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Magnetic, DC Electrical, and Impedance Properties of Zn Doped Yttrium Iron Garnet Nanoparticles 锌掺杂钇铁石榴石纳米颗粒的磁性、直流电性和阻抗特性
VNU Journal of Science: Mathematics - Physics Pub Date : 2023-06-20 DOI: 10.25073/2588-1124/vnumap.4786
Dao Thi Thuy Nguyet, N. P. Duong, L. N. Anh
{"title":"Magnetic, DC Electrical, and Impedance Properties of Zn Doped Yttrium Iron Garnet Nanoparticles","authors":"Dao Thi Thuy Nguyet, N. P. Duong, L. N. Anh","doi":"10.25073/2588-1124/vnumap.4786","DOIUrl":"https://doi.org/10.25073/2588-1124/vnumap.4786","url":null,"abstract":"Y3Fe5-xZnxO12 with x = 0; 0.02; 0.04; 0.06; 0.08; 0.1 (YIG) particle materials were fabricated by sol-gel method combined with heat treatment at 900 °C and 1,000 °C with different annealing times (2 h and 5 h) and heating rates (5 °C/min and 2 °C/min).  X-ray diffraction patterns show that the obtained samples are single crystalline phases at the condition of an annealing temperature of 900 °C for 5 h and a heating rate of 2 degrees/min. FESEM images of the samples show particle sizes from the submicron to the micrometer. The magnetization of the samples decreases as the doping concentration increases. I-V characteristics and complex impedance spectra at room temperature of samples were measured. The results show that the resistivity value of the doped samples decreases in the range of 5-6 orders in magnitude compared with that of the pure YIG sample. The contribution of the grain boundaries to the impedance was analyzed. The conducting process is explained due to the tunneling of charge carriers across the grain boundary.","PeriodicalId":303178,"journal":{"name":"VNU Journal of Science: Mathematics - Physics","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128694601","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
The Photothermal Effect of a Single Gold-magnetic Nanocrescent in A Glycerol-water Mixture Media 单金磁性纳米新月在甘油-水混合介质中的光热效应
VNU Journal of Science: Mathematics - Physics Pub Date : 2023-06-20 DOI: 10.25073/2588-1124/vnumap.4801
Vu Xuan Hoa, Pham Thi Thu Ha, T. T. Trang
{"title":"The Photothermal Effect of a Single Gold-magnetic Nanocrescent in A Glycerol-water Mixture Media","authors":"Vu Xuan Hoa, Pham Thi Thu Ha, T. T. Trang","doi":"10.25073/2588-1124/vnumap.4801","DOIUrl":"https://doi.org/10.25073/2588-1124/vnumap.4801","url":null,"abstract":"The photothermal effect of gold nanostructures has been majority known as the nanothermal effect of gold clusters under laser irradiation. However, there are still many challenges to measuring the local temperature generated by a single nano gold in a complex media. In this work, a gold magnetic nanocrescent (G-MNC) has been studied, it composed of a superparamagnetic iron oxide core and gold shell with a size of 170 nm in glycerol/water (80:20), under 650 nm laser irradiation. Using rotational scattering correlation spectroscopy (RSCS), a sophisticated technique has been developed, the local temperature generated by only single magnetic nanocrescent was measured. The dependence of the heat generation according to the power of the laser shows that the heat generated by the gold NC is proportional to the power of the laser, and the maximum temperature was 19.5 oC, corresponding to the laser power was 29×103 W.cm-2. Under using the proper laser irradiation to the plasmon resonance, G-MNCs act as nano thermometers. The photothermal effect of the single G-MNC was implemented in a mixing solution of glycerol and water.","PeriodicalId":303178,"journal":{"name":"VNU Journal of Science: Mathematics - Physics","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132198606","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Preliminary Study on Alternative Reflectors for LOTUS Reactor LOTUS反应器替代反射器的初步研究
VNU Journal of Science: Mathematics - Physics Pub Date : 2023-06-20 DOI: 10.25073/2588-1124/vnumap.4791
Bui Thi Hong, Thanh Mai Vu, D. Hartanto
{"title":"Preliminary Study on Alternative Reflectors for LOTUS Reactor","authors":"Bui Thi Hong, Thanh Mai Vu, D. Hartanto","doi":"10.25073/2588-1124/vnumap.4791","DOIUrl":"https://doi.org/10.25073/2588-1124/vnumap.4791","url":null,"abstract":"LOTUS reactor - a compact lead-cooled fast reactor is currently being studied to generate 200 MWth of capacity and operate for 20 years without refueling for the floating nuclear power plant (FNPP) application. Therefore, it would be a big advantage to achieve a long operation without refueling. However, a small reactor usually has a higher neutron leakage, and a good neutron reflector is essential to maintain the neutron economy. The main objective is selecting potential reflectors materials for the LOTUS reactor using Monte Carlo code, Serpent. The various candidate reflector materials, including Al2O3, BeO, MgO, PbO, SiO2, and ZrO2 are calculated from the neutronics characteristics to determine a good neutron reflector. In this work, we have investigated the parameters of neutronics characteristics, such as core neutron flux spectrum, evolution of keff due to burn-up, power distribution, and lead coolant void reactivity with each reflector. From the comparison of those parameters, MgO material was found to be a good candidate for the relector of LOTUS reactor.","PeriodicalId":303178,"journal":{"name":"VNU Journal of Science: Mathematics - Physics","volume":"72 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128386393","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Bohl Theorem for Volterra Equations Volterra方程的Bohl定理
VNU Journal of Science: Mathematics - Physics Pub Date : 2023-06-20 DOI: 10.25073/2588-1124/vnumap.4820
Nguyen Thu Ha
{"title":"Bohl Theorem for Volterra Equations","authors":"Nguyen Thu Ha","doi":"10.25073/2588-1124/vnumap.4820","DOIUrl":"https://doi.org/10.25073/2588-1124/vnumap.4820","url":null,"abstract":"This work deals with the preservation of exponential stability under small perturbations for Volterra differential equations. The so-called Bohl-Perron type stability theorems for these systems are also studied.","PeriodicalId":303178,"journal":{"name":"VNU Journal of Science: Mathematics - Physics","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115215376","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Effect of Electron-impurity Interaction on the Optical Absorption in A Quasi-one-dimensional Electron System 准一维电子系统中电子-杂质相互作用对光吸收的影响
VNU Journal of Science: Mathematics - Physics Pub Date : 2023-06-20 DOI: 10.25073/2588-1124/vnumap.4796
Tran Cong Phong, N. T. Linh, N. T. Nam, N. Hieu
{"title":"Effect of Electron-impurity Interaction on the Optical Absorption in A Quasi-one-dimensional Electron System","authors":"Tran Cong Phong, N. T. Linh, N. T. Nam, N. Hieu","doi":"10.25073/2588-1124/vnumap.4796","DOIUrl":"https://doi.org/10.25073/2588-1124/vnumap.4796","url":null,"abstract":"In this work, we investigated the optical absorption in a quasi-one-dimensional system subjected to an external electromagnetic wave. The optical absorption coefficient was calculated by using the perturbation theory taking account of the effect of the electron - impurity interaction. The numerical result for the GaAs/AlAs cylindrical semiconductor quantum wire showed the presence of the resonant absorption peaks. The full width at half maximum (FWHM) decreased with increasing the wire radius and increases with increasing temperature. In particular, in the limit of large wire radius, the contribution of transitions between electronic subbands to the absorption spectrum becomes identical, t meaning that the system tends to behave as a bulk (there-dimensional) system when the confinement length is large. The obtained results are of significance for further studies and applications of the low dimensional systems in nano-optoelectronic devices.","PeriodicalId":303178,"journal":{"name":"VNU Journal of Science: Mathematics - Physics","volume":"423 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116169772","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Optimization of Dispersions in GeO2-doped Photonic Crystal Fibers with Square Lattice 方形晶格掺geo2光子晶体光纤色散的优化
VNU Journal of Science: Mathematics - Physics Pub Date : 2023-06-20 DOI: 10.25073/2588-1124/vnumap.4787
N. Thuy
{"title":"Optimization of Dispersions in GeO2-doped Photonic Crystal Fibers with Square Lattice","authors":"N. Thuy","doi":"10.25073/2588-1124/vnumap.4787","DOIUrl":"https://doi.org/10.25073/2588-1124/vnumap.4787","url":null,"abstract":"Germanium doped photonic crystal fibers with differences in the layers' air hole diameters in the cladding are presented to obtain flat dispersion, small effective mode area, and low attenuation property for supercontinuum generation applications. The flatness and small value of the dispersion depend on the lattice geometry when the fibers have the same germanium doping concentration. The dispersion of the square lattice fibers is a flatter and smaller value at the pump wavelength than the circular lattice fibers. Square lattice fibers with Ʌ = 0.9 µm, d1/Ʌ = 0.4 and Ʌ = 1.0 µm, d1/Ʌ = 0.45 are proposed for supercontinuum generation which has anomalous and all-normal dispersion, respectively. Their small dispersion values of 0.449 ps /nm.km and −1.096 ps/nm.km are suitable for broad spectrum supercontinuum generation. The small effective mode area and low attenuation of the two fibers of 3.221 µm2, 2.361 µm2 and 1.805×10−7 dB/m, 1.322×10−15 dB/m, respectively are favorable conditions for choosing a laser pump sources with low peak power. The proposed fibers can be new supercontinuum generation source replacing traditional glass core fibers.","PeriodicalId":303178,"journal":{"name":"VNU Journal of Science: Mathematics - Physics","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130321915","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Fe2O3 Synthesized by Sol-Gel Method for Energy Storage Applications 溶胶-凝胶法制备Fe2O3用于储能
VNU Journal of Science: Mathematics - Physics Pub Date : 2023-06-08 DOI: 10.25073/2588-1124/vnumap.4848
Bui Thi Hang
{"title":"Fe2O3 Synthesized by Sol-Gel Method for Energy Storage Applications","authors":"Bui Thi Hang","doi":"10.25073/2588-1124/vnumap.4848","DOIUrl":"https://doi.org/10.25073/2588-1124/vnumap.4848","url":null,"abstract":"Fe2O3 nanopowders were synthesized by sol-gel method from the iron source material Fe(NO3)3.9H2O and citric acid C6H8O7.H2O without any refined process. The structure and size of the synthesized materials were determined by X-ray diffraction and scanning electron microscopy. The obtained product is α-Fe2O3 with different shapes and sizes depending on the preparation conditions. α-Fe2O3 was applied as anode of iron-air battery. The cyclic voltammetry measurements showed that the size and morphology of Fe2O3 particles affect their electrochemical characteristics. Using K2S as an electrolyte additive improved the electrochemical properties of Fe2O3/AB electrodes as evidenced by increased redox reaction rate of iron, increased capacity of Fe2O3/AB electrode and reduced H2 evolution.","PeriodicalId":303178,"journal":{"name":"VNU Journal of Science: Mathematics - Physics","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127974829","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Investigate Cross-sections for (α, γ) reactions on p-nuclei 90Zr, 121Sb, 151Eu, and 162Er using Different Models of Radiative Strength Functions 用不同的辐射强度函数模型研究90Zr, 121Sb, 151Eu和162Er上p核(α， γ)反应的截面
VNU Journal of Science: Mathematics - Physics Pub Date : 2023-05-18 DOI: 10.25073/2588-1124/vnumap.4817
N. Nhu Le
{"title":"Investigate Cross-sections for (α, γ) reactions on p-nuclei 90Zr, 121Sb, 151Eu, and 162Er using Different Models of Radiative Strength Functions","authors":"N. Nhu Le","doi":"10.25073/2588-1124/vnumap.4817","DOIUrl":"https://doi.org/10.25073/2588-1124/vnumap.4817","url":null,"abstract":"In this work, we examine cross sections for (α, γ) reactions on p-nuclei, including 90Zr, 121Sb, 151Eu, and 162Er at astrophysically relevant energies. By using our recently developed α optical model potential (α-OMP), the (α, γ) cross sections were calculated within six models of radiative strength functions (RSF) which consisted of the microscopic HFB-QRPA model based on the BSk-14 Skyrme force, the HF-BCS theory using Skyrme parameters, the EGLO model, SMLO model, the empirical SMLO (SMLOg) and global semi-microscopic (D1M-QRPAg) models. The numerical results is then compared to the measured data of (α, γ) cross sections. For the considered (α, γ) reactions, the EGLO, SMLO, and HFB results are typically greater than the measured data. In addition, the comparison has indicated that the RSF models of SMLOg and D1M-QRPAg best fit the measured data with rms smaller than 0.2 within our proposed α-OMP. Therefore, for the (α, γ) reactions on the selected targets, RSF models of SMLOg and D1M-QRPAg are strongly recommended. The results are significant for a further systematic examination to evaluate which RSF model is most appropriate for studying (α, γ) reactions on p-nuclei in general.  ","PeriodicalId":303178,"journal":{"name":"VNU Journal of Science: Mathematics - Physics","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132030823","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Construction of Sn3O4/g-C3N4 Composite with Enhanced Photocatalytic Activities Under Visible Light Irradiation Sn3O4/g-C3N4复合材料在可见光下增强光催化活性的构建
VNU Journal of Science: Mathematics - Physics Pub Date : 2023-03-27 DOI: 10.25073/2588-1124/vnumap.4761
Vu Hoang Huong
{"title":"Construction of Sn3O4/g-C3N4 Composite with Enhanced Photocatalytic Activities Under Visible Light Irradiation","authors":"Vu Hoang Huong","doi":"10.25073/2588-1124/vnumap.4761","DOIUrl":"https://doi.org/10.25073/2588-1124/vnumap.4761","url":null,"abstract":"The Sn3O4/g-C3N4 composites were produced by an annealing mixture of g-C3N4 and Sn3O4, which were prepared by calcining urea and hydrothermally treating of SnCl2 solution, respectively. Chacterization of the samples was investigated by powder X-ray diffraction (XRD), Scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), Photoluminescence (PL) and UV-Vis spectra. Studying the degradation of Rhodamine B (RhB) in the presence of visible light showed that the combination of Sn3O4 and g-C3N4 has an enhanced ability in the photocatalysis in comparison with the individual components. From kinetic investigations of RhB degradation, it is found that the SCN25 catalyst has the highest rate constant of 18.14 (min-1 x 103), which was about 11.4 times larger than that of pure g-C3N4. It is possible to explain the improved photocatalytic activity of Sn3O4/g-C3N4 composites by using the Z-scheme pathway. \u0000  \u0000  \u0000 ","PeriodicalId":303178,"journal":{"name":"VNU Journal of Science: Mathematics - Physics","volume":"92 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128460425","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
A New Design of Ultra-flat Dispersion Photonic Crystal Fiber using Benzene Infiltration 利用苯渗透设计一种新型超平色散光子晶体光纤
VNU Journal of Science: Mathematics - Physics Pub Date : 2023-03-27 DOI: 10.25073/2588-1124/vnumap.4762
Hoang Trong Duc, Nguyen Anh Tu, Nguyễn Thi Thuy
{"title":"A New Design of Ultra-flat Dispersion Photonic Crystal Fiber using Benzene Infiltration","authors":"Hoang Trong Duc, Nguyen Anh Tu, Nguyễn Thi Thuy","doi":"10.25073/2588-1124/vnumap.4762","DOIUrl":"https://doi.org/10.25073/2588-1124/vnumap.4762","url":null,"abstract":"This paper presents new results on dispersion in photonic crystal fibers (PCF) based on a circular lattice, with benzene infiltration into the hollow-core. We achieved near-zero, ultra-flat dispersion through the appropriate adjustment of air hole diameters and pitch of cladding. The result gives a dispersion of ±0.484 ps/nm-1.km over a wavelength range of 450 nm. Besides, we also obtained very high nonlinear coefficients, up to several thousand W–1.km–1, and a very low attenuation, about 10–21 dB/m for optimal structures suitable for supercontinuum generation application. \u0000 ","PeriodicalId":303178,"journal":{"name":"VNU Journal of Science: Mathematics - Physics","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132257976","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
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