The quantification of transparent exopolymer particles(TEP) by colorimetric method is of large error and low repeatability,one major reason of which is related to the absence of clear definition and evaluation for par...The quantification of transparent exopolymer particles(TEP) by colorimetric method is of large error and low repeatability,one major reason of which is related to the absence of clear definition and evaluation for part steps of the original method.It is obscure that the 80% sulfuric acid solution,acted as the extraction solution in the determination of TEP,is prepared based on a volume ratio or mass ratio.Furthermore,the change of solubility of recently available Gum Xanthan(GX) from the market means that the original protocol is no longer applicable,and the grinding of GX stock solution with a tissue grinder is replaced by shaking with a rotating shaker in the study to prevent the excessive dissolution of GX.We found that different preparation techniques could result in the varied concentrations of 80% H_(2)SO_(4).The duration of shaking during the preparation of standard solution significantly affected the slope of the calibration curve,which caused different correction results of TEP.The impacts of different extraction solution concentrations and shaking time of GX solution on the quantification of TEP were investigated based on the field sampling and laboratory analysis.The extraction capacities of H_(2)SO_(4) with different concentrations for Alcian Blue were distinct,but had limited effect on the final measuring result of TEP.The change of the standard curve slope came along with the variation of shaking time,which markedly altered the detection limit and calibration result,and the extended shaking time was in favor of the determination of low-concentration TEP.It was suggested that the extraction solution concentration,shaking time and filtration volume of standard solution are required to be well controlled and selected to obtain more accurate results for TEP with different concentrations.展开更多
We fabricate flexible conductive and transparent graphene films on position-emission-tomography substrates and prepare large area graphene films by graphite oxide sheets with the new technical process. The multi-layer...We fabricate flexible conductive and transparent graphene films on position-emission-tomography substrates and prepare large area graphene films by graphite oxide sheets with the new technical process. The multi-layer graphene oxide sheets can be chemically reduced by HNO3 and HI to form a highly conductive graphene film on a substrate at lower temperature. The reduced graphene oxide sheets show a high conductivity sheet with resistance of 476Ω/sq and transmittance of 76% at 550nm （6 layers）. The technique used to produce the transparent conductive graphene thin film is facile, inexpensive, and can be tunable for a large area production applied for electronics or touch screens.展开更多
β-Na YF4:Yb3+,Er3+ microrods were synthesized through hydrothermal methods. Polyethylene glycol with molecular weight of 6000 was used as surfactant. A series of transparent silica gel films with upconversion lumines...β-Na YF4:Yb3+,Er3+ microrods were synthesized through hydrothermal methods. Polyethylene glycol with molecular weight of 6000 was used as surfactant. A series of transparent silica gel films with upconversion luminescence property was prepared through sol-gel method; the prepared β-Na YF4:Yb3+,Er3+ microrods were used as activator. The silica gel films show strong upconversion emission under excitation of 980-nm laser beam.展开更多
Nd^3＋： Gd3Ga5O12（Nd ： GGG） nanopowder for transparent laser ceramics was synthesized using sol-gel method. XRD, SEM, and fluorescence spectrum were used to study the properties of Nd^3＋ ：Gd3Ga5O12 nanopowder. X...Nd^3＋： Gd3Ga5O12（Nd ： GGG） nanopowder for transparent laser ceramics was synthesized using sol-gel method. XRD, SEM, and fluorescence spectrum were used to study the properties of Nd^3＋ ：Gd3Ga5O12 nanopowder. XRD patterns of samples show that it has a cubic structure. Meanwhile, pure Nd：GGG crystals were obtained at 1000 ℃ for 12 h. SEM photographs show that dispersed, uniform, ball-like Nd：GGG nanopowder is obtained. Both XRD and SEM results show that the crystallization degree and the grain size increase with the increase in calcining temperature. Analysis of fluorescence spectrum shows that fluorescence emission occurs at 1062.7 nm, which is the result of Nd^3＋ （^4F3/2→^4I11/2） transition. Homogenous Nd ： GGG nanopewder with a small grain size synthesized using the sol-gel method is favorable for sintering the transparent ceramic, which proves that the nanopewder obtained is suitable as a precursor for preparing GGG transparent ceramics.展开更多
基金The National Key Research and Development Project of China under contract No.2019YFC1407805the National Natural Science Foundation of China under contract Nos 41876134, 41676112 and 41276124+1 种基金the Tianjin 131 Innovation Team Program under contract No.20180314the Changjiang Scholar Program of Chinese Ministry of Education under contract No.T2014253。
文摘The quantification of transparent exopolymer particles(TEP) by colorimetric method is of large error and low repeatability,one major reason of which is related to the absence of clear definition and evaluation for part steps of the original method.It is obscure that the 80% sulfuric acid solution,acted as the extraction solution in the determination of TEP,is prepared based on a volume ratio or mass ratio.Furthermore,the change of solubility of recently available Gum Xanthan(GX) from the market means that the original protocol is no longer applicable,and the grinding of GX stock solution with a tissue grinder is replaced by shaking with a rotating shaker in the study to prevent the excessive dissolution of GX.We found that different preparation techniques could result in the varied concentrations of 80% H_(2)SO_(4).The duration of shaking during the preparation of standard solution significantly affected the slope of the calibration curve,which caused different correction results of TEP.The impacts of different extraction solution concentrations and shaking time of GX solution on the quantification of TEP were investigated based on the field sampling and laboratory analysis.The extraction capacities of H_(2)SO_(4) with different concentrations for Alcian Blue were distinct,but had limited effect on the final measuring result of TEP.The change of the standard curve slope came along with the variation of shaking time,which markedly altered the detection limit and calibration result,and the extended shaking time was in favor of the determination of low-concentration TEP.It was suggested that the extraction solution concentration,shaking time and filtration volume of standard solution are required to be well controlled and selected to obtain more accurate results for TEP with different concentrations.
基金Supported by the Basic Research Program of Nanjing University of Posts and Telecommunications under Grant No NY212002the Innovative Research Team in University under Grant No IRT1148the 2014 Shuangchuang Program of Jiangsu Province
文摘We fabricate flexible conductive and transparent graphene films on position-emission-tomography substrates and prepare large area graphene films by graphite oxide sheets with the new technical process. The multi-layer graphene oxide sheets can be chemically reduced by HNO3 and HI to form a highly conductive graphene film on a substrate at lower temperature. The reduced graphene oxide sheets show a high conductivity sheet with resistance of 476Ω/sq and transmittance of 76% at 550nm （6 layers）. The technique used to produce the transparent conductive graphene thin film is facile, inexpensive, and can be tunable for a large area production applied for electronics or touch screens.
基金Supported by the National Natural Science Foundation of China(No.61308085)
文摘β-Na YF4:Yb3+,Er3+ microrods were synthesized through hydrothermal methods. Polyethylene glycol with molecular weight of 6000 was used as surfactant. A series of transparent silica gel films with upconversion luminescence property was prepared through sol-gel method; the prepared β-Na YF4:Yb3+,Er3+ microrods were used as activator. The silica gel films show strong upconversion emission under excitation of 980-nm laser beam.
基金Project supported bythe Nature Science Foundation of Jilin Province (20000516)
文摘Nd^3＋： Gd3Ga5O12（Nd ： GGG） nanopowder for transparent laser ceramics was synthesized using sol-gel method. XRD, SEM, and fluorescence spectrum were used to study the properties of Nd^3＋ ：Gd3Ga5O12 nanopowder. XRD patterns of samples show that it has a cubic structure. Meanwhile, pure Nd：GGG crystals were obtained at 1000 ℃ for 12 h. SEM photographs show that dispersed, uniform, ball-like Nd：GGG nanopowder is obtained. Both XRD and SEM results show that the crystallization degree and the grain size increase with the increase in calcining temperature. Analysis of fluorescence spectrum shows that fluorescence emission occurs at 1062.7 nm, which is the result of Nd^3＋ （^4F3/2→^4I11/2） transition. Homogenous Nd ： GGG nanopewder with a small grain size synthesized using the sol-gel method is favorable for sintering the transparent ceramic, which proves that the nanopewder obtained is suitable as a precursor for preparing GGG transparent ceramics.
