A simple and efficient radical coupling of 2-isocyanobiphenyl with ethers was developed, providing a variety of 6-alkylated phenanthridines. Both cyclic and acyclic ethers are suitable substrates for this transformati...A simple and efficient radical coupling of 2-isocyanobiphenyl with ethers was developed, providing a variety of 6-alkylated phenanthridines. Both cyclic and acyclic ethers are suitable substrates for this transformation, which comprised the functional- ization of two C-H bonds： the sp3 C-H of ether and sp2 C-H of phenyl group. The kinetic isotope effect （KIE） revealed that the cleavage of sp3 C-H bond would be involved in the rate-determining step.展开更多
Methane （CH4） plasma was used to produce amorphous hydrogenated carbon （a- C：H） films by a single capacitively coupled radio frequency （RF） powered plasma system. The system consists of two parallel electrodes...Methane （CH4） plasma was used to produce amorphous hydrogenated carbon （a- C：H） films by a single capacitively coupled radio frequency （RF） powered plasma system. The system consists of two parallel electrodes： the upper electrode is connected to 13.56 MHz RF power and the lower one is connected to the ground. Thin films were deposited on glass slides with different sizes and on silicon wafers. The influence of the plasma species on film characteristics was studied by changing the plasma parameters. The changes of plasma species during the deposition were investigated by optical emission spectroscopy （OES）. The structural and optical properties were analyzed via Fourier transform infrared （FTIR） spectroscopy, X-ray diffraction （XRD） and UV-visible spectroscopy, and the thicknesses of the samples were measured by a profilometer. The sp3/sp2 ratio and the existing H atoms play a significant role in the determination of the chemical properties of thin films in the plasma. The film quality and deposition rate were both increased by raising the power and the flow rate.展开更多
Glassy carbon(GC)is a type of non-graphitizing disordered carbon material at ambient pressure and high temperatures,which has been widely used due to its excellent mechanical properties.Here we report the changes in t...Glassy carbon(GC)is a type of non-graphitizing disordered carbon material at ambient pressure and high temperatures,which has been widely used due to its excellent mechanical properties.Here we report the changes in the microstructure and mechanical properties of GC treated at high pressures(up to 5 GPa)and high temperatures.The formation of intermediate sp2-sp3 phases is identified at moderate treatment temperatures before the complete graphitization of GC,by analyzing synchrotron X-ray diffraction,Raman spectra,and transmission electron microscopy images.The intermediate metastable carbon materials exhibit superior mechanical properties with hardness reaching up to 10 GPa and compressive strength reaching as high as 2.5 GPa,nearly doubling those of raw GC,and improving elasticity and thermal stability.The synthesis pressure used in this study can be achieved in the industry on a commercial scale,enabling the scalable synthesis of this type of strong,hard,and elastic carbon materials.展开更多
基金This work was supported by the National Natural Science Foundation of China(21172106,21074054 and 21372114)the National Basic Research Program of China(2010CB923303)+1 种基金the Research FundJbr the Doctoral Program of Higher Education of China(20120091110010)PAN ChangDuo is thankful the support of the Natural Science Foundation of China(21272178).
文摘A simple and efficient radical coupling of 2-isocyanobiphenyl with ethers was developed, providing a variety of 6-alkylated phenanthridines. Both cyclic and acyclic ethers are suitable substrates for this transformation, which comprised the functional- ization of two C-H bonds： the sp3 C-H of ether and sp2 C-H of phenyl group. The kinetic isotope effect （KIE） revealed that the cleavage of sp3 C-H bond would be involved in the rate-determining step.
基金supported by the Scientific Research Project Fund of Duzce University under the projectnumber 2013.05.02.195
文摘Methane （CH4） plasma was used to produce amorphous hydrogenated carbon （a- C：H） films by a single capacitively coupled radio frequency （RF） powered plasma system. The system consists of two parallel electrodes： the upper electrode is connected to 13.56 MHz RF power and the lower one is connected to the ground. Thin films were deposited on glass slides with different sizes and on silicon wafers. The influence of the plasma species on film characteristics was studied by changing the plasma parameters. The changes of plasma species during the deposition were investigated by optical emission spectroscopy （OES）. The structural and optical properties were analyzed via Fourier transform infrared （FTIR） spectroscopy, X-ray diffraction （XRD） and UV-visible spectroscopy, and the thicknesses of the samples were measured by a profilometer. The sp3/sp2 ratio and the existing H atoms play a significant role in the determination of the chemical properties of thin films in the plasma. The film quality and deposition rate were both increased by raising the power and the flow rate.
基金supported by the National Key R&D Program of China(Grants No.2018YFA0703400)the National Natural Science Foundation of China(Grants Nos.51672238,91963203,51722209,and 51525205)+2 种基金M.Hu acknowledges fellowship support by the Alexander von Humboldt Foundation.Z.Zhao acknowledges 100 talents plan of Hebei Province(Grants No.E2016100013)NSF for Distinguished Young Scholars of Hebei Province of China(Grants No.E2018203349)K.Luo acknowledges the China Postdoctoral Science Foundation(Grants No.2017M620097).
文摘Glassy carbon(GC)is a type of non-graphitizing disordered carbon material at ambient pressure and high temperatures,which has been widely used due to its excellent mechanical properties.Here we report the changes in the microstructure and mechanical properties of GC treated at high pressures(up to 5 GPa)and high temperatures.The formation of intermediate sp2-sp3 phases is identified at moderate treatment temperatures before the complete graphitization of GC,by analyzing synchrotron X-ray diffraction,Raman spectra,and transmission electron microscopy images.The intermediate metastable carbon materials exhibit superior mechanical properties with hardness reaching up to 10 GPa and compressive strength reaching as high as 2.5 GPa,nearly doubling those of raw GC,and improving elasticity and thermal stability.The synthesis pressure used in this study can be achieved in the industry on a commercial scale,enabling the scalable synthesis of this type of strong,hard,and elastic carbon materials.
