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| 1 | Relativistic polytropic models of charged anisotropic compact objects显示文摘In this paper,we introduce new viable solutions to the Einstein-Maxwell field equations by incorporating the features of anisotropic matter distributions within the realm of the general theory of relativity(GR).To obtain these solutions,we employed the Finch-Skea spacetime,along with a generalized polytropic equation of state( EoS).We constructed various models of generalized polytropes by assuming different values of the polytropic index,i.e.,η=1/2,2/3,1,and 2.Next,numerous physical characteristics of these considered models were studied via graphical analysis,and they were found to obey all the essential conditions for astrophysical compact objects.Furthermore,such outcomes of charged anisotropic compact star models could be reproduced in various other cases including linear,quadratic,and polytropic EoS. | H.Nazar M.Azam G.Abbas Riaz Ahmed R.Naeem | 2023 | Chinese Physics C2023，47，3： | 0 |
| 2 | Stability of Quark Star Models显示文摘In this paper,we investigate the stability of quark stars with four different types of inner matter configurations;isotropic,charged isotropic,anisotropic and charged anisotropic by using the concept of cracking.For this purpose,we have applied local density perturbations technique to the hydrostatic equilibrium equation as well as on physical parameters involved in the model.We conclude that quark stars become potentially unstable when inner matter configuration is changed and electromagnetic field is applied. | M.Azam S.A.Mardan M.A.Rehman | 2016 | Communications in Theoretical Physics2016，65，5： | 0 |
| 3 | Accretion onto the Magnetically Charged Regular Black Hole显示文摘We investigate the accretion process for static spherically symmetric geometry, i.e., magnetically charged regular black hole with isotropic fluid. We obtain generalized expressions for the velocity(u(r)), speed of sound(c_s^2),energy density(ρ(r)) and accretion rate(M) at the critical point near the regular black hole during the accretion process. We also plot these physical parameters against fixed values of charge, mass and different values of equation of state parameter to study the process of accretion. We find that radial velocity and energy density of the fluid remain positive and negative as well as rate of change of mass is increased and decreased for dust, stiff,quintessence fluid and phantom-like fluid, respectively. | M.Azam A.Aslam | 2017 | Chinese Physics Letters2017，34，7： | 0 |
| 4 | The Stability of Some Viable Stars and Electromagnetic Field显示文摘We examine the impact of electromagnetic field on the stability of compact stars corresponding' to embedded class one metric using the concept of cracking.For this purpose,we develop the generalized hydrostatic equilibrium equation for charged perfect fluid distribution of compact stars and perturb it by means of local density perturbation scheme to check the stability of inner matter configuration.We investigate the cracking of Her X-1,PSR 1937+21,PSR J 1614-2230,PSR J 0348+0432 and RX J 1856-37.We conclude that PSR J 0348+0432 and RX J 1856-37 exhibit cracking when charge is introduced on these astrophysical objects. | M.Azam S.A.Mardan M.A.Rehman | 2016 | Chinese Physics Letters2016，33，7： | 0 |
| 5 | Cost Effective Scheme for OLT in Next Generation Passive Optical Access Network Based on Noise Free Optical Multi Carrier显示文摘We propos e a cos t-effective multi-carrier generation technique which minimizes the passive optical access network(PON) costs. In this study replacement of laser array with multi-carrier source at optical line terminal(OLT) side in PON is addressed. With 25-GHz frequency spacing, the generated optical multi-carriers exhibit good tone to noise ratio(TNR) i. e. above 20 d B, and least amplitude difference i. e. 1.5d B. At the OLT, multi-carriers signal based multiplexed differential phase shift keying(DPSK) data from all the channels each having 10 Gbps for downlink is transmitted through 25 km single mode fiber. While the transmitted information is retrieved at optical network unit(ONU), part of the downlink signal is re-modulated using intensity modulated(IM) on-off keying(OOK) for upstream transmission at 10-Gbps. Simulation results are in good agreement with the theoretical analysis, showing error free transmission in downlink and uplink with 10 Gbps symmetric data rate at each channel. The receivedpower, both for uplink and downlink transmission, is adequate for all channels at BER of 10-9 with minimum power penalties. Power budget is calculated for different splitting ratios showing excellent system margins for any unseen losses. The proposed setup provides a cost-effective way minimizing transmission losses, and providing greater system's margin in PON architecture. | Rahat Ullah Bo Liu Qi Zhang Qinghua Tian Amjad Ali Yousaf Khan Feng Tian M.Azam Zia Haseeb Ahmad Lijia Zhang Xiangjun Xin | 2016 | China Communications2016，13，6： | 0 |
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