Diamond films were prepared by hot filament chemical vapor deposition(HFCVD) in a gas mixtures system of methane, argon and hydrogen. The composition and morphology in different deposition pressures and filament struc...Diamond films were prepared by hot filament chemical vapor deposition(HFCVD) in a gas mixtures system of methane, argon and hydrogen. The composition and morphology in different deposition pressures and filament structures were investigated, as well as the friction and wear-resistant properties. The sp3-bonded content was measured and nano-mechanics properties were also tested. Results of atomic force microscopy and X-ray photoelectron spectroscopy show that the diamond films whose surface roughness is less than 10 nm and sp3-bonded content is greater than 70% can be prepared by bistratal filament structure with optimized proportion of Ar. It is also shown that the friction coefficient of diamond films is 0.13 and its wear-resistant property is excellent. Nano-mechanics of films shows that its elastic modulus is up to 650 MPa and hardness can reach higher than 60 GPa. The diamond films with excellent performance have a broad application prospect in microelectromechanical systems(MEMS).展开更多
A simple method to prepare of DNA template suitable for PCR amplification from filamentous fungi will be valuable for improving experimental efficiency.Here,a method was developed which just needed ultrasonic treatmen...A simple method to prepare of DNA template suitable for PCR amplification from filamentous fungi will be valuable for improving experimental efficiency.Here,a method was developed which just needed ultrasonic treatment of the mycelium at usual condition,and the produced solution could directly be used as DNA template for internal transcribed spacer(ITS)amplification successfully.The PCR could be improved by additional treatment of 60℃water baths,but was not centrifugation.When the template amount was 0.5-2μL and the ultrasonic time was 7-11 min,there was no distinctly influences on PCR.The method was commonly used for M.purpureus,I.cicadae,Lentinula sp.,Flammul sp.and Dictyophora sp.etc.to detect target sequences of ITS,hygromycin resistance gene(Hyg),CRISPR-associated protein 9(Cas9),Citrinin gene C(CtnC),Citrinin gene D(CtnD),large subunit rRNA gene(NL),and so on.The method could provide a simple,rapid,safe and economic approach to prepare the DNA template for large-scale PCR of the special filamentous fungi materials.展开更多
Hot-filament chemical vapor deposition ( HFCVD) is a promising method for commercial production of diamond films. Filament performance in heat transfer and hydrogen decomposition in reactive environment was investigat...Hot-filament chemical vapor deposition ( HFCVD) is a promising method for commercial production of diamond films. Filament performance in heat transfer and hydrogen decomposition in reactive environment was investigated. Power consumption by the filament in vacuum, helium and 2% CH4/H2 was experimentally determined in temperature range 1300℃-2200℃. Filament heat transfer mechanism in C-H reactive environment was calculated and analyzed. The result shows that due to surface carburization and slight carbon deposition, radiation in stead of hydrogen dissociation, becomes the largest contributor to power consumption. Filament-surface dissociation of H2 was observed at temperatures below 1873K, demonstrating the feasibility of diamond growth at low filament temperatures. The effective activation energies of hydrogen dissociation on several clean refractory flaments were derived from power consumption data in literatures. They are all lower than that of thermal dissociation of hydrogen revealing the nature of catalytic dissociation of hydrogen on filament surface. Observation of substrate temperature suggested a weaker role of atomic hydrogen recombination in heating substrates in C-H environment than in pure hydrogen.展开更多
基金Projects(5130121121271188)supported by the National Natural Science Foundation of China+4 种基金Project(ZZ13005)supported by the Foundation of Laboratory of Ultra Precision Manufacturing Technology of China Academy of Engineering PhysicsProject(2010A0302013)supported by Research Foundation of China Academy of Engineering PhysicsProject(2012M521541)supported by the China Postdoctoral Science FoundationProject(20110933K)supported by the State Key Laboratory of Powder Metallurgy(Central South University),ChinaProject(CSU2013016)supported by the Open-End Fund for Valuable and Precision Instruments of Central South University,China
文摘Diamond films were prepared by hot filament chemical vapor deposition(HFCVD) in a gas mixtures system of methane, argon and hydrogen. The composition and morphology in different deposition pressures and filament structures were investigated, as well as the friction and wear-resistant properties. The sp3-bonded content was measured and nano-mechanics properties were also tested. Results of atomic force microscopy and X-ray photoelectron spectroscopy show that the diamond films whose surface roughness is less than 10 nm and sp3-bonded content is greater than 70% can be prepared by bistratal filament structure with optimized proportion of Ar. It is also shown that the friction coefficient of diamond films is 0.13 and its wear-resistant property is excellent. Nano-mechanics of films shows that its elastic modulus is up to 650 MPa and hardness can reach higher than 60 GPa. The diamond films with excellent performance have a broad application prospect in microelectromechanical systems(MEMS).
基金Supported by the National Natural Science Foundation of China(81960692)the Science and Technology Support Program of Guizhou Province(2019-2776)。
文摘A simple method to prepare of DNA template suitable for PCR amplification from filamentous fungi will be valuable for improving experimental efficiency.Here,a method was developed which just needed ultrasonic treatment of the mycelium at usual condition,and the produced solution could directly be used as DNA template for internal transcribed spacer(ITS)amplification successfully.The PCR could be improved by additional treatment of 60℃water baths,but was not centrifugation.When the template amount was 0.5-2μL and the ultrasonic time was 7-11 min,there was no distinctly influences on PCR.The method was commonly used for M.purpureus,I.cicadae,Lentinula sp.,Flammul sp.and Dictyophora sp.etc.to detect target sequences of ITS,hygromycin resistance gene(Hyg),CRISPR-associated protein 9(Cas9),Citrinin gene C(CtnC),Citrinin gene D(CtnD),large subunit rRNA gene(NL),and so on.The method could provide a simple,rapid,safe and economic approach to prepare the DNA template for large-scale PCR of the special filamentous fungi materials.
基金Supported by the National Natural Science Foundation of China under contract No.59976038.
文摘Hot-filament chemical vapor deposition ( HFCVD) is a promising method for commercial production of diamond films. Filament performance in heat transfer and hydrogen decomposition in reactive environment was investigated. Power consumption by the filament in vacuum, helium and 2% CH4/H2 was experimentally determined in temperature range 1300℃-2200℃. Filament heat transfer mechanism in C-H reactive environment was calculated and analyzed. The result shows that due to surface carburization and slight carbon deposition, radiation in stead of hydrogen dissociation, becomes the largest contributor to power consumption. Filament-surface dissociation of H2 was observed at temperatures below 1873K, demonstrating the feasibility of diamond growth at low filament temperatures. The effective activation energies of hydrogen dissociation on several clean refractory flaments were derived from power consumption data in literatures. They are all lower than that of thermal dissociation of hydrogen revealing the nature of catalytic dissociation of hydrogen on filament surface. Observation of substrate temperature suggested a weaker role of atomic hydrogen recombination in heating substrates in C-H environment than in pure hydrogen.
