مدونة الموقع

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In this short paper, we present an interesting and welcome connection between two different approaches to the mathematical structure of the standard genetic code, we have considered in the last years. The first one relies on the use of the unique number 23! and the second is based on the atomic composition of the four ribonucleotides UMP, CMP, AMP and GMP, the building-blocks of RNA, where several Fibonacci numbers are seen to occur.

[ تم التعديل: الجمعة، 29 مايو 2020، 10:48 PM ]
 
Ahmed BENDRIS
بواسطة الجمعة، 15 مايو 2020، 4:48 AM - Ahmed BENDRIS
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محاضرات مقياس مخبر السمعي البصري  ماستر السداسي الثاني تخصص سمعي بصري   الدكتور بن دريس أحمد

عزيزي الطالب تجد في الملف المدرج أسفله ملخص عن محاضرات المقياس إضافة للمحاضرات التي قمنا بتقديمها قبل الحجر

وفقك الله 

[ تم التعديل: الجمعة، 9 فبراير 2024، 7:30 PM ]
 
بواسطة الاثنين، 11 مايو 2020، 2:10 PM - SALIH HACINI
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TD  Halogénation

 
بواسطة الاثنين، 11 مايو 2020، 12:24 PM - SALIH HACINI
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Chapitre III  Halogénation

Partie III

 
بواسطة الاثنين، 11 مايو 2020، 12:22 PM - SALIH HACINI
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Chapitre III  Halogénation

Partie I

 
Kheira Zineb BOUSMAHA
بواسطة السبت، 9 مايو 2020، 10:25 PM - Kheira Zineb BOUSMAHA
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exercices sur la récursivité

 
Kheira Zineb BOUSMAHA
بواسطة السبت، 9 مايو 2020، 10:20 PM - Kheira Zineb BOUSMAHA
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corrigé détaillé de l'exo1 et l'exo2 de la fiche sur la récursivité

 
بواسطة السبت، 9 مايو 2020، 3:04 PM - Douniazad ElAbed
أي شخص بالعالم
[ تم التعديل: السبت، 9 مايو 2020، 3:12 PM ]
 
أي شخص بالعالم
Abstract
Feynman–Hibbs corrections in molecular dynamics computer calculations of solid C60 are implemented within the classical effective pair potential approach. The potential model chosen for the site–site interactions is of the Buckingham exp-6 type (Rigby 1986 The Forces Between Molecules (New York: Oxford University Press)), fitted to the Cheng and Klein or the Kitaïgorodsky potential. Structural and thermodynamic properties of the C60 crystal lattice are investigated over a wide range of pressures and temperatures, and data obtained are compared to experimental results and those obtained from a classical approach (Baameur et al 2000 Phys. Status Solidi 220 821). It will be demonstrated that 'quantum corrections' applied in a simple quasi-classical simulations have a great influence upon most calculated properties and increase their accuracy when compared to classical approaches. The observed transition pressure with the distorted lattice and cell contraction compares favourably well with experimental data and equation of state calculations. All measured properties are reported together with the phonon density of states at different pressures.
 
أي شخص بالعالم
Abstract
Quantum mechanical studies were carried out in order to understand and describe the nature and strength of the hydrogen bond topology in three dimensional water cluster systems (H2O)n, in the size range 6–20 molecules. Optimal structures and vibrational frequencies of cage like water clusters are computed at the Hartree–Fock (HF) and the electronic density functional theory (DFT) level of theory with a detailed data analysis. Theoretical results are compared to experimental data when available. The general tendency is a decrease of the global minimum energy as the cluster size increases. The nearest neighbour separation between oxygen atoms decreases exponentially when the cluster size increases. The present work suggests that DFT results are in a good agreement with the corresponding HF data, however slight differences remain with regard to values of the nearest neighbour separation between oxygen atoms. The Morokuma’s decomposition of the total interaction energy performed on two and three-dimensional clusters lead to a better understanding of the cluster formation with a strong polarization energy component.