RESUMO
Herein, we disclose a highly chemoselective room-temperature deoxygenation method applicable to various functionalized N-heterocyclic N-oxides via visible light-mediated metallaphotoredox catalysis using Hantzsch esters as the sole stoichiometric reductant. Despite the feasibility of catalyst-free conditions, most of these deoxygenations can be completed within a few minutes using only a tiny amount of a catalyst. This technology also allows for multigram-scale reactions even with an extremely low catalyst loading of 0.01 mol %. The scope of this scalable and operationally convenient protocol encompasses a wide range of functional groups, such as amides, carbamates, esters, ketones, nitrile groups, nitro groups, and halogens, which provide access to the corresponding deoxygenated N-heterocycles in good to excellent yields (an average of an 86.8% yield for a total of 45 examples).
RESUMO
A scalable and operationally simple method is described that allows for the chemoselective deoxygenation of a wide range of N-heterocyclic N-oxides (a total of 36 examples). This visible-light-induced protocol features the use of only commercially available reagents, room-temperature conditions, and unprecedented chemoselective removal of the oxygen atom in a quinoline N-oxide in the presence of a pyridine N-oxide in the same molecule through the judicious selection of a photocatalyst.
RESUMO
The effects of dry cleaning of a HfO2 gate stack using NF3 only and a NF3/NH3 gas mixture plasma were investigated. The plasma dry cleaning process was carried out after HfO2 deposition using an indirect down-flow capacitively coupled plasma (CCP) system. An analysis of the chemical composition of the HfO2 gate stacks by XPS indicated that fluorine was incorporated into the HfO2 films during the plasma dry cleaning. Significant changes in the HfO2 chemical composition were observed as a result of the NF3 dry cleaning, while they were not observed in this case of NF3/NH3 dry cleaning. TEM results showed that the interfacial layer (IL) between the HfO2 and Si thickness was increased by the plasma dry cleaning. However, in the case of NF3/NH3 dry cleaning using 150 W, the IL thickness was suppressed significantly compared to the sample that had not been dry cleaned. Its electrical properties were also improved, including the low gate leakage currents, and reduced EOT. Finally, the finding show that the IL thickness of the HfO2 gate stack can be controlled by using the novel NF3/NH3 dry cleaning process technique without any the significant changes in chemical composition and metal-oxide-semiconductor (MOS) capacitor characteristics.
RESUMO
A signal transformation system of posture movement for the stable state was designed in order to measure the bio-physical signal. To estimate the subject in a stable state on the basis of the bio-physical signal in the posture movement, the conditions of vision, vestibular, somatosensory apparatus and the central nervous system (CNS) were detected. Based on the vision condition, there was a greater average variation (Vi-αAVG-MAX and Vi-αAVG-MIN) in position with eyes closed and eyes opened (PC and PO), which was 27.11 ± 6.36 units. The vestibular condition showed a slightly larger average variation (Ve-αAVG-MAX and Ve-αAVG-MIN) in the body position with PC and PO, which was 6.60 ± 1.65 units. The somatosensory condition demonstrated a lower average variation (So-αAVG-MAX and So-αAVG-MIN) in position with PC and PO that amounted to 3.653 ± 2.424 units. The CNS condition was confirmed to indicate very little average variation (C-αAVG-MAX and C-αAVG-MIN) in body position with PC and PO that was at 0.401 ± 0.56 units. As the model depends on the bio-physical transformation system of posture movement, the average values of these perturbations were computed (0.01-2 Hz, range of Fourier frequency). The system consists of a data algorithm, an acquisition system, a data signal processing unit and a network system for the evaluated stability.
