Crystalline and Spectroscopic Experimental Study of the Dinitromesithylen (DNM) Compared with the Theoretical Results

International audienceThe aim by our group is to understand the behavior of the grouping Me starting from the study of mols. having a great symmetry. In this part of work, it is had the cryst. structure of the dinitromesitylen (DNM) who is solved starting from the diffraction of x-​rays starting from a monocrystal at the ambient temp. Parallel to the exptl. study, we undertook theor. calcns. conformation of the insulated mol. of DNM by using the methods of the DFT (D. Functional Theory)​. Calcns. of optimization of the mol. conformation of the DNM by using the chain of program GAUSSIAN03 and functional MPW1PW91, B3LYP level with the 6-​311G and LANL2DZ bases gave a conformation Cs with results very close to the expt. for the lengths and the angles of bond. The computation results obtained starting from the base set (6-​311G) and functional MPW1PW91 give for the conformation of Dinitromesitylen (DNM) a good agreement of about a 1.9​% for the lengths of bond and 1.2​% for the angles of bond compared with the results of the diffraction of x-​rays. Calcns. of Raman and infra-​red spectroscopy undertaken starting from the results of optimization by using same functional MPW1PW91 and B3LYP and the sets of bases 6-​311G LanL2DZ led to the values of frequencies very close to the exptl. results

Synthesis growth and optical properties of semi organic non linear optical single crystal

A new and efficient semi organic nonlinear optical crystal from the amino acid family has been grown by slow evaporation technique from aqueous solution. The crystals structures were solved by direct methods using SIR92 (WINGX) and refined by a full matrix least-square method using SHELXL97. All this compounds crystallized in noncentrosymetric groups. Second harmonic generation measurements were performed by applying the Kurtz and Perry model, to powder samples of compounds at 1,064 nm

Early-onset breast cancer in a Lebanese family with Lynch syndrome due to MSH2 gene mutation

<p>Abstract</p> <p>Background</p> <p>There are still controversies about the integration of breast cancer as a part of the disease spectrum in Lynch syndrome.</p> <p>Methods</p> <p>A regular follow-up of a Lebanese pedigree with Lynch syndrome due to a point mutation of MSH2 gene at the splice donor site of intron 3 started in 1996.</p> <p>Results</p> <p>A 26-year-old pregnant woman, mutation carrier, developed an aggressive breast cancer, refractory to standard chemotherapy regimens. The microsatellite analysis of the tumor showed an unstable pattern for markers BAT25 and BAT26. The immunohistochemical staining was negative for MSH2 and MSH6 and normal for MLH1 and PMS6 enzymes.</p> <p>Conclusion</p> <p>The segregation of the mutation with the disease phenotype and these results suggest that MSH2 inactivation may be involved in the accelerated breast carcinogenesis and might be considered in the cancer screening program.</p

Моделювання впливу типу захисного кільця на електричні характеристики планарних кремнієвих детекторів типу n-on-p

Оновлення високоенергетичних фізичних експериментів на великому адронному коллайдері (LHC) у ЦЕРНі вимагатиме застосування нових випромінювальних технологій у наступних поколіннях пристроїв стеження, які будуть необхідні для витримування надзвичайно високих доз опромінення. Планарні піксельні датчики n-on-p є перспективними кандидатами і повинні бути реалізовані у майбутньому піксельному детекторі ATLAS. У роботі представлено порівняльне дослідження двох різних конструкцій багатозахисних структур до і після опромінення. Обидві структури засновані на технології підкладки p-типу з та без стопорної ізоляції між імплантами. Більш того, одна структура має захисні кільця p-типу, в той час як інша – n-типу. Для вивчення електричних характеристик конструкцій змінювалися різні технологічні параметри, такі як товщина і легування кремнієвої підкладки, глибина і легування захисних кілець, та товщина діоксиду кремнію. Ефективність багатозахисних кільцевих структур оцінюється за допомогою моделювання TCAD до флюенсу випромінювання 1×10+16 neq/см2 з використанням існуючої моделі об'ємного радіаційного пошкодження p-типу на основі так званої "Perugia tri level traps model", де опромінення генерує два акцепторних рівня, розташованих трохи вище середньої забороненої зони, і один донорний рівень, розташований трохи нижче середини забороненої зони. Ми розглянули збільшення кількості оксидного заряду з ростом дози опромінення. Для високоякісного шару SiO2 початкова щільність заряду на інтерфейсному шарі встановлювалася рівною 5×10+10 cm–2 для неопроміненого детектора, тоді як для сильно опроміненої структури значення щільності заряду може сягати 1×10+12 cm–2. Вони моделювалися на високоомних кремнієвих пластинах з використанням програмного забезпечення Silvaco Virtual Wafer Fab (VWF).The upgrades of high-energy physics experiments at the Large Hadron Collider (LHC) at CERN will call for new radiation hard technologies to be applied in the next generations of tracking devices that will be required to withstand extremely high radiation doses. N-on-p planar pixel sensors are promising candidates and to be implemented in the future ATLAS pixel detector. In this work, we present a comparative study for two different designs of multi-guard structures, before and after irradiation. Both structures are based on the p-type substrate technology with and without p-stop isolation between implants. Moreover, one structure has p-type guard rings while the other has n-type ones. Various technological parameters are varied like thickness and doping of the silicon substrate, depth and doping of the guard rings, and thickness of the silicon dioxide to study the electrical performances of the structures. The performance of the multi-guard ring structures are evaluated with TCAD simulations up to a radiation fluence of 1 x 1016 neq/cm2 using an existing p-type bulk radiation damage model based on the so called "Perugia three level traps model", where irradiation generates two acceptor levels, positioned slightly above the mid bandgap, and one donor level, located below the mid bandgap. We have considered an increasing amount of oxide charge with the irradiation dose. For a good quality SiO2 layer, an initial charge density at the interface layer was set to 5 x 1010 cm–2 for a non-irradiated detector, whereas for a heavily irradiated structure the charge density value can reach 1 x 1012 cm–2. They have been simulated on high resistivity silicon wafers using Silvaco Virtual Wafer Fab (VWF) software

Mechanism and Kinetics of Precipitation and Dissolution of GP Zone and Metastable Phase in Al-3wt% Cu Alloy

Thermal analysis techniques remain important tools amongst the large variety of methods used for analysis of the precipitation and dissolution of the Guinier-Preston zone and metastable phase θ' in Al-3wt% Cu. In the present study, the kinetics of precipitation and dissolution of the Guinier-Preston zone and metastable phase θ' in Al-3wt% Cu was investigated using differential scanning calorimetry carried out between room temperature and 430°C at heating rates of 20, 25, and 30°C min¯¹. The activation energies evaluated through isothermal differential scanning calorimetry treatment using the Johnson-Mehl-Avrami theory were 25, 100, and 80 kJ mol¯¹ for the Guinier-Preston zone precipitation, formation of θ'/θ and dissolution of θ', respectively. The Avrami constant n obtained by the Ligero method was about 1.5 for the formation of θ'/θ indicating that bulk nucleation is dominant in θ'/θ formation controlled by diffusion from a constant number of nuclei

The effect of thickness on the physico-chemical properties of nanostructured ZnO:Al TCO thin films deposited on flexible PEN substrates by RF-magnetron sputtering from a nanopowder target

International audienceNanostructured aluminum-doped ZnO (ZnO:Al) thin films of various thicknesses were deposited on flexible Poly-Ethylene Naphthalate (PEN) substrates by RF-magnetron sputtering without intentionally heating them to fabricate Transparent Conductive Oxides (TCOs). The compacted ZnO:Al nanopowder with an [Al]/[Zn] ratio of 2%, which was synthesized by the sol-gel method combined with a supercritical drying process, was used as target in the sputtering system. The structural, morphological, optical and electrical properties of the deposited thin films of various thicknesses have been investigated. X-ray diffraction results indicate that all of the deposited thin films have a hexagonal wurtzite structure with c-axis orientation without any secondary phases. The Scanning Electron Microscopy (SEM) cross section images revealed that the films have a dense columnar nanostructure. The atomic percentage of the compositional elements in the films was nearly the same as that in the sputtering nanopowder target. Below a critical thickness of 500 nm, the films exhibit a high transmittance (>77% including the contribution of the PEN substrate) in the visible region. However, the electrical resistivity, Hall mobility and carrier concentration were significantly affected with the increase of film thickness. For thicknesses higher than 500 nm, the thin films exhibit similar electrical properties (resistivity of 3.5×10−4 Ω cm and Hall mobility of 22 cm2 V−1 s−1) but the transmittance decreases in the visible region. The Photoluminescence spectra showed that the Zn interstitial atoms, which enhance the conductivity of the films, are more dominant than the other defects