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VNU Journal of Science: Mathematics - Physics最新文献

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Normal Impact of A Rigid Cone-shaped against A Viscoelastic Plate on Viscoelastic Foundation 粘弹性基础上刚性圆锥体对粘弹性板的法向冲击
VNU Journal of Science: Mathematics - Physics Pub Date : 2021-12-03 DOI: 10.25073/2588-1124/vnumap.4661
Dương Tuan Manh
{"title":"Normal Impact of A Rigid Cone-shaped against A Viscoelastic Plate on Viscoelastic Foundation","authors":"Dương Tuan Manh","doi":"10.25073/2588-1124/vnumap.4661","DOIUrl":"https://doi.org/10.25073/2588-1124/vnumap.4661","url":null,"abstract":"This paper considers the problem of a low-velocity normal impact of a rigid cone-shaped upon a viscoelastic plate. The contact force is defined by the modified Hertz's contact law. Approximate solutions of the system of nonlinear integro-differential equations for the contact force and local indentation have been obtained. \u0000 ","PeriodicalId":303178,"journal":{"name":"VNU Journal of Science: Mathematics - Physics","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114082488","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: 1
Linear and Nonlinear Magneto-optical Absorption Coefficients and Refractive Index Changes in Wse2 Monolayer Wse2单层膜线性和非线性磁光吸收系数和折射率的变化
VNU Journal of Science: Mathematics - Physics Pub Date : 2021-12-03 DOI: 10.25073/2588-1124/vnumap.4629
Luong Van Tung, Nguyen Quang Bau, Tran Thi Ngoc Bich, Pham Tuan Vinh, Huynh Vinh Phuc
{"title":"Linear and Nonlinear Magneto-optical Absorption Coefficients and Refractive Index Changes in Wse2 Monolayer","authors":"Luong Van Tung, Nguyen Quang Bau, Tran Thi Ngoc Bich, Pham Tuan Vinh, Huynh Vinh Phuc","doi":"10.25073/2588-1124/vnumap.4629","DOIUrl":"https://doi.org/10.25073/2588-1124/vnumap.4629","url":null,"abstract":"This work studies the linear, the third-order nonlinear, and the total optical absorption coefficients (OACs) and the refractive index changes (RICs) caused by both intra- and inter-band transitions in the WSe2 monolayer. The expression for the OACs and RICs in the presence of a magnetic field as well as the Zeeman and electric fields are found by using the compact density matrix approach. The results show that the spin states strongly affect the OACs and RICs, which display the violet-shift behavior with the increase of the magnetic field. The Zeeman fields do not affect the peak positions but slightly reduce peak intensities. The OACs and RICs due to intra-band transition display only one peak in the THz range, while the inter-band spectra show a series of peaks in the near-infrared optical range, making monolayer WSe2 be a promising candidate for novel optoelectronic applications. \u0000 ","PeriodicalId":303178,"journal":{"name":"VNU Journal of Science: Mathematics - Physics","volume":"230 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121868369","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
Excess Conductivity Analyses in Bi-Pb-Sr-Ca-Cu-O Systems Sintered at Different Temperatures 不同温度烧结Bi-Pb-Sr-Ca-Cu-O体系的超导电性分析
VNU Journal of Science: Mathematics - Physics Pub Date : 2021-12-03 DOI: 10.25073/2588-1124/vnumap.4602
Trần Tiến Dũng, P. An, Tran Ba Duong, N. K. Man, Nguyen Thi Minh Hien, Tran Hai Duc
{"title":"Excess Conductivity Analyses in Bi-Pb-Sr-Ca-Cu-O Systems Sintered at Different Temperatures","authors":"Trần Tiến Dũng, P. An, Tran Ba Duong, N. K. Man, Nguyen Thi Minh Hien, Tran Hai Duc","doi":"10.25073/2588-1124/vnumap.4602","DOIUrl":"https://doi.org/10.25073/2588-1124/vnumap.4602","url":null,"abstract":"This paper studies the effects of the sintering temperature on crystal structure, critical temperature (Tc) and excess conductivity of Bi-Pb-Sr-Ca-Cu-O (BPSCCO) system. Bulk BPSCCO samples were fabricated by the solid-state reaction method. Four different temperatures of 835 °C, 840 °C, 845 °C, and 850 °C were applied to sinter four different samples. The crystal structure of the samples was investigated through X-ray diffraction measurements (XRD) and scanning electron microscopy (SEM). Superconductivity of the samples was analyzed by the temperature-dependent resistivity measurement. The experimental results showed the existence of both Bi-2223 and Bi-2212 phases in all samples. Quantitatively, the volume fraction of the Bi-2223 phase was found to increase from 53.56% to 75.97%, and the average grain size of Bi-2223 phase was observed to enlarge from 57.95 nm to 86.50 nm as the sintering temperature increased from 835 °C to 850 °C. In addition, the excess conductivity analyses based on the theory of Aslamazov - Larkin (AL) and Lawrence - Doniach (LD) showed decreases in the coherence lengths (ξc(0)) from 1.957 Å to 1.565 Å and the effective inter-layering spacing (d) from 79.7 Å to 64.5 Å. Meanwhile, the interlayer coupling strength (J) between two CuO2 planes was estimated to increase from 0.00083 to 0.00137. These results might be evidence to conclude that the increasing of the sintering temperature obviously improves the superconductivity in the BPSCCO system. \u0000  \u0000 ","PeriodicalId":303178,"journal":{"name":"VNU Journal of Science: Mathematics - Physics","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131458234","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
Effective Couplings between Two Photons and Axion in the 3-3-1 Model 3-3-1模型中双光子与轴子的有效耦合
VNU Journal of Science: Mathematics - Physics Pub Date : 2021-12-03 DOI: 10.25073/2588-1124/vnumap.4627
Hoang Ngoc Long, Vo Van Vien, Vu Hoa Binh
{"title":"Effective Couplings between Two Photons and Axion in the 3-3-1 Model","authors":"Hoang Ngoc Long, Vo Van Vien, Vu Hoa Binh","doi":"10.25073/2588-1124/vnumap.4627","DOIUrl":"https://doi.org/10.25073/2588-1124/vnumap.4627","url":null,"abstract":"The one-loop contribution axion-photon-photon coupling is presented in the framework of the 3-3-1 model, in which the loop diagrams are finite. The decay of axion into two photons is demonstrated. This study shows that it is easy to fulfill dark matter candidate conditions for the axion in the model. \u0000 ","PeriodicalId":303178,"journal":{"name":"VNU Journal of Science: Mathematics - Physics","volume":"116 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124225283","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
Enhanced Photocatalytic Activity Using Near Visible Light of ZnO Nanorods by Doping with Mn2+ Ions 在近可见光下掺杂Mn2+离子增强ZnO纳米棒的光催化活性
VNU Journal of Science: Mathematics - Physics Pub Date : 2021-12-03 DOI: 10.25073/2588-1124/vnumap.4626
Luong Hoai Nhon, Nguyen Huu Khoa, Lai Thi Ngoc Huyen, Huynh Hung Quang, Dinh Tan Muon, Nguyễn Hoàng Ngọc Phương, Tran Cong Khanh, Phan Bach Thang, Dang Vinh Quang
{"title":"Enhanced Photocatalytic Activity Using Near Visible Light of ZnO Nanorods by Doping with Mn2+ Ions","authors":"Luong Hoai Nhon, Nguyen Huu Khoa, Lai Thi Ngoc Huyen, Huynh Hung Quang, Dinh Tan Muon, Nguyễn Hoàng Ngọc Phương, Tran Cong Khanh, Phan Bach Thang, Dang Vinh Quang","doi":"10.25073/2588-1124/vnumap.4626","DOIUrl":"https://doi.org/10.25073/2588-1124/vnumap.4626","url":null,"abstract":"ZnO is a promising photocatalyst for photocatalytic oxidation of organic compounds under the influence of sunlight that provides clean energy and decomposes sustainable organic pollutants substances. ZnO is found to have non-toxic properties, long-term stability, high carrier mobility, low cost and biocompatibility. However, some disadvantages of ZnO limit its use in photocatalysis. Due to its wide bandgap, ZnO can only be activated under UV illumination. On the other hand, the photo-excited electron-hole pairs that recombine quickly on ZnO surface, suppress its photocatalytic properties. To improve its properties and performance, doping with transition metals was used to improve the optical properties of ZnO. Among the transition metal ions, Manganese (Mn) was commonly used to improve and tune the optical, electrical, diameter, height, and the number of nanorods (NRs) per unit area. Introduction of Mn into ZnO could enhance the photocatalytic activity due to the increase in the defect sites that effectively decreased the recombination of free electrons and holes. This study successfully synthesized ZnO nanorod arrays generated on glass substrates with different concentrations of doping Mn (0, 0.5, 1, 1.5 and 2%) at 100 °C by a simple hydrothermal method. To investigate the structure, morphology and optical properties, ultraviolet-visible spectroscopy (UV-Vis), X-ray diffraction (XRD) and scanning electron microscopy (SEM) were conducted. With the range of Mn doping ≤ 2% mol, the band gap reduced slightly, and the most optimized Mn doping concentration was of 0.5%. Overall, this work shows that the most effective way to increase ZnO’s photocatalytic activity in the visible region by reducing its band gap was the reduction in the size of the material or denaturation of ZnO by certain metals or non-metals. \u0000 ","PeriodicalId":303178,"journal":{"name":"VNU Journal of Science: Mathematics - Physics","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116454057","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: 2
Free Vibration and Bending of Gradient Auxetic Plate Using Finite Element Method 梯度减振板的自由振动与弯曲有限元分析
VNU Journal of Science: Mathematics - Physics Pub Date : 2021-12-03 DOI: 10.25073/2588-1124/vnumap.4664
Pham Hong Cong, Vu Dinh Tung, Do Duc Hai, Nguyen Dinh Khoa
{"title":"Free Vibration and Bending of Gradient Auxetic Plate Using Finite Element Method","authors":"Pham Hong Cong, Vu Dinh Tung, Do Duc Hai, Nguyen Dinh Khoa","doi":"10.25073/2588-1124/vnumap.4664","DOIUrl":"https://doi.org/10.25073/2588-1124/vnumap.4664","url":null,"abstract":"In recent years, there has been a new approach to the material industry that uses sandwich structures with auxetic honeycomb cores with the interesting property of negative Poisson's ratios. In this paper, the Finite Element Method (in ANSYS) is used to investigate natural frequency of vibration and bending characteristics under varying pressure loads applied on the top skin when changing fundamental properties of some gradient configurations, including angular gradient, thickness gradient and functional gradient configurations of the auxetic plate with honeycomb structure. Thereby, the advantages of each configuration are investigated, studied, and obtained; therefore, it is expected to be applied in various industry sectors, such as wind turbine blades, aircraft wings, among others. \u0000 ","PeriodicalId":303178,"journal":{"name":"VNU Journal of Science: Mathematics - Physics","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117286129","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
Evaluation of Thick Target PIXE Analysis in the 5SDH-2 Pelletron Accelerator Facility at VNU University of Science VNU理学院5SDH-2颗粒加速器设备厚靶pixie分析评价
VNU Journal of Science: Mathematics - Physics Pub Date : 2021-12-03 DOI: 10.25073/2588-1124/vnumap.4623
B. T. Hoa, N. T. Nghia, V. Phong, T. T. Anh
{"title":"Evaluation of Thick Target PIXE Analysis in the 5SDH-2 Pelletron Accelerator Facility at VNU University of Science","authors":"B. T. Hoa, N. T. Nghia, V. Phong, T. T. Anh","doi":"10.25073/2588-1124/vnumap.4623","DOIUrl":"https://doi.org/10.25073/2588-1124/vnumap.4623","url":null,"abstract":"This paper presents the evaluation of the Thick Target Particle Induced X-rays Emission (TTPIXE) technique using standard samples. The element-dependent standardization factor, H, as a function of X-ray energies is calibrated using standard sample NIST-611 and validated with two standard samples: IAEA-Soil7 and NIES-Pepperbush. The obtained results are in good agreement with the reference data. \u0000 ","PeriodicalId":303178,"journal":{"name":"VNU Journal of Science: Mathematics - Physics","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122413360","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
Photoluminescent Properties of Red-emitting AlPO4:Cr3+ Phosphor for Plant Growth LEDs 植物生长led用红发AlPO4:Cr3+荧光粉的光致发光特性
VNU Journal of Science: Mathematics - Physics Pub Date : 2021-09-27 DOI: 10.25073/2588-1124/vnumap.4617
Tran Manh Trung, N. Tu, N. V. Quang, D. Q. Trung, P. T. Huy
{"title":"Photoluminescent Properties of Red-emitting AlPO4:Cr3+ Phosphor for Plant Growth LEDs","authors":"Tran Manh Trung, N. Tu, N. V. Quang, D. Q. Trung, P. T. Huy","doi":"10.25073/2588-1124/vnumap.4617","DOIUrl":"https://doi.org/10.25073/2588-1124/vnumap.4617","url":null,"abstract":"In this study, red-emitting AlPO4:Cr3+ phosphors have been successfully synthesized by a facile sol-gel method. The Tanabe–Sugano diagram demonstrates that the surrounding sites of Cr3+ ions has a high crystal field with Dq/B=2.47. The sharp 694-nm peak on the PL of AlPO4:Cr3+ phosphor could be attributed to the 2E→4A2 electron transition of Cr3+ ions. The AlPO4:0.3%Cr3+ phosphor presents the highest PL intensity, then a purple LED prototype is obtained by coating the optimum powder on a UV LED chip. The color coordinates (0.2412, 0.1330) of the purple LED prototype implies that AlPO4:Cr3+ phosphors are promosing to be used as deep red phosphor powder for horticulture LED lighting.","PeriodicalId":303178,"journal":{"name":"VNU Journal of Science: Mathematics - Physics","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130887571","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
CTAB-assisted Synthesis and Characterization of FePd Nanoparticles ctab辅助制备FePd纳米颗粒及其表征
VNU Journal of Science: Mathematics - Physics Pub Date : 2021-09-20 DOI: 10.25073/2588-1124/vnumap.4669
N. Hoang Nam, Nguyen Thi Bich Ngoc, Truong THANH TRUNG, Tran Thi Hong, Phi Thi Huong, N. H. Luong
{"title":"CTAB-assisted Synthesis and Characterization of FePd Nanoparticles","authors":"N. Hoang Nam, Nguyen Thi Bich Ngoc, Truong THANH TRUNG, Tran Thi Hong, Phi Thi Huong, N. H. Luong","doi":"10.25073/2588-1124/vnumap.4669","DOIUrl":"https://doi.org/10.25073/2588-1124/vnumap.4669","url":null,"abstract":"Fe50Pd50 nanoparticles with small size of around 5-9 nm were prepared by sonoelectrodeposition in the presence of cetyltrimethylammonium bromide (CTAB) surfactant. The as-prepared nanoparticles were annealed at 550oC for a series of times from 1 h to 6 h. After annealing a transformation from a disordered face-centered-cubic structure to the ordered L10 structure occurred. It was revealed that the coercivity of the nanoparticles is larger compared to that of the samples prepared by the same method in the absence of CTAB. The structural and magnetic properties of the samples were studied in dependence of annealing time. The results indicate a similar behavior of the evolution of tetragonality ratio and coercivity with annealing time in the nanoparticles.","PeriodicalId":303178,"journal":{"name":"VNU Journal of Science: Mathematics - Physics","volume":"81 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117248930","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: 1
Steady State Calculations of the PWR MOX/UO2 Core with the Monte Carlo Code MCNP6 基于蒙特卡罗代码MCNP6的压水堆MOX/UO2堆芯稳态计算
VNU Journal of Science: Mathematics - Physics Pub Date : 2021-09-20 DOI: 10.25073/2588-1124/vnumap.4621
N. Dung, Tran Viet Phu, D. Hartanto, Luu Thi Phuong Lan, Mai Viet Thuan, P. Ha
{"title":"Steady State Calculations of the PWR MOX/UO2 Core with the Monte Carlo Code MCNP6","authors":"N. Dung, Tran Viet Phu, D. Hartanto, Luu Thi Phuong Lan, Mai Viet Thuan, P. Ha","doi":"10.25073/2588-1124/vnumap.4621","DOIUrl":"https://doi.org/10.25073/2588-1124/vnumap.4621","url":null,"abstract":"This paper presents the steady-state analysis results of the OECD/NEA and U.S. NRC PWR MOX/UO2 (MOX: Mixed Oxide) Core Transient Benchmark with the modern MCNP6 Monte Carlo code based on the ENDF/B-VII.1 evaluated nuclear data library. The purpose was to verify an MCNP6 model proposed for calculations of a heterogeneous MOX/UO2 fuelled PWR core, which has different neutronic characteristics from the popular homogeneous ones loaded with the UO2 fuel due to its partial loading of the MOX fuel. The effective neutron multiplication factors, assembly power distributions, and control rod worths calculated using MCNP6 showed a reasonable agreement within 390 pcm, 6%, and 175 pcm, respectively, with the available benchmark data. The discrepancies between the MCNP6 results and the benchmark data were also discussed. Consequently, these results obtained with MCNP6 and ENDF/B-VII.1 can be considered as a new full-core heterogeneous transport solution to supplement for the available benchmark solutions at the steady-state conditions.","PeriodicalId":303178,"journal":{"name":"VNU Journal of Science: Mathematics - Physics","volume":"256 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124214302","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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