Communications in Physics
http://vjs.ac.vn/index.php/cip
<p>The object of <em>Communications in Physics</em> is the publication of new theoretical and experimental research works in all fields of physics.</p>Publishing House for Science and Technology, Vietnam Academy of Science and Technologyen-USCommunications in Physics0868-3166<span>Authors who publish with this journal agree to the following terms:</span><br /><ol type="a"><br /><li>Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a <a href="http://creativecommons.org/licenses/by/3.0/" target="_new">Creative Commons Attribution License</a> that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.</li><br /><li>Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.</li><br /><li>Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See <a href="http://opcit.eprints.org/oacitation-biblio.html" target="_new">The Effect of Open Access</a>).</li></ol>Propagation of Ultrashort Pulses in Nonlinear Media
http://vjs.ac.vn/index.php/cip/article/view/9184
<p>In this paper, a general propagation equation of ultrashort pulses in an arbitrary dispersive nonlinear medium derived in [9] has been used for the case of Kerr media. This equation which is called Generalized Nonlinear Schroedinger Equation usually has very complicated form and looking for its solutions is usually a very difficult task. Theoretical methods reviewed in this paper to solve this equation are effective only for some special cases. As an example we describe the method of developed elliptic Jacobi function expansion and its expended form: F-expansion Method. Several numerical methods of finding approximate solutions are briefly discussed. We concentrate mainly on the methods: Split-Step, Runge-Kutta and Imaginary-time algorithms. Some numerical experiments are implemented for soliton propagation and interacting high order solitons. We consider also an interesting phenomenon, namely the collapse of solitons, where the variational formalism has been used.</p>Cao Long Van2017-03-102017-03-1026Study of Optimized Coupling Based on Micro-lensed Fibers for Fibers and Photonic Integrated Circuits in the Framework of Telecommunications and Sensing Applications
http://vjs.ac.vn/index.php/cip/article/view/8951
<p>We demonstrate the interest of expanded beam microlenses (around 55 µm of mode field diameter) to relax positioning tolerances and to decrease reflectance in single mode fiber to fiber interconnexions. We also point out the interest of micro-lenses of very small mode field diameter (around 2 µm) to improve coupling efficiency in specialty fibers and integrated waveguides for non linear effects based functions and for sensors applications at a wavelength of 1.55 µm.</p>Si Dat LeEnguerran DelcourtPauline GiraultAldo Gutierrez-ArroyoPaul AzuelosNathalie LorrainLoïc BodiouLuiz PoffoJean-Marc GoujonYannick DumeigeIsabelle HardyPhilippe RochardJonathan LemaitreParastesh PirastehMohammed GuendouzThierry ChartierLionel QuételSébastien ClaudotJoël CharrierMonique Thual2017-01-122017-01-1226Calculation of Effective Emissivity of Isothermal Diffuse Cylindrical-inner-cone Cavity using Polynomial Interpolation Technique
http://vjs.ac.vn/index.php/cip/article/view/8371
A precise calculation of the effective emissivity of isothermal diffuse cylindrical-inner-cone cavities is presented using the polynomial interpolation technique. Particularly, results are obtained for the effective emissivity of conical bases of the isothermal diffuse cylindrical-inner-cone cavities. Comparisons are made between Chu Zaixiang's and our results for various values of the axial length, the radius of aperture in the lid and the half-angle of the inner cone. These demonstrate considerable simplicity and high accuracy of the calculating technique can be achieved, especially for the cavities of high intrinsic emissivity of the wall, long cylinder length, and small aperture radius. For application, a series of explicit analytical expressions in the polynomial forms are also presented.Ta Van TuanNguyen Quang Minh2017-02-272017-02-2726The Sensitivity of Animal Cells Sensitized With Bilirubin under Irradiation of Blue and Green Spectral Range
http://vjs.ac.vn/index.php/cip/article/view/9004
<p>It has been shown that exposure to radiation of LED sources of light with an emission band maximum at about 465 and 520 nm having substantially identical damaging effects on animal cells in culture, that are in a logarithmic growth phase and preincubated with pigment. Photobiological effect is caused by photodynamic processes involving singlet oxygen generated by triplet excited sensitizer. Mono-exponential type dependence of cell survival on the energy dose indicates that it is bilirubin that acts as a sensitizer but not its photoproducts. The inclusion of bilirubin in the cells, where it is primarily localized in the mitochondria cells, it is accompanied by multiple amplification photochemical stability compared to pigment molecules bound with albumin.</p>O. A. KozlenkovaL. G. PlavskayaA. V. MikulichI. A. LeusenkoA. I. TretyakovaV. Yu PlavskiiJ. GaoD. XiongX. Wu2017-03-072017-03-0726Thermal Conductivity of Ethylene Glycol Based Copper Nanoparticle Decorated Graphene Nanofluids
http://vjs.ac.vn/index.php/cip/article/view/8705
In this paper, thermal conductivity of ethylene glycol based copper nanoparticle decorated graphene (Cu/Gr) nanofluids are successfully synthesized by a chemical reduction tecnique using ascorbic acid antioxidant agent. Nano-sized copper nanoparticles is decorated on functionalized graphene, and then dispersed uniformly in ethylene glycol (EG) to make the nanofluids. Morphology, phase composition and thermal conductivity of nanofluids are investigated in detail. Thermal conductivity of nanofluid containg Cu/Gr with mass ratio of 5:1 shows an enhancement about 10% and 29% at 30<sup>o</sup>C and 60<sup>o</sup>C comparing with EG fluid only. The results show the high potential application of Cu/Gr nanofluid in heat transfer fields.Pham Van TrinhNguyen Ngoc AnhLe Dinh QuangBui Hung ThangPhan Ngoc HongNguyen Tuan HongPhan Hong KhoiPhan Ngoc Minh2017-03-082017-03-0826Structure and Electrochemical Impedance of LiNi\(_{x}\)Mn\(_{2 - x}\)O\(_{4}\)
http://vjs.ac.vn/index.php/cip/article/view/8953
<p>Ni-substitution spinel LiNi<sub>x</sub>Mn<sub>2−x</sub>O<sub>4</sub> (<em>x</em> = 0, 0.1, 0.2) materials were synthesized by the sol--gel method. The structure and <span> </span>morphology of the samples were characterized by the X-ray diffraction (XRD) <span> </span>and the scanning electron microscopy. The ac conduction of the materials was <span> </span>investigated by electrochemical impedance spectroscopy (EIS) measurements. <span> </span>The refinement results showed that the substitution of Ni decreased the <span> </span>lattice constant and Mn--O distance, while increased Li--O bond length and <span> </span>16c octahedral volume. The EIS results confirmed the decrease of <span> </span>conductivity with increasing Ni substitution content. Based on XRD and EIS <span> </span>results, the relationship between the crystal structure and electrochemical <span> </span>behavior of the materials was discussed and explained.</p>Ta Anh TanNguyen Si HieuLe Ha ChiDang Tran ChienLe Dinh TrongPham Duy Long2017-03-062017-03-0626Higgs Mass Constraint on a Low Scale SUSY Model
http://vjs.ac.vn/index.php/cip/article/view/9117
Randal-Sundrum models have an interesting feature that an effective physical scale can be generated from a much larger one of the underlying theory. In this paper, we investigate a model of supersymmetry in the Randall-Sundrum spacetime with a low cutoff scale. Due to the warp factor, the Kaluza-Klein scale is warped down to \(\mathcal{O}\)(100) TeV. With the MSSM superfields living in the bulk, the soft SUSY breaking terms of the 4D effective theory are derived from the original 5D Lagrangian by integrating out the extra-dimension. We examine the constraint of the Higgs boson mass measurement on the model. As a result, the viable parameter space with the ability to reproduce a 125 GeV Higgs mass is identified. The constraint rules out parameter regions with the stop masses larger than 20 TeV. Therefore, the parameter space of the model can be explored in a future 100 TeV collider.Tran Minh HieuNguyen Thu HuongTrieu Quynh Trang2017-03-062017-03-0626Dependence of Melting Process on Size and Edge Type of Graphene Nanoribbon
http://vjs.ac.vn/index.php/cip/article/view/8805
<p>The study of variation of the size, armchair and zigzag types effects on the melting process of graphene nanoribbon. A numerical thermodynamical model has been devoted for the study. The phase transition has first order behaviour. The formation of different defects, ring size and coordination number is dependent on the size and the edge type of GNR. The nuclei of heating appear at temperature around 2300K and that can be considered as pre-melting point. The melting process shows the case that the results of Berezinsky-Kosterlitz-Thouless-Nelson-Halperin-Young (BKTNHY) theory cannot be applied.</p><p> </p>Hang Thi Thuy Nguyen2017-02-172017-02-1726