Ultra-high strength and modulus polyethylene fibers can be produced from UHMW-PE(ul-tra-high molecular weight polyethylene) by gel spinning and ultra-high drawing method.The spe-cial supermolecular structure of″shish...Ultra-high strength and modulus polyethylene fibers can be produced from UHMW-PE(ul-tra-high molecular weight polyethylene) by gel spinning and ultra-high drawing method.The spe-cial supermolecular structure of″shish-kebabs″ is the intrinsic course for the fiber having highperformance.In this paper,the formation mechanism of the characteristic structure of PE fibershas been investigated by means of SEM,DSC,WAXD,SAXS and TEM,The experimental resultsshow that the extended-chain structure of PE fibers is formed originally from the bridged mole-cules in amorphous region and increased gradually during further drawing porcess.The″shish-kebab″ structure is formed by the combination of extended-chalnS and originalfolded-chains.展开更多
Some noticeable effects of process conditions, such as coagulation bath, solvent extraction, drying shrinkage and ultra-drawing, on the structure and properties of gel-spun PVA fibers are studied and discussed. High s...Some noticeable effects of process conditions, such as coagulation bath, solvent extraction, drying shrinkage and ultra-drawing, on the structure and properties of gel-spun PVA fibers are studied and discussed. High strength and high modulus PVA fibers with tensile strength of 11.3 cN / dtex and initial modulus of 430 cN / dtex have been obtained.展开更多
Polycrystalline 3Y-TZP/Al2O3 tetragonal zirconia fiber was obtained by the pyrolysis of gel fibers using zirconium oxychloride octahydrate(ZOC) as the raw material. The spinnable zirconia sol was prepared by electro...Polycrystalline 3Y-TZP/Al2O3 tetragonal zirconia fiber was obtained by the pyrolysis of gel fibers using zirconium oxychloride octahydrate(ZOC) as the raw material. The spinnable zirconia sol was prepared by electrolyzing the zirco-nium oxychloride octahydrate(ZOC) solution in the presence of acetic acid and sugar( sucrose, glucrose or fructose) , in which the molar ratios of CH3 COOH/ZOC and sugar/ZOC were 1.0-4.0 and 0.2-0.4, respectively. The pre- pared tetragonal zireonia fibers sintered at different temperatures showed smooth and crack-free surfaces with diame, ters of 5-10 μm. The addition of Al2O3 enhanced the sintering process and prevented the crystals from growing. Thermogravimetric analysis(TG), X-ray diffraction ( XRD ), Fourier transform infrared spectroscopy(FTIR), and scanning electron microscope(SEM) techniques were used to characterize the prepared fibers.展开更多
AIM: To investigate diffusion in mammalian cell culture by gel entrapment within hollow fibers.METHODS: Freshly isolated rat hepatocytes or human oral epidermoid carcinoma (KB) cells were entrapped in type Ⅰ collagen...AIM: To investigate diffusion in mammalian cell culture by gel entrapment within hollow fibers.METHODS: Freshly isolated rat hepatocytes or human oral epidermoid carcinoma (KB) cells were entrapped in type Ⅰ collagen solutions and statically cultured inside microporous and ultrafiltration hollow fibers. During the culture time collagen gel contraction, cell viability and specific function were assessed. Effective diffusion coefficients of glucose in cell-matrix gels were determined by lag time analysis in a diffusion cell.R ESULTS: Significant gel contractions occurred in the collagen gels by entrapment of either viable hepatocytes or KB cells. And the gel contraction caused a significant reduction on effective diffusion coefficient of glucose. The cell viability assay of both hepatocytes and KB cells statically cultured in hollow fibers by collagen entrapment further confirmed the existence of the inhibited mass transfer by diffusion. Urea was secreted about 50% more by hepatocytes entrapped in hollow fibers with pore size of 0.1 pm than that in hollow fibers with MWCO of 100 ku.CONCLUSION: Cell-matrix gel and membrane pore size are the two factors relevant to the limited mass transfer by diffusion in such gel entrapment of mammalian cell culture.展开更多
Long alumina fibers were prepared by sol-gel method.The spinning sol was obtained by mixing aluminum nitrate,tartaric acid,and polyvinylpyrrolidone with a mass ratio of 10∶3∶1.5.Thermogravimetry-differential scannin...Long alumina fibers were prepared by sol-gel method.The spinning sol was obtained by mixing aluminum nitrate,tartaric acid,and polyvinylpyrrolidone with a mass ratio of 10∶3∶1.5.Thermogravimetry-differential scanning calorimetry (TG-DSC),Fourier transform infrared (FT-IR) spectra,X-ray diffraction (XRD),and scanning electron microscopy (SEM) were used to characterize the properties of the gel and ceramic fibers.A little of α-Al2O3 phase is observed in the alumina precursor gel fibers sintered at 1273 K.The fibers with a uniform diameter can be obtained when sintered at 1473 K,and its main phase is also indentified as α-Al2O3.展开更多
It is believed that gel spun polyethylene(PE)fibers have a somewhat extended chain crystalstructure,because of the disentangling of the chains which takes place in semi-dilute solutionand the ultra high draw ratio use...It is believed that gel spun polyethylene(PE)fibers have a somewhat extended chain crystalstructure,because of the disentangling of the chains which takes place in semi-dilute solutionand the ultra high draw ratio used.Ten years ago,PE shish-kebabs grown from dilute solutionwere proved to have extended chain backbone which causes the raising of its melting point.These crystals were found to have a triclinic crystal phase,This study shows a different result forgel spun ultra high drawn PE fiber.The unit cell remains orthorhombic even if the draw ratioreaches 50;as the draw ratio increases,the length in a and b axes are shortened while that in c ax-is changes quite insignificantly.When the draw ratio is over 10,two endothermic melting peakscan be seen in the DSC curves with corresponding peak temperature of 136.7-145.3℃.The lat-ter peak is attributed to the amount of extended chain crystal.展开更多
Ferromagnetic metal fibers with a high aspect ratio (length/diameter) are attractive for use as high performance electromagnetic interference shielding materials. Ferromagnetic binary alloy fine fibers of iron-nickel,...Ferromagnetic metal fibers with a high aspect ratio (length/diameter) are attractive for use as high performance electromagnetic interference shielding materials. Ferromagnetic binary alloy fine fibers of iron-nickel, iron-cobalt and cobalt-nickel were prepared by the organic gel-thermal reduction process from the raw materials of critic acid and metal salts. These alloy fibers synthesized were featured with a diameter of about 1 μm and a length as long as 1 m. The structure, thermal decomposition process and morphologies of the gel precursors and fibers derived from thermal reduction of the gel precursors were characterized by FTIR, XRD, TG/DSC and SEM. The gel spinnability largely depends on the molecular structure of metal- carboxylates formed during the gel formation. The gel consisting of linear-type structural molecules shows good spinnability.展开更多
BaFe12O19 fibers was prepared via an aqueous sol-gel process using Fe(OH)(HCOO)2 synthesized in laboratory and Ba(CH3COO)2 as the original materials and citrate as the chelate. The rheological behaviour of spinnable s...BaFe12O19 fibers was prepared via an aqueous sol-gel process using Fe(OH)(HCOO)2 synthesized in laboratory and Ba(CH3COO)2 as the original materials and citrate as the chelate. The rheological behaviour of spinnable sol was characterized on rheometer, and the development of gel fibers to barium ferrite fibers was studied by IR, TG and XRD. Morphology observation of the fibers was given on SEM, and the diameter of the obtained fibers was between 5 and 10 μm corresponding to different additives. The additives affected the surface tension of the precursor sol which had close relation to the microstructure of fibers. Sucrose and hydroxyethylic cellulose could improve the surface tension while diethanolamine and hexadecylamine reduce that of the precursor sol. And using diethanolamine or hexadecylamine as an additive, well-structured BaFe12O19 fibers could be obtained.展开更多
The organic gel-thermal reduction process was successfully used for the preparation of magnetic metal Ni, Fe, Fe-Ni fine fibers from raw materials of citric acid or lactic acid and metal salts. Ni, Fe and Fe-Ni fine f...The organic gel-thermal reduction process was successfully used for the preparation of magnetic metal Ni, Fe, Fe-Ni fine fibers from raw materials of citric acid or lactic acid and metal salts. Ni, Fe and Fe-Ni fine fibers synthesized were featured with diameters of around 1 μm and lengths of as long as 2 m for Ni fibers, 0.5 m for iron fibers, 1 m for Fe-Ni fibers. The structure, thermal decomposition process and morphologies of the gel precursors and fibers derived from thermal reduction of these gel precursors were characterized by FTIR, XRD,TG/DSC and SEM, respectively. The gel spinnability largely depends on molecular structures of metal-carboxylate complexes formed in the gel. It is reasoned that these gels consist of linear-type structural molecules [(C6H6O7)Ni]n or [(C6H5O7)2Ni3] for the nickel citrate gel, [(C3H5O3)3Fe] for the ferric lactate gel, [(C6H5O7)5(NiFe)3] for the iron-nickel citrate gel respectively and the gels obtain showed a good spinning performance.展开更多
The organic gel-thermal reduction process was used for the preparation of ferromagnetic metal Ni, Co and Fe fine fibers from the raw materials of citric acid, lactic acid and metal salts. The structure, thermal decomp...The organic gel-thermal reduction process was used for the preparation of ferromagnetic metal Ni, Co and Fe fine fibers from the raw materials of citric acid, lactic acid and metal salts. The structure, thermal decomposition process and morphologies of the gel precursors and fibers derived from thermal reduction of these gel precursors were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, thermo-gravimetric/differential scanning calorimetry and scanning electron microscopy. The results show that spinnability of gel largely depends on molecular structure of metal-carboxylate complex that is a linear-type structure formed in the gel. As a result, the gels exhibit a good spinnability. Metal Ni, Co and Fe fine fibers are featured with diameters of around 1 μm and a high aspect ratio up to 1×106.展开更多
The nanocomposite xCoFe2O4-(1-x)BaTiO3(x=0.2,0.3,0.4,0.5,molar fraction) fibers with fine diameters and high aspect ratios(length to diameter ratios) were prepared by the organic gel-thermal decomposition process from...The nanocomposite xCoFe2O4-(1-x)BaTiO3(x=0.2,0.3,0.4,0.5,molar fraction) fibers with fine diameters and high aspect ratios(length to diameter ratios) were prepared by the organic gel-thermal decomposition process from citric acid and metal salts.The structures and morphologies of gel precursors and fibers derived from thermal decomposition of the gel precursors were characterized by Fourier transform infrared spectroscopy,X-ray diffractometry and scanning electron microscopy.The magnetic properties of the nanocomposite fibers were measured by vibrating sample magnetometer.The nanocomposite fibers consisting of ferrite(CoFe2O4) and perovskite(BaTiO3) are formed at the calcination temperature of 900 ℃ for 2 h.The average grain sizes of CoFe2O4 and BaTiO3 in the nanocomposite fibers increase from 25 to 65 nm with the calcination temperature from 900 to 1 180 ℃.The single fiber constructed from these nanograins of CoFe2O4 and BaTiO3 has a necklace-like morphology.The saturation magnetization of the nanocomposite 0.4CoFe2O4-0.6BaTiO3 fibers increases with the increase of CoFe2O4 grain size,while the coercivity reaches a maximum value when the average grain size of CoFe2O4 is around the critical single-domain size of 45 nm obtained at 1 000 ℃.The saturation magnetization and remanence of the nanocomposite xCoFe2O4-(1-x)BaTiO3(x=0.2,0.3,0.4,0.5) fibers almost exhibit a linear relationship with the molar fraction of CoFe2O4 in the nanocomposites.展开更多
Ultrafine apatite fibers were prepared by electrospinning of sol-gel precursor/poly( vinyl pyrrolidone) (PVP) solutions followed by subsequent calcination. The as-electrospun and calcinated fibers were observed un...Ultrafine apatite fibers were prepared by electrospinning of sol-gel precursor/poly( vinyl pyrrolidone) (PVP) solutions followed by subsequent calcination. The as-electrospun and calcinated fibers were observed under a scanning electron microscope and an optical polarizing microscope. Results show that the morphology and the diameter of as-electrospun fibers strongly depend on the viscosity and the surface tension of sol-gel precursor/PVP solutions. After calcination, the smooth as-electrospun fibers shrink and the fiber diameter decreases because of the removal of the polymer. The chemical evolution upon the transformation of the precursor from a gel to the final apatite fibers was investigated by thermogravimetric-differenfial thermal analysis, X-ray diffraction, and Fourier transform infrared spectroscopy. It is thus suggested that the crystalline structure of the calcined fibers is largely influenced by the calcination temperature. After being calcined at 600 ℃, the apatite fibers with a diameter of about 280 nm containing β-tricalcium phosphate were obtained.展开更多
An optical fiber bienzyme sensor based on the luminol chemiluminescent reaction was developed and demonstrated to be sensitive to glucose. Glucose oxidase(GOD) and horseradish peroxidase(HRP) were co-immobilized by mi...An optical fiber bienzyme sensor based on the luminol chemiluminescent reaction was developed and demonstrated to be sensitive to glucose. Glucose oxidase(GOD) and horseradish peroxidase(HRP) were co-immobilized by microencapsulation in a sol-gel film derived from tetraethyl orthosilicate(TEOS). The calibration plots for glucose were established by the optical fiber glucose sensor fabricated by attaching the bienzyme silica gel onto the glass window of the fiber bundle. The linear range was 0 2-2 mmol/L and the detection limit was approximately 0 12 mmol/L. The relative standard deviation was 5.3% ( n =6). The proposed biosensor was applied to glucose assay in ofloxacin injection successfully.展开更多
Modified sensing membranes based on fluorescence quenching were prepared by the sol-gel method,using formamide as the drying control chemical additive,tetraethoxysilane as the main material,Ru(phen) 3Cl 2 as the ind...Modified sensing membranes based on fluorescence quenching were prepared by the sol-gel method,using formamide as the drying control chemical additive,tetraethoxysilane as the main material,Ru(phen) 3Cl 2 as the indicator.The membrane with the optimum thickness of 20-50μm is uniform and crack-free,in which the indicator has a very small leaking rate.The membrane is immersed in water for 50h,the membrane sensing parameter M decreases by less than 5%.The fiber optic oxygen sensor with the sensing membrane has a detection limit of 5×10 -6M(ppm),a response time of less than 30s,excellent reproducibility and stability.展开更多
文摘Ultra-high strength and modulus polyethylene fibers can be produced from UHMW-PE(ul-tra-high molecular weight polyethylene) by gel spinning and ultra-high drawing method.The spe-cial supermolecular structure of″shish-kebabs″ is the intrinsic course for the fiber having highperformance.In this paper,the formation mechanism of the characteristic structure of PE fibershas been investigated by means of SEM,DSC,WAXD,SAXS and TEM,The experimental resultsshow that the extended-chain structure of PE fibers is formed originally from the bridged mole-cules in amorphous region and increased gradually during further drawing porcess.The″shish-kebab″ structure is formed by the combination of extended-chalnS and originalfolded-chains.
文摘Some noticeable effects of process conditions, such as coagulation bath, solvent extraction, drying shrinkage and ultra-drawing, on the structure and properties of gel-spun PVA fibers are studied and discussed. High strength and high modulus PVA fibers with tensile strength of 11.3 cN / dtex and initial modulus of 430 cN / dtex have been obtained.
基金Supported by National High Technology Research and Development Program of China(No.2002AA2040).
文摘Polycrystalline 3Y-TZP/Al2O3 tetragonal zirconia fiber was obtained by the pyrolysis of gel fibers using zirconium oxychloride octahydrate(ZOC) as the raw material. The spinnable zirconia sol was prepared by electrolyzing the zirco-nium oxychloride octahydrate(ZOC) solution in the presence of acetic acid and sugar( sucrose, glucrose or fructose) , in which the molar ratios of CH3 COOH/ZOC and sugar/ZOC were 1.0-4.0 and 0.2-0.4, respectively. The pre- pared tetragonal zireonia fibers sintered at different temperatures showed smooth and crack-free surfaces with diame, ters of 5-10 μm. The addition of Al2O3 enhanced the sintering process and prevented the crystals from growing. Thermogravimetric analysis(TG), X-ray diffraction ( XRD ), Fourier transform infrared spectroscopy(FTIR), and scanning electron microscope(SEM) techniques were used to characterize the prepared fibers.
基金Supported by the National Natural Science Foundation of China,No.90209053Zhejiang Scientific Project, No. 2003C31042
文摘AIM: To investigate diffusion in mammalian cell culture by gel entrapment within hollow fibers.METHODS: Freshly isolated rat hepatocytes or human oral epidermoid carcinoma (KB) cells were entrapped in type Ⅰ collagen solutions and statically cultured inside microporous and ultrafiltration hollow fibers. During the culture time collagen gel contraction, cell viability and specific function were assessed. Effective diffusion coefficients of glucose in cell-matrix gels were determined by lag time analysis in a diffusion cell.R ESULTS: Significant gel contractions occurred in the collagen gels by entrapment of either viable hepatocytes or KB cells. And the gel contraction caused a significant reduction on effective diffusion coefficient of glucose. The cell viability assay of both hepatocytes and KB cells statically cultured in hollow fibers by collagen entrapment further confirmed the existence of the inhibited mass transfer by diffusion. Urea was secreted about 50% more by hepatocytes entrapped in hollow fibers with pore size of 0.1 pm than that in hollow fibers with MWCO of 100 ku.CONCLUSION: Cell-matrix gel and membrane pore size are the two factors relevant to the limited mass transfer by diffusion in such gel entrapment of mammalian cell culture.
基金supported by the Natural Science Foundation of Shaanxi Province,China (No.2010K10-21)
文摘Long alumina fibers were prepared by sol-gel method.The spinning sol was obtained by mixing aluminum nitrate,tartaric acid,and polyvinylpyrrolidone with a mass ratio of 10∶3∶1.5.Thermogravimetry-differential scanning calorimetry (TG-DSC),Fourier transform infrared (FT-IR) spectra,X-ray diffraction (XRD),and scanning electron microscopy (SEM) were used to characterize the properties of the gel and ceramic fibers.A little of α-Al2O3 phase is observed in the alumina precursor gel fibers sintered at 1273 K.The fibers with a uniform diameter can be obtained when sintered at 1473 K,and its main phase is also indentified as α-Al2O3.
基金This project is supported by National Science Foundation of China
文摘It is believed that gel spun polyethylene(PE)fibers have a somewhat extended chain crystalstructure,because of the disentangling of the chains which takes place in semi-dilute solutionand the ultra high draw ratio used.Ten years ago,PE shish-kebabs grown from dilute solutionwere proved to have extended chain backbone which causes the raising of its melting point.These crystals were found to have a triclinic crystal phase,This study shows a different result forgel spun ultra high drawn PE fiber.The unit cell remains orthorhombic even if the draw ratioreaches 50;as the draw ratio increases,the length in a and b axes are shortened while that in c ax-is changes quite insignificantly.When the draw ratio is over 10,two endothermic melting peakscan be seen in the DSC curves with corresponding peak temperature of 136.7-145.3℃.The lat-ter peak is attributed to the amount of extended chain crystal.
基金Project(50474038) supported by the National Natural Science Foundation of China
文摘Ferromagnetic metal fibers with a high aspect ratio (length/diameter) are attractive for use as high performance electromagnetic interference shielding materials. Ferromagnetic binary alloy fine fibers of iron-nickel, iron-cobalt and cobalt-nickel were prepared by the organic gel-thermal reduction process from the raw materials of critic acid and metal salts. These alloy fibers synthesized were featured with a diameter of about 1 μm and a length as long as 1 m. The structure, thermal decomposition process and morphologies of the gel precursors and fibers derived from thermal reduction of the gel precursors were characterized by FTIR, XRD, TG/DSC and SEM. The gel spinnability largely depends on the molecular structure of metal- carboxylates formed during the gel formation. The gel consisting of linear-type structural molecules shows good spinnability.
基金Supported by National Natural Science Foundation of China(No.50506020)Natural Science Foundation of Tianjin(No.043605211)Young Teacher Foundation of Tianjin University(No.5110103)
文摘BaFe12O19 fibers was prepared via an aqueous sol-gel process using Fe(OH)(HCOO)2 synthesized in laboratory and Ba(CH3COO)2 as the original materials and citrate as the chelate. The rheological behaviour of spinnable sol was characterized on rheometer, and the development of gel fibers to barium ferrite fibers was studied by IR, TG and XRD. Morphology observation of the fibers was given on SEM, and the diameter of the obtained fibers was between 5 and 10 μm corresponding to different additives. The additives affected the surface tension of the precursor sol which had close relation to the microstructure of fibers. Sucrose and hydroxyethylic cellulose could improve the surface tension while diethanolamine and hexadecylamine reduce that of the precursor sol. And using diethanolamine or hexadecylamine as an additive, well-structured BaFe12O19 fibers could be obtained.
基金the National Natural Science Foundation of China(No.50474038,50674048)
文摘The organic gel-thermal reduction process was successfully used for the preparation of magnetic metal Ni, Fe, Fe-Ni fine fibers from raw materials of citric acid or lactic acid and metal salts. Ni, Fe and Fe-Ni fine fibers synthesized were featured with diameters of around 1 μm and lengths of as long as 2 m for Ni fibers, 0.5 m for iron fibers, 1 m for Fe-Ni fibers. The structure, thermal decomposition process and morphologies of the gel precursors and fibers derived from thermal reduction of these gel precursors were characterized by FTIR, XRD,TG/DSC and SEM, respectively. The gel spinnability largely depends on molecular structures of metal-carboxylate complexes formed in the gel. It is reasoned that these gels consist of linear-type structural molecules [(C6H6O7)Ni]n or [(C6H5O7)2Ni3] for the nickel citrate gel, [(C3H5O3)3Fe] for the ferric lactate gel, [(C6H5O7)5(NiFe)3] for the iron-nickel citrate gel respectively and the gels obtain showed a good spinning performance.
基金Projects(50474038 50674048) supported by the National Natural Science Foundation of China
文摘The organic gel-thermal reduction process was used for the preparation of ferromagnetic metal Ni, Co and Fe fine fibers from the raw materials of citric acid, lactic acid and metal salts. The structure, thermal decomposition process and morphologies of the gel precursors and fibers derived from thermal reduction of these gel precursors were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, thermo-gravimetric/differential scanning calorimetry and scanning electron microscopy. The results show that spinnability of gel largely depends on molecular structure of metal-carboxylate complex that is a linear-type structure formed in the gel. As a result, the gels exhibit a good spinnability. Metal Ni, Co and Fe fine fibers are featured with diameters of around 1 μm and a high aspect ratio up to 1×106.
基金Project(50674048) supported by the National Natural Science Foundation of China Project(20080431069) supported by China Postdoctoral Science FoundationProject(CX10B-257Z) supported by Postgraduate Cultivation and Innovation Foundation of Jiangsu Province,China
文摘The nanocomposite xCoFe2O4-(1-x)BaTiO3(x=0.2,0.3,0.4,0.5,molar fraction) fibers with fine diameters and high aspect ratios(length to diameter ratios) were prepared by the organic gel-thermal decomposition process from citric acid and metal salts.The structures and morphologies of gel precursors and fibers derived from thermal decomposition of the gel precursors were characterized by Fourier transform infrared spectroscopy,X-ray diffractometry and scanning electron microscopy.The magnetic properties of the nanocomposite fibers were measured by vibrating sample magnetometer.The nanocomposite fibers consisting of ferrite(CoFe2O4) and perovskite(BaTiO3) are formed at the calcination temperature of 900 ℃ for 2 h.The average grain sizes of CoFe2O4 and BaTiO3 in the nanocomposite fibers increase from 25 to 65 nm with the calcination temperature from 900 to 1 180 ℃.The single fiber constructed from these nanograins of CoFe2O4 and BaTiO3 has a necklace-like morphology.The saturation magnetization of the nanocomposite 0.4CoFe2O4-0.6BaTiO3 fibers increases with the increase of CoFe2O4 grain size,while the coercivity reaches a maximum value when the average grain size of CoFe2O4 is around the critical single-domain size of 45 nm obtained at 1 000 ℃.The saturation magnetization and remanence of the nanocomposite xCoFe2O4-(1-x)BaTiO3(x=0.2,0.3,0.4,0.5) fibers almost exhibit a linear relationship with the molar fraction of CoFe2O4 in the nanocomposites.
基金Supported in part by the Tianjin Natural Science Foundation(No07JCYBJC02900)
文摘Ultrafine apatite fibers were prepared by electrospinning of sol-gel precursor/poly( vinyl pyrrolidone) (PVP) solutions followed by subsequent calcination. The as-electrospun and calcinated fibers were observed under a scanning electron microscope and an optical polarizing microscope. Results show that the morphology and the diameter of as-electrospun fibers strongly depend on the viscosity and the surface tension of sol-gel precursor/PVP solutions. After calcination, the smooth as-electrospun fibers shrink and the fiber diameter decreases because of the removal of the polymer. The chemical evolution upon the transformation of the precursor from a gel to the final apatite fibers was investigated by thermogravimetric-differenfial thermal analysis, X-ray diffraction, and Fourier transform infrared spectroscopy. It is thus suggested that the crystalline structure of the calcined fibers is largely influenced by the calcination temperature. After being calcined at 600 ℃, the apatite fibers with a diameter of about 280 nm containing β-tricalcium phosphate were obtained.
文摘An optical fiber bienzyme sensor based on the luminol chemiluminescent reaction was developed and demonstrated to be sensitive to glucose. Glucose oxidase(GOD) and horseradish peroxidase(HRP) were co-immobilized by microencapsulation in a sol-gel film derived from tetraethyl orthosilicate(TEOS). The calibration plots for glucose were established by the optical fiber glucose sensor fabricated by attaching the bienzyme silica gel onto the glass window of the fiber bundle. The linear range was 0 2-2 mmol/L and the detection limit was approximately 0 12 mmol/L. The relative standard deviation was 5.3% ( n =6). The proposed biosensor was applied to glucose assay in ofloxacin injection successfully.
文摘Modified sensing membranes based on fluorescence quenching were prepared by the sol-gel method,using formamide as the drying control chemical additive,tetraethoxysilane as the main material,Ru(phen) 3Cl 2 as the indicator.The membrane with the optimum thickness of 20-50μm is uniform and crack-free,in which the indicator has a very small leaking rate.The membrane is immersed in water for 50h,the membrane sensing parameter M decreases by less than 5%.The fiber optic oxygen sensor with the sensing membrane has a detection limit of 5×10 -6M(ppm),a response time of less than 30s,excellent reproducibility and stability.