The IR spectra of R2O-RO-B2O3-SiO2 and R2O-RO-B2O3-Al2O3-SiO2 glasses were tested for the study of coordination state of B, Al and their content. The results show that no matter Na2O/B2O3〉1, =1, or〈1, both [BO3] and...The IR spectra of R2O-RO-B2O3-SiO2 and R2O-RO-B2O3-Al2O3-SiO2 glasses were tested for the study of coordination state of B, Al and their content. The results show that no matter Na2O/B2O3〉1, =1, or〈1, both [BO3] and destroyed Si-O bond exist in glass structure; the addition of Al2O3 to borosilicate glass reduced both the number of non-bridging oxygen in the silicate network and the number of [BO4] units.展开更多
Both titanium and germanium were introduced into silicon dioxide system by sol-gel method to move its region of anomalous dispersion caused by IR resonance absorption towards the wavelength of CO 2 laser.It is indica...Both titanium and germanium were introduced into silicon dioxide system by sol-gel method to move its region of anomalous dispersion caused by IR resonance absorption towards the wavelength of CO 2 laser.It is indicated by IR absorption spectra that as the content of SiO 2 decreases in this glass system TiO 2 and GeO 2 tends to exist in their own phases.As for the gel glass with a composition of 40SiO 2·30TiO 2·30GeO 2,when the temperature is below 600℃,germanium atoms exist mainly in Ge-O-Ge bonds.With the temperature increasing from 800℃ to 1000℃, titanium atoms in Si-O-Ti bonds almost transform into Ti-O-Ti bonds.Furthermore,a large number of Si-O-Ti and Si-O-Ge bonds formed when the temperature approaches 800℃,which makes a notable IR absorption band round the wavelength of CO 2 laser.Therefore, sol-gel based SiO 2-TiO 2-GeO 2 gel glass is a candidate material for CO 2 laser hollow waveguide.展开更多
Using the method of IR spectroscopy it was ascertained that in pectinates and alginates of polyvalent metals the coordination bonds between cations Pb2+, Cu2+, Zn2+, Cr3+, Mn2+, Fe2+, Co2+, Ni2+ and the oxygen atoms o...Using the method of IR spectroscopy it was ascertained that in pectinates and alginates of polyvalent metals the coordination bonds between cations Pb2+, Cu2+, Zn2+, Cr3+, Mn2+, Fe2+, Co2+, Ni2+ and the oxygen atoms of carboxyl and hydroxyl groups, pyranose cycle and glycosidic linkage of polyuronides, the water molecules are formed. It was also ascertained that Cu2+ cations form asymmetrical structures with carboxyl groups of polyuronides (monodentate ligands) and cations of other metals—symmetrical structures with carboxyl groups of polyuronides (bidentate ligands).展开更多
Equilibrium geometries of 16 possible isomers for C74（BN）2 were studied by INDO series of methods, to indicate that the most stable three geometries are those where boron and nitrogen atoms substitute carbon atoms l...Equilibrium geometries of 16 possible isomers for C74（BN）2 were studied by INDO series of methods, to indicate that the most stable three geometries are those where boron and nitrogen atoms substitute carbon atoms located at the same hexagon near the longest axis of C78 （C2v） to form B-N-B-N unit. Electronic spectra of C74（BN）2 were investigated with INDO/CIS method. The reason for the red shift of UV absorptions for C74（BN）2 compared with those of C78 （C2v） was discussed. IR spectra for 9,8,28,29-C74（BN）2 and 28,29,30,31-C74（BN）2 were calculated on the basis of AM1 geometries.展开更多
IR spectra play an important role in determining the structure of compounds qualitatively andquantitatively.In general a great number of data are required to exactly show the features ofthe compounds.Regarding various...IR spectra play an important role in determining the structure of compounds qualitatively andquantitatively.In general a great number of data are required to exactly show the features ofthe compounds.Regarding various compounds,there are massive IR spectra.With the basicfeatures of IR spectra being reserved,it is important to compress IR spectra for improving thestorage,index and process of IR spectra.The wavelet neural network(WNN)is a newneural network model based on wavelet analysis.However,its introduction and applica-tion in chemistry have not been reported.In this note,WNN is applied to the compression ofthe IR spectra of polystyrene.The results show that the original spectra can be展开更多
Chitosans with various degrees of deacetylation (D.D.), which were used as standard sample for FTIR determination, were prepared from completely deacetylated chitosan by homogeneous N-acetylation reaction. By combinin...Chitosans with various degrees of deacetylation (D.D.), which were used as standard sample for FTIR determination, were prepared from completely deacetylated chitosan by homogeneous N-acetylation reaction. By combining four probable probe bands, i.e. 1655, 1560, 1380 and 1320 cm-1, eight probable reference bands, i.e. 3430, 2920, 2880, 1425, 1155, 1070, 1030 and 895 cm-1 and two baseline methods, the most suitable ratios Aprobe band/Areference band from IR spectra to determine the degree of acetylation of chitosan were evaluated from 48 combinations to be A1560/A2880, A1560/A2920 and A1655/A3430(A1560/A2880 is mostly recommended). The second baseline method, i.e. linking between adjacent two valleys, was better for measuring the absorbances of 1560 and 1655 cm-1 bands. The determination range of the D.D. (1%-100%) covered almost the whole range. The standard curves with A1560/A2880 and A1655/A3430 were also suitable for the determination of degree of substitution of other N-acylated chitosan, such as N-propionyl chitosan, N-butyryl chitosan and N-hexanoyl chitosan.展开更多
Among new low-melting-point glasses, bismuth ate glass is deemed to have the most potential as an environmentally friendly replacement for polluting Pb-containing glasses. Current studies of boro-bismuthate glasses fo...Among new low-melting-point glasses, bismuth ate glass is deemed to have the most potential as an environmentally friendly replacement for polluting Pb-containing glasses. Current studies of boro-bismuthate glasses focus on the structural influence of the additional oxide in the context of low-melting-point electronic sealing applications. In this study, the structure of quaternary Bi2O3- ZnO-B2O3-BaO glasses was investigated spectroscopic ally, with Fourier-transform-infrared (FT-IR) and Raman spectra recorded for glasses with different main oxide contents. Signals in the FT-IR are mainly observed around 500 cm﹣1, 720 cm﹣1, 840 cm﹣1, 980 - 1080 cm﹣1, and 1200 - 1500 cm﹣1, while the Raman scattering peaks are located at 130 cm﹣1, 390 cm﹣1, 575 cm﹣1, 920 cm﹣1, and 1250 cm﹣1. The glasses are mainly structured around [BO3] units and the numbers of [BiO6] and [BiO3] units increase with the Bi2O3 content increasing. Concurrently, the FT-IR absorption peaks associated with [BO4] units shift to lower wave numbers, indicating a loosening of the glass structure. However, as the B2O3 content is increased, the numbers of [BO3] and [BO4] units increase, while those of [BiO3] and [BiO6] units decrease, highlighting a densification of the glass structure. ZnO acts as a network modifier in these glasses.展开更多
Some heteropolyacids and their salts display unique activities and selectivities in both homophase and heterophase catalytic reactionst, and have attracted more and more attention. The following four tungstosilicates ...Some heteropolyacids and their salts display unique activities and selectivities in both homophase and heterophase catalytic reactionst, and have attracted more and more attention. The following four tungstosilicates have recently been synthesized, in which展开更多
This work presents a new spectral data compression-rebuilding technique to translate the full IR spectral data into compact codes based on the analysis and comprehension encoding approach. This method has been success...This work presents a new spectral data compression-rebuilding technique to translate the full IR spectral data into compact codes based on the analysis and comprehension encoding approach. This method has been successfully applied to a sample set of 505 IR spectra randomly picked from 100 000 spectra. The results show that the compression ratio reaches 12.7:1 under a very weak curve distortion. The choice of the number and shape of the basis functions is flexible. The IR spectra can be compressed in a fixed data size in fulfilling the distortion criteria. The data after compression have no significance in the sense of 蜶 spectra. To recover the original spectra, a specific algorithm must be applied. So the method can be used as a cryptic tool. Furthermore, the method can be applied to the compression of other complex curve by utilizing some of proper basis functions.展开更多
Nanometer-sized semiconductor clusters demonstrate novel non-linear optical propertyand capability of storing light energy. The cluster will display quantum-confined effect if itssize is less than 5 nm, i.e. the atoms...Nanometer-sized semiconductor clusters demonstrate novel non-linear optical propertyand capability of storing light energy. The cluster will display quantum-confined effect if itssize is less than 5 nm, i.e. the atoms sitting on the interface of clusters are different fromthose of intra molecule and bulk crystal. The semiconductor clusters show correspondingchange in optical absorption. For example, the optical absorption of nanometer-sized展开更多
The interactions between ferric ion and various nucleotides are no doubt very important in the fate of iron in vivo, especially in the process of iron absorption and transportation, as well as to seek potential drugs ...The interactions between ferric ion and various nucleotides are no doubt very important in the fate of iron in vivo, especially in the process of iron absorption and transportation, as well as to seek potential drugs in the treatment of iron-deficiency anemia.展开更多
Spectral feature channels are selected based on the optimization theory and by makinguse of Shannon's formula with main effective wavenumber regions ranging from 1600 cm^(-1)to 400 cm^(-1). Ten characteristic code...Spectral feature channels are selected based on the optimization theory and by makinguse of Shannon's formula with main effective wavenumber regions ranging from 1600 cm^(-1)to 400 cm^(-1). Ten characteristic codes are sufficient for retrieving a spectrum using the spec-tral data re-compressed in the selected channels. Results of retrieving 50 substances includ-ed in the databank show that the accuracy and the precision of the system are 1.00 and 0.85respectively. Results of retrieving substances not included in the databank show a credibleinterpretative capacity of the system. The average time for retrieving a spectrum is ca.0. 98s.展开更多
The differential FT-IR spectroscopic method was used to identify the polyborate anions in aqueous solutions during dissolution and transformation of 2MgO·2B 2O 3 ·MgCl 2·14H 2O in 6.45%H 3BO 3 solution ...The differential FT-IR spectroscopic method was used to identify the polyborate anions in aqueous solutions during dissolution and transformation of 2MgO·2B 2O 3 ·MgCl 2·14H 2O in 6.45%H 3BO 3 solution at 30℃. The recorded IR-spectroscopic frequencies of the borate aqueous solution subtract, with that of water as a bland value and their assignments were given. The existing forms of polyborate anions and thir interaction in three boron-con-taining aqueous solutions have been proposed. On the basis of solution structure, the mechanisms of dissolution and phase transformation of chlorpinnoite in 6.45% H 3BO 3 solution at 30℃ have been discussed.展开更多
基金Funded by the Key Science and Technology Project of Hubei Province(No.2004AA103B03)
文摘The IR spectra of R2O-RO-B2O3-SiO2 and R2O-RO-B2O3-Al2O3-SiO2 glasses were tested for the study of coordination state of B, Al and their content. The results show that no matter Na2O/B2O3〉1, =1, or〈1, both [BO3] and destroyed Si-O bond exist in glass structure; the addition of Al2O3 to borosilicate glass reduced both the number of non-bridging oxygen in the silicate network and the number of [BO4] units.
文摘Both titanium and germanium were introduced into silicon dioxide system by sol-gel method to move its region of anomalous dispersion caused by IR resonance absorption towards the wavelength of CO 2 laser.It is indicated by IR absorption spectra that as the content of SiO 2 decreases in this glass system TiO 2 and GeO 2 tends to exist in their own phases.As for the gel glass with a composition of 40SiO 2·30TiO 2·30GeO 2,when the temperature is below 600℃,germanium atoms exist mainly in Ge-O-Ge bonds.With the temperature increasing from 800℃ to 1000℃, titanium atoms in Si-O-Ti bonds almost transform into Ti-O-Ti bonds.Furthermore,a large number of Si-O-Ti and Si-O-Ge bonds formed when the temperature approaches 800℃,which makes a notable IR absorption band round the wavelength of CO 2 laser.Therefore, sol-gel based SiO 2-TiO 2-GeO 2 gel glass is a candidate material for CO 2 laser hollow waveguide.
文摘Using the method of IR spectroscopy it was ascertained that in pectinates and alginates of polyvalent metals the coordination bonds between cations Pb2+, Cu2+, Zn2+, Cr3+, Mn2+, Fe2+, Co2+, Ni2+ and the oxygen atoms of carboxyl and hydroxyl groups, pyranose cycle and glycosidic linkage of polyuronides, the water molecules are formed. It was also ascertained that Cu2+ cations form asymmetrical structures with carboxyl groups of polyuronides (monodentate ligands) and cations of other metals—symmetrical structures with carboxyl groups of polyuronides (bidentate ligands).
文摘Equilibrium geometries of 16 possible isomers for C74（BN）2 were studied by INDO series of methods, to indicate that the most stable three geometries are those where boron and nitrogen atoms substitute carbon atoms located at the same hexagon near the longest axis of C78 （C2v） to form B-N-B-N unit. Electronic spectra of C74（BN）2 were investigated with INDO/CIS method. The reason for the red shift of UV absorptions for C74（BN）2 compared with those of C78 （C2v） was discussed. IR spectra for 9,8,28,29-C74（BN）2 and 28,29,30,31-C74（BN）2 were calculated on the basis of AM1 geometries.
文摘IR spectra play an important role in determining the structure of compounds qualitatively andquantitatively.In general a great number of data are required to exactly show the features ofthe compounds.Regarding various compounds,there are massive IR spectra.With the basicfeatures of IR spectra being reserved,it is important to compress IR spectra for improving thestorage,index and process of IR spectra.The wavelet neural network(WNN)is a newneural network model based on wavelet analysis.However,its introduction and applica-tion in chemistry have not been reported.In this note,WNN is applied to the compression ofthe IR spectra of polystyrene.The results show that the original spectra can be
基金the National Natural Science Foundation of China (Grant No. 29974023) and the Natural Science Foundation of Fujian Province, China (Grant No. Z9910006).
文摘Chitosans with various degrees of deacetylation (D.D.), which were used as standard sample for FTIR determination, were prepared from completely deacetylated chitosan by homogeneous N-acetylation reaction. By combining four probable probe bands, i.e. 1655, 1560, 1380 and 1320 cm-1, eight probable reference bands, i.e. 3430, 2920, 2880, 1425, 1155, 1070, 1030 and 895 cm-1 and two baseline methods, the most suitable ratios Aprobe band/Areference band from IR spectra to determine the degree of acetylation of chitosan were evaluated from 48 combinations to be A1560/A2880, A1560/A2920 and A1655/A3430(A1560/A2880 is mostly recommended). The second baseline method, i.e. linking between adjacent two valleys, was better for measuring the absorbances of 1560 and 1655 cm-1 bands. The determination range of the D.D. (1%-100%) covered almost the whole range. The standard curves with A1560/A2880 and A1655/A3430 were also suitable for the determination of degree of substitution of other N-acylated chitosan, such as N-propionyl chitosan, N-butyryl chitosan and N-hexanoyl chitosan.
文摘Among new low-melting-point glasses, bismuth ate glass is deemed to have the most potential as an environmentally friendly replacement for polluting Pb-containing glasses. Current studies of boro-bismuthate glasses focus on the structural influence of the additional oxide in the context of low-melting-point electronic sealing applications. In this study, the structure of quaternary Bi2O3- ZnO-B2O3-BaO glasses was investigated spectroscopic ally, with Fourier-transform-infrared (FT-IR) and Raman spectra recorded for glasses with different main oxide contents. Signals in the FT-IR are mainly observed around 500 cm﹣1, 720 cm﹣1, 840 cm﹣1, 980 - 1080 cm﹣1, and 1200 - 1500 cm﹣1, while the Raman scattering peaks are located at 130 cm﹣1, 390 cm﹣1, 575 cm﹣1, 920 cm﹣1, and 1250 cm﹣1. The glasses are mainly structured around [BO3] units and the numbers of [BiO6] and [BiO3] units increase with the Bi2O3 content increasing. Concurrently, the FT-IR absorption peaks associated with [BO4] units shift to lower wave numbers, indicating a loosening of the glass structure. However, as the B2O3 content is increased, the numbers of [BO3] and [BO4] units increase, while those of [BiO3] and [BiO6] units decrease, highlighting a densification of the glass structure. ZnO acts as a network modifier in these glasses.
基金Project supported by the Natural Science Foundation of Zhejiang Province.
文摘Some heteropolyacids and their salts display unique activities and selectivities in both homophase and heterophase catalytic reactionst, and have attracted more and more attention. The following four tungstosilicates have recently been synthesized, in which
文摘This work presents a new spectral data compression-rebuilding technique to translate the full IR spectral data into compact codes based on the analysis and comprehension encoding approach. This method has been successfully applied to a sample set of 505 IR spectra randomly picked from 100 000 spectra. The results show that the compression ratio reaches 12.7:1 under a very weak curve distortion. The choice of the number and shape of the basis functions is flexible. The IR spectra can be compressed in a fixed data size in fulfilling the distortion criteria. The data after compression have no significance in the sense of 蜶 spectra. To recover the original spectra, a specific algorithm must be applied. So the method can be used as a cryptic tool. Furthermore, the method can be applied to the compression of other complex curve by utilizing some of proper basis functions.
文摘Nanometer-sized semiconductor clusters demonstrate novel non-linear optical propertyand capability of storing light energy. The cluster will display quantum-confined effect if itssize is less than 5 nm, i.e. the atoms sitting on the interface of clusters are different fromthose of intra molecule and bulk crystal. The semiconductor clusters show correspondingchange in optical absorption. For example, the optical absorption of nanometer-sized
文摘The interactions between ferric ion and various nucleotides are no doubt very important in the fate of iron in vivo, especially in the process of iron absorption and transportation, as well as to seek potential drugs in the treatment of iron-deficiency anemia.
文摘Spectral feature channels are selected based on the optimization theory and by makinguse of Shannon's formula with main effective wavenumber regions ranging from 1600 cm^(-1)to 400 cm^(-1). Ten characteristic codes are sufficient for retrieving a spectrum using the spec-tral data re-compressed in the selected channels. Results of retrieving 50 substances includ-ed in the databank show that the accuracy and the precision of the system are 1.00 and 0.85respectively. Results of retrieving substances not included in the databank show a credibleinterpretative capacity of the system. The average time for retrieving a spectrum is ca.0. 98s.
文摘The differential FT-IR spectroscopic method was used to identify the polyborate anions in aqueous solutions during dissolution and transformation of 2MgO·2B 2O 3 ·MgCl 2·14H 2O in 6.45%H 3BO 3 solution at 30℃. The recorded IR-spectroscopic frequencies of the borate aqueous solution subtract, with that of water as a bland value and their assignments were given. The existing forms of polyborate anions and thir interaction in three boron-con-taining aqueous solutions have been proposed. On the basis of solution structure, the mechanisms of dissolution and phase transformation of chlorpinnoite in 6.45% H 3BO 3 solution at 30℃ have been discussed.
