A5024056764- Multiferroics and related materials
- Magnetic and transport properties of perovskites and related materials
- Advanced Condensed Matter Physics
- Chalcogenide Semiconductor Thin Films
- Quantum Dots Synthesis And Properties
- Crystal Structures and Properties
- Ga2O3 and related materials
- ZnO doping and properties
- Mineralogy and Gemology Studies
- Advanced Photocatalysis Techniques
- Perovskite Materials and Applications
- Natural product bioactivities and synthesis
- Magnetic Properties and Synthesis of Ferrites
- Gas Sensing Nanomaterials and Sensors
- Diverse Industrial Engineering Technologies
- Piezoelectric Actuators and Control
- Copper-based nanomaterials and applications
- Magnesium Oxide Properties and Applications
- Geological and Geochemical Analysis
- Ferroelectric and Piezoelectric Materials
- Recycling and Waste Management Techniques
- Efficiency Analysis Using DEA
- Plant biochemistry and biosynthesis
- Fuzzy Systems and Optimization
- Mesoporous Materials and Catalysis
Vietnam Academy of Science and Technology
2022-2024
Ho Chi Minh City University of Science
2023
Vietnam National University Ho Chi Minh City
2023
International Center for Tropical Agriculture
2022
Institute for Tropical Technology
2022
Hue Central Hospital
2021
Hanoi University of Industry
2021
Ton Duc Thang University
2014-2020
Institute of Materials Science
2020
Advanced Institute of Materials Science
2020
In this report, we describe the structure of a robust and highly conductive 3D graphene oxide hydrogel. The reduced hydrogel or rGH is fabricated by crosslinking reaction with ethylene diamine followed hydrazine reduction. material showed high electrical conductivity 1351 S m−1 specific surface area 745 m2 g−1 10.3 MPa break strength. When used as electrodes for supercapacitor, it capacitance 232 F g−1.
Phonon softening in hexagonal BaFe12O19 single crystal is observed temperature dependent polarized Raman spectroscopy. The phonon significantly enhanced below ∼80 K, at which the magnetization a magnetic field along c-axis shows clear change dependence, indicating phase transition near 80 K. Possible interpretations of anomalous dependence frequencies–phonon behaviors are discussed. would be correlated to local structural and BaFe12O19, spin-phonon coupling have major contribution for...
Abstract The pulse laser deposition method is recognized for its ability to minimize defects in semiconductors by carefully controlling gas pressure and temperature during deposition. This research discusses the presence of defect states β-Ga2O3/p-Si heterojunction created using pulsed at different oxygen pressures through Deep Level Transient Spectroscopy (DLTS). When rose from 0 25 mTorr, electron trap EC – 1.21 eV associated with an vacancy vanished, resulting a 1.6-fold decrease total...
Murdannia nudiflora (L.) Brenan has been found in many provinces and cities, such as Lao Cai, Lang Son, Quang Ninh, Bac Giang, Phu Tho, Lam Dong, etc. This plant is known for its effects, anti-oxidation, protection of damaged liver cells, pain relief, anti-inflammation, anti-cancer. In this study, we collected determined the scientific name based on analysis morphological microscopic characteristics Tho province. Then, qualitatively screened some common groups compounds medicinal herbs. The...
Abstract We have measured polarized Raman spectra of MnWO 4 single crystals at low temperatures, and studied the temperature dependence various phonon modes. From our studies , a new transition temperature, ∼180 K, was found. completely assigned symmetries 18 observed modes as expected from group theoretical analysis. These been classified into three groups according to weak, intermediate strong in each group. Six internal identified by their weak wavenumbers. The wavenumbers B g MgO bonds,...
Abstract Both polarized and unpolarized Raman scattering studies of seven tourmalines from the Lucyen mines in Vietnam are presented. These tourmalines, according to their chemical compositions, can be classified into four groups: G1, liddicoatite; G2, elbaite; G3, uvite; G4, feruvite. The spectra were recorded two spectral ranges, i.e. 150–1600 cm −1 3000–4000 . In lower range, which covers metal ion‐oxygen bond vibrations, all observed A 1 E modes identified. higher we investigated OH...
We present the results of polarized Raman spectroscopy hexagonal BaFe 12 O 19 single crystal. The spectra, recorded from 200 to 800 cm –1 and 1100 1700 in 20–250 K temperature range, are analyzed on basis both crystal vibrations spin‐waves. In low wavenumber Γ‐point phonons observed. high phonon mixings observed; more interestingly, four modes spin‐waves identified . Both have not been studied previously. Our analyses provide an optical method for quantitatively estimating spin exchange...
Abstract We present the results of temperature dependence Raman spectra hexagonal HoMnO 3 thin films in 13–300 K range. The were grown on Pt(111)//Al 2 O (0001) substrates using laser ablation method. In films, we initially observedseveral broad peaks at ∼510, 760, 955, 1120, and 1410 cm −1 . These display an anomalous behavior near magnetic transition temperature, intensity difference different temperatures shows several pairs negative positive as is lowered below Néel temperature. Our...
Abstract Spin-wave (magnon) scattering, when clearly observed by Raman spectroscopy, can be simple and powerful for studying magnetic phase transitions. In this paper, we present how to observe magnon scattering then apply the method study spin-ordering spin-reorientation transitions of hexagonal manganite single crystal thin films compare directly with results magnetization measurements. Our show that choosing strong resonance condition appropriate polarization configuration, temperature...
Background In response to the spread of coronavirus disease 2019 (COVID-19), plenty control measures were proposed. To assess impact current on number new case indices 14 countries with highest confirmed cases, mortality rate, and having a close relationship outbreak’s origin; selected analyzed. Methods study, we analyzed five measures, including centralized isolation all closure schools, public areas, cities, borders targeted according their timing; by comparing its absolute effect average,...
Abstract The room‐temperature ferromagnetism and the Raman spectroscopy of Cu‐doped Zn 1− x Co O powders prepared by sol–gel method are reported. x‐ray diffraction (XRD) data confirmed that wurtzite structure ZnO is maintained for doped with below 10 at%. magnetization–field curves measured at room temperature demonstrated all Co‐doped were paramagnetic. Ferromagnetic ordering observed samples Cu in 0.98 0.02 strongly depends on concentration Cu. relative strength second‐order LO peak to...
Keteleeria davidiana (C.E.Bertrand) Beissn. is a species of conifer native to southern China, Laos and Vietnam. The has been listed as vulnerable in Essential oil samples have isolated from leaves, twigs wood, their compositions investigated for the first time by combination chromatographic spectroscopic techniques [GC-FID, GC-MS and13C NMR]. composition leaf essential was dominated α-pinene (28.1%), β-pinene (15.8%) (E)-β-caryophyllene (13.8%). Twig contained mainly (37.9%) (24.7%)...
We present the results of resonant Raman scattering A1 phonon at 680 cm−1 and four-magnon 760 in hexagonal HoMnO3 thin film. find that shows a strong resonance effect near on-site Mn d–d transition ∼1.7 eV. Our show can be selectively excited with red lasers 647 nm (1.92 eV) 671 (1.85 eV), but are not detectable green 532 (2.33 indicating has an extremely also Furthermore, through analyses our study earlier studies two-magnon scattering, we propose simple general model for all magnon...
Abstract We have studied the rare‐earth (R) dependence of phonon and magnon scattering in hexagonal RMnO 3 (R = Tb, Dy, Ho, Er) thin films using Raman spectroscopy. found, as ionic radius R decreases from Tb to Er, phonons shift higher energies. Our results indicate that both lattice constants a c would decrease when decreases, constant weaker dependence. The magnons also energies ion they show faster upshift than phonons. In addition, Néel temperature shows systematic increasing behavior...
We present the results of an optical method quantitatively estimating spin exchange interactions in hexagonal manganites RMnO3 (R = Tb, Dy, Ho, Er) epitaxial thin films. The two in-plane (a-b plane) integrals J1 (intratrimer Mn-Mn interaction) and J2 (intertrimer are deduced from magnon scattering peak wavenumbers. found that decreases systematically when R ionic radius increases, while is nearly independent radius, contrary to expectation single crystals. show dependence could be understood...
A new concept of inner product on the space compact convex subsets ℝ is introduced. Using this we investigate global existence and uniqueness solution interval-valued functional differential equations. We apply these results to interval equations with distributed delays. MSC:34K05, 34K30, 47G20.
Abstract A simple and environment‐friendly electrochemical method using activated glassy carbon electrodes (aGCE) for monitoring the residues of tetracycline in pork samples was developed. two‐step pretreatment procedure established activating electrode surface, including mechanical polishing pretreatment. In supporting electrolyte solution 0.2 M sodium sulfate (at pH 2.5), response TC characterized by two irreversible oxidation peaks at +0.95 V +1.05 vs. saturated calomel electrode. The...
Abstract LiFe 1 − x Mn PO 4 olivines are promising material for improved performance of Li‐ion batteries. Spin–phonon coupling ( = 0, 0.3, 0.5) is studied through temperature‐dependent Raman spectroscopy. Among the observed phonon modes, external mode at ~263 cm −1 directly correlated with motions magnetic Fe 2+ /Mn ions. This displays anomalous behavior near Néel temperature, indicating a this spin ordering. As doping increases, becomes clearly weaker, spin–phonon quickly decreases. Our...
Essential oils isolated from leaves, twigs, fruit bark and seeds of Michelia tonkinensis collected in Muong Nhe Nature Reserve, Dien Bien province were obtained by hydrodistillation with yields 1.5, 0.42, 0.16 4.6% respectively (v/w on dry weight basis). After analysis through GC, GC-MS 13C NMR, 30, 34, 31 13 compounds (representing 96.4%, 96.8%, 97.1% 99.9% the whole composition, respectively) identified leave, twig, seed essential oils. The main components limonene (43.2%) germacrene D...
Abstract Tetrapod-quantum well (TW) with CdSe core and quantum wells in gradient alloyed CdSeS arms was synthesized using the one-pot colloidal method. The morphology, crystal structure, UV–vis absorption, photoluminescence (PL), excitation power-dependent PL properties of TWs prepared within a 30 min reaction time were investigated. Their spectrum exhibited two emission peaks centered at 2.187 eV 2.207 due to radiative transitions wells, respectively. Analysis spectra showed that wells’...