Based on a simulative experiment and a comparison analysis, the effect of bivalve Corbiculafluminea activity on sediment-water exchange of dissolved inorganic nitrogen （DIN） is studied. The areas included three inte...Based on a simulative experiment and a comparison analysis, the effect of bivalve Corbiculafluminea activity on sediment-water exchange of dissolved inorganic nitrogen （DIN） is studied. The areas included three intertidal flat sites of the Changjiang （Yangtze） River estuary in China. The interface exchange flux of ammonium, nitrate and nitrite in the short experiment （6 h） was -46.4-40, -74.8-929.1 and 2.5-14.6 μmol/（m^2·h）, respectively. It was found that the burrowing activities of C. fluminea increased NH4 and NOi release from sediments to overlying water in the short-term experiment. During long-term incubation, NH4 and NOi released in turn from the sediments. At the beginning of incubation, bioturbation by C. fluminea could accelerate NH2 release from sediments 2-17 times in different sites, resulting in stronger nitrification and increased NOi concentrations in the overlying water. Sediment profile analysis post-incubation shows that organic matter mineralization and sediment-water NH4 exchange had been stimulated by C. fluminea bioturbation and bioirrigation during the experiment. Therefore, C. fluminea activities such as excretion, burrowing, irrigation and turbation can effectively alter nitrogen dynamics and accelerate and stimulate nitrogen exchange and cycling at the sediment-water interface.展开更多
A high-throughput multi-plume pulsed-laser deposition （MPPLD） system has been demonstrated and compared to previous techniques. Whereas most combinatorial pulsedlaser deposition （PLD） systems have focused on achie...A high-throughput multi-plume pulsed-laser deposition （MPPLD） system has been demonstrated and compared to previous techniques. Whereas most combinatorial pulsedlaser deposition （PLD） systems have focused on achieving thickness uniformity using sequential multilayer deposition and masking followed by post-deposition annealing, MPPLD directly deposits a compositionally varied library of compounds using the directionality of PLD plumes and the resulting spatial variations of deposition rate. This system is more suitable for high-throughput compound thin-film fabrication.展开更多
Fluorine doped tin oxide SnO2：F thin films were prepared by the spray pyrolysis （SP） technique on glass substrates by using SnC12.2H2O as a precursor and NH4F and HF as doping compounds. A comparison between the pr...Fluorine doped tin oxide SnO2：F thin films were prepared by the spray pyrolysis （SP） technique on glass substrates by using SnC12.2H2O as a precursor and NH4F and HF as doping compounds. A comparison between the properties of the films obtained by using the two doping compounds was performed by using I-V characteristics in the dark at room temperature, AC measurements, and transmittance. It is found that the films prepared by using HF have smaller resistivity, lower impedance and they are less capacitive than films prepared by using NH4F. In addition, these films have higher transmittance, higher optical bandgap energy and narrower Urbach tail width. These results are interesting for the use of SnO2：F as forecontact in CdS/CdTe solar cells.展开更多
Electrical detection schemes using nanoscale devices offer fast and label-free alternatives to biosensing techniques based on chemical and optical interactions. Here we report on the design, fabrication, and operation...Electrical detection schemes using nanoscale devices offer fast and label-free alternatives to biosensing techniques based on chemical and optical interactions. Here we report on the design, fabrication, and operation of oxide-on-graphene ion-sensitive field effect sensor arrays using large-area graphene sheets synthesized by chemical vapor deposition. In this scheme, HfO2 and SiO2 thin films are deposited atop the graphene sheet and play the dual role of the sensing interface, as well as the passivation layer protecting the channel and electrodes underneath from direct contact with the electrolyte. We further demonstrate the functionalization of the SiO2 surface with 3-aminopropyltrimethoxysilane （APTMS）. The oxide-on-graphene sensors operate in solution with high stability and a high average mobility of 5,000 cm2/（V＇s）. As a proof of principle, we demonstrate pH sensing using the bare or the APTMS-functionalized SiO2 as the sensing surface. The measured sensitivities, 46 mV/pH and 43 mV/pH, respectively, agree well with existing studies. We further show that by applying the solution gate voltage in pulse, the hysteresis in the transfer curve of the graphene transducer can be eliminated, greatly improving the ionic potential resolution of the sensor. These experiments demonstrate the potential of oxide-on-graphene ion-sensitive field effect sensors in on-chip, label-free and real-time biosensing applications.展开更多
An ordered nanostructure formed by epitaxial crystallization of a semicrystalline block copolymer on a substrate has been used as a patterned template for the selective deposition of thermally evaporated gold nanopart...An ordered nanostructure formed by epitaxial crystallization of a semicrystalline block copolymer on a substrate has been used as a patterned template for the selective deposition of thermally evaporated gold nanoparticles, resulting in the formation of structure-guiding host nanocomposites in which the ordered distribution of the guest particles is guided by the ordering of the host nanostructured block copolymer matrix. This opens new perspectives in the field of polymeric composites related to the maximum enhancement of effective physical properties and to the numerous possible applications that arise due to the presence of long-range order in the spatial distribution of functional nanoparticles.展开更多
基金NSFC(No40173030, 40701164)Science and Technology Committee of Shanghai (No 04DZ19301)
文摘Based on a simulative experiment and a comparison analysis, the effect of bivalve Corbiculafluminea activity on sediment-water exchange of dissolved inorganic nitrogen （DIN） is studied. The areas included three intertidal flat sites of the Changjiang （Yangtze） River estuary in China. The interface exchange flux of ammonium, nitrate and nitrite in the short experiment （6 h） was -46.4-40, -74.8-929.1 and 2.5-14.6 μmol/（m^2·h）, respectively. It was found that the burrowing activities of C. fluminea increased NH4 and NOi release from sediments to overlying water in the short-term experiment. During long-term incubation, NH4 and NOi released in turn from the sediments. At the beginning of incubation, bioturbation by C. fluminea could accelerate NH2 release from sediments 2-17 times in different sites, resulting in stronger nitrification and increased NOi concentrations in the overlying water. Sediment profile analysis post-incubation shows that organic matter mineralization and sediment-water NH4 exchange had been stimulated by C. fluminea bioturbation and bioirrigation during the experiment. Therefore, C. fluminea activities such as excretion, burrowing, irrigation and turbation can effectively alter nitrogen dynamics and accelerate and stimulate nitrogen exchange and cycling at the sediment-water interface.
基金partially supported by the US Department of Energy
文摘A high-throughput multi-plume pulsed-laser deposition （MPPLD） system has been demonstrated and compared to previous techniques. Whereas most combinatorial pulsedlaser deposition （PLD） systems have focused on achieving thickness uniformity using sequential multilayer deposition and masking followed by post-deposition annealing, MPPLD directly deposits a compositionally varied library of compounds using the directionality of PLD plumes and the resulting spatial variations of deposition rate. This system is more suitable for high-throughput compound thin-film fabrication.
文摘Fluorine doped tin oxide SnO2：F thin films were prepared by the spray pyrolysis （SP） technique on glass substrates by using SnC12.2H2O as a precursor and NH4F and HF as doping compounds. A comparison between the properties of the films obtained by using the two doping compounds was performed by using I-V characteristics in the dark at room temperature, AC measurements, and transmittance. It is found that the films prepared by using HF have smaller resistivity, lower impedance and they are less capacitive than films prepared by using NH4F. In addition, these films have higher transmittance, higher optical bandgap energy and narrower Urbach tail width. These results are interesting for the use of SnO2：F as forecontact in CdS/CdTe solar cells.
文摘Electrical detection schemes using nanoscale devices offer fast and label-free alternatives to biosensing techniques based on chemical and optical interactions. Here we report on the design, fabrication, and operation of oxide-on-graphene ion-sensitive field effect sensor arrays using large-area graphene sheets synthesized by chemical vapor deposition. In this scheme, HfO2 and SiO2 thin films are deposited atop the graphene sheet and play the dual role of the sensing interface, as well as the passivation layer protecting the channel and electrodes underneath from direct contact with the electrolyte. We further demonstrate the functionalization of the SiO2 surface with 3-aminopropyltrimethoxysilane （APTMS）. The oxide-on-graphene sensors operate in solution with high stability and a high average mobility of 5,000 cm2/（V＇s）. As a proof of principle, we demonstrate pH sensing using the bare or the APTMS-functionalized SiO2 as the sensing surface. The measured sensitivities, 46 mV/pH and 43 mV/pH, respectively, agree well with existing studies. We further show that by applying the solution gate voltage in pulse, the hysteresis in the transfer curve of the graphene transducer can be eliminated, greatly improving the ionic potential resolution of the sensor. These experiments demonstrate the potential of oxide-on-graphene ion-sensitive field effect sensors in on-chip, label-free and real-time biosensing applications.
文摘An ordered nanostructure formed by epitaxial crystallization of a semicrystalline block copolymer on a substrate has been used as a patterned template for the selective deposition of thermally evaporated gold nanoparticles, resulting in the formation of structure-guiding host nanocomposites in which the ordered distribution of the guest particles is guided by the ordering of the host nanostructured block copolymer matrix. This opens new perspectives in the field of polymeric composites related to the maximum enhancement of effective physical properties and to the numerous possible applications that arise due to the presence of long-range order in the spatial distribution of functional nanoparticles.
