Thermal fatigue crack networks parameters and stability: an experimental study

A thermal fatigue device––called SPLASH––similar to the facility developed by Marsh [Fatigue crack initiation and propagation in stainless steels subjected to thermal cycling, International Conference on Mechanical Behaviour and Nuclear Applications of Stainless Steels at Elevated Temperature, 1981] has been built in CEA/SRMA in 1985. Since then, it was used mostly on austenitic stainless steels to assess the initiation and growth of thermal fatigue crack networks. In 1998, a leak appeared in an auxiliary loop of the primary circuit of a pressurized water nuclear plant in Civaux (France). Thermal fatigue was suspected and studies began on AISI 304 L type austenitic stainless steel. They were eventually compared to results obtained earlier on AISI 316 L(N). First, the initiation conditions were determined and the damage before initiation was qualitatively observed. Then, some crack networks parameters were chosen and quantitatively determined by image analysis. This part of the study was done at the surface, during crack growth, and at the end of the tests, in depth. Finally, the stability of the crack networks obtained by thermal fatigue was tested under isothermal load controlled four point bending fatigue test, and some conclusions were drawn on the mechanisms of propagating crack selection.     

Molecular vibrations and force fields of alkyl sulfides—XIV. Infrared spectra of ethyl isopropyl,propyl isopropyl,butyl isopropyl and diisopropyl sulfides

Infrared spectra of ethyl isopropyl and propyl isopropyl sulfides were examined in the liquid and glassy states, and those of butyl isopropyl and diisopropyl sulfides were observed in the liquid and crystalline solid states. The spectra observed were assigned. Normal coordinates were treated. We have then discussed on the rotational isomers and molecular conformations for these sulfides.     

丝网印刷法制备高催化活性对电极

对电极在染料敏化太阳能电池（DSCs）中主要起催化氧化还原反应及收集电荷的作用,铂对电极常用的制备方法为磁控溅射法,但其成本较高,制备条件苛刻. 本文通过引入低成本的表面活性剂Span-85,所制得的铂对电极的附着力、透光率和均匀性显著改善,实现了面积可控,与两步浸泡法和旋涂热解法制备的对电极在DSCs中的光电转换效率分别为7.30%,6.96%和7.03%. 紫外-可见吸收光谱、扫描电镜和附着力测试等结果表明,（1）添加表面活性剂有利于增加附着力及改善透光率和均匀性;（2）使用该法制备的Pt/FTO对电极的透光率与两步浸泡法制作的相同,且铂粒子分布更加均匀. 电化学阻抗图谱、塔菲尔极化曲线和循环伏安曲线结果表明,丝网印刷方法制备的Pt/FTO对电极具有更加优异的催化性能,且该法更有利于降低其生产成本和大规模生产.     

Effects of hydrogen flux on the properties of Al-doped ZnO films sputtered in Ar + H2 ambient at low temperature

Al-doped ZnO (AZO) transparent conductive thin films were grown by magnetron sputtering with AZO (98 wt.% ZnO, 2 wt.% Al₂O₃) ceramic target in Ar + H₂ ambient at a relatively low temperature of 100 °C. To investigate the dependence of crystalline and properties of as-grown AZO films on the H₂-flux, X-ray diffraction (XRD), X-ray photoemission spectrometer (XPS), Hall and transmittance spectra measurements were employed to analyze the AZO samples deposited with different H₂-flux. The results indicate that H₂-flux has a considerable influence on the transparent conductive properties of AZO films. The resistivity of 4.15 × 10⁻⁴ Ω cm and the average transmittance of more than 94% in the visible range were obtained with the optimal H₂-flux of 1.0 sccm. Such a low temperature growing method present here may be especially useful for some low-melting point photoelectric devices and substrates.     

Behavior of CO2/water flow in porous media for CO2 geological storage

A clear understanding of two-phase fluid flow properties in porous media is of importance to CO₂ geological storage. The study visually measured the immiscible and miscible displacement of water by CO₂ using MRI (magnetic resonance imaging), and investigated the factor influencing the displacement process in porous media which were filled with quartz glass beads. For immiscible displacement at slow flow rates, the MR signal intensity of images increased because of CO₂ dissolution; before the dissolution phenomenon became inconspicuous at flow rate of 0.8 mL min^− 1. For miscible displacement, the MR signal intensity decreased gradually independent of flow rates, because supercritical CO₂ and water became miscible in the beginning of CO₂ injection. CO₂ channeling or fingering phenomena were more obviously observed with lower permeable porous media. Capillary force decreases with increasing particle size, which would increase permeability and allow CO₂ and water to invade into small pore spaces more easily. The study also showed CO₂ flow patterns were dominated by dimensionless capillary number, changing from capillary finger to stable flow. The relative permeability curve was calculated using Brooks-Corey model, while the results showed the relative permeability of CO₂ slightly decreases with the increase of capillary number.     

Development of a simple and stability-indicating RP-HPLC method for determining olanzapine and related impurities generated in the preparative process

A simple and stability-indicating reverse phase high performance liquid chromatographic (RP-HPLC) method was developed and validated for the determination of olanzapine (OLN) and related impurities in bulk drugs. Eight impurities were characterized respectively, and particularly a new process impurity from OLN synthesis was structurally confirmed as 1-(5-methylthionphen-2-yl)-1H-benzimidazol-2(3H)-one (Imp-7) by X-ray single crystal diffraction, MS, (1)H NMR, (13)C NMR and HSQC. A mechanism of formation pathway for Imp-7 was proposed. Optimum separation for OLN and eight related impurities was carried out on an Agilent Octyldecyl silica column (TC-C(18), 4.6 mm × 250 mm, 5 μm) using a gradient HPLC method. The method was validated with respect to specificity, linearity, accuracy, precision, LOD and LOQ. Regression analysis showed good correlation (r(2) > 0.9985) between the investigated component concentrations and their peak areas within the test ranges for OLN and eight impurities. The repeatability and intermediate precision, expressed as RSD, were less than 1.74%. The proposed stability-indicating method was suitable for routine quality control and drug analysis of OLN in bulk drugs.     

Separation of Liquiritin by simulated moving bed chromatography

Liquiritin was extracted from the natural product Licorice, and then purified using a three-zone simulated moving bed set up in our laboratory, with a C(18)-bonded silica as the stationary phase and an aqueous solution of ethanol as the mobile phase. The isotherm parameters of Liquiritin and of the only closely eluting impurity were obtained using the inverse method, fitting the experimental elution profiles to calculated elution profiles, assuming a binary Langmuir isotherm model as an approximation. The operating parameters of the simulated moving bed were selected according to the Equilibrium Theory. This allowed the preparation of 85% pure Liquiritin. Finally, 99% pure Liquiritin was obtained through a last step of recrystallization.     

Dissipation of System and Atom in Two-Photon Jaynes–Cummings Model with Degenerate Atomic Levels

A method of perturbative expansion of master equation is employed to study the dissipative properties of system and of atom in the two-photon Jaynes–Cummings model (JCM) with degenerate atomic levels. The numerical results show that the degeneracy of atomic levels prolongs the period of entanglement between the atom and the field. The asymptotic value of atomic linear entropy is apparently increased by the degeneration. The amplitude of local entanglement and disentanglement is suppressed. The better the initial coherence property of the degenerate atom, the larger the coherence loss.