During hydraulic fracturing operations of low-permeability reservoirs,packers are the key component to ensure the success of multistage fracturing.Packers enable sections of the wellbore to be sealed off and separatel...During hydraulic fracturing operations of low-permeability reservoirs,packers are the key component to ensure the success of multistage fracturing.Packers enable sections of the wellbore to be sealed off and separately fractured by hydraulic pressure,one at a time,while the remainder of the wellbore is not affected.However,reliable sealing properties of the packer rubber are required to meet the high-pressure and high-temperature(HPHT)conditions of reservoirs(such as 70 MPa and 170 ℃).In this study,the structures of the packer rubber with two different materials are optimized numerically by ABAQUS and validated by experiments.The optimization process starts from the packer rubber with a conventional structure,and then,the weakest spots are identified by ABAQUS and improved by slightly varying its structure.This process is iterative,and the final optimized structure of a single rubber barrel with expanding back-up rings is achieved.For the structure of three rubber barrels with metallic protective covers,both HNBR and AFLAS fail under HPHT conditions.For the final optimized structure,the packer rubber made of AFLAS can work better under HPHT than that made of HNBR which ruptures after setting.The results show that the optimized structure of a single rubber barrel with expanding back-up rings and the material AFLAS are a good combination for the packer rubber playing an excellent sealing performance in multistage fracturing in horizontal wells.展开更多
Hydrogenated dimer acid-based Nylon 636/Nylon 66 copolymers were synthesized by in situ polymerization. The effects of Nylon 66 contents on the copolymers were characterized by intrinsic viscosity measurements, attenu...Hydrogenated dimer acid-based Nylon 636/Nylon 66 copolymers were synthesized by in situ polymerization. The effects of Nylon 66 contents on the copolymers were characterized by intrinsic viscosity measurements, attenuated total reflection-Fourier transform infrared spectroscopy, X-ray diffraction, differential scanning calorimetry, thermogravimetric analysis and mechanical tests. The results showed that incorporation of Nylon 66 into hydrogenated dimer acid-based Nylon had no significant effect on the glass transition or melting temperatures. However, the crystallization temperature, crystallinity degree and the maximum rate of decomposition temperature from derivative thermogravimetry measurements vary. Mechanical testing data revealed that with increasing Nylon 66 concentrations, the tensile strength of copolymers increased, while the elongation at break point and notched izod impact strength decreased. The physical and mechanical properties of HN-40, HN-50 and HN-60 are similar to those of the current PAl 1, PAl212, and PAlll 1 Nylon products.展开更多
Vitamin D3 （VD3） proliposomes （VDP）, consisted of hydrogenated phosphatidycholine （HPC） and VD3, were prepared using supercritical anti-solvent technology （SAS）. The effects of operation conditions （temperatu...Vitamin D3 （VD3） proliposomes （VDP）, consisted of hydrogenated phosphatidycholine （HPC） and VD3, were prepared using supercritical anti-solvent technology （SAS）. The effects of operation conditions （temperature, pressure and components） on the VD3 loading in VDP were studied. At the optimum conditions of pressure of 8.0 MPa, temperature of 45 ℃, and the mass ratio of 15.0% between VD3 and HPC, the VD3 loading reached 12.89%. VD3 liposomes （VDL） were obtained by hydrating VDP and the entrapment efficiency of VD3 in VDL reached 98.5%. The morphology and structure of VDP and VDL were characterized by SEM （scanning electron micro-scope）, TEM （transmission electron microscope） and XRD （X-ray diffractometer）. The structure of VD3 nanoparti-cles in HPC matrix was formed. The size of VDL with an average diameter of about 1μm was determined by dynamic light scattering instrument （DLS）. The results indicated that VDP can be made by SAS and VDL with high entrapment efficiency can be formed easily via the hydration of VDP.展开更多
The combined microarc oxidation （MAO） and magnetron sputtering deposition process was used to deposit duplex a-C：H/MAO and Ti-a-C：H/MAO coatings on AM80 magnesium alloy. The microstructure, mechanical properties a...The combined microarc oxidation （MAO） and magnetron sputtering deposition process was used to deposit duplex a-C：H/MAO and Ti-a-C：H/MAO coatings on AM80 magnesium alloy. The microstructure, mechanical properties and tribological behavior of the two duplex coatings were investigated. The experimental results showed that the a-C：H and Ti-a-C：H top films on Si substrates were dense and had a low G peak position and ID/IG ratio, compared with the hydrogen-free amorphous carbon films. Numerous micropores were found on the duplex a-C：H/MAO and Ti-a-C：H/MAO coatings together with low values of hardness （H） and elastic modulus （E）, which also showed good binding strength with the Mg alloy substrates. Compared to MAO treated substrate used for the protection of the Mg alloy, the duplex a-C：H/MAO and Ti-a- C：H/MAO coatings still had stable and low value of friction coefficient, even though the surface of the duplex coatings was rough and porous. Furthermore, the mechanism of friction reduction of the two duplex coatings on the Mg alloy substrates was discussed.展开更多
Hydrogenated amorphous silicon(a-Si:H) films were deposited by reactive facing target sputtering(FTS) technique with a mixture of Ar and H2 reaction gas.Fourier transform infrared(FTIR) absorption,Raman scattering and...Hydrogenated amorphous silicon(a-Si:H) films were deposited by reactive facing target sputtering(FTS) technique with a mixture of Ar and H2 reaction gas.Fourier transform infrared(FTIR) absorption,Raman scattering and ultraviolet-visible optical absorption are used to investigate the microstructure and optical properties of the deposited films.The decrease of the concentration of bonded hydrogen,especially that of(Si-H2)n with increasing substrate temperature(Ts),was observed in FTIR spectra,suggesting the atomic density increases and the concentration of microvoids decrease in a-Si:H films.The increase of both the short range order and the intermediate range order of amorphous network for a-Si:H films were verified by Raman scattering spectra,in which increasing Ts decreasing the band width of TO and the scattering intensity ratio ITA/ITO were obtained.All above results clarify the effect of increasing Ts on the microstructure amelioration for a-Si:H films.The reduction of disordered domains is correlated with the film growing process,where the increased surface diffusion mobility and etching of weak bonds is induced by increasing Ts.Furthermore,analysis of optical absorption indicates that the films with a lower optical band gap and a narrower band edge can be obtained by this FTS technique.展开更多
Hydrogenated amorphous silicon (a-Si:H) thin films were deposited by plasma-enhanced vapor deposition (PECVD) at different silane temperatures (Tg) before glow-discharge. The effect of Tg on the amorphous network and ...Hydrogenated amorphous silicon (a-Si:H) thin films were deposited by plasma-enhanced vapor deposition (PECVD) at different silane temperatures (Tg) before glow-discharge. The effect of Tg on the amorphous network and optoelectronic properties of the films has been investigated by Raman scattering spectra, ellipsometric transmittance spectra, and dark conductivity measurement, respectively. The results show that the increase in Tg leads to an improved ordering of amorphous network on the short and intermediate scales and an increase of both refractive index and absorption coefficient in a-Si:H thin films. It is indicated that the dark conductivity increases by two orders of magnitude when Tg is raised from room temperature (RT) to 433 K. The continuous ordering of amorphous network of a-Si:H thin films deposited at a higher Tg is the main cause for the increase of dark conductivity.展开更多
In contrast to the exploration of novel photocatalytic materials,vacancy engineering of traditionalphotocatalysts comprising earth‐abundant elements represents an effective method for enhancingphotocatalytic performa...In contrast to the exploration of novel photocatalytic materials,vacancy engineering of traditionalphotocatalysts comprising earth‐abundant elements represents an effective method for enhancingphotocatalytic performance without introducing alien elements.This minireview analyzes the latestprogress in engineering vacancies in photocatalysts,remarks on state‐of‐the‐art characterizationtechniques for vacancies,and reviews the formation chemistry and fundamental benefits of anionand cation vacancies in typical photocatalysts.Although knowledge of these vacancies is increasing,challenges remain in this field,and possible further research is therefore also discussed.展开更多
The method of numerical simulation is used to fit the relationship between the photoconductivity in films and the illumination time. The generation and process rule of kinds of different charged defect states during i...The method of numerical simulation is used to fit the relationship between the photoconductivity in films and the illumination time. The generation and process rule of kinds of different charged defect states during illumination are revealed. It is found surprisingly that the initial photoconductivity determines directly the total account of photoconductivity degradation of sample.展开更多
Electron cyclotron resonance （ECR） plasma was applied to enhance the direct current magnetron sputtering to prepare hydrogenated diamond-like carbon （H-DLC） films. For different microwave powers, both argon and hy...Electron cyclotron resonance （ECR） plasma was applied to enhance the direct current magnetron sputtering to prepare hydrogenated diamond-like carbon （H-DLC） films. For different microwave powers, both argon and hydrogen gas are introduced separately as the ECR working gas to investigate the influence of microwave power on the microstructure and electrical property of the H-DLC films deposited on P-type silicon substrates. A series of characterization methods including the Raman spectrum and atomic force microscopy are used. Results show that, within a certain range, the increase in microwave power affects the properties of the thin films, namely the sp3 ratio, the hardness, the nanoparticle size and the resistivity all increase while the roughness decreases with the increase in microwave power. The maximum of resistivity amounts to 1.1×10^9 Ω.cm. At the same time it is found that the influence of microwave power on the properties of H-DLC films is more pronounced when argon gas is applied as the ECR working gas, compared to hydrogen gas.展开更多
The degradation of hydrogenated nitrile-butadiene rubber（HNBR） soaped in aqueous solutions of HzS and HC1 was investigated, The samples unexposed and exposed to different solutions were characterized by 13C nuclear ...The degradation of hydrogenated nitrile-butadiene rubber（HNBR） soaped in aqueous solutions of HzS and HC1 was investigated, The samples unexposed and exposed to different solutions were characterized by 13C nuclear magnetic resonance（~3C NMR）, X-ray photoelectron and infrared spectroscopies. In contrast to those of unexposed samples and samples soaped in HCI solution, the mechanical properties of samples exposed to H2S solution signifi- cantly deteriorated, in which the new groups of C（=O）--NH2, C--S--C and C=S emerged. The mechanism of C=S and C--S--C formation was speculated, except for that of the formation of group C（=O）--NH2, which was widely discussed in acidic condition such as HC1 solution. The formation of C--S--C was due to radical reaction in- itiated by mercapto radical and that of C=S was due to nucleophilic reaction initiated by mercapto cations. This finding is helpful to understanding the seal failure of HNBR in working cnvironment containing H2S.展开更多
We have investigated the structural and electronic characteristics of hydrogenated boron-nitride bilayer（H–BNBN–H） using first-principles calculations. The results show that hydrogenation can significantly reduce ...We have investigated the structural and electronic characteristics of hydrogenated boron-nitride bilayer（H–BNBN–H） using first-principles calculations. The results show that hydrogenation can significantly reduce the energy gap of the BN–BN into the visible-light region. Interestingly, the electric field induced by the interface dipoles helps to promote the formation of well-separated electron–hole pairs, as demonstrated by the charge distribution of the VBM and CBM.Moreover, the applied bias voltage on the vertical direction of the bilayer could modulate the band gap, resulting in transition from semiconductor to metal. We conclude that H–BNBN–H could improve the solar energy conversion efficiency, which may provide a new way for tuning the electronic devices to meet different environments and demands.展开更多
Hydrogenated amorphous silicon （a-Si：H） films with high and same order of magnitude photosensitivity （-10^5） but different stability were prepared by using microwave electron cyclotron resonance chemical vapour d...Hydrogenated amorphous silicon （a-Si：H） films with high and same order of magnitude photosensitivity （-10^5） but different stability were prepared by using microwave electron cyclotron resonance chemical vapour deposition system under the different deposition conditions. It was proposed that there was no direct correlation between the photosensitivity and the hydrogen content （CH） as well as H-Si bonding configurations, but for the stability, they were the critical factors. The experimental results indicated that higher substrate temperature, hydrogen dilution ratio and lower deposition rate played an important role in improving the microstructure of a-Si：H films. We used hydrogen elimination model to explain our experimental results.展开更多
A series of hydrogenated silicon thin films were prepared by the radio frequency plasma enhanced chemical vapor deposition method (RF-PECVD) with various si-lane concentrations. The influence of silane concentration o...A series of hydrogenated silicon thin films were prepared by the radio frequency plasma enhanced chemical vapor deposition method (RF-PECVD) with various si-lane concentrations. The influence of silane concentration on structural and elec-trical characteristics of these films was investigated to study the phase transition region from amorphous to microcrystalline phase. At the same time,optical emis-sion spectra (OES) from the plasma during the deposition process were monitored to get information about the plasma properties,Raman spectra were measured to study the structural characteristics of the deposited films. The combinatorial analysis of OES and Raman spectra results demonstrated that the OES can be used as a fast method to diagnose phase transition from amorphous to microcrystalline silicon. At last the physical mechanism,why both OES and Raman can be used to diagnose the phase transition,was analyzed theoretically.展开更多
The present analytical review is devoted to the current problem of thermodynamic stability and related thermodynamic characteristics of the following graphene layers systems: 1) double-side hydrogenated graphene of co...The present analytical review is devoted to the current problem of thermodynamic stability and related thermodynamic characteristics of the following graphene layers systems: 1) double-side hydrogenated graphene of composition CH (theoretical graphane) (Sofo et al. 2007) and experimental graphane (Elias et al. 2009);2) theoretical single-side hydrogenated graphene of composition CH;3) theoretical single-side hydrogenated graphene of composition C2H (graphone);4) experimental hydrogenated epitaxial graphene, bilayer graphene and a few layers of graphene on SiO2 or other substrates;5) experimental and theoretical single-external side hydrogenated single-walled carbon nanotubes, and experimental hydrofullerene C60H36;6) experimental single-internal side hydrogenated (up to C2H or CH composition) graphene nanoblisters with intercalated high pressure H2 gas inside them, formed on a surface of highly oriented pyrolytic graphite or epitaxial graphene under the atomic hydrogen treatment;and 7) experimental hydrogenated graphite nanofibers-multigraphene with intercalated solid H2 nano-regions of high density inside them, relevant to solving the problem of hydrogen on-board storage (Nechaev 2011-2012).展开更多
According to the different penetration depths for the incident lights of 472 nm and 532 nm in hydrogenated amorphous silicon (a-Si:H) thin films, the depth profile study on Raman spectra of a-Si:H films was carried ou...According to the different penetration depths for the incident lights of 472 nm and 532 nm in hydrogenated amorphous silicon (a-Si:H) thin films, the depth profile study on Raman spectra of a-Si:H films was carried out. The network ordering evolution in the near surface and interior region of the unirradiated and irradiated a-Si:H films was investigated. The results show that there is a structural improvement in the shortand intermediate-range order towards the surface of the unirradiated a-Si:H films. The amorphous silicon network in the near and interior region becomes more disordered on the shortand intermediate-range scales after being irradiated with high energy electrons. However, the surface of the irradiated films becomes more disordered in comparison with their interior region, indicating that the created defects caused by electron irradiation are concentrated in the near surface of the irradiated films. Annealing eliminates the irradiation effects on a-Si:H thin films and the structural order of the irradiated films is similar to that of the unirradiated ones after being annealed. There exists a structural improvement in the shortand intermediate-range order towards the surface of the irradiated a-Si:H films after being annealed.展开更多
Ferromagnetism of pure carbon-based materials has been widely researched for several years. In therocially and experimentally, semi-hydrogenation graphene sheets exhibit ferromagnitism, which is related to the degree ...Ferromagnetism of pure carbon-based materials has been widely researched for several years. In therocially and experimentally, semi-hydrogenation graphene sheets exhibit ferromagnitism, which is related to the degree of hydrogenation. Here we reported the controllable hydrogenation of graphene using ball-milling method with acetic acid as hydrogenating agent. The hydrogenation graphene sheets were characterized by means of transmission electron microscopy（TEM）, Raman spectroscopy and X-ray photoelectron spectroscopy, and magnetic measurement. The relusts of Raman spectroscopy demonstrate that the relative intensity of D band increases with the hydrogenation degree. The resluts of magnetic meansurement indicate the maximal magnetic moment of 0.274 A·m^2/kg at 2 K for semi-hydrogenation graphene.展开更多
Using first-principles calculations based on density functional theory(DFT), the structural and electronic properties of hydrogenated antimonene have been systematically investigated. Phonon dispersion and molecular d...Using first-principles calculations based on density functional theory(DFT), the structural and electronic properties of hydrogenated antimonene have been systematically investigated. Phonon dispersion and molecular dynamics(MD)simulation reveal that fully hydrogenated(FH) antimonene has high dynamic stability and could be synthesized. A newσ-type Dirac cone related to Sb-px,y orbitals is found in FH antimonene, which is robust to tensile strain. Noticeably, the spin orbital coupling(SOC) opens a quantum spin Hall(QSH) gap of 425 meV at the Dirac cone, sufficiently large for practical applications at room temperature. Semi-hydrogenated antimonene is a non-magnetic metal. Our results show that FH antimonene may have great potential applications in next generation high-performance devices.展开更多
基金financial support from the Fundamental Research Funds for the Central Universities under Grant nos. 17CX05020 and 17CX06002the Research Funds for Introducing Talent (PhD) of China University of Petroleum under Grant no. YJ20170026+1 种基金the National Science and Technology Major Project under Grant no. 2016ZX05042004the Joint Funds of the National Natural Science Foundation of China under Grant no. U1762104
文摘During hydraulic fracturing operations of low-permeability reservoirs,packers are the key component to ensure the success of multistage fracturing.Packers enable sections of the wellbore to be sealed off and separately fractured by hydraulic pressure,one at a time,while the remainder of the wellbore is not affected.However,reliable sealing properties of the packer rubber are required to meet the high-pressure and high-temperature(HPHT)conditions of reservoirs(such as 70 MPa and 170 ℃).In this study,the structures of the packer rubber with two different materials are optimized numerically by ABAQUS and validated by experiments.The optimization process starts from the packer rubber with a conventional structure,and then,the weakest spots are identified by ABAQUS and improved by slightly varying its structure.This process is iterative,and the final optimized structure of a single rubber barrel with expanding back-up rings is achieved.For the structure of three rubber barrels with metallic protective covers,both HNBR and AFLAS fail under HPHT conditions.For the final optimized structure,the packer rubber made of AFLAS can work better under HPHT than that made of HNBR which ruptures after setting.The results show that the optimized structure of a single rubber barrel with expanding back-up rings and the material AFLAS are a good combination for the packer rubber playing an excellent sealing performance in multistage fracturing in horizontal wells.
基金the 863 program(No. 2011AA02A204) for financial support
文摘Hydrogenated dimer acid-based Nylon 636/Nylon 66 copolymers were synthesized by in situ polymerization. The effects of Nylon 66 contents on the copolymers were characterized by intrinsic viscosity measurements, attenuated total reflection-Fourier transform infrared spectroscopy, X-ray diffraction, differential scanning calorimetry, thermogravimetric analysis and mechanical tests. The results showed that incorporation of Nylon 66 into hydrogenated dimer acid-based Nylon had no significant effect on the glass transition or melting temperatures. However, the crystallization temperature, crystallinity degree and the maximum rate of decomposition temperature from derivative thermogravimetry measurements vary. Mechanical testing data revealed that with increasing Nylon 66 concentrations, the tensile strength of copolymers increased, while the elongation at break point and notched izod impact strength decreased. The physical and mechanical properties of HN-40, HN-50 and HN-60 are similar to those of the current PAl 1, PAl212, and PAlll 1 Nylon products.
基金Supported by the National High Technology Research and Development Program of China （2007AA 10Z350） and the National Natural Science Foundation of China （20976103）.
文摘Vitamin D3 （VD3） proliposomes （VDP）, consisted of hydrogenated phosphatidycholine （HPC） and VD3, were prepared using supercritical anti-solvent technology （SAS）. The effects of operation conditions （temperature, pressure and components） on the VD3 loading in VDP were studied. At the optimum conditions of pressure of 8.0 MPa, temperature of 45 ℃, and the mass ratio of 15.0% between VD3 and HPC, the VD3 loading reached 12.89%. VD3 liposomes （VDL） were obtained by hydrating VDP and the entrapment efficiency of VD3 in VDL reached 98.5%. The morphology and structure of VDP and VDL were characterized by SEM （scanning electron micro-scope）, TEM （transmission electron microscope） and XRD （X-ray diffractometer）. The structure of VD3 nanoparti-cles in HPC matrix was formed. The size of VDL with an average diameter of about 1μm was determined by dynamic light scattering instrument （DLS）. The results indicated that VDP can be made by SAS and VDL with high entrapment efficiency can be formed easily via the hydration of VDP.
基金Funded by the National Natural Science Foundation of China(No.51201176)the Zhejiang Provincial Natural Science Foundation of China(No.Y2110401)the Natural Science Foundation of Shaanxi Province(No.2015JM5176)
文摘The combined microarc oxidation （MAO） and magnetron sputtering deposition process was used to deposit duplex a-C：H/MAO and Ti-a-C：H/MAO coatings on AM80 magnesium alloy. The microstructure, mechanical properties and tribological behavior of the two duplex coatings were investigated. The experimental results showed that the a-C：H and Ti-a-C：H top films on Si substrates were dense and had a low G peak position and ID/IG ratio, compared with the hydrogen-free amorphous carbon films. Numerous micropores were found on the duplex a-C：H/MAO and Ti-a-C：H/MAO coatings together with low values of hardness （H） and elastic modulus （E）, which also showed good binding strength with the Mg alloy substrates. Compared to MAO treated substrate used for the protection of the Mg alloy, the duplex a-C：H/MAO and Ti-a- C：H/MAO coatings still had stable and low value of friction coefficient, even though the surface of the duplex coatings was rough and porous. Furthermore, the mechanism of friction reduction of the two duplex coatings on the Mg alloy substrates was discussed.
基金supported by the National Natural Science Foundation of China (Grant No. 60940020)the Natural Foundation of Hebei Province (Grant Nos. E2008000619 and E2009000208)
文摘Hydrogenated amorphous silicon(a-Si:H) films were deposited by reactive facing target sputtering(FTS) technique with a mixture of Ar and H2 reaction gas.Fourier transform infrared(FTIR) absorption,Raman scattering and ultraviolet-visible optical absorption are used to investigate the microstructure and optical properties of the deposited films.The decrease of the concentration of bonded hydrogen,especially that of(Si-H2)n with increasing substrate temperature(Ts),was observed in FTIR spectra,suggesting the atomic density increases and the concentration of microvoids decrease in a-Si:H films.The increase of both the short range order and the intermediate range order of amorphous network for a-Si:H films were verified by Raman scattering spectra,in which increasing Ts decreasing the band width of TO and the scattering intensity ratio ITA/ITO were obtained.All above results clarify the effect of increasing Ts on the microstructure amelioration for a-Si:H films.The reduction of disordered domains is correlated with the film growing process,where the increased surface diffusion mobility and etching of weak bonds is induced by increasing Ts.Furthermore,analysis of optical absorption indicates that the films with a lower optical band gap and a narrower band edge can be obtained by this FTS technique.
基金Supported by the National Outstanding Young Scientists Foundation of China (Grant No.60425101)the Science Foundation of General Armament Department of China (Grant No.06DZ02)
文摘Hydrogenated amorphous silicon (a-Si:H) thin films were deposited by plasma-enhanced vapor deposition (PECVD) at different silane temperatures (Tg) before glow-discharge. The effect of Tg on the amorphous network and optoelectronic properties of the films has been investigated by Raman scattering spectra, ellipsometric transmittance spectra, and dark conductivity measurement, respectively. The results show that the increase in Tg leads to an improved ordering of amorphous network on the short and intermediate scales and an increase of both refractive index and absorption coefficient in a-Si:H thin films. It is indicated that the dark conductivity increases by two orders of magnitude when Tg is raised from room temperature (RT) to 433 K. The continuous ordering of amorphous network of a-Si:H thin films deposited at a higher Tg is the main cause for the increase of dark conductivity.
基金supported by the National Natural Science Foundation of China (21377084)Special Fund for Agro-scientific Research in the Public Interest (201503107)~~
文摘In contrast to the exploration of novel photocatalytic materials,vacancy engineering of traditionalphotocatalysts comprising earth‐abundant elements represents an effective method for enhancingphotocatalytic performance without introducing alien elements.This minireview analyzes the latestprogress in engineering vacancies in photocatalysts,remarks on state‐of‐the‐art characterizationtechniques for vacancies,and reviews the formation chemistry and fundamental benefits of anionand cation vacancies in typical photocatalysts.Although knowledge of these vacancies is increasing,challenges remain in this field,and possible further research is therefore also discussed.
文摘The method of numerical simulation is used to fit the relationship between the photoconductivity in films and the illumination time. The generation and process rule of kinds of different charged defect states during illumination are revealed. It is found surprisingly that the initial photoconductivity determines directly the total account of photoconductivity degradation of sample.
基金supported by Shenzhen Key Laboratory of Sensors Technology Open Fund of China (Nos.SST200908, SST200911)
文摘Electron cyclotron resonance （ECR） plasma was applied to enhance the direct current magnetron sputtering to prepare hydrogenated diamond-like carbon （H-DLC） films. For different microwave powers, both argon and hydrogen gas are introduced separately as the ECR working gas to investigate the influence of microwave power on the microstructure and electrical property of the H-DLC films deposited on P-type silicon substrates. A series of characterization methods including the Raman spectrum and atomic force microscopy are used. Results show that, within a certain range, the increase in microwave power affects the properties of the thin films, namely the sp3 ratio, the hardness, the nanoparticle size and the resistivity all increase while the roughness decreases with the increase in microwave power. The maximum of resistivity amounts to 1.1×10^9 Ω.cm. At the same time it is found that the influence of microwave power on the properties of H-DLC films is more pronounced when argon gas is applied as the ECR working gas, compared to hydrogen gas.
基金Supporter by the National Natural Science Foundation of China（No.51003121） and the Cultivation Fund of the Key Scien- tific and Technical Innovation Project, Ministry of Education of China（No. 707010）.
文摘The degradation of hydrogenated nitrile-butadiene rubber（HNBR） soaped in aqueous solutions of HzS and HC1 was investigated, The samples unexposed and exposed to different solutions were characterized by 13C nuclear magnetic resonance（~3C NMR）, X-ray photoelectron and infrared spectroscopies. In contrast to those of unexposed samples and samples soaped in HCI solution, the mechanical properties of samples exposed to H2S solution signifi- cantly deteriorated, in which the new groups of C（=O）--NH2, C--S--C and C=S emerged. The mechanism of C=S and C--S--C formation was speculated, except for that of the formation of group C（=O）--NH2, which was widely discussed in acidic condition such as HC1 solution. The formation of C--S--C was due to radical reaction in- itiated by mercapto radical and that of C=S was due to nucleophilic reaction initiated by mercapto cations. This finding is helpful to understanding the seal failure of HNBR in working cnvironment containing H2S.
基金Project supported by the National Natural Science Foundation of China(Grant No.11574167)
文摘We have investigated the structural and electronic characteristics of hydrogenated boron-nitride bilayer（H–BNBN–H） using first-principles calculations. The results show that hydrogenation can significantly reduce the energy gap of the BN–BN into the visible-light region. Interestingly, the electric field induced by the interface dipoles helps to promote the formation of well-separated electron–hole pairs, as demonstrated by the charge distribution of the VBM and CBM.Moreover, the applied bias voltage on the vertical direction of the bilayer could modulate the band gap, resulting in transition from semiconductor to metal. We conclude that H–BNBN–H could improve the solar energy conversion efficiency, which may provide a new way for tuning the electronic devices to meet different environments and demands.
文摘Hydrogenated amorphous silicon （a-Si：H） films with high and same order of magnitude photosensitivity （-10^5） but different stability were prepared by using microwave electron cyclotron resonance chemical vapour deposition system under the different deposition conditions. It was proposed that there was no direct correlation between the photosensitivity and the hydrogen content （CH） as well as H-Si bonding configurations, but for the stability, they were the critical factors. The experimental results indicated that higher substrate temperature, hydrogen dilution ratio and lower deposition rate played an important role in improving the microstructure of a-Si：H films. We used hydrogen elimination model to explain our experimental results.
基金Supported by the National Basic Research Program of China (Grant Nos. 2006CB202602 and 2006CB202603)
文摘A series of hydrogenated silicon thin films were prepared by the radio frequency plasma enhanced chemical vapor deposition method (RF-PECVD) with various si-lane concentrations. The influence of silane concentration on structural and elec-trical characteristics of these films was investigated to study the phase transition region from amorphous to microcrystalline phase. At the same time,optical emis-sion spectra (OES) from the plasma during the deposition process were monitored to get information about the plasma properties,Raman spectra were measured to study the structural characteristics of the deposited films. The combinatorial analysis of OES and Raman spectra results demonstrated that the OES can be used as a fast method to diagnose phase transition from amorphous to microcrystalline silicon. At last the physical mechanism,why both OES and Raman can be used to diagnose the phase transition,was analyzed theoretically.
文摘The present analytical review is devoted to the current problem of thermodynamic stability and related thermodynamic characteristics of the following graphene layers systems: 1) double-side hydrogenated graphene of composition CH (theoretical graphane) (Sofo et al. 2007) and experimental graphane (Elias et al. 2009);2) theoretical single-side hydrogenated graphene of composition CH;3) theoretical single-side hydrogenated graphene of composition C2H (graphone);4) experimental hydrogenated epitaxial graphene, bilayer graphene and a few layers of graphene on SiO2 or other substrates;5) experimental and theoretical single-external side hydrogenated single-walled carbon nanotubes, and experimental hydrofullerene C60H36;6) experimental single-internal side hydrogenated (up to C2H or CH composition) graphene nanoblisters with intercalated high pressure H2 gas inside them, formed on a surface of highly oriented pyrolytic graphite or epitaxial graphene under the atomic hydrogen treatment;and 7) experimental hydrogenated graphite nanofibers-multigraphene with intercalated solid H2 nano-regions of high density inside them, relevant to solving the problem of hydrogen on-board storage (Nechaev 2011-2012).
基金Supported by the National Outstanding Young Scientists Foundation of China (Grant No. 60425101)the Science Foundation of General Armament Department of China (Grant No. 06DZ02)
文摘According to the different penetration depths for the incident lights of 472 nm and 532 nm in hydrogenated amorphous silicon (a-Si:H) thin films, the depth profile study on Raman spectra of a-Si:H films was carried out. The network ordering evolution in the near surface and interior region of the unirradiated and irradiated a-Si:H films was investigated. The results show that there is a structural improvement in the shortand intermediate-range order towards the surface of the unirradiated a-Si:H films. The amorphous silicon network in the near and interior region becomes more disordered on the shortand intermediate-range scales after being irradiated with high energy electrons. However, the surface of the irradiated films becomes more disordered in comparison with their interior region, indicating that the created defects caused by electron irradiation are concentrated in the near surface of the irradiated films. Annealing eliminates the irradiation effects on a-Si:H thin films and the structural order of the irradiated films is similar to that of the unirradiated ones after being annealed. There exists a structural improvement in the shortand intermediate-range order towards the surface of the irradiated a-Si:H films after being annealed.
基金Supported by the National Natural Science Foundation of China（Nos.21271082, 21371068）.
文摘Ferromagnetism of pure carbon-based materials has been widely researched for several years. In therocially and experimentally, semi-hydrogenation graphene sheets exhibit ferromagnitism, which is related to the degree of hydrogenation. Here we reported the controllable hydrogenation of graphene using ball-milling method with acetic acid as hydrogenating agent. The hydrogenation graphene sheets were characterized by means of transmission electron microscopy（TEM）, Raman spectroscopy and X-ray photoelectron spectroscopy, and magnetic measurement. The relusts of Raman spectroscopy demonstrate that the relative intensity of D band increases with the hydrogenation degree. The resluts of magnetic meansurement indicate the maximal magnetic moment of 0.274 A·m^2/kg at 2 K for semi-hydrogenation graphene.
基金supported by Research Funds of Sichuan University of Arts and Science,China(Grant No.2012Z009Y)
文摘Using first-principles calculations based on density functional theory(DFT), the structural and electronic properties of hydrogenated antimonene have been systematically investigated. Phonon dispersion and molecular dynamics(MD)simulation reveal that fully hydrogenated(FH) antimonene has high dynamic stability and could be synthesized. A newσ-type Dirac cone related to Sb-px,y orbitals is found in FH antimonene, which is robust to tensile strain. Noticeably, the spin orbital coupling(SOC) opens a quantum spin Hall(QSH) gap of 425 meV at the Dirac cone, sufficiently large for practical applications at room temperature. Semi-hydrogenated antimonene is a non-magnetic metal. Our results show that FH antimonene may have great potential applications in next generation high-performance devices.
