American Journal of Modern Physics最新文献

{"title":"Best Performance of n+ - p Crystalline Silicon Junction Solar Cells at 300 K, Due to the Effects of Heavy Doping and Impurity Size. I","authors":"H. V. Cong, P. Blaise, O. Henri-Rousseau","doi":"10.11648/J.AJMP.20190802.12","DOIUrl":"https://doi.org/10.11648/J.AJMP.20190802.12","url":null,"abstract":"The effects of heavy doping and donor (acceptor) size on the hole (electron)-minority saturation current density JEo(JBo), injected respectively into the heavily (lightly) doped crystalline silicon (Si) emitter (base) region of n+ - p junction, which can be applied to determine the performance of solar cells, being strongly affected by the dark saturation current density: Jo≡JEo + JBo, were investigated. For that, we used an effective Gaussian donor-density profile to determine JEo, and an empirical method of two points to investigate the ideality factor n, short circuit current density Jsc, fill factor (FF), and photovoltaic conversion efficiency η, expressed as functions of the open circuit voltage Voc, giving rise to a satisfactory description of our obtained results, being compared also with other existing theoretical-and-experimental ones. So, in the completely transparent and heavily doped (P-Si) emitter region, CTHD(P-Si)ER, our obtained JEo-results were accurate within 1.78%. This accurate expression for JEo is thus imperative for continuing the performance improvement of solar cell systems. For example, in the physical conditions (PCs) of CTHD (P-Si) ER and of lightly doped (B-Si) base region, LD(B-Si)BR, we obtained the precisions of the order of 8.1% for Jsc, 7.1% for FF, and 5% for η, suggesting thus an accuracy of JBo (≤ 8.1%). Further, in the PCs of completely opaque and heavily doped (S-Si) emitter region, COHD(S-Si)ER, and of lightly doped (acceptor-Si) base region, LD(acceptor-Si)BR, our limiting η-results are equal to: 27.77%,…, 31.55%, according to the Egi-values equal to: 1.12eV ,…, 1.34eV, given in various (B,…, Tl)-Si base regions, respectively, being due to the acceptor-size effect. Furthermore, in the PCs of CTHD (donor-Si) ER and of LD(Tl-Si)BR, our maximal η-values are equal to: 24.28%,…, 31.51%, according to the Egi-values equal to: 1.11eV ,…, 1.70eV, given in various (Sb,…, S)-Si emitter regions, respectively, being due to the donor-size effect. It should be noted that these obtained highest η-values are found to be almost equal, as: 31.51%%≃31.55%, coming from the fact that the two obtained limiting J_o-values are almost the same.","PeriodicalId":7717,"journal":{"name":"American Journal of Modern Physics","volume":"10 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72853062","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":"Ions Beam Properties Produced by NX2 Plasma Focus Device with Helium and Nitrogen Gas","authors":"Sahyouni Walid, Nassif Alaa","doi":"10.11648/J.AJMP.20190801.11","DOIUrl":"https://doi.org/10.11648/J.AJMP.20190801.11","url":null,"abstract":"Numerical experiments carried out using the Lee code to study some properties of ions beam (flux, fluence and ion beam energy) produced by the NX2 dense plasma device when using light gas (helium) and heavy gas (nitrogen) when gas pressure changes. The results showed that in the case of light gas (helium), the flux and fluence of the beam were higher while the ion beam energy was higher in the case of heavy gas (nitrogen) because the effective charge of nitrogen's ion is greater and also the voltage generated by the collapse of pinch was higher.","PeriodicalId":7717,"journal":{"name":"American Journal of Modern Physics","volume":"42 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74667198","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 Vacancy Cluster Tubes Formation and Metal Properties Changes After Dynamic Centrifugal Casting","authors":"Y. Tarasov, V. Kryachko, V. Novikov","doi":"10.11648/J.AJMP.20180706.11","DOIUrl":"https://doi.org/10.11648/J.AJMP.20180706.11","url":null,"abstract":"Presents experimental results of Al and Pb metals crystallization carried out under high intensity plastic deformation (HIPD) [e′ = (102–104) sec-1] reaching the level of so called «solid-liquid» state in the new type of centrifugal casting device at rotor speeds of up to 2000 rpm. Using the method of atomic force microscopy (AFM), vacancy cluster tubes (VCT) with average diameters of 39 nm for Al and 25 nm for Pb have been detected in the crystallized volume of Al and Pb metals. Physical model of the formation of a new substructure within the metals in the form of vacancy cluster tubes, received in the process of high-intensive plastic deformation (HIPD) during the process of mass crystallization of Al and Pb melts, and, also the changes in the mechanical, magnetic and superconducting properties of the above metals, which followed this process. When crystallizing Al and Pb under high-intensive plastic deformation (HIPD) of e′ = (102–104) per second type, in high-speed centrifugal casting devices, specially selected modes of metal crystallization are being chosen and special conditions are being created to achieve the dimensional effect of dynamic (shift) re-crystallization. Shift deformation during centrifugal crystallization is caused primarily by a large incline of the temperature field from the periphery (relative to the cold wall of the rotor) to the molten central part of the rotor. The difference in the angular movement velocities of the already-frozen part of the metal (adjacent to the outer surface of the rotor wall) and the central part, where the metal still remains in the molten state, leads to a high-intensity deformation [e′ = (102–104) sec-1] of the crystallized metal melt solidified phase. Since the grain sizes at the crystallized phase initially comprise around tens of nano-meters (approximately crystal nucleation size), it becomes possible to achieve the dimensional effect of the dynamic re-crystallization of a «nanocrystalline» solidified metal at high shift of strain velocities. The «non-equilibrium vacancies» formed this way condense into vacancy clusters, which are formed in the centrifugal force field in the form of vacancy-shaped cluster tubes stretched out to the center of rotation of the rotor. The process undergoes conditions that are considerably different from the «equilibrium» conditions as compared to the ordinary metal crystallization from the melt. Such processes can lead to the formation of highly ordered non-equilibrium states characteristic of non-equilibrium open systems.","PeriodicalId":7717,"journal":{"name":"American Journal of Modern Physics","volume":"66 1","pages":"194"},"PeriodicalIF":0.0,"publicationDate":"2019-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75279521","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":"Nitrogen Soft X-Ray Yield Optimization from UNU/ICTP PFF Plasma Focus Device","authors":"W. Sahyouni, Alaa Nassif","doi":"10.11648/J.AJMP.20190806.12","DOIUrl":"https://doi.org/10.11648/J.AJMP.20190806.12","url":null,"abstract":"The aim of this research studying soft x-ray emission from United Nations University/International Centre for Theoretical Physics Plasma Fusion Facility (UNU/ICTP PFF) plasma focus device with nitrogen gas pressure changes and find the maximum value of soft x-ray yield by using the standard parameters of device and do optimization to obtain the combination of pressure and electrodes dimensions that gives the maximum value of soft x-ray yield. Many numerical experiments were carried out using Lee code and obtained the maximum value of soft x-ray yield 0.193J at pressure 1.9 Torr by using the standard parameters of device. We optimized the device and found the optimum combination of pressure and electrode dimensions (P0 = 0.5 Torr, z0 = 9 cm, a = 3.19 cm, b = 3.2 cm,) that gives the maximum value of soft x-ray yield Ysxr = 2.7 J without changing the energy of the device.","PeriodicalId":7717,"journal":{"name":"American Journal of Modern Physics","volume":"80 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82273026","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":"Implementation of the 8-Nucleon Yakubovsky Formalism for Halo Nucleus 8He","authors":"E. Ahmadi Pouya, Ali Akbar Rajabi","doi":"10.11648/j.ajmp.20190803.12","DOIUrl":"https://doi.org/10.11648/j.ajmp.20190803.12","url":null,"abstract":"","PeriodicalId":7717,"journal":{"name":"American Journal of Modern Physics","volume":"22 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72929983","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":"Architecture of an Education and Research Network: Case of TogoRER","authors":"Eyouléki Tcheyi Gnadi Palanga","doi":"10.11648/j.ajmp.20190801.12","DOIUrl":"https://doi.org/10.11648/j.ajmp.20190801.12","url":null,"abstract":"","PeriodicalId":7717,"journal":{"name":"American Journal of Modern Physics","volume":"75 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87042746","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 Effect of Super-Radiance on the C-A Transition of the Excimer Molecule XeCl* at 352 nm Excited Only by 235U Fission Fragments","authors":"Aleksey Iustinovich Mis’kevich, Jin Bo Guo, Yurii Alekseevich Duyzhov, Anton Viktorovich Podkopaev","doi":"10.11648/j.ajmp.20190802.11","DOIUrl":"https://doi.org/10.11648/j.ajmp.20190802.11","url":null,"abstract":"","PeriodicalId":7717,"journal":{"name":"American Journal of Modern Physics","volume":"340 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82955009","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":"Kinetic Modelling of Atmospheric Pressure Nitrogen Plasma","authors":"M. Rahman, Mohammed Mynuddin","doi":"10.11648/J.AJMP.20180705.13","DOIUrl":"https://doi.org/10.11648/J.AJMP.20180705.13","url":null,"abstract":"This model describes the production and destruction mechanism of nitrogen plasma at atmospheric pressure. We have studied the mechanisms of chemical dissociation, ionization, ion conversion and recombination in nitrogen plasmas, with kinetic temperature ( T g ) of the free electrons being higher than the kinetic temperature ( T g ) of heavy species. Therefore, the investigation of nitrogen plasma species in a wide range of pressure from 1 Torr to 760 Torr is interesting phenomena for obtaining the equilibrium state when the nitrogen species breakdown. In order to calculate the species densities to reach thermodynamic equilibrium under various conditions, a set of chemical kinetic reactions of nitrogen under consideration have been simulated. It solves the particle balance equations for a set of interacting species. In this study 16 reactions and 4 species of Nitrogen N, N 2 , N + , N 2 + and electron have been considered. The densities of the charged and neutral species are modeled by continuity equations which includes the relevant plasma-chemical kinetics. Nitrogen species density is guided by continuity equation where chemical processes and Arrhenius form are used to follow the change of species density over the time. To calculate the species densities over pressure, temperature and time the continuity equations of the 16 reactions for the 5 species under consideration giving their initial pressure, densities and temperatures, with the latter held constant have been solved. The variations of species densities have been investigated as a function of pressure ranging from 1 to 760 Torr. This model shows that as the pressure is increased the species densities of nitrogen plasma also increase from pressure 1 to 200 Torr and after pressure above 200 Torr the species densities become almost saturated. The change of species densities at various temperatures ranging from 2000 Kelvin to 25000 Kelvin is successfully investigated. The destruction and production rates of the nitrogen species also have been calculated within the time ranging from 0 to 19nS and it shows that the density of nitrogen plasma increases with time. In our study we have considered the gas and electron temperature as 10k Kelvin and 4eV respectively.","PeriodicalId":7717,"journal":{"name":"American Journal of Modern Physics","volume":"5 1","pages":"185"},"PeriodicalIF":0.0,"publicationDate":"2018-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84450652","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":"Quantum Zeno Effect and Atomic Population Inversion","authors":"Jiu-Ming Li, Bo-Ying Zhang, Xue-qun Yan","doi":"10.11648/J.AJMP.20180705.12","DOIUrl":"https://doi.org/10.11648/J.AJMP.20180705.12","url":null,"abstract":"Quantum Zeno effect can be applied to quantum information processing，and can reveal the nature of quantum measurement. In addition, it has also many potential applications. This suggests that studying the quantum Zeno effect has great theoretical and experimental significance. In this work, the system of a two-level atom interacting with a single mode field is considered and the dynamics of the system subjected to successive projection measurements is studied, and the quantum Zeno effect is presented. Moreover, the influence of the quantum Zeno effect on atomic population inversion is discussed. Based on Schrodinger equation, the survival probability of the initial state of the two-level atom subjected to frequently repeated measurements can be obtained. The survival probability depends on the time interval between measurements. It is seen that the exponential decay of the system under slowly frequent measurements is presented instead of the naturally oscillatory process. For slowly repeated measurements the atomic population inversion and the survival probability of initial state decline rapidly at the early time and then both of them become unchanged. As the time intervals of the measurements are sufficiently short, the quantum Zeno effect occurs. These results have also shown how the measurement can inhibit the atomic population inversion.","PeriodicalId":7717,"journal":{"name":"American Journal of Modern Physics","volume":"66 1","pages":"180"},"PeriodicalIF":0.0,"publicationDate":"2018-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77284076","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 Pulse Energy on the Optical Properties of ZnS Thin Films Prepared Using Pulse Laser Technique","authors":"K. M. Haroun, M. Abdalla, S. S. Elwakeel, Yousif Hassan Alsheikh Abd Alraheim","doi":"10.11648/J.AJMP.20180705.11","DOIUrl":"https://doi.org/10.11648/J.AJMP.20180705.11","url":null,"abstract":"In these work four samples of ZnS thin films deposited on glass substrate using pulse laser deposition method with different pulse energies, the effect of the laser pulse energy on the optical properties of the four ZnS thin films fabricated was studied. Q-Switched Nd: YAG laser with the fundamental wavelength 1064 nm, laser Pulse energies of (125, 150, 175, and 200) mj with fixed number of pulses of 20, and pulse repetition rate of 5 Hz were used. The target to the substrate distance and angle were kept fixed. The film thicknesses were measured using FESEM measurement tool. The thickness of the deposited ZnS thin films was found to be linearly dependent on the pulse energy used. The transmission spectra in the tested region (532 to 915) nm were found to be in the range from 0.41 to 0.59% depending on the ZnS thin film thickness, and for each ZnS thin film the transmission spectrum is unique. The refractive indices of all samples were determined; and for each sample and it were found to change with wavelength, the highest refractive index of 5.6 at 915 nm was obtained for the sample of the smallest thickness 0.49 microns. Transmission spectra, absorption coefficients and the refractive indices they were in good agreement with the literature.","PeriodicalId":7717,"journal":{"name":"American Journal of Modern Physics","volume":"70 1","pages":"173"},"PeriodicalIF":0.0,"publicationDate":"2018-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81804951","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}