VNU-UET Repository: No conditions. Results ordered -Date Deposited. 2024-03-29T10:24:16ZEPrintshttp://eprints.uet.vnu.edu.vn/images/sitelogo.pnghttps://eprints.uet.vnu.edu.vn/eprints/2019-12-12T09:40:23Z2019-12-12T09:41:05Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3795This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/37952019-12-12T09:40:23ZCompressibility of a periodic lattice of atomic hydrogenWe report on the compressibility of a pseudo-cubic P1 lattice of atomic hydrogen from 0 up to 3000 GPa by modeling the lattice under hydraulic stress using the Density Functional Theory (DFT). The lattice compression does not fit well to the known Murnaghan's equation and shows sharp increase near 2500 GPa. On the other hand, the bulk modulus shows anomalous behavior in the vicinity of 280 GPa. We also obtain the values of ground state energy and enthalpy for pressure up to 2500 GPa, above this pressure the convergence fails as the H-H distance approaches the bonding length in H2.Nam Nhat Hoangnhathn@vnu.edu.vn2019-01-07T02:43:25Z2019-01-07T02:43:25Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3401This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/34012019-01-07T02:43:25ZCrystal Structure and Magnetic Properties of La0.8R0.2(Fe0.88Si0.12)13 (R = Sm and Tb) CompoundsVan Hiep VuongKhac Thuan NguyenThi Kim Anh DoNam Nhat Hoangnhathn@vnu.edu.vn2019-01-07T02:40:13Z2019-01-07T02:40:13Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3402This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/34022019-01-07T02:40:13ZLow Field Magnetocaloric Effect in Bulk and Ribbon Alloy La(Fe0.88Si0.12)13Van Hiep VuongThi Kim Anh DoDuy Thien NguyenQuang Hoa NguyenNam Nhat Hoangnhathn@vnu.edu.vn2019-01-07T02:36:19Z2019-01-07T02:36:19Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3403This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/34032019-01-07T02:36:19ZValence Illustration for Large Structure: A Fast Empirical
Approach Based on Bond-Valence MethodNam Nhat Hoangnhathn@vnu.edu.vn2019-01-07T02:34:43Z2019-01-07T02:34:43Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3404This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/34042019-01-07T02:34:43ZRaman Spectroscopy of CaCu3Ti4O12 Ceramics RevisitedNam Nhat Hoang2016-07-11T12:46:42Z2016-07-11T12:47:25Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1816This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/18162016-07-11T12:46:42ZStable Gold Carbide NanostructuresThe exemplars of gold carbide AuC in cubic F-43m structure and cluster form Au<sub>6</sub>C<sub>3</sub> are reported. The characteristics of structures were obtained on basis of Time-Dependent Density Functional Theory (TD-DFT) embedded within the framework of Generalized Gradient Approximation (GGA) and utilized Pardew-Burke-Ernzerhof functional (PBE) and spin-polarized wave functions. We found that the modeled forms of gold carbide exhibited no ferromagnetism while maintaining metallic ground state. The calculation showed the dominance of optical transitions which preserved spin.Khac Thuan NguyenVan Hiep VuongThi Kim Anh DoNam Nhat Hoangnhathn@vnu.edu.vn2016-07-11T12:39:42Z2016-07-11T12:40:30Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1809This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/18092016-07-11T12:39:42ZEstimation of Valence Distribution in Perovskites using the Bond Valence MethodThis paper presents the application of the bond valence method to estimate the valence charge distribution in several perovskite systems: La1-xxPbxMn03 (x=0.1-0.5), La0.6Sr0.4.xTixMnO3 (x=0.0- 0.25) and La1=xSrxCoO3 (x=0.1-0.5). The results showed a failure of elastic bonding mechanism in all compounds and revealed a deficit of valence charge in the unit cells. This valence deficit was not associated with the structural defects and is equally localized in all coordination spheres. As the content of substitution increased, the charge deficit declined systematically from balanced level, signifying the transfer of charge from the B-O6 to A-O12 spheres. This transfer reaches near 2 electrons per unit cell. The possible impact of the limitted accuracy of available structural data was considered.D.H. Yen P.T. Hang N.Van Chau Dinhdinhchau@vnu.edu.vnVan Thuong DinhNam Nhat Hoangnhathn@vnu.edu.vn2016-07-11T12:38:17Z2016-07-11T12:39:16Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1808This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/18082016-07-11T12:38:17ZEffect of Cerium Doping on Crystal Structure and Magnetic Properties of La1-yCeyFe11.44Si1.56 CompoundsKim Anh DoVan Chau Dinhdinhchau@vnu.edu.vnNam Nhat Hoangnhathn@vnu.edu.vnVan Hiep VuongKurisu Makio2016-05-23T01:25:57Z2016-05-23T01:26:56Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1569This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/15692016-05-23T01:25:57ZChế tạo, nghiên cứu cấu trúc và tính chất của một số hệ màng mỏng hợp kim AuFeCông nghệ cấy ion bằng máy gia tốc hiện nay là một trong những phương pháp rất hiện đại trong việc chế tạo và nghiên cứu tính chất của vật liệu, đặc biệt trong việc chế tạo các vật liệu khó hòa tan như H, C ...vào các màng mỏng kim loại. Màng mỏng hợp kim AuFe được chế tạo bằng phương pháp bốc bay nhiệt trong chân không. Sau đó, bằng máy gia tốc pelletron 5SDH-2 chúng tôi đã cấy ion C để tạo nên 5 hệ mẫu AuFe+C với nồng độ C khác nhau. Các hình thái cấu trúc, các tính chất điện, từ, quang học cũng đã được chúng tôi khảo sát. Các kết quả cho thấy rằng, màng mỏng AuFe được hình thành với tỉ lệ 1:3 và tương đối đồng đều. Các màng mỏng AuFe+C đã có sự thay đổi kích thước ô mạng, đặc biệt độ dẫn tương đối của màng này lớn hơn với màng AuFe gốc và thể hiện tính dẫn điện khá tốt, đỉnh hấp thụ cực đại nằm trong vùng ánh sáng tím và đặc biệt là sự xuất hiện của đỉnh phát xạ ở khoảng 415nm. Ngoài ra, chúng tôi còn khảo sát thêm một số tính chất khác của màng mỏng này như tính chất từ tại vùng nhiệt độ từ 80K đến 1000K.Khac Thuan NguyenNam Nhat Hoangnhathn@vnu.edu.vn2015-11-07T13:24:55Z2015-11-09T05:59:16Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1277This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/12772015-11-07T13:24:55ZApplication of Bond Valence Method to Estimate the Valence Charge Distribution in the Metal-to-Oxygen Bonding Spheres in PerovskitesVan Chau Dinhdinhchau@vnu.edu.vnVan Thuong DinhNam Nhat Hoangnhathn@vnu.edu.vnThi Hang Nguyen2015-11-07T13:24:00Z2015-11-09T05:55:17Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1278This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/12782015-11-07T13:24:00ZStructure and Electrical Properties of the Thin Gold Leaves Fabricated by Vietnam Traditional Laminating TechnologyThe structure and electrical properties of the thin gold leaves fabricated by Vietnam traditional laminating technology are introduced. The gold leaves are usually created with the average size of 3x3cm, and 200nm thickness, they can easily be broken when handling carelessly. By the measurements of X-ray Diffraction (XRD), and Electron Scanning Microscopy (SEM), the structure and surface morphology were investigated. We have also measured the absorption spectra and determined the resistivity of the samples and found that the gold films possessed the Ca impurities stuck on the surface of the leaves. The conductivity of the films is relatively higher and the absorption maximum is red-shifted in comparison with that of the bulk.Khac Thuan NguyenNam Nhat Hoangnhathn@vnu.edu.vn