World Journal of Applied Physics最新文献

{"title":"Comparative Investigation of Pressure Effect on Structural Stability, Electronic and Optical Response of LaXO₃ (X = Al, In, Ga) for Optoelectronic Applications","authors":"Muhammad Moin, A. Anwar, Mehrunisa Babar, Udayabhaskararao Thumu, Anwar Ali","doi":"10.11648/j.wjap.20240901.11","DOIUrl":"https://doi.org/10.11648/j.wjap.20240901.11","url":null,"abstract":"A first principle study intense on the density functional theory with Heydscuseria-Ernzerhof screened hybrid functional hybrid function (HSEO6) is used to assess the structural, Electronic, elastic, mechanical and optical responses of LaXO₃ (X = Al, In, Ga) perovskite materials. The compressive investigation under the external static isotropic pressure (P= 0 to 80GaP), phase stability, band structure and their important impact on the optical response of LaAlO₃, LaInO₃ and LaGaO₃. Electronic band structure shows that LaXO₃ (X = Al, In Ga) semiconductor with indirect band gap and an optically inactive response up to 20GPa, while the band gap becomes direct at 80GaP. There are gamma points (G-X-Q) at 80GPa and the band gap changes from indirect to direct nature. Under main desperation physical parameters of perovskite materials are well explained the response of TDOS, PDOS and EPDOS contour plots have been well understood for the full description of the band gap. It is further observed that the external pressure enhanced upto 40GPa both materials are significantly more mechanically stable compared to pristine LaXO₃ (X = Al, In, Ga) at 0GPa. The optical properties of LaAlO₃, LaGaO₃and LaInO₃, dielectric coefficient <i>(ε₁, iε₂)</i> have been employed along with the optical responses like absorption, energy loss function, reflectivity and reflective index are obtained in the energy scale from 0 to 60 eV. It was observed that static dielectric constant decreases with the decrease in optical band gap. The optical tunings under the effect of pressure which are good candidates in practical optoelectronic applications are extensively used and interpreted by the calculation of the dielectric function.","PeriodicalId":131530,"journal":{"name":"World Journal of Applied Physics","volume":"91 11","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140709398","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}

{"title":"Simulation Mobile Phone Radiation of Dipole Antenna Using HFSS","authors":"K. Elwasife, Heba Aboamra, M. Shabat","doi":"10.11648/j.wjap.20230801.12","DOIUrl":"https://doi.org/10.11648/j.wjap.20230801.12","url":null,"abstract":"","PeriodicalId":131530,"journal":{"name":"World Journal of Applied Physics","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133405348","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}

{"title":"Effect of Annealing on Thermoelectric Properties of Crystals Yb_xBi_2-xTe₃","authors":"Famil Imran Mamedov, Seyyara Adil Nabieva, Sevinj Zellabdin Melikova, Gunel Talat Imanova","doi":"10.11648/j.wjap.20230801.11","DOIUrl":"https://doi.org/10.11648/j.wjap.20230801.11","url":null,"abstract":"","PeriodicalId":131530,"journal":{"name":"World Journal of Applied Physics","volume":"82 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122692004","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}

{"title":"Terahertz TWT on a Rectangular Waveguide Folded in a Circular Spiral","authors":"A. Kurayev, V. Matveyenka","doi":"10.11648/J.WJAP.20210603.13","DOIUrl":"https://doi.org/10.11648/J.WJAP.20210603.13","url":null,"abstract":"The most promising in the THz range is traveling-wave tubes (TWTs) and backward-wave tubes (BWTs) on a serpentine-curved (zigzag-rolled) rectangular waveguide. They are implemented in the THz range (220 GHz), although their characteristics are far from satisfactory due to the strict restriction on the tape electron beam width, that does not allow reaching the summarizing beam current optimum level. To replace the zigzag convoluted waveguide with the spiraled for the TWT and BWT on a curved rectangular waveguide is the best way to remove the ribbon beam width restriction. In the early TWT and BWT design a waveguide planar spiral was also flat in the upper and lower parts connected by vertical idle (without beam) transitions. Proposed design can be significantly improved both in relation to the electron interaction process with the waveguide field and in relation to the TWT-BWT manufacturing technology if instead of a planar waveguide spiral, a circular one is used. The article proposes the TWT designing a terahertz rectangular waveguide folded as a circular spiral. The design differs from the previously proposed TWT with a planar-spiral waveguide by the improved interaction conditions between the electron beam and the waveguide field, as well as the manufacturing technology simplification for terahertz range. Based on numerical simulation, it is shown that proposed TWT achieves Gн= 42 ÷ 48dB saturation gain in the 220 GHz range with the waveguide turn number n = 40 ÷ 50. The proposed TWT design on a rectangular waveguide folded in a circular spiral is more technologically advanced than the TWT on a planar-spiral waveguide. In the most necessary 220 GHz range the efficiency is very high and can provide the need for amplifiers and generators in this and other ranges. We also note that the TWT on a spirally folded waveguide can operate in the BWT mode and, moreover, simultaneously in the TWT and BWT modes. The latter is possible in modes close to linear one. The TWT magnetic system of the type described above can be implemented in the form of a permanent magnet with pluses on the TWT end parts. The proposed TWT characteristics can be significantly improved by optimizing the waveguide helical winding pitch. Exactly as it is achieved with using the spiral wire deceleration system. The efficiency of such optimized TWT reaches 70% efficiency.","PeriodicalId":131530,"journal":{"name":"World Journal of Applied Physics","volume":"92 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":"115971841","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}

{"title":"The Pattern Efficiency of Energy Transfer Within the Newton's Cradle and Its Practical Usage","authors":"David Liu, Chenyu Liang","doi":"10.11648/J.WJAP.20210602.11","DOIUrl":"https://doi.org/10.11648/J.WJAP.20210602.11","url":null,"abstract":"In the modern society, the concept of “efficiency” has been emphasized in numerous areas, and is especially critical in discussing the transfer-efficiency of the energy generated. If the concept is not being emphasized in, it is likely that numerous severe consequences would be resulted, for instance, the kinetic energy received by drivers might be massive and even ultimately terminate their lives. The paper targets the factor that affects most in the inertial energy transfer of Newton’s Cradle used in the experiment as a subject, getting the information of the actual energy transfer efficiency within the cradle through recording video and locating the position of the balls on a graph paper, analysing the rebounded height level data quantitatively, obtaining the relevant parameters of Cradle such as the mass of the balls and the length of the strings as well as the diameter of the balls through direct measurement. Then, the calculation of the energy loss during the collision would be made and the regression model would be constructed. After that, taking advantage of the hypothesis testing method to testify the significance of the relevant parameter within the Newton’s Cradle model. Next, further modifications, which allows a simulation of the energy transfer efficiency of colliding process to be conducted, could be made and the most influencing factor for energy transferring would be revealed and thus find link with the car accident in the method of reducing the damage caused during the incidents.","PeriodicalId":131530,"journal":{"name":"World Journal of Applied Physics","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125499875","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}

{"title":"A Classical Electron Model with Synchrotron Radiation","authors":"G. Poelz","doi":"10.11648/J.WJAP.20210601.12","DOIUrl":"https://doi.org/10.11648/J.WJAP.20210601.12","url":null,"abstract":"A classical model of the electron based on Maxwell’s equations is presented in which the wave character is described by classical physics. Most properties follow from the description of a classical massless charge circulating with v=c. The magnetic moment of the electron yields the radius of this circulation and the generated synchrotron radiation removes the singularity of the Coulomb field. The residual field equals then to the mass of the electron. Quantum mechanics yields its spin and the fine structure constant α compares this dynamic structure of the electron with the classical point-like static view. This configuration is not stable. It will decay by the emission of synchrotron radiation. The stability of this description is therefor investigated by extending this model to 3 dimensions. The field lines within the free electromagnetic fields of the creation process, solved in polar coordinates, yield possible tracks for a massless charge. Many possible circulating tracks are found but only a combination of background fields yield environments in which stable tracks for β = 1 - charges may be created. Knotted toroidal tracks yield the stability. A knotted field line e.g. with T(3,2)-symmetry may describe a spin-1/3-particle and a field line with T(2,3)-symmetry in form of a knotted trefoil may belong to an electron as a stable spin-1/2-particle. With its fixed internal revolution frequency this electron appears to the external world as a standing wave with an amplitude propagating like the de Broglie wave.","PeriodicalId":131530,"journal":{"name":"World Journal of Applied Physics","volume":"100 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123782784","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}

{"title":"Simple Small-Signal HEMT Model Suitable for GaN Stability Analysis and Technologies Benchmarking","authors":"A. Issaoun, T. Roedle","doi":"10.11648/J.WJAP.20210601.11","DOIUrl":"https://doi.org/10.11648/J.WJAP.20210601.11","url":null,"abstract":"This article deals with the extension of the small-signal model usage to GaN technologies benchmarking, and to the detection of internal oscillations occurring in highly optimized multi-finger GaN high-electron-mobility transistors (HEMTs). The proposed small-signal model consists of only 14 circuit elements. Its simple semi-analytical extraction procedure is developed in Keysight ADS circuit simulator, letting instantaneous comparison between modelled and simulated small-signal parameters. The simplicity and the adaptability of the technique always ensures a physical model parameter extraction. The technique is demonstrated for various technology processes, layouts, dimensions, and for three commercially available GaN vendors. The extracted data and the number of circuit elements are used to benchmark GaN technologies in terms of bias dependency, efficiency, and static linearity. By coupling the small-signal model to the electromagnetic (EM) GaN HEMT layout simulation results in a powerful tool for detecting odd-mode and even-mode instabilities. The technique is proven for various GaN basic cells as well as for power bars. Even prior to structure fabrication, the tool can be used to analyze its stability behavior by exploring its layout.","PeriodicalId":131530,"journal":{"name":"World Journal of Applied Physics","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133881623","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}

{"title":"Analytical Solutions in the Framework of Brightness and Color Spectral Pyrometry Methods","authors":"K. Ludanov","doi":"10.11648/J.WJAP.20190403.11","DOIUrl":"https://doi.org/10.11648/J.WJAP.20190403.11","url":null,"abstract":"The article provides an analytical solution to the problem of pyrometric determination of the actual surface temperature T(K) by calculating its value from a system of three equations, including the results of three measurements of the brightness temperature TS (λі), which were obtained at three wave length sof the spectrum: λ1<λ2<λ3 with unknown emissivity e1, e2 and e3, in the framework of the two main methods of spectral pyrometry according to the patents of Ukraine No.73231 (color) and No.82870 (brightness). It is shown in the article that exact analytical solutions are possible only in cases when the nature of the dispersion of the selective surface e=f(λ) (for example, linear, logarithmic, etc.) is known apriori, which, together with the equation of coupling e2 = F(e1, e3), allows us to determine the exact value of the intermediate (effective) length λ2 waves based on the extreme (or basic) values of λ1 and λ3. The arithmetic mean (for the color method) and the proportional mean (for the brightness method) are use dascoupling equations.","PeriodicalId":131530,"journal":{"name":"World Journal of Applied Physics","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125176226","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}

{"title":"Complex Dynamics of the Chua’s Circuit System with Adjustable Symmetry and Nonlinearity: Multistability and Simple Circuit Realization","authors":"N. Tsafack, J. Kengne","doi":"10.11648/j.wjap.20190402.12","DOIUrl":"https://doi.org/10.11648/j.wjap.20190402.12","url":null,"abstract":"Background: Since the invention of Chua’s circuit, numerous generalizations based on substitution of the nonlinear function have been reported. One of the generalizations is obtained by replacing the piecewise-linear with the cubic and/or quadratic polynomial. These nonlinearities are used to be implement using analog multipliers which are relatively expensive. In this realization we propose a different approach to synthetize both cubic and quadratic nonlinearities of empirical Chua’s circuit. Methods: The idea is to use diodes, Opamps and resistors to derive a PWL approximation of the cubic and quadratic functions. To demonstrate some complex phenomena observed in the system using the fourth order Runge-Kutta numerical integration method with a very small integration step. The bifurcation diagram which is the plot of local maxima of the temporal trace of a system’s coordinate as a function of the control parameter also constitutes an excellent tool for the study of dynamic systems. Results: The above mentioned standard nonlinear analysis tools have been exploited and it is found that the system with adjustable symmetry experiences a plethora of symmetric and asymmetric coexisting attractors. A particular feature of the system is related to the simplicity of the corresponding electronic analog circuit (no analog multiplier chip used to implement the cubic and quadratic nonlinearities). Conclusions: It is observed that the proposed Chua’s circuit system is more flexible (both symmetric and asymmetric) and displays complex dynamics behaviors of symmetric and asymmetric coexisting attractors. Note that this striking dynamic can be exploited in encryption algorithms.","PeriodicalId":131530,"journal":{"name":"World Journal of Applied Physics","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128026071","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}

{"title":"The Study of the Parameters that Affect the Performance of Suspension in HDD","authors":"Joompon Bamrungwong","doi":"10.11648/J.WJAP.20190402.11","DOIUrl":"https://doi.org/10.11648/J.WJAP.20190402.11","url":null,"abstract":"The suspension in a hard disk drive is a component of hard disk drives (HDD(s)) that commonly consist of three main components; Baseplate, Loadbeam and Gimbal, which are welded together. The suspension is attached to a slider fly on the surface of a rapidly spinning disk. The suspension assembly and slider that is formed is called a Head Gimbal Assembly (HGA). If that assembly is not attached to the slider, that is called a Trace Gimbal Assembly (TSA). Defects in the suspension may occur from machining and assembly. The aim of this research is to study the effect of suspension defects on the performance of the suspension resonance using a finite element method, whereby the suspension was created by SolidWorks and imported into Ansys in order to conduct resonance analysis. The results from finite element analysis compared with laser doppler velocimetry (LDV) found that the trend is the same. The suspension bias was revealed, in that Delta RG, welding diameter, program asymmetry, program asymmetry, tip height and tip twist influence the performance of the suspension may possibly come from the suspension production process. Obviously, this process needs to be controlled with regard to certain aspects, such as laser power, fixtures and so on. However, the swaging process in the head stack assembly might also have an impact tin tip height and tip twist.","PeriodicalId":131530,"journal":{"name":"World Journal of Applied Physics","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129319579","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}