Functionalizing and patterning of the silicon surface can be realized simultaneously by the chemomechanical method. The oxide-coated crystalline silicon （100） surface is scratched with a diamond tool in the presence...Functionalizing and patterning of the silicon surface can be realized simultaneously by the chemomechanical method. The oxide-coated crystalline silicon （100） surface is scratched with a diamond tool in the presence of aryldiazonium salt （C6H5N2BF4）. Scratching activates the silicon surface by removing the passivation oxide layer to expose fresh Si atoms. The sur- face morphologies before and after chemomechanical reaction are characterized with atomic force microscopy. Time-of-flight secondary ion mass spectroscopy confirms the presence of C6H5 and provides evidence for the formation of self-assembled monolayer （SAM） on silicon surface via Si-C covalent bonds by scratching the silicon in the presence of C6H5N2BF4. C6H5 groups further bond with surface Si atoms via Si-C covalent bonds as confirmed from infrared spectroscopy results. We propose that chemomechanical reaction, which occurred during scratching the silicon surface, produce C6H5 groups from aryldiazonium salt. The relevant adhesion of SAM is measured. It is found that SAM can reduce the adhesion of silicon. The monolayer can be used as anti-adhesion monolayer for micro/nanoelectromechanical systems components under different environments and operating conditions.展开更多
The distribution of Si atoms in the SAPO-34 framework determines its acidity and catalytic effects.This was investigated using the charge balance between the inorganic framework and trapped template ions.Three types o...The distribution of Si atoms in the SAPO-34 framework determines its acidity and catalytic effects.This was investigated using the charge balance between the inorganic framework and trapped template ions.Three types of templates,which yielded R~＋,2R~＋ and 2R^（2＋） positive charges in the cages of SAPO-34,were obtained from single crystal data and they were used to direct the synthesis of SAPO-34 with different Si contents and formation of isolated Si atoms and Si islands in the lattice.The concentration limits of SiO2 in the gel for constituting isolated Si atoms were calculated and verified experimentally.Si islands,including 5-Si,8-Si,11-Si,14-Si island were described on the basis of host-guest charge compensation.An overall view of the distribution of Si atoms in SAPO-34 was given and a criterion for the strength and density of acid sites in SAPO-34 for it to be an efficient catalyst for MTO was made available.展开更多
The adsorption equilibria of n-heptane, n-octane and n-nonane on silicalite and ZSM-5 have been measured in the temperature range of 373.15--473.15K under low pressure (0---5.332kPa). All the experimental data can be ...The adsorption equilibria of n-heptane, n-octane and n-nonane on silicalite and ZSM-5 have been measured in the temperature range of 373.15--473.15K under low pressure (0---5.332kPa). All the experimental data can be represented by a generalized characteristic curve of the extended adsorption potential theory utilizing the parameter of the initial heat of adsorption, which is estimated reasonably by a new approach.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
A series of metal chlorides supported solid catalysts were prepared by simple wet impregnation method. Their catalytic performances for Friedel-Crafts acylation of toluene with benzoyl chloride were evaluated and the ...A series of metal chlorides supported solid catalysts were prepared by simple wet impregnation method. Their catalytic performances for Friedel-Crafts acylation of toluene with benzoyl chloride were evaluated and the excellent results were obtained over FeC13/SiO2. These catalysts were characterized by BET, NH3-TPD and FT-IR of pyridine adsorption to clarify the structure-activity relationship. It was found that FeC13/SiO2 has larger pore size and pore volume than other catalysts, which increased the accessibility of the catalyst. In addition, FeC13/SiO2 ex- hibited higher molar ratio of Lewis acid sites and Brtpnsted acid sites, which might be another reason for the in- crease of toluene conversion. Furthermore, the reaction parameters, including temperature, time and molar ratio, were optimized. Under the optimized conditions, 91.2% conversion and 82.0% selectivity were obtained. Mean- while, the generality of the catalyst was demonstrated by the acylations of alkyl substituted aromatics. Finally, the catalyst was reused for four runs with slight loss in catalytic activity, which attributed to the drain of the active component.展开更多
In this paper, poly(amide-6-β-ethylene oxide) (PEBA1657) copolymer was used to prepare multilayer polyetherimide (PEI)/polydimethylsiloxane (PDMS)/PEBA1657/PDMS composite membranes by dip-coating method. Permeation b...In this paper, poly(amide-6-β-ethylene oxide) (PEBA1657) copolymer was used to prepare multilayer polyetherimide (PEI)/polydimethylsiloxane (PDMS)/PEBA1657/PDMS composite membranes by dip-coating method. Permeation behaviors of ethylene, ethane, propylene, propane, n-butane, methane and nitrogen through the multilayer composite membranes were investigated over a range of operating temperature and pressure. The permeances of light hydrocarbons through PEI/PDMS/PEBA1657/PDMS composite membranes increase with their increasing condensability, and the olefins are more permeable than their corresponding paraffins. For light hydrocarbons, the gas permeances increase significantly as temperature increasing. When the transmembrane pressure difference increases, the gas permeance increases moderately due to plasticization effect, while their apparent activation energies for permeation decrease.展开更多
To enhance the process of phenyltrichlorosilane synthesis using gas phase condensation, a series of chloralkanes were introduced. The influence of temperature and chloralkane amount on the synthesis was studied based ...To enhance the process of phenyltrichlorosilane synthesis using gas phase condensation, a series of chloralkanes were introduced. The influence of temperature and chloralkane amount on the synthesis was studied based on the product distribution from a tubular reactor. The promoting effect of chloralkane addition was mainly caused by the chloralkane radicals generated by the dissociation of C–Cl bond. The promoting effect of the chloromethane with more chlorine atoms was better than those with less chlorine atoms. Intermediates detected from the reactions with isoprene and bromobenzene demonstrated that both trichlorosilyl radical and dichlorosilylene existed in the reaction system in the presence of chloralkanes. A detailed reaction scheme was proposed.展开更多
Three new silica gel modified with calix[4]arene derivatives （p-tert-butyl-calix[4]arene （PC4）, calix[4]arene （C4） and calix[4]arene sulfonate （C4S）） have been prepared via modification of activated silica gel...Three new silica gel modified with calix[4]arene derivatives （p-tert-butyl-calix[4]arene （PC4）, calix[4]arene （C4） and calix[4]arene sulfonate （C4S）） have been prepared via modification of activated silica gel with toluene 2,4-di-iso-cyanate （TDI） as linker in tow step. The modified silica were characterized by fourier transform infrared spectroscopy （FT1R）, thermal analysis （TGA） and elemental analysis. The FTIR spectra and TGA analysis verified that the calix[4]arene derivates are covalent attached to the silica. Scanning electron microscope SEM and Brunauer-Emmett-Teller BET analysis have been done to get information about the sample＇s surface shape and area. SEM and BET analysis reveal that the modified silica are in the range of microporous adsorbent.展开更多
In this paper, we produce porous silicon （PSi） by electrochemical etching, and it is the first time to evaluate the performance of label-free porous silicon biosensor for detection of variable domain of heavy chain ...In this paper, we produce porous silicon （PSi） by electrochemical etching, and it is the first time to evaluate the performance of label-free porous silicon biosensor for detection of variable domain of heavy chain of heavy-chain antibody （VHH）. The binding of hen egg white lysozyme （HEWL） and VHH causes a red shift in the reflection spectrum of the biosensor. The red shift is proportional to the VHH concenlration in the range from 14 gg.ml-I to 30 pg.ml~ with a detection limit of 0.648 ng.ml~. The research is useful for the development of label-free biosensor applied in the rapid and sensitive determination of small molecules.展开更多
基金We thank Prof. Yang Gan of Harbin Institute of Technology, and Prof. Fu-long Yuan of Heilongjiang University for the help in the experiments. This work was supported by the Center for Precision Engineering of Harbin Institute of Technology, the Youth the Colleges and Universities in Heilongjiang Province in 2010 （No.1155G54）, the Training Fund Project of Jiamusi University （No.RC2009-037）, and the National Natural Science Foundation of China （No.51105174）.
文摘Functionalizing and patterning of the silicon surface can be realized simultaneously by the chemomechanical method. The oxide-coated crystalline silicon （100） surface is scratched with a diamond tool in the presence of aryldiazonium salt （C6H5N2BF4）. Scratching activates the silicon surface by removing the passivation oxide layer to expose fresh Si atoms. The sur- face morphologies before and after chemomechanical reaction are characterized with atomic force microscopy. Time-of-flight secondary ion mass spectroscopy confirms the presence of C6H5 and provides evidence for the formation of self-assembled monolayer （SAM） on silicon surface via Si-C covalent bonds by scratching the silicon in the presence of C6H5N2BF4. C6H5 groups further bond with surface Si atoms via Si-C covalent bonds as confirmed from infrared spectroscopy results. We propose that chemomechanical reaction, which occurred during scratching the silicon surface, produce C6H5 groups from aryldiazonium salt. The relevant adhesion of SAM is measured. It is found that SAM can reduce the adhesion of silicon. The monolayer can be used as anti-adhesion monolayer for micro/nanoelectromechanical systems components under different environments and operating conditions.
基金supported by the Natural Science Foundation of Tianjin(12JCYBJC 12700)~~
文摘The distribution of Si atoms in the SAPO-34 framework determines its acidity and catalytic effects.This was investigated using the charge balance between the inorganic framework and trapped template ions.Three types of templates,which yielded R~＋,2R~＋ and 2R^（2＋） positive charges in the cages of SAPO-34,were obtained from single crystal data and they were used to direct the synthesis of SAPO-34 with different Si contents and formation of isolated Si atoms and Si islands in the lattice.The concentration limits of SiO2 in the gel for constituting isolated Si atoms were calculated and verified experimentally.Si islands,including 5-Si,8-Si,11-Si,14-Si island were described on the basis of host-guest charge compensation.An overall view of the distribution of Si atoms in SAPO-34 was given and a criterion for the strength and density of acid sites in SAPO-34 for it to be an efficient catalyst for MTO was made available.
文摘The adsorption equilibria of n-heptane, n-octane and n-nonane on silicalite and ZSM-5 have been measured in the temperature range of 373.15--473.15K under low pressure (0---5.332kPa). All the experimental data can be represented by a generalized characteristic curve of the extended adsorption potential theory utilizing the parameter of the initial heat of adsorption, which is estimated reasonably by a new approach.
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.
基金Supported by the National Basic Research Program of China("973"Program,No.21476163)
文摘A series of metal chlorides supported solid catalysts were prepared by simple wet impregnation method. Their catalytic performances for Friedel-Crafts acylation of toluene with benzoyl chloride were evaluated and the excellent results were obtained over FeC13/SiO2. These catalysts were characterized by BET, NH3-TPD and FT-IR of pyridine adsorption to clarify the structure-activity relationship. It was found that FeC13/SiO2 has larger pore size and pore volume than other catalysts, which increased the accessibility of the catalyst. In addition, FeC13/SiO2 ex- hibited higher molar ratio of Lewis acid sites and Brtpnsted acid sites, which might be another reason for the in- crease of toluene conversion. Furthermore, the reaction parameters, including temperature, time and molar ratio, were optimized. Under the optimized conditions, 91.2% conversion and 82.0% selectivity were obtained. Mean- while, the generality of the catalyst was demonstrated by the acylations of alkyl substituted aromatics. Finally, the catalyst was reused for four runs with slight loss in catalytic activity, which attributed to the drain of the active component.
基金Supported by Key Projects in the National Science & Technology Pillar Program (2011BAC08B00)
文摘In this paper, poly(amide-6-β-ethylene oxide) (PEBA1657) copolymer was used to prepare multilayer polyetherimide (PEI)/polydimethylsiloxane (PDMS)/PEBA1657/PDMS composite membranes by dip-coating method. Permeation behaviors of ethylene, ethane, propylene, propane, n-butane, methane and nitrogen through the multilayer composite membranes were investigated over a range of operating temperature and pressure. The permeances of light hydrocarbons through PEI/PDMS/PEBA1657/PDMS composite membranes increase with their increasing condensability, and the olefins are more permeable than their corresponding paraffins. For light hydrocarbons, the gas permeances increase significantly as temperature increasing. When the transmembrane pressure difference increases, the gas permeance increases moderately due to plasticization effect, while their apparent activation energies for permeation decrease.
文摘To enhance the process of phenyltrichlorosilane synthesis using gas phase condensation, a series of chloralkanes were introduced. The influence of temperature and chloralkane amount on the synthesis was studied based on the product distribution from a tubular reactor. The promoting effect of chloralkane addition was mainly caused by the chloralkane radicals generated by the dissociation of C–Cl bond. The promoting effect of the chloromethane with more chlorine atoms was better than those with less chlorine atoms. Intermediates detected from the reactions with isoprene and bromobenzene demonstrated that both trichlorosilyl radical and dichlorosilylene existed in the reaction system in the presence of chloralkanes. A detailed reaction scheme was proposed.
文摘Three new silica gel modified with calix[4]arene derivatives （p-tert-butyl-calix[4]arene （PC4）, calix[4]arene （C4） and calix[4]arene sulfonate （C4S）） have been prepared via modification of activated silica gel with toluene 2,4-di-iso-cyanate （TDI） as linker in tow step. The modified silica were characterized by fourier transform infrared spectroscopy （FT1R）, thermal analysis （TGA） and elemental analysis. The FTIR spectra and TGA analysis verified that the calix[4]arene derivates are covalent attached to the silica. Scanning electron microscope SEM and Brunauer-Emmett-Teller BET analysis have been done to get information about the sample＇s surface shape and area. SEM and BET analysis reveal that the modified silica are in the range of microporous adsorbent.
基金supported by the National Natural Science Foundation of China (No.60968002)
文摘In this paper, we produce porous silicon （PSi） by electrochemical etching, and it is the first time to evaluate the performance of label-free porous silicon biosensor for detection of variable domain of heavy chain of heavy-chain antibody （VHH）. The binding of hen egg white lysozyme （HEWL） and VHH causes a red shift in the reflection spectrum of the biosensor. The red shift is proportional to the VHH concenlration in the range from 14 gg.ml-I to 30 pg.ml~ with a detection limit of 0.648 ng.ml~. The research is useful for the development of label-free biosensor applied in the rapid and sensitive determination of small molecules.
