[en] The thesis aims to improve the understanding and simulation of microcrack initiation induced by thermal fatigue and the induced crack network formation. The polycrystalline simulations allow the prediction of both macroscopic cyclic behavior and mean grain distributions of stress, plastic strain and number of cycles to microcrack initiation. Various aggregate meshes have been used, from the simplest ones using cubic grains up to a real 3D aggregate built thanks to many re-polishing and EBSD measurement sequences (Institut P', Poitiers). Tension-compression, cyclic shear and equi-biaxial loadings, with and without mean strain, have been considered. All the predictions are in qualitative agreement with many experimental observations obtained at various scales. The single crystal simulations allow us to predict the effect of slip localization in thin persistent slip bands (PSBs). Inside PSBs, vacancies are produced and annihilated because of cyclic dislocation interactions and may diffuse towards the surrounding matrix. This induces extrusion growth at the free surface of PSBs. Microcracking is modelled by cohesive zones located along the PSB - matrix interfaces. The predicted extrusion rates and numbers of cycles to microcrack initiation are in fair agreement with numerous experimental data concerning single and polycrystals, copper and 316L(N), under either air or inert environment. (author)

[en] The overall objective of this study was to compare the effects of Au/Fe and Fe nanoparticles on the growth and performance of Serratia Jl0300. The nanoparticle effect was quantified not only by the bacterial growth on agar plate after 1 hour interaction with the nanoparticles, but also by its production of a biosurfactant from used vegetable oil. The nanoparticles were prepared using the foam method. The concentrations of the nanoparticles used for the bacterial interaction study were varied from 1 mg/L to 1 g/L. The test results showed that the effect of nanoparticles on the bacterial growth and biosurfactant production varied with nanoparticle type, concentrations, and interaction time with the bacteria. Au/Fe nanoparticles didn't show toxicity to Serratia after short time (1 h) exposure, while during 8 days fermentation Au/Fe nanoparticles inhibited the growth of Serratia as well as the biosurfactant production when the concentration of the nanoparticles was higher than 10 mg/L. Fe nanoparticles showed inhibition effects to bacterial growth both after short time and long time interaction with Serratia, as well as to biosurfactant production when its concentration was higher than 100 mg/L. Based on the trends observed in this study, analytical models have been developed to predict the bacterial growth and biosurfactant production with varying concentrations of nanoparticles. - Highlights: • Modeled the effect of nanoparticles on the bacterial growth and biosurfactant production. • Effects of Au/Fe nonoparticles on Serratia Bacterial Growth and Production of Biosurfactant. • Scanning Electron Micrograph of bacteria-nanoparticles interaction

[en] Research on the Very Incomplete Meissner Effect has been pursued with the aim of learning whether monolithic high T_c superconductor materials can be developed to provide candidate magnets for external beam lines. Presently, materials exist to fabricate magnets of 1.5T, with materials for 3.0T probable within a year, and 6.0T possible in the future. Stability of the order of a few percent per year is readily attainable

[en] Measurements of thermal photons emitted from the rapidly expanding hot and dense medium (“Little Bang”) formed in ultra relativistic heavy-ion collisions, and their current theoretical interpretation, are reviewed

[en] Dye-sensitized solar cell with V_B group (vanadium (V), niobium (Nb) and tantalum (Ta)) doped TiO₂ prepared by hydrothermal method shows a higher photovoltaic efficiency compared with the undoped TiO₂. All the V_B doping shift the flat band potential positively and increase the doping density which is investigated by Mott–Schottky plot. The positive shift of flat band potential improves the driving force of injecting electron from the LUMO of dye to the conduction band of TiO₂ and the photocurrent. On the other hand, the increase of doping density accelerates transfer rate of electrons in TiO₂ than the un-doped, which is confirmed by intensity-modulated photocurrent. V-, Nb-, Ta-doped TiO₂ exhibited photovoltaic performance with 7.80%, 8.33%, 8.18%, respectively, compared with that of the cells based on pure TiO₂ (7.42%).

[en] In the design of intermediate heat exchanger (IHX) for demonstration fast reactor plant, the influence of flow induced vibration should be considered. The structure of the space elbow tube is a technical difficulty for inherent frequency calculation of IHX heat exchange tube. Inherent frequency of China Experimental Fast Reactor (CEFR) IHX heat exchange tube was calculated by using finite element method. Through the comparison and analysis, the reasonable calculation model and its applicable range are obtained. The design principle of tubes support is propounded by sensitive analysis. (authors)

[en] Highlights: • The 3D OMCs are prepared by nanocasting pathway and carbonized subsequently at different temperatures. • The synthesized technology is a crucial factor impacting the structure and characteristics of OMCs. • The OMC-600 exhibits ordered honeycomb-like structure, which is an inverse replica of KIT-6 template. - Abstract: 3D cubic-ordered mesoporous carbons (OMCs) are prepared by nanocasting approach using silica KIT-6 as the template, furfuryl alcohol as the carbon precursor and subsequently carbonized at the temperature of 500 °C, 600 °C and 700 °C. The physicochemical and electrochemical properties of the as-prepared OMCs are investigated by transmission electron microscopy (TEM), nitrogen adsorption/desorption isotherm, Fourier infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry, galvanostatic charge/discharge, electrochemical impedance spectroscopy (EIS) and cycle life measurement in 6 mol L"−"1 KOH electrolyte. The results demonstrate that the synthesized technology is a crucial factor impacting the characteristics of OMCs. With the change of carbonization temperature, the OMC-600 exhibits the honeycomb-like morphology with high specific surface area (1257.8 m"2 g"−"1), large pore volume (1.56 cm"3 g"−"1), and high capacitance of 221.8 F g"−"1 at the current density of 1 A g"−"1. In addition, the supercapacitor using OMC-600 as the active material shows high specific capacitance and excellent cycle stability, which exhibits a specific capacitance of 52.8 F g"−"1 at the charge/discharge current density of 0.5 A g"−"1. Moreover, the OMC-600 supercapacitor delivers high energy density of 6.53 Wh kg"−"1 at the power density of 5000 W kg"−"1, indicating a promising application for the high performance supercapacitors

[en] The mitochondrial calcium uniporter (MCU) transports free Ca"2"+ into the mitochondrial matrix, maintaining Ca"2"+ homeostasis, thus regulates the mitochondrial morphology. Previous studies have indicated that there was closely crosstalk between MCU and mitochondrial fission during the process of ischemia/reperfusion injury. This study constructed a hypoxia reoxygenation model using primary hippocampus neurons to mimic the cerebral ischemia/reperfusion injury and aims to explore the exactly effect of MCU on the mitochondrial fission during the process of ischemia/reperfusion injury and so as the mechanisms. Our results found that the inhibitor of the MCU, Ru360, decreased mitochondrial Ca"2"+ concentration, suppressed the expression of mitochondrial fission protein Drp1, MIEF1 and Fis1, and thus improved mitochondrial morphology significantly. Whereas spermine, the agonist of the MCU, had no significant impact compared to the I/R group. This study demonstrated that the MCU regulates the process of mitochondrial fission by controlling the Ca"2"+ transport, directly upregulating mitochondrial fission proteins Drp1, Fis1 and indirectly reversing the MIEF1-induced mitochondrial fusion. It also provides new targets for brain protection during ischemia/reperfusion injury. - Highlights: • We study MCU with primary neuron culture. • MCU induces mitochondrial fission. • MCU reverses MIEF1 effect

[en] Background: China experimental fast reactor (CEFR) is the first fast reactor in China, the piping designs are very important for the fast reactor. Purpose: The purpose is to improve the economy of pipeline design for the fast reactor. Methods: According to the optimization principles, redesign the support system of emergency decay heat removal system. Results: The piping of emergency decay heat removal system meets the ASME standard stress limit value under various prospective loads, and reduces the number of dampers, spring hangers. Conclusions: We accumulate layout experience for the support design of high temperature piping by the optimization design for emergency decay heat removal system, lay the foundation for the fast reactor piping design in the future. (authors)

[en] This paper aims to study the corrosion behavior of tetrafuloro-resin coatings in specialty gas by surface analysis and weight-loss method. The protection specialty gas corrosion ability to compound material,resin and aluminum metal alloy with tetrafuloro-resin coates was investigated. The strength properties of adhesive in shear by tension loading of tetrafuloro-resin coates on compound material was compared with the strength properties of adhesive in shear by tension loading of tetrafuloro-resin coates on aluminum metal alloy. The results showed that tetrafuloro-resin coates could endured specialty gas corrosion, air impermeability of tetrafuloro-resin coates was good, the adhesive strength of tetrafuloro-resin coates on compound material was high. This experiment method could also be used to evaluate the properties of other protection layeres on compound materials. (authors)