under the concentric compressive load. Horizontal and vertical cracks also were observed immediately for tested columns with high r. The effect of r of RAC on the mechanical behaviros, however, became relatively small and did not affect the behaviors of RAC columns, indicating that the RAC tested in this study was feasible for use in recycled concrete structures.

Research Objectives: Assess students' process of problem-solving situations in real contexts, through selection and evaluation of solutions to see whether the solutions they offer are really applicable in real-world contexts. Research Methods: We chose the first group of 3 students who have been taught by teachers the method of mathematical modeling; the second group of 3 students did not learn about mathematical modeling. Content 1: Teachers prepare some problematic situations in the real world, students perform problem solving; Content 2: we ask the teacher to create conditions for students to search for problematic situations themselves in real contexts, students solve problem. Research result: We found that, in the first group, students significantly increased their mathematical modeling ability, they could easily identify problematic situations; convert from life language into mathematical language. Moreover, students in the first group not only offer solutions to solve mathematical problems, they also consider, evaluate solutions, consider whether this mathematical result is converted to practical and applied in context. Students are confident in communicating; proposing ideas for model improvement, changing solutions, finding the most acceptable options in practice. On the other hand, 3 students of the second group had difficulty in solving problems. The students were mainly dealing with situations that were purely mathematical, lack of creativity when proposing solutions, as well as not yet considered whether the solution is appropriate in the practical context or not.

In this work, the ohmic contact mechanism of Ni electrodes on C-faced 4H-n-SiC was investigated by evaluating the electrical and microstructural properties in the contact interface as a function of annealing temperatures ranging from 950 to 1100°C. We determined that Ni-silicide, especially the NiSi phase, plays a key role in the formation of ohmic contacts rather than an increase in carbon vacancies in the C-faced SiC substrate. A vertically oriented NiSi phase was observed in the thermally annealed sample at the optimized temperature that behaves as a current path. A further increase in annealing temperature leads to the degradation of ohmic behavior due to the formation of horizontal-type NiSi in the Ni-rich Ni-silicide/NiSi/SiC structure.

We introduce a low temperature process for coating InGaN/GaN light-emitting diodes (LEDs) with h-BN as a passivation layer. The effect of h-BN on device performance and reliability is investigated. At −5 V, the leakage current of the h-BN passivated LED was −1.15 × 10−9 A, which was one order lower than the reference LED’s leakage current of −1.09 × 10−8 A. The h-BN layer minimizes the leakage current characteristics and operating temperature by acting as a passivation and heat dispersion layer. With a reduced working temperature of 33 from 45 °C, the LED lifetime was extended 2.5 times following h-BN passivation. According to our findings, h-BN passivation significantly improves LED reliability.

A multidimensional graphene and ZnO-based heterostructure for flexible transparent ultraviolet photodetector (UV-PD) applications is successfully fabricated on an indium tin oxide-coated polyethylene terephthalate substrate (ITO-coated PET). In this prototype, chemically reduced graphene oxide film is used as a charge transfer network and a template layer for the low-temperature growth of high quality vertically aligned zinc oxide nanorods array (ZNRA) on ITO-coated PET substrate. Graphene quantum dots decorated on the ZNRA significantly enhanced the photocurrent of the device. The synergistic effects of the rGO film and GQDs on the performance of the UV-PD are also systematically explored. The fabricated flexible UV-PD shows high detectivity (~1012 cmHz1/2 W−1), high responsivity (~13 AW−1) and good response time (~5 s) at a low bias of 2 V. Importantly, the fabrication process is facile, inexpensive, solution-based, low-temperature (120 °C), and provides a promising platform for flexible transparent UV-PD applications.

Three–dimensional thermal interface materials made of graphene oxide (GO) and copper nanoparticles (Cu NPs) were applied for enhancing light–emitting diode heat dissipation. The effect of the stacking order of GO and Cu NPs on thermal resistance was explored by creating two types of samples: spray–coated with a mixed GO–Cu NPs and layer–by–layer stacked with GO/Cu NPs/GO. A reduction of thermal resistance for mixed GO–Cu NPs and layer–by–layer stacked structure by 37% and 33%, respectively, compared to that of Al heat sink. The lower thermal resistance of the mixed GO–Cu NPs sample is attributed to the fact that distributed Cu NPs at the step edge of GO sheets enhances the out–of–plane heat transfer at wrinkles/folds of GO interlayers. Therefore, a mixed GO–Cu NPs is considered as a promising composite for effective thermal management of high–performance optoelectronic devices.

Hexagonal boron nitride (hBN) combined with III-nitride materials is attracting increasing attention for widening the applications of III-nitride materials. Three methods were used to grow the hBN buffer layer: (i) 2-step (low and high temperature), (ii) 1-step (high temperature), and (iii) pre-TEB surface treatment method. The optical properties of the hBN buffer layers were determined through Raman spectroscopy and absorbance measurements to characterize the combination between the III-nitride material (AlN) and hBN. The crystal quality of the AlN film grown under the same conditions on three hBN buffer layers has investigated by X-ray diffraction (XRD). XRD data established that the surface roughness of the hBN layer and density of the AlN nuclei are important factors for crystal quality of III-nitride material. The surface roughness of the hBN layers varied for the different growth methods, while the V/III ratio for each method remained unchanged. This difference in the surface roughness was confirmed to be related to the bonding configuration within the hBN layer, and was further confirmed by X-ray photoelectron spectroscopy to be due to the strong interactions between BN with the substrate (B1). In addition, the strongly interacting BN bond, which is dependent on the method used for the growth of the buffer layer, resulted in a peel-off of the AlN layer. This phenomenon did not occur at the hBN/sapphire interface, but occurred at the AlN/hBN interface, confirming that the strong interaction bonding between BN and the substrate weakens adhesion at the AlN/hBN interface.

Stack and composite are the two ways of hybridization between gold nanoparticles (AuNPs) and reduced graphene oxide (rGO) which have been fabricated and tested the ability to detect NH3 gas at room temperature. The device based on the rGO-AuNP composite structure exhibited the highest response and the fastest response and recovery time compared to stack and bare rGO. The red shift of a resonant peak in the absorption spectra and the negative shift in the binding energy of 4f5/2 peak indicated that the remarkable NH3 gas-sensing properties of this composite are mainly attributed to a chemical bonding formed between AuNPs and rGO at the defective sites. This type of interaction facilitates the electron transfer from the defect states to the AuNP surface wherein it easily reacts with the oxygen molecules in the atmosphere to create oxygen absorbents. Consequently, NH3 not only reacts with sp3-hybridized atoms but also reacts primarily with oxygen absorbents on the surface of AuNPs, resulting in a better sensing behavior of composite samples.

A combination of graphene quantum dots and chemically reduced graphene oxide films was obtained by spray-coating their dispersions onto an indium tin oxide coated polyethylene terephthalate substrate. Herein, the graphene quantum dots played a major role in the absorption of ultraviolet light and generation of carriers, whereas the reduced graphene films acted as the transparent electron pathway network. Consequently, the fabricated structure showed good transparency and flexibility, and achieved noticeable ultraviolet sensing. The facile, inexpensive, and extremely low temperature techniques used can be easily upgraded to a larger scale and are compatible with other substrates. In addition, a combination of reduced graphene oxide and graphene quantum dots offers a potential graphene-based platform for foldable optoelectronic device applications.

We investigated the thermal stability and electrical properties of nitrogen-doped reduced graphene oxide (NrGO)/n–type Si solar cells. A NrGO layer was used as a transparent electrode as well as an electron-hole separation layer simultaneously. The effect of doping on the carbon and nitrogen bonding configurations in NrGO was investigated using X–ray photoelectron spectroscopy (XPS). The XPS data indicate that pyridinic–N is the dominant bonding configuration. This bonding configuration leads to a reduction in the power conversion efficiency and a decrease in the short circuit current. However, on being subjected to thermal oxidation, the NrGO/n–type Si solar cells exhibit a smaller variation in series resistance compared to the undoped rGO/Si solar cells. Results of accelerated thermal tests suggest that nitrogen doping prevents re-oxidation of the reduced graphene oxide layer.

We investigated the carrier transport mechanism at Al/n-type 4H-SiC contacts. As-deposited Al exhibited the good ohmic behavior, while the thermal annealing leads the significant degradation of contact properties, i.e., the specific contact resistance was 3.97 × 10−3, 4.1 × 10−2, and 0.153 Ω cm2 for the as-deposited, 200 and 400 °C-annealed condition, respectively. The ohmic mechanism of as-deposited contact could be explained by field emission model, yielding a tunneling parameter of 0.44 eV, i.e., the ohmic behavior is due to the tunneling through the thin barrier. The degradation of ohmic contact after thermal annealing caused by the formation of oxide layer between the Al and SiC.

Social media presents a new method for readers who can freely discuss the content of an event mentioned in a Web document by posting relevant comments. The comments provide additional information which can be used to enrich the information of the main document. This paper introduces a new model which integrates user comments into the summarization process. While prior methods consider the same topic number between sentences and comments of a document, we argue that sentences and comments should own their different topics and they also share common hidden topics in term of same or inferred words. From this, we define a new objective function which jointly combines sentences and comments to achieve global optimization. The objective function is optimized by our non-negative matrix factorization algorithm to find out weights of sentence-matrix and comment-matrix for ranking sentences and comments. Experimental results on two datasets in English and Vietnamese show that our model achieves promising results for single-document summarization.

We investigated the effect of the size of graphene oxide (GO) sheets made with two different types of GO solution on the performance of Si-based solar cells. Large-sized reduced GO (rGO) with an in-plane crystalline diameter of 3.42 nm has smaller defect sites and thus the Si/rGO Schottky junction solar cell shows a lower leakage current than the solar cell with small-sized rGO (i.e. an in-plane crystalline diameter of 3.03 nm). Enhanced open-circuit voltage ( V oc ) and improved short-circuit current ( J sc ) are observed for the solar cell with large-sized rGO due to the increased work function and Schottky barrier height at the Si and rGO junction. In other words, an increased built-in potential and a wider depletion region of the solar cell with large-sized rGO contribute to the increased carrier absorption and generation. These findings indicate that (i) rGO acts as a good transparent conducting layer and hole-transporting layer, and (ii) the control of rGO size in Si/rGO Schottky junction solar cell is important to improve the performance.

The effect of ZnO nanostructures on the light output power of 375 nm near-ultraviolet light-emitting diodes (NUV-LEDs) was investigated by comparing one-dimensional (1D) nanorods (NR-ZnO) with two-dimensional (2D) nanosheets (NS-ZnO). ZnO nanostructures were grown on a planar indium tin oxide (ITO) by solution based method at low temperature of 90°C without degradation of the forward voltage. At an injection current of 100 mA, the light output efficiency of NUV-LED with NR-ZnO was enhanced by around 30% compared to the conventional NUV-LEDs without ZnO nanostructures. This improvement is due to the formation of a surface texturing, resulting in a larger escape cone and a multiple scattering for the photons in the NUV-LED, whereas the light output efficiency of NUV-LED with NS-ZnO was lower than that of the conventional NUV-LEDs due to the internal reflection and light absorption in the defective sites of NS-ZnO.

We demonstrated that a reduced graphene oxide (rGO) layer inserted between a poly(3,4-etylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and Si interface improves the stability of Si-organic hybrid solar cells. Thermal reduction of a graphene oxide layer at different temperatures results in a change of water contact angle that is designed to eliminate the surface oxidation of the Si substrate. Higher temperatures generate a smaller aromatic sp2 domain size that changes the GO surface from hydrophilic to hydrophobic. Additionally, two-dimensional GO layers can serve as a barrier for both liquid and vapor permeation. Consequently, the PEDOT:PSS/Si device with a rGO passivation layer shows a significantly enhanced air-stability from the J–V characteristic under illumination during a one-month storage period. The application of rGO is a promising technique to extend the stability of Si-organic solar cells without an encapsulation process.

We demonstrated experimentally that an approximate 15% reduction in wafer bowing was achieved by spray-coating of graphene oxide (GO) with an O-ring pattern on the sapphire substrate before the metal organic chemical vapor deposition-grown AlN template. At the 1350 °C growth temperature of AlN, GO was thermally reduced to graphene, which is favorable to alleviate thermal compressive stress between the AlN template and sapphire substrate during the cooling process due to the natural high thermal conductivity of graphene. Consequently, the GO O-ring pattern can play an important role in dramatically reduce cracks, edge delamination and threading dislocation density of AlN templates grown on sapphire substrates.

A series of zinc oxide nanorods (ZnO NRs) were grown by chemical bath deposition and their optical properties as a retarder for display devices were investigated. The effect of the precursors, growth time, and calcination time on the morphology and the optical properties was examined. The vertically-grown ZnO NRs layer represented positive c-plate property. We simulated the antireflection property of a quasi-circular polarizer containing the ZnO NRs layer for an organic light emitting diode (OLED) display. The quasi-circular polarizer with the ZnO NRs layer showed better antireflection property than the polarizer containing no ZnO NRs layer.

An attempt to degrade volatile organic compounds (VOCs) and sterilize air simultaneously is highly desirable to improve indoor air quality. With the help of deep ultraviolet (UVC) lighting, harmful bacteria that exists in the air can be destroyed. Thus, a new photocatalytic substance that can break down VOCs under UVC irradiation is required. Here, we demonstrate the photocatalytic activity of &beta, Ga2O3 nanostructures, synthesized via the solvothermal method for removing formaldehyde (HCHO) under deep ultraviolet irradiation. The Raman and XRD results indicated that as-synthesized nanostructures showed &beta, crystalline phase with a monoclinic structure. The photoluminescence spectrum exhibited a broad and strong green emission peak at 510 nm, which was likely attributed to a considerable amount of oxygen and gallium vacancies formed during the calcinating process. The photocatalytic efficiency for decomposing HCHO at room temperature under deep ultraviolet irradiation (278 nm) of the synthesized &beta, Ga2O3 nanoparticles is higher than that of the &beta, Ga2O3 nanorods. Both nanoparticles and nanorods obeyed the pseudo-first-order Langmuir-Hinshelwood kinetic model with a degradation rate constant of 0.057 and 0.033 min&minus, 1, corresponding to the efficiency of 82% and 62% in the formaldehyde removal, respectively.

A mixed intermediate layer of silica and zinc oxide (SZO) with architecturally dome-shaped microstructure is fabricated and characterized by combining a hydrothermal method and a plasma-enhanced chemical vapor deposition technique. Our results demonstrated that 200 °C was an optimum deposition temperature for dome shape architecture SZO layer, acting as an antireflection layer in the ultraviolet range and buffer layer for growth ZnO nanorods (NRs) arrays. Consequently, at 2.0 V reverse bias, the photo-to-dark current ratio measured with an p-Si/n-ZnONRs photodiode employing the dome-shaped SZO layer is improved by almost three orders of magnitude in the ultraviolet range as compared to that under visible-light illumination.

We report the fabrication of hybridization between graphene quantum dots (GQDs) and ZnO nanoflowers (NFs) for mediating photoluminescence by using a straightforward solution-based technique. Hydrothermally grown two-dimensional ZnO NFs played an essential role in assembling GQDs. The large surface area to volume ratio of ZnO NFs led to a highly dense distribution of GQDs, giving rise to photoluminescence (PL) emission at around 442 nm from GQDs and the synergic effects. Thus, GQDs/ZnO hybrid results in strong and broad PL over the spectral range from near UV to red region. We also suggested that an energy interaction between GQDs and various defect sites in ZnO NFs can promote the radiative recombination of both components, thereby providing PL peak intensities more than two times higher than individual components. Fabricated GQDs/ZnO heterojunctions on both soft and hard substrates emit similar intense and wide PL spectrum under ultraviolet irradiation, indicating that this heterojunction can consider as a promising platform for flexible and transparent optoelectronic applications.

In this paper, we present a smart wearable hand-gesture recognition system based on the movement of the hand and fingers. The proposed smart wearable system is built using the fewest sensors necessary for gesture recognition. Thus, motion sensors are placed on the thumb and index finger to detect finger motions. Another sensor is placed on the back of the hand to measure hand movement. A total of six gestures are analyzed via hand and finger movement using a dynamic time-warping method. Gestures include "swipe right," "swipe left," "zoom in," "zoom out," "rotate left," and "rotate right." An Android-based mobile device application simulator measures gesture recognition effectiveness. Gestures are analyzed using a trained recognition model. Once a gesture is detected, it is transmitted to the mobile application via Bluetooth low energy communication. Received gestures then trigger corresponding commands, as specified in the mobile application. The proposed smart wearable system can detect gestures at mean accuracy of 93.19 %.