In order to clarify the effect of pt addition on the stress of NiSi film, in situ stress measurements were taken to evaluate the stress evolution during heating and cooling treatment of Ni1- x Ptx Si alloy films with ...In order to clarify the effect of pt addition on the stress of NiSi film, in situ stress measurements were taken to evaluate the stress evolution during heating and cooling treatment of Ni1- x Ptx Si alloy films with different Pt concentrations. The room temperature stress, which is mainly thermal stress, was measured to be 775MPa and 1.31GPa for pure NiSi and pure PtSi films grown on Si （100） substrates,respectively. For Ni1-x Ptx Si alloy film, the room temperature stress was observed to increase steadily with Pt concentration. From the temperature dependent stress evolution curves,the stress relaxation temperature was found to increase from 440℃ （for pure NiSi film） to 620℃ （for pure PtSi film） with increasing Pt concentration, thus influencing the residual stress at room temperature.展开更多
[SiO2/FePt]5/Ag thin films were deposited by RF magnetron sputtering on the glass substrates and post annealing at 550 ℃ for 30 min in vacuum. Vibrating sample magnetometer and X-ray diffraction analyser were applied...[SiO2/FePt]5/Ag thin films were deposited by RF magnetron sputtering on the glass substrates and post annealing at 550 ℃ for 30 min in vacuum. Vibrating sample magnetometer and X-ray diffraction analyser were applied to study the magnetic properties and microstructures of the films. The results show that without Ag underlayer [SiO2/FePt]5 films deposited onto the glass are FCC disordered; with the addition of Ag underlayer [SiO]FePt]5/Ag films are changed into L10 and （111） mixed texture. The variation of the SiO2 nonmagnetic layer thickness in [SiO2/FePt]5/Ag films indicates that SiO2-doping plays an important role in improving the order parameter and the perpendicular magnetic anisotropy, and reducing the grain size and intergrain interactions. By controlling SiO2 thickness the highly perpendicular magnetic anisotropy can be obtained in the [SiO2 （0.6 nm）/FePt （3 nm）]5/Ag （50 nm） films and highly （001）-oriented films can be obtained in the [SiO2 （2 nm）/FePt （3 nm）]5/Ag （50 nm） films.展开更多
A new 128×128 element PtSi Schottky barrier infrared image sensor with ITCCD readout structure and PtSi thin film optical cavity detector structure has been fabricated,which has 50μm×50 μm pixels,a fill fa...A new 128×128 element PtSi Schottky barrier infrared image sensor with ITCCD readout structure and PtSi thin film optical cavity detector structure has been fabricated,which has 50μm×50 μm pixels,a fill factor of 40 percent,the nonuniformity of 5% or less and the dynamic range of over or equal to 50 dB.The noise equivalent temperature difference is 0.2 K with f/1.0 optics at 300 K background. In this paper,the principle of operation,design consideration and fabrication technology for the device are described.展开更多
A series of aromatic acids has been tested as additives for the platinum-catalyzed hydrosilylation of styrene with triethoxysilane. Both excellent conversion of styrene and selectivity in favor of the ,β-adduct were ...A series of aromatic acids has been tested as additives for the platinum-catalyzed hydrosilylation of styrene with triethoxysilane. Both excellent conversion of styrene and selectivity in favor of the ,β-adduct were achieved using aminobenzoic acids as additive. Moreover, the use of 4-aminobenzoic acid led to significantly superior enhancement in both catalytic activity and selectivity among the tested aminobenzoic acids. Indeed, 100% conversion of styrene and 98.4% selectivity in favor of the β-adduct were obtained. Additionally, hydrosilylations of various alkenes with a variety of platinum catalysts have also been tested, and in each case the conversion of substrate and the selectivity of the β-adduct were promoted by using 4-aminobenzoic acid as additive.展开更多
Network crewn ether polymer with pendant sulfide side ohain in the networkstructure units has been synthesized via ring- opening copolymerization of β-ethylthioethyl glycidyl ether and diethylene glycol bisglycidyl e...Network crewn ether polymer with pendant sulfide side ohain in the networkstructure units has been synthesized via ring- opening copolymerization of β-ethylthioethyl glycidyl ether and diethylene glycol bisglycidyl ether. A kind of active catalyst suitable for this reaction was suggested. The title polymer was found tobe a good ligand for platinous chloride, and the platinous complex could catalyze thehydrosilylation of olefins with triethoxysilane efficiently.展开更多
A series of carboxylated long chain polyethylene glycols(abbreviated as PEGCOOH) has been synthesized and used to support chloroplatinic acid.These supported catalysts were then tested for their efficiency in the hydr...A series of carboxylated long chain polyethylene glycols(abbreviated as PEGCOOH) has been synthesized and used to support chloroplatinic acid.These supported catalysts were then tested for their efficiency in the hydrosilylation of alkenes.The factors affecting their catalytic properties,e.g.relative molecular mass of polyethylene glycol,reaction temperature,platinum content,and type of alkenes,have been studied.It was found that the activity of the platinum catalyst decreased with increasing length of the polyethylene glycol chain,and increased with reaction temperature.Moreover,these catalysts could be reused several times without a noticeable decrease in activity or selectivity.The reaction pathway leading to excellent selectivity for the β-adduct of hydrosilylation of alkenes with triethoxysilane catalyzed by this catalysis system was discussed.展开更多
Ferroelectric materials were widely applied for actuators and sensors. Barium zirconate titanate Ba(Zr0.25Ti0.75)O3 thin film was grown on Pt/Ti/SiO2/Si(100) substrates by pulsed laser deposition. Structure and surfac...Ferroelectric materials were widely applied for actuators and sensors. Barium zirconate titanate Ba(Zr0.25Ti0.75)O3 thin film was grown on Pt/Ti/SiO2/Si(100) substrates by pulsed laser deposition. Structure and surface morphology of the thin film were studied by X-ray diffractometry(XRD) and scan electronic microscopy(SEM). The composition and chemical state near the film surface were obtained by X-ray photoelectron spectroscopy(XPS). On the sample surface,O 1s spectra can be assigned to those from the lattice and surface adsorbed oxygen ions,while C1s only result from surface contamination. The result shows that only one chemical state is found for each spectrum of Ba 3d,Zr 3d and Ti 2p photoelectron in the BZT thin film.展开更多
CO self-poisoning and slow surface kinetics pose major challenges to a CO oxidation catalyst that should work at ambient temperature.Furthermore,the presence of moisture would cause passivation of the catalyst A highl...CO self-poisoning and slow surface kinetics pose major challenges to a CO oxidation catalyst that should work at ambient temperature.Furthermore,the presence of moisture would cause passivation of the catalyst A highly active ceria promoted Pt catalyst（4%Pt-12%CeO_2/SiO_2;conversion≥99%at low（ 500 ppm） and high（ 2500 ppm） CO concentrations was developed for CO oxidation at ambient temperature in humid air.Catalyst preparation variables such as Pt and CeO_2 loading,ceria deposition method,drying and calcination conditions for the ceria and Pt precursors were optimized experimentally.The activity was correlated with surface properties using CO/H_2 chemisorption,O_2-H_2 titration,X-ray diffraction and BET surface area analysis.The method of CeO_2 deposition had a significant impact on the catalytic activity.CeO_2 deposition by impregnation resulted in a catalyst that was three times more active than that prepared by deposition precipitation or CeO_2grafting.O_2-H_2 titration results revealed that the close association of ceria and Pt in the case of CeO_2deposition by impregnation resulted in higher activity.The catalyst support used was also crucial as a silica supported catalyst was five times more active than an alumina supported catalyst.The particle size and pore structure of the catalyst support were also crucial as the reaction was diffusion controlled.The drying and calcination conditions of the ceria and Pt precursors also played a crucial role in determining the catalytic activity.The Pt-CeO_2/SiO_2 catalysts with Pt 2.5 wt%and CeO_2 15 wt%were highly active（TOF 0.02 s^（-1）） and stable（conversion 99%after 15 h） at ambient conditions.展开更多
A new synthetic strategy has been developed to encapsulate supported Pt nanoparticles in heterogeneous catalysts to prevent their sintering. Model catalysts were first prepared by dispersing -3-nm Pt nanoparticles on ...A new synthetic strategy has been developed to encapsulate supported Pt nanoparticles in heterogeneous catalysts to prevent their sintering. Model catalysts were first prepared by dispersing -3-nm Pt nanoparticles on -120-nm silica beads. These were then covered with a fresh layer of mesoporous silica, a few tens of nanometers thick, and etched to re-expose the metal surface to the reaction mixtures. TEM images were used to confirm the success of each of the synthesis steps, and both CO titrations and kinetic measurements for the catalytic conversion of cis- and trans-2-butenes with hydrogen were employed to test the degree of re-activation of the catalyst obtained after the etching treatment, which had to be tuned to give simultaneous maximum activity and maximum catalyst stability. The resulting encapsulated platinum nanoparticles were shown to resist sintering during calcination at temperatures as high as 1075 K, whereas the unprotected catalysts were seen to sinter by 875 K.展开更多
The oxo-functionalization of hydrocarbons is themost important type of reaction in organic chemical productions. Among various oxidizing reagents, more andmore studies have focused on the employment of molecular oxyge...The oxo-functionalization of hydrocarbons is themost important type of reaction in organic chemical productions. Among various oxidizing reagents, more andmore studies have focused on the employment of molecular oxygen as oxidizing species in order to realize innovative and economically advantageous process, and at thesame time, move toward a “sustainable chemistry”.展开更多
文摘In order to clarify the effect of pt addition on the stress of NiSi film, in situ stress measurements were taken to evaluate the stress evolution during heating and cooling treatment of Ni1- x Ptx Si alloy films with different Pt concentrations. The room temperature stress, which is mainly thermal stress, was measured to be 775MPa and 1.31GPa for pure NiSi and pure PtSi films grown on Si （100） substrates,respectively. For Ni1-x Ptx Si alloy film, the room temperature stress was observed to increase steadily with Pt concentration. From the temperature dependent stress evolution curves,the stress relaxation temperature was found to increase from 440℃ （for pure NiSi film） to 620℃ （for pure PtSi film） with increasing Pt concentration, thus influencing the residual stress at room temperature.
基金Project(10574085) supported by the National Natural Science Foundation of ChinaProject(207020) supported by the Science Technology Key Project of the Ministry of Education, China
文摘[SiO2/FePt]5/Ag thin films were deposited by RF magnetron sputtering on the glass substrates and post annealing at 550 ℃ for 30 min in vacuum. Vibrating sample magnetometer and X-ray diffraction analyser were applied to study the magnetic properties and microstructures of the films. The results show that without Ag underlayer [SiO2/FePt]5 films deposited onto the glass are FCC disordered; with the addition of Ag underlayer [SiO]FePt]5/Ag films are changed into L10 and （111） mixed texture. The variation of the SiO2 nonmagnetic layer thickness in [SiO2/FePt]5/Ag films indicates that SiO2-doping plays an important role in improving the order parameter and the perpendicular magnetic anisotropy, and reducing the grain size and intergrain interactions. By controlling SiO2 thickness the highly perpendicular magnetic anisotropy can be obtained in the [SiO2 （0.6 nm）/FePt （3 nm）]5/Ag （50 nm） films and highly （001）-oriented films can be obtained in the [SiO2 （2 nm）/FePt （3 nm）]5/Ag （50 nm） films.
文摘A new 128×128 element PtSi Schottky barrier infrared image sensor with ITCCD readout structure and PtSi thin film optical cavity detector structure has been fabricated,which has 50μm×50 μm pixels,a fill factor of 40 percent,the nonuniformity of 5% or less and the dynamic range of over or equal to 50 dB.The noise equivalent temperature difference is 0.2 K with f/1.0 optics at 300 K background. In this paper,the principle of operation,design consideration and fabrication technology for the device are described.
基金Supported by the National High Technology Research and Development Program of China (2006AA03A134)Zhejiang Province Program (2008C14041)
文摘A series of aromatic acids has been tested as additives for the platinum-catalyzed hydrosilylation of styrene with triethoxysilane. Both excellent conversion of styrene and selectivity in favor of the ,β-adduct were achieved using aminobenzoic acids as additive. Moreover, the use of 4-aminobenzoic acid led to significantly superior enhancement in both catalytic activity and selectivity among the tested aminobenzoic acids. Indeed, 100% conversion of styrene and 98.4% selectivity in favor of the β-adduct were obtained. Additionally, hydrosilylations of various alkenes with a variety of platinum catalysts have also been tested, and in each case the conversion of substrate and the selectivity of the β-adduct were promoted by using 4-aminobenzoic acid as additive.
文摘Network crewn ether polymer with pendant sulfide side ohain in the networkstructure units has been synthesized via ring- opening copolymerization of β-ethylthioethyl glycidyl ether and diethylene glycol bisglycidyl ether. A kind of active catalyst suitable for this reaction was suggested. The title polymer was found tobe a good ligand for platinous chloride, and the platinous complex could catalyze thehydrosilylation of olefins with triethoxysilane efficiently.
基金Supported by the Educational Commission of Zhejiang Province of China (Y201017419)Zhejiang Province Program(2008C14041)
文摘A series of carboxylated long chain polyethylene glycols(abbreviated as PEGCOOH) has been synthesized and used to support chloroplatinic acid.These supported catalysts were then tested for their efficiency in the hydrosilylation of alkenes.The factors affecting their catalytic properties,e.g.relative molecular mass of polyethylene glycol,reaction temperature,platinum content,and type of alkenes,have been studied.It was found that the activity of the platinum catalyst decreased with increasing length of the polyethylene glycol chain,and increased with reaction temperature.Moreover,these catalysts could be reused several times without a noticeable decrease in activity or selectivity.The reaction pathway leading to excellent selectivity for the β-adduct of hydrosilylation of alkenes with triethoxysilane catalyzed by this catalysis system was discussed.
基金Project(05001825) supported by Guangdong Provincial Natural Science Foundation of Chinaproject(KF0707) supported by the Opening Project Program of Key Laboratory of Low Dimensional Materials and Application Technology (Xiangtan University), Ministry ofEducation, China
文摘Ferroelectric materials were widely applied for actuators and sensors. Barium zirconate titanate Ba(Zr0.25Ti0.75)O3 thin film was grown on Pt/Ti/SiO2/Si(100) substrates by pulsed laser deposition. Structure and surface morphology of the thin film were studied by X-ray diffractometry(XRD) and scan electronic microscopy(SEM). The composition and chemical state near the film surface were obtained by X-ray photoelectron spectroscopy(XPS). On the sample surface,O 1s spectra can be assigned to those from the lattice and surface adsorbed oxygen ions,while C1s only result from surface contamination. The result shows that only one chemical state is found for each spectrum of Ba 3d,Zr 3d and Ti 2p photoelectron in the BZT thin film.
基金supported by US Army contract(W56HZV-05-C0686) at Auburn University administered through TARDEC
文摘CO self-poisoning and slow surface kinetics pose major challenges to a CO oxidation catalyst that should work at ambient temperature.Furthermore,the presence of moisture would cause passivation of the catalyst A highly active ceria promoted Pt catalyst（4%Pt-12%CeO_2/SiO_2;conversion≥99%at low（ 500 ppm） and high（ 2500 ppm） CO concentrations was developed for CO oxidation at ambient temperature in humid air.Catalyst preparation variables such as Pt and CeO_2 loading,ceria deposition method,drying and calcination conditions for the ceria and Pt precursors were optimized experimentally.The activity was correlated with surface properties using CO/H_2 chemisorption,O_2-H_2 titration,X-ray diffraction and BET surface area analysis.The method of CeO_2 deposition had a significant impact on the catalytic activity.CeO_2 deposition by impregnation resulted in a catalyst that was three times more active than that prepared by deposition precipitation or CeO_2grafting.O_2-H_2 titration results revealed that the close association of ceria and Pt in the case of CeO_2deposition by impregnation resulted in higher activity.The catalyst support used was also crucial as a silica supported catalyst was five times more active than an alumina supported catalyst.The particle size and pore structure of the catalyst support were also crucial as the reaction was diffusion controlled.The drying and calcination conditions of the ceria and Pt precursors also played a crucial role in determining the catalytic activity.The Pt-CeO_2/SiO_2 catalysts with Pt 2.5 wt%and CeO_2 15 wt%were highly active（TOF 0.02 s^（-1）） and stable（conversion 99%after 15 h） at ambient conditions.
文摘A new synthetic strategy has been developed to encapsulate supported Pt nanoparticles in heterogeneous catalysts to prevent their sintering. Model catalysts were first prepared by dispersing -3-nm Pt nanoparticles on -120-nm silica beads. These were then covered with a fresh layer of mesoporous silica, a few tens of nanometers thick, and etched to re-expose the metal surface to the reaction mixtures. TEM images were used to confirm the success of each of the synthesis steps, and both CO titrations and kinetic measurements for the catalytic conversion of cis- and trans-2-butenes with hydrogen were employed to test the degree of re-activation of the catalyst obtained after the etching treatment, which had to be tuned to give simultaneous maximum activity and maximum catalyst stability. The resulting encapsulated platinum nanoparticles were shown to resist sintering during calcination at temperatures as high as 1075 K, whereas the unprotected catalysts were seen to sinter by 875 K.
文摘The oxo-functionalization of hydrocarbons is themost important type of reaction in organic chemical productions. Among various oxidizing reagents, more andmore studies have focused on the employment of molecular oxygen as oxidizing species in order to realize innovative and economically advantageous process, and at thesame time, move toward a “sustainable chemistry”.
