In this work, a computer optimization model has been developed that allows one to load the initial data of observations of supernovae 1a into a table and, in simple steps, by searching for the best fit between observa...In this work, a computer optimization model has been developed that allows one to load the initial data of observations of supernovae 1a into a table and, in simple steps, by searching for the best fit between observations and theory, obtain the values of the parameters of cosmological models. The optimization is carried out assuming that the absolute magnitude of supernovae is not constant, but evolves with time. It is assumed that the dependence of the absolute magnitude on the redshift is linear: M = M( z = 0) + ε<sub>c </sub>z, where ε<sub>c</sub> is the evolution coefficient of the absolute magnitude of type 1a supernovae. In the case of a flat universe ( Ω<sub>M</sub> + Ω<sub>Λ</sub> = 1 ), the best fit between theory and observation is εc </sub>= 0.304. In this case, for the cosmological parameters we obtain Ω<sub>Λ</sub> = 0.000, Ω<sub>M</sub><sub></sub> =1.000. Naturally, this result exactly coincides with the simulation result for the model with zero cosmological constant ( εc</sub> = 0.304, q<sub>0</sub> = 0.500 ). Within the framework of the ΛCDM model, without restriction on space curvature ( Ω<sub>M</sub> + Ω<sub>Λ</sub>+ Ω<sub>K</sub><sub></sub> = 1 ), we obtain the following values: εc</sub> </sub>= 0.304, ΩΛ</sub> = 0.000, ΩM </sub>= 1.000, Ω<sub>K</sub></sub></sub></sub> =0.000. Those, this case also leads to a flat model of the Universe ( Ω<sub>K</sub><sub></sub></sub></sub> =0.000 ). In this work, the critical influence of the absolute magnitude M of type 1a supernovae on the cosmological parameters is also shown. In particular, it was found that a change in this value by only 0.4<sup>m </sup>(from -19.11 to -18.71) leads to a change in the parameters from ΩΛ</sub> = 0.7 and ΩM</sub></sub> = 0.3 to ΩΛ</sub> = 0 and ΩM</sub> =1.展开更多
The parallel scaling (parallel performance up to 48 cores) of NAMD package has been investigated by estimation of the sensitivity of interconnection on speedup and benchmark results—testing the parallel performance o...The parallel scaling (parallel performance up to 48 cores) of NAMD package has been investigated by estimation of the sensitivity of interconnection on speedup and benchmark results—testing the parallel performance of Myrinet, Infiniband and Gigabit Ethernet networks. The system of ApoA1 of 92 K atoms, as well as 1000 K, 330 K, 210 K, 110 K, 54 K, 27 K and 16 K has been used as testing systems. The Armenian grid infrastructure (ArmGrid) has been used as a main platform for series of benchmarks. According to the results, due to the high performance of Myrinet and Infiniband networks, the ArmCluster system and the cluster located in the Yerevan State University show reasonable values, meanwhile the scaling of clusters with various types of Gigabit Ethernet interconnections breaks down when interconnection is activated. However, the clusters equipped by Gigabit Ethernet network are sensitive to change of system, particularly for 1000 K systems no breakdown in scaling is observed. The infiniband supports in comparison with Myrinet, make it possible to receive almost ideally results regardless of system size. In addition, a benchmarking formula is suggested, which provides the computational throughput depending on the number of processors. These results should be important, for instance, to choose most appropriate amount of processors for studied system.展开更多
This paper theoretically studies the impurity states and the effects of impurity concentration and configuration on the optical,electrical,and statistical properties of CdSe nanoplatelets(NPLs).An image charge-based m...This paper theoretically studies the impurity states and the effects of impurity concentration and configuration on the optical,electrical,and statistical properties of CdSe nanoplatelets(NPLs).An image charge-based model of electron-impurity interaction is proposed.The charge-carrier energy spectra and corresponding wave functions depending on the impurity number and configuration are calculated.The electron binding energies are calculated for different NPL thicknesses.It is shown that the image charge-based interaction potential that arises due to the dielectric constants mismatch is much stronger than the interaction potential that does not take such a mismatch into account.Also,it is demonstrated that the binding energies are increasing with the number of impurities.We calculate the canonical partition function using the energy levels of the electron,which in turn is used to obtain the mean energy,heat capacity,and entropy of the non-interacting electron gas.The thermodynamic properties of the non-interacting electron gas that depend on the geometric parameters of the NPL,impurity number,configuration,and temperature are studied.展开更多
文摘In this work, a computer optimization model has been developed that allows one to load the initial data of observations of supernovae 1a into a table and, in simple steps, by searching for the best fit between observations and theory, obtain the values of the parameters of cosmological models. The optimization is carried out assuming that the absolute magnitude of supernovae is not constant, but evolves with time. It is assumed that the dependence of the absolute magnitude on the redshift is linear: M = M( z = 0) + ε<sub>c </sub>z, where ε<sub>c</sub> is the evolution coefficient of the absolute magnitude of type 1a supernovae. In the case of a flat universe ( Ω<sub>M</sub> + Ω<sub>Λ</sub> = 1 ), the best fit between theory and observation is εc </sub>= 0.304. In this case, for the cosmological parameters we obtain Ω<sub>Λ</sub> = 0.000, Ω<sub>M</sub><sub></sub> =1.000. Naturally, this result exactly coincides with the simulation result for the model with zero cosmological constant ( εc</sub> = 0.304, q<sub>0</sub> = 0.500 ). Within the framework of the ΛCDM model, without restriction on space curvature ( Ω<sub>M</sub> + Ω<sub>Λ</sub>+ Ω<sub>K</sub><sub></sub> = 1 ), we obtain the following values: εc</sub> </sub>= 0.304, ΩΛ</sub> = 0.000, ΩM </sub>= 1.000, Ω<sub>K</sub></sub></sub></sub> =0.000. Those, this case also leads to a flat model of the Universe ( Ω<sub>K</sub><sub></sub></sub></sub> =0.000 ). In this work, the critical influence of the absolute magnitude M of type 1a supernovae on the cosmological parameters is also shown. In particular, it was found that a change in this value by only 0.4<sup>m </sup>(from -19.11 to -18.71) leads to a change in the parameters from ΩΛ</sub> = 0.7 and ΩM</sub></sub> = 0.3 to ΩΛ</sub> = 0 and ΩM</sub> =1.
文摘The parallel scaling (parallel performance up to 48 cores) of NAMD package has been investigated by estimation of the sensitivity of interconnection on speedup and benchmark results—testing the parallel performance of Myrinet, Infiniband and Gigabit Ethernet networks. The system of ApoA1 of 92 K atoms, as well as 1000 K, 330 K, 210 K, 110 K, 54 K, 27 K and 16 K has been used as testing systems. The Armenian grid infrastructure (ArmGrid) has been used as a main platform for series of benchmarks. According to the results, due to the high performance of Myrinet and Infiniband networks, the ArmCluster system and the cluster located in the Yerevan State University show reasonable values, meanwhile the scaling of clusters with various types of Gigabit Ethernet interconnections breaks down when interconnection is activated. However, the clusters equipped by Gigabit Ethernet network are sensitive to change of system, particularly for 1000 K systems no breakdown in scaling is observed. The infiniband supports in comparison with Myrinet, make it possible to receive almost ideally results regardless of system size. In addition, a benchmarking formula is suggested, which provides the computational throughput depending on the number of processors. These results should be important, for instance, to choose most appropriate amount of processors for studied system.
基金funded by the RA Science Committee as part of a‘Leading scientific research support program’within the framework of research project 21AG-1C022。
文摘This paper theoretically studies the impurity states and the effects of impurity concentration and configuration on the optical,electrical,and statistical properties of CdSe nanoplatelets(NPLs).An image charge-based model of electron-impurity interaction is proposed.The charge-carrier energy spectra and corresponding wave functions depending on the impurity number and configuration are calculated.The electron binding energies are calculated for different NPL thicknesses.It is shown that the image charge-based interaction potential that arises due to the dielectric constants mismatch is much stronger than the interaction potential that does not take such a mismatch into account.Also,it is demonstrated that the binding energies are increasing with the number of impurities.We calculate the canonical partition function using the energy levels of the electron,which in turn is used to obtain the mean energy,heat capacity,and entropy of the non-interacting electron gas.The thermodynamic properties of the non-interacting electron gas that depend on the geometric parameters of the NPL,impurity number,configuration,and temperature are studied.
