The NiCoCrAlY coatings strengthened by three nano-particles with the same addition were prepared on a Ni-base super alloy using laser cladding technique. The dry frictional wear behaviors of the coatings at 500 ℃ in ...The NiCoCrAlY coatings strengthened by three nano-particles with the same addition were prepared on a Ni-base super alloy using laser cladding technique. The dry frictional wear behaviors of the coatings at 500 ℃ in static air were investigated. The comparison was made with the coating without nano-particles. The results show that the wear mechanism of the NiCoCrAlY coatings with nano-particles, like the coating without nano-particles, is the delamination wear due to the strong plastic deformation and oxidative wear. However, the frictional coefficient of the coatings increases and presents the decrease trend with the increase of sliding distance after adding nano-particles. Moreover, the wear rate of the coatings with nano-particles is only 34.0%-64.5% of the coating without nano-particles. Among the three nano-particles, the improvement of nano-SiC on the high temperature wear resistance of the coating is the most significant.展开更多
The viscoplastic friction and nanostructure formation mechanism of laser-clad Co-based coating were studied by rotary friction between laser-clad Co-Cr-Ni-Mo coating and WC-Co rod.The friction coefficient,friction int...The viscoplastic friction and nanostructure formation mechanism of laser-clad Co-based coating were studied by rotary friction between laser-clad Co-Cr-Ni-Mo coating and WC-Co rod.The friction coefficient,friction interface temperature and axial displacement—time curves during rotary friction process were measured.The results showed that all the curves firstly experienced rising stage and then steady stage.The rising stage corresponded to sliding friction while the steady stage corresponded to viscoplastic friction.After viscoplastic friction processing,three typical zones of viscoplastic deformation zone,thermo-mechanically affected zone,and original laser-clad zone can be observed successively from the friction surface to the interior.The viscoplastic deformation significantly crushed the network M23C7 phase in original laser-clad zone and made it dispersively distributed with equiaxial shape and in nano-scale.The viscoplastic zone,in width of 37-131 μm,is mainly characterized by refined M23C7 and α-Co phase with grain size bellow 50 nm,and even a small quantity of amorphous.Thus,the hardness of viscoplastic zone about HV997 was improved compared with the hardness of original laser-clad zone about HV600.展开更多
In this work a novel strategy has been developed to prepare well-dispersed amine-functionalized SiO2 nanodot-coated layered double hydroxide nano- composite （NH2-SiO2@LDH） via electrostatic interactions and condensa...In this work a novel strategy has been developed to prepare well-dispersed amine-functionalized SiO2 nanodot-coated layered double hydroxide nano- composite （NH2-SiO2@LDH） via electrostatic interactions and condensation of （3-aminopropyl）triethoxysilane （APTES）. This nanocomposite system is well dispersed in culture media and phosphate buffered saline, and exhibits low cytotoxicity and good biocompatibility. The fluorescence microscopy images and flow cytometry data indicate that such an NH2-SiO2@LDH nanocomposite is able to efficiently deliver small interfering RNA （siRNA） into the U2OS cell line to inhibit cell proliferation. Thus, NH2-SiOR@LDH nanocomposite has a great potential as a nanocarrier for efficient gene delivery.展开更多
Urchin-like SnO2 microspheres have been grown for use as photoanodes in dye-sensitized solar cells （DSSCs）. We observed that a thin layer coating of TiO2 on urchin-like SnO2 microsphere photoanodes greatly enhanced ...Urchin-like SnO2 microspheres have been grown for use as photoanodes in dye-sensitized solar cells （DSSCs）. We observed that a thin layer coating of TiO2 on urchin-like SnO2 microsphere photoanodes greatly enhanced dye loading capability and light scattering ability, and achieved comparable solar cell per- formance even at half the thickness of a typical nanocrystalline TiO2 photoanode. In addition, this photoanode only required attaching -55% of the amount of dye for efficient light harvesting compared to one based on nanocrystalline TiO2. Longer decay of transient photovoltage and higher charge recombination resistance evidenced from electrochemical impedance spectroscopy of the devices based on TiO2 coated urchin-like SnO2 revealed slower recombination rates of electrons as a result of the thin blocking layer of TiO2 coated on urchin- like SnO2. TiO2 coated urchin-like SnO2 showed the highest value （76.1 ms） of electron lifetime （＇r） compared to 2.4 ms for bare urchin-like SnO2 and 14.9 ms for nanocrystalline TiO2. TiO2 coated SnO2 showed greatly enhanced open circuit voltage （Voc）, short-circuit current density （Jsc） and fill factor （FF） leading to a four-fold increase in efficiency increase compared to bare SnO2. Although TiO2 coated urchin-like SnO2 showed slightly lower cell efficiency than nanocrystalline TiO2, it only used a half thickness of photoanode and saved -45% of the amount of dye for efficient light harvesting compared to normal nanocrystalline TiO2.展开更多
A localized surface plasmon resonance(LSPR) biosensor was prepared with gold nanospheres(Au NSs) coated on the tip face of the optical silica fiber. Au NSs with the sizes of 20 nm and 80 nm were used. The sensitivitie...A localized surface plasmon resonance(LSPR) biosensor was prepared with gold nanospheres(Au NSs) coated on the tip face of the optical silica fiber. Au NSs with the sizes of 20 nm and 80 nm were used. The sensitivities of Au NS_(20 nm) and Au NS_(80 nm) modified sensors to bulk refractive index(RI) variation are 82.86 nm/RIU and 218.98 nm/RIU, respectively. The Au NS_(80 nm) modified sensor was used for the detection of 40 bases DNA hybridization and the limit of detection is 50 nmol/L, where the 40-bases DNA probe was covalently linked with Au NS_(80 nm). The complementary DNA sequence in tris-acetate-EDTA(TAE) buffer solution was detected as the target DNA. This fiber sensor has the advantages of small sample consumption, easy fabrication and high sensitivity.展开更多
基金Project(20060287019)supported by the Research Fund for Doctoral Program of Higher Education of ChinaProject(kjsmcx07001)supported by the Opening Research Fund of Jiangsu Key Laboratory of Tribology,ChinaProject(BK2010267)supported by the Jiangsu Provincial Natural Science Foundation of Jiangsu Province,China
文摘The NiCoCrAlY coatings strengthened by three nano-particles with the same addition were prepared on a Ni-base super alloy using laser cladding technique. The dry frictional wear behaviors of the coatings at 500 ℃ in static air were investigated. The comparison was made with the coating without nano-particles. The results show that the wear mechanism of the NiCoCrAlY coatings with nano-particles, like the coating without nano-particles, is the delamination wear due to the strong plastic deformation and oxidative wear. However, the frictional coefficient of the coatings increases and presents the decrease trend with the increase of sliding distance after adding nano-particles. Moreover, the wear rate of the coatings with nano-particles is only 34.0%-64.5% of the coating without nano-particles. Among the three nano-particles, the improvement of nano-SiC on the high temperature wear resistance of the coating is the most significant.
基金Project(51101126) supported by the National Natural Science Foundation of ChinaProjects(20110491684,2012T50817) supported by the China Postdoctoral Science FoundationProject(20110942K) supported by the Open Fund of State Key Laboratory of Powder Metallurgy,China
文摘The viscoplastic friction and nanostructure formation mechanism of laser-clad Co-based coating were studied by rotary friction between laser-clad Co-Cr-Ni-Mo coating and WC-Co rod.The friction coefficient,friction interface temperature and axial displacement—time curves during rotary friction process were measured.The results showed that all the curves firstly experienced rising stage and then steady stage.The rising stage corresponded to sliding friction while the steady stage corresponded to viscoplastic friction.After viscoplastic friction processing,three typical zones of viscoplastic deformation zone,thermo-mechanically affected zone,and original laser-clad zone can be observed successively from the friction surface to the interior.The viscoplastic deformation significantly crushed the network M23C7 phase in original laser-clad zone and made it dispersively distributed with equiaxial shape and in nano-scale.The viscoplastic zone,in width of 37-131 μm,is mainly characterized by refined M23C7 and α-Co phase with grain size bellow 50 nm,and even a small quantity of amorphous.Thus,the hardness of viscoplastic zone about HV997 was improved compared with the hardness of original laser-clad zone about HV600.
文摘In this work a novel strategy has been developed to prepare well-dispersed amine-functionalized SiO2 nanodot-coated layered double hydroxide nano- composite （NH2-SiO2@LDH） via electrostatic interactions and condensation of （3-aminopropyl）triethoxysilane （APTES）. This nanocomposite system is well dispersed in culture media and phosphate buffered saline, and exhibits low cytotoxicity and good biocompatibility. The fluorescence microscopy images and flow cytometry data indicate that such an NH2-SiO2@LDH nanocomposite is able to efficiently deliver small interfering RNA （siRNA） into the U2OS cell line to inhibit cell proliferation. Thus, NH2-SiOR@LDH nanocomposite has a great potential as a nanocarrier for efficient gene delivery.
文摘Urchin-like SnO2 microspheres have been grown for use as photoanodes in dye-sensitized solar cells （DSSCs）. We observed that a thin layer coating of TiO2 on urchin-like SnO2 microsphere photoanodes greatly enhanced dye loading capability and light scattering ability, and achieved comparable solar cell per- formance even at half the thickness of a typical nanocrystalline TiO2 photoanode. In addition, this photoanode only required attaching -55% of the amount of dye for efficient light harvesting compared to one based on nanocrystalline TiO2. Longer decay of transient photovoltage and higher charge recombination resistance evidenced from electrochemical impedance spectroscopy of the devices based on TiO2 coated urchin-like SnO2 revealed slower recombination rates of electrons as a result of the thin blocking layer of TiO2 coated on urchin- like SnO2. TiO2 coated urchin-like SnO2 showed the highest value （76.1 ms） of electron lifetime （＇r） compared to 2.4 ms for bare urchin-like SnO2 and 14.9 ms for nanocrystalline TiO2. TiO2 coated SnO2 showed greatly enhanced open circuit voltage （Voc）, short-circuit current density （Jsc） and fill factor （FF） leading to a four-fold increase in efficiency increase compared to bare SnO2. Although TiO2 coated urchin-like SnO2 showed slightly lower cell efficiency than nanocrystalline TiO2, it only used a half thickness of photoanode and saved -45% of the amount of dye for efficient light harvesting compared to normal nanocrystalline TiO2.
基金supported by the National Basic Research Program of China(No.2014M561055)the National High Technology Research and Development Program(No.2012AA101608)the National Natural Science Foundation of China(No.61401433)
文摘A localized surface plasmon resonance(LSPR) biosensor was prepared with gold nanospheres(Au NSs) coated on the tip face of the optical silica fiber. Au NSs with the sizes of 20 nm and 80 nm were used. The sensitivities of Au NS_(20 nm) and Au NS_(80 nm) modified sensors to bulk refractive index(RI) variation are 82.86 nm/RIU and 218.98 nm/RIU, respectively. The Au NS_(80 nm) modified sensor was used for the detection of 40 bases DNA hybridization and the limit of detection is 50 nmol/L, where the 40-bases DNA probe was covalently linked with Au NS_(80 nm). The complementary DNA sequence in tris-acetate-EDTA(TAE) buffer solution was detected as the target DNA. This fiber sensor has the advantages of small sample consumption, easy fabrication and high sensitivity.
