Correction to: Impact of leg bending in the patient-specific computational fluid dynamics of popliteal stenting

Acta Mechanica Sinica - A Correction to this paper has been published: https://doi.org/10.1007/s10409-021-01066-2     

Production of octadienal in the marine diatom Skeletonema costatum

[reaction: see text] Marine diatoms produce alpha,beta,gamma,delta-unsaturated aldehydes that have detrimental effects on the reproduction of their natural predators. The production of these defensive metabolites is suggested to involve enzymatic oxidation of polyunsaturated fatty acids. In this paper, feeding experiments with labeled precursor provide clear evidence in support of the origin of octadienals 1 and 2 from 6,9,12-hexadecatrienoic acid (5), thus proving the involvement of novel lipoxygenase/lyase activity for the oxidation of C(16) fatty acids.     

Cs2CO3 Promoted coupling reactions for the preparation of skipped diynes

An improved methodology for the preparation of copper(I) alkynides has been developed using cesium carbonate as base. In the presence of cesium carbonate and CuI various 1-alkynes were converted smoothly to the corresponding copper alkynides which in situ reacted with propargylic halides in order to synthesize skipped diynes.     

Influence of oxygen on the ion-assisted regrowth of deposited Si layers

Summary The ion-assisted regrowth of chemical-vapour deposited Si films onto (100) Si substrates is reported. The regrowth was induced by a 600 keV Kr⁺⁺ beam at doses in the range (2·10¹⁵÷6·10¹⁵)/cm² and at a dose rate of 1·10¹²/cm²s. The target temperature was set at 450°C. During irradiations the crystal-amorphous interface velocity was measuredin situ by monitoring the reflectivity of a He-Ne laser light focused onto the sample surface. After irradiation some samples were also analysed by Rutherford backscattering in combination with the channelling effect and by transmission electron microscopy. The growth rate of deposited layers depends on the cleaning procedure performed prior to deposition,i.e on the total amount of oxygen present at the deposited layer/substrate interface. Moreover, twinned material is observed in the recrystallized layers and its concentration is strongly dependent on substrate cleaning. These phenomena are explained in terms of a decrease in the ion-assisted growth rate in the presence of high oxygen concentrations. The data are discussed and compared with those obtained during pure thermal annealing. To speed up publication, the authors of this paper has agreed to not receive the proofs for correction.     

Extended defect removal in silicon by rapid thermal annealing

Summary Germanium, arsenic and krypton ions of 600 keV energy were implanted in <100> silicon substrate at 250°C. The hot implantation results in the formation of extended defects (dislocation loops and cluster of point defects) as residual damage. Rapid thermal annealing process at a temperature above 1000°C was used to remove the damage. Rutherford-backscattering channelling technique was used to measure the amount of defects and their annealing. In some cases the channelling results were correlated to transmission electron microscopy (TEM) analysis. The annealing process of the damage is governed by an activation energy of (4.4±0.2) eV for both germanium and arsenic implants. During RTA processes broadening of the As and Ge distributions is quite negligible. The Kr atoms interact instead with defects and the annealing even after a prolonged time at 1100°C is not complete, bubbles surrounded by extended defects are left The authors of this paper have agreed to not receive the proofs for correction.     

The early oxynitridation stages of hydrogen-terminated (100) silicon after exposure to N2:N2O. Nitrogen bonding states

Nitridation of hydrogen-terminated silicon in a diluted N₂:N₂O atmosphere was studied by X-ray photoemission spectroscopy and high-resolution electron microscopy. Our analysis showed that the broad N(1s) peak of width 1.5 eV at 398–399 eV, usually reported in the literature, is preceded by the formation of a narrow peak of width around 1.0 eV at 397.5 eV, attributed to the moiety Si₃N in which silicon is only marginally oxidized, and two other peaks at 400.0 eV and 401.5 eV, attributed to the moieties Si₂NOSi and SiNO, respectively. Received: 11 July 2001 / Accepted: 19 September 2001 / Published online: 20 December 2001     

Similar Structural Dynamics for the Degradation of CH3NH3PbI3 in Air and in Vacuum

We investigate the degradation path of MAPbI₃ (MA=methylammonium) films over flat TiO₂ substrates at room temperature by means of X‐ray diffraction, spectroscopic ellipsometry, X‐ray photoelectron spectroscopy, and high‐resolution transmission electron microscopy. The degradation dynamics is found to be similar in air and under vacuum conditions, which leads to the conclusion that the occurrence of intrinsic thermodynamic mechanisms is not necessarily linked to humidity. The process has an early stage, which drives the starting tetragonal lattice in the direction of a cubic atomic arrangement. This early stage is followed by a phase change towards PbI₂. We describe how this degradation product is structurally coupled with the original MAPbI₃ lattice through the orientation of its constituent PbI₆ octahedra. Our results suggest a slight octahedral rearrangement after volatilization of HI+CH₃NH₂ or MAI, with a relatively low energy cost. Our experiments also clarify why reducing the interfaces and internal defects in the perovskite lattice enhances the stability of the material.     

Synthesis of uracil derivatives by oxidation of Fischer tungsten-carbene uracil complexes

A study on the oxidation of Fischer tungsten-carbene uracil complexes has been carried out. Several commonly used oxidants gave results strongly influenced by the presence of substituent on nitrogen atoms. In particular, usual oxidants failed in the oxidation of 3-alkyl uracil carbene complexes. Finally, we showed that t-butyl hydroperoxide is able to oxidize successfully also 3-alkyl uracil carbene complexes and can be used as a good alternative to the other methods.