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1.
To systematically evaluate the quality of SiNx films in multi-stacked structures, we investigated the effects of post-deposition annealing (PDA) on the film properties of SiNx within the SiO2/SiNx/SiO2/Si stacked structure by performing X-ray photoelectron spectroscopy (XPS), X-ray reflectivity (XRR), Fourier transform infrared (FT-IR) spectroscopy, and scanning transmission electron microscope–electron energy loss spectroscopy (STEM-EELS) analyses. The XPS results showed that PDA induces the oxidation of the SiNx layer. In particular, new finding is that Si-rich SiNx in the SiNx layer is preferentially oxidized by PDA even in multi-stacked structure. The XRR results showed that the SiNx layer becomes thinner, whereas the interface layer between the SiNx layer and Si becomes thicker. It is concluded by STEM-EELS and XPS that this interface layer is SiON layer. The density of N–H and Si–H bonding within the stacked structure strongly depends on the PDA temperature. Our study helps elucidate the properties of SiNx films in stacked structures from various perspectives.  相似文献   
2.
New protocols for controlled reduction of carboxamides to either alcohols or amines were established using a combination of sodium hydride (NaH) and zinc halides (ZnX2). Use of a different halide on ZnX2 dictates the selectivity, wherein the NaH‐ZnI2 system delivers alcohols and NaH‐ZnCl2 gives amines. Extensive mechanistic studies by experimental and theoretical approaches imply that polymeric zinc hydride (ZnH2) is responsible for alcohol formation, whereas dimeric zinc chloride hydride (H?Zn?Cl)2 is the key species for the production of amines.  相似文献   
3.
The proof of the asymptotic quadratic convergence is provided for the parallel two-sided block-Jacobi EVD algorithm with dynamic ordering for Hermitian matrices. The discussion covers the case of well-separated eigenvalues as well as clusters of eigenvalues. Having p processors, each parallel iteration step consists of zeroing 2p off-diagonal blocks chosen by dynamic ordering with the aim to maximize the decrease of the off-diagonal Frobenius norm. Numerical experiments illustrate and confirm the developed theory.  相似文献   
4.
A synthetic methodology to access all possible stereoisomers of spectomycin A1 (SMA1) and A2 (SMA2) has been established through late-stage diversification. The key reaction for the construction of all four diastereomers is an intramolecular cyclization based on the umpolung of π-allyl palladium species with bis(pinacolato)diborane (B2(pin)2). Silyl group assisted direct benzylic oxidation of each isomer enabled construction of the fragile β-hydroxytetralone skeleton to provide the SMAs. The relative and absolute stereochemistry of SMA2 was also determined, and the absolute stereochemistry of SMA1 was extrapolated based on the optical rotation of SMA2. The axial chirality of SMAs is discussed based on circular dichroism spectra and DFT calculations, and it is concluded that the M isomer is predominant in solution. Biochemical assessment of all isomers in vitro revealed that the C9 hydroxyl group and dimeric structure were both important for protein SUMOylation-inhibitory activity.  相似文献   
5.
Abstract

The microscopic state of the positively charged light particle in the transition metal dichalcogenide 2H-NbSe2 was studied using the muon spin relaxation method (μ+SR) and muon level crossing resonance method (μ-LCR). Muons are expected to stay at interlayer position and behaves as a hydrogen like intercalant. We discuss the relation between conduction electron properties and the muon's behavior.  相似文献   
6.
The mechanism underlying the bioinertness of the self-assembled monolayers of oligo(ethylene glycol)-terminated alkanethiol (OEG-SAM) was investigated with protein adsorption experiments, platelet adhesion tests, and surface force measurements with an atomic force microscope (AFM). In this work, we performed systematic analysis with SAMs having various terminal groups (-OEG, -OH, -COOH, -NH(2), and -CH(3)). The results of the protein adsorption experiment by the quartz crystal microbalance (QCM) method suggested that having one EG unit and the neutrality of total charges of the terminal groups are essential for protein-resistance. In particular, QCM with energy dissipation analyses indicated that proteins absorb onto the OEG-SAM via a very weak interaction compared with other SAMs. Contrary to the protein resistance, at least three EG units as well as the charge neutrality of the SAM are found to be required for anti-platelet adhesion. When the identical SAMs were formed on both AFM probe and substrate, our force measurements revealed that only the OEG-SAMs possessing more than two EG units showed strong repulsion in the range of 4 to 6 nm. In addition, we found that the SAMs with other terminal groups did not exhibit such repulsion. The repulsion between OEG-SAMs was always observed independent of solution conditions [NaCl concentration (between 0 and 1 M) and pH (between 3 and 11)] and was not observed in solution mixed with ethanol, which disrupts the three-dimensional network of the water molecules. We therefore concluded that the repulsion originated from structured interfacial water molecules. Considering the correlation between the above results, we propose that the layer of the structured interfacial water with a thickness of 2 to 3 nm (half of the range of the repulsion observed in the surface force measurements) plays an important role in deterring proteins and platelets from adsorption or adhesion.  相似文献   
7.
8.
Catalytic degradation of polyolefins was performed in a continuous flow reactor that allows the study of the degradation processes at steady state, characterized by constant values of reaction parameters and properties of the products. The continuous flow reactor was operated at atmospheric pressure and at feed rate of 0–1.5 kg h?1 polyolefins over two silica–alumina catalysts having different SiO2/Al2O3 mole ratio. Polyethylene (PE), polypropylene (PP) and polystyrene (PS) were degraded at 420, 380 and 360 °C respectively. The cracking effect of silica–alumina was proved by the increased amount of gaseous products and by the decreased molecular weight of liquid products. The differences in surface area and in concentration and acidic strength of active centers of the two catalysts affected the distribution of degradation products. Molar rate of degradation was increased in the presence of catalysts, however the mass rate of degradation was decreased leading to higher values of the calculated activation energies. These interesting results might open new perspectives in understanding the macroscopic mechanism for catalytic degradation of polyolefins.  相似文献   
9.
A new approach to reduce the reverse current of Ge pin photodiodes on Si is presented, in which an i-Si layer is inserted between Ge and top Si layers to reduce the electric field in the Ge layer. Without post- growth annealing, the reverse current density is reduced to -10 mA/cm^2 at -1 V, i.e., over one order of magnitude lower than that of the reference photodiode without i-Si layer. However, the responsivity of the photodiodes is not severely compromised. This lowered-reverse-current is explained by band-pinning at the i-Si/i-Ge interface. Barrier lowering mechanism induced by E-field is also discussed. The presented "non-thermal" approach to reduce reverse current should accelerate electronics-photonics convergence by using Oe on the Si complementary metal oxide semiconductor (CMOS) platform.  相似文献   
10.
A continuous flow reactor was operated at atmospheric pressure and feed rate of 0–1.5 kg h−1 for degradation of PE, PP and PS in presence of 1–2 wt% PVC. The degradation temperatures were between 360 and 440 °C depending on the feeding material. The influence of PVC, temperature and silica-alumina catalysts on degradation behavior and on the properties of the products was studied and discussed. Different effects were observed for binary PE/PVC, PP/PVC, PS/PVC and complex PE/PP/PS/PVC mixtures due to specific interactions between PVC and each hydrocarbon polyolefin. Silica-alumina catalysts decreased the Cl concentration in oils but it seems to generate high amounts of Cl-containing organic compounds in gases.  相似文献   
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