Low density polyethylene film surface-grafted phenolic resole was prepared by a sequential processes. Firstly, acrylic acid was grafted to the surface of low density polyethylene by photo-grafting. Secondly, the carbo...Low density polyethylene film surface-grafted phenolic resole was prepared by a sequential processes. Firstly, acrylic acid was grafted to the surface of low density polyethylene by photo-grafting. Secondly, the carboxylic groups in poly（acrylic acid） chains were transferred to sulfonic groups by the reaction of carboxylic groups with sulfanilic acid. Finally, a thin layer of phenolic resole was cured onto the surface of low density polyethylene. The grafting process was characterized by FTIR-ATR and gravimetric analysis. A possible model was proposed to interpret the experimental results.展开更多
The complexation reaction between borate ions and phenol-formaldehyde resol resin in aqueous solution was studied by pH measurement, small model molecules and infrared spectroscopy. The results show that the complexat...The complexation reaction between borate ions and phenol-formaldehyde resol resin in aqueous solution was studied by pH measurement, small model molecules and infrared spectroscopy. The results show that the complexation can proceed completely and rapidly at room temperature. Borate ion attacks phenol hydroxyl groups and adjacent position hydroxymethyl groups on the phenol ring of the resin, and forms the coordinate bond between boron atom in borate ion and oxygen atom in the hydroxyl groups. The complexation is a quantitative reaction. The complex is a six member ring containing two oxygens and one boron. The complexation can release hydrogen ions resulting in the decreasing pH in the resin solution.展开更多
Two carborane-containing resol phenolic resins（P1 and P2） with high boron content were synthesized via the reaction of carborane bisphenols（1 and 2） with formaldehyde in the presence of alkaline. HRMS results indi...Two carborane-containing resol phenolic resins（P1 and P2） with high boron content were synthesized via the reaction of carborane bisphenols（1 and 2） with formaldehyde in the presence of alkaline. HRMS results indicate that P1 is mainly composed of hydroxymethylated o-carborane bisphenols, the Mw of which was restrained around 500 due to the strong steric hindrance of o-carborane bisphenol. In contrast, the molecular weight of P2 was well regulated under various reaction conditions. The obtained resins were characterized with spectroscopic techniques including FTIR, 1H-NMR, ^13C-NMR, and 11B-NMR, which gave satisfactory results. TGA studies show that P2 shows char yield of 88.9% and 92.9% at 900 ℃ under nitrogen and air respectively. The imported carborane cage endows phenolic resin with ultrahigh char yield. Particularly, the char yield of the obtained carborane-containing phenolic resin under air is higher than that under nitrogen. FTIR and XRD confirm that the carborane cage could react with oxygen to form B2O3 at elevated temperatures, which postpones the thermal decomposition of phenolic resin and accounts for the high char yield.展开更多
In this paper, we discuss the stability of the elastic vibration of a cantilever beam with structural damping in homogeneous mass. Suppose u(t, x) represents the deviation of elastic beam from body axis. The elastic v...In this paper, we discuss the stability of the elastic vibration of a cantilever beam with structural damping in homogeneous mass. Suppose u(t, x) represents the deviation of elastic beam from body axis. The elastic vibration of a cantilever beam can be described by the following partial differential equation stated by Song Jian:展开更多
Ⅰ. INTRODUCTION There exist many vibration-rotation transition lines between 5μm to 6.5μm in electric-discharge CO lasers with a low temperature or fast gas flow or chemical CO lasers. These lines will find wide ap...Ⅰ. INTRODUCTION There exist many vibration-rotation transition lines between 5μm to 6.5μm in electric-discharge CO lasers with a low temperature or fast gas flow or chemical CO lasers. These lines will find wide application in laser spectroscopy, laser chemistry, isotope separation, pollution monitoring, and optical pumping of other lasers. Since展开更多
Ⅰ.INTRODUCTION In modern physics (such as hypernuclei, baryonic structure and fractional parentage coefficient) symmetry group normal units are more and more useful. And it is thought that to deal with reduction of g...Ⅰ.INTRODUCTION In modern physics (such as hypernuclei, baryonic structure and fractional parentage coefficient) symmetry group normal units are more and more useful. And it is thought that to deal with reduction of groups product in terms of normal units is展开更多
This paper gives a characteristic property of the Euler characteristic for IBN rings. The following results: are proved. （1） If R is a commutative ring, M, N are two stable free R-modules, then χ（MN）=χ（M）χ（N...This paper gives a characteristic property of the Euler characteristic for IBN rings. The following results: are proved. （1） If R is a commutative ring, M, N are two stable free R-modules, then χ（MN）=χ（M）χ（N）, where χ denotes the Euler characteristic. （2） If f: K<sub>0</sub>（R）→Z is a ring isomorphism, where K<sub>0</sub>（R） denotes the Grothendieck group of R, K<sub>0</sub>（R） is a ring when R is commutative, then f（[M]）=χ（M） and χ（MN）=χ（M）χ（N） when M, N are finitely generated projective R-modules, where.the isomorphism class [M] is a generator of K<sub>0</sub>（R）. In addition, some applications of the results above are also obtained.展开更多
S. L. Sobolev proposed a successful imbedding method for solving linear Fredholm integral equations. This method leads to the Cauchy problem of the first-order differential equation for the resolvent kernel with an in...S. L. Sobolev proposed a successful imbedding method for solving linear Fredholm integral equations. This method leads to the Cauchy problem of the first-order differential equation for the resolvent kernel with an initial condi-展开更多
文摘Low density polyethylene film surface-grafted phenolic resole was prepared by a sequential processes. Firstly, acrylic acid was grafted to the surface of low density polyethylene by photo-grafting. Secondly, the carboxylic groups in poly（acrylic acid） chains were transferred to sulfonic groups by the reaction of carboxylic groups with sulfanilic acid. Finally, a thin layer of phenolic resole was cured onto the surface of low density polyethylene. The grafting process was characterized by FTIR-ATR and gravimetric analysis. A possible model was proposed to interpret the experimental results.
文摘The complexation reaction between borate ions and phenol-formaldehyde resol resin in aqueous solution was studied by pH measurement, small model molecules and infrared spectroscopy. The results show that the complexation can proceed completely and rapidly at room temperature. Borate ion attacks phenol hydroxyl groups and adjacent position hydroxymethyl groups on the phenol ring of the resin, and forms the coordinate bond between boron atom in borate ion and oxygen atom in the hydroxyl groups. The complexation is a quantitative reaction. The complex is a six member ring containing two oxygens and one boron. The complexation can release hydrogen ions resulting in the decreasing pH in the resin solution.
基金financially supported by the Fundamental Research Funds for the Central Universities(No.JD-1512)
文摘Two carborane-containing resol phenolic resins（P1 and P2） with high boron content were synthesized via the reaction of carborane bisphenols（1 and 2） with formaldehyde in the presence of alkaline. HRMS results indicate that P1 is mainly composed of hydroxymethylated o-carborane bisphenols, the Mw of which was restrained around 500 due to the strong steric hindrance of o-carborane bisphenol. In contrast, the molecular weight of P2 was well regulated under various reaction conditions. The obtained resins were characterized with spectroscopic techniques including FTIR, 1H-NMR, ^13C-NMR, and 11B-NMR, which gave satisfactory results. TGA studies show that P2 shows char yield of 88.9% and 92.9% at 900 ℃ under nitrogen and air respectively. The imported carborane cage endows phenolic resin with ultrahigh char yield. Particularly, the char yield of the obtained carborane-containing phenolic resin under air is higher than that under nitrogen. FTIR and XRD confirm that the carborane cage could react with oxygen to form B2O3 at elevated temperatures, which postpones the thermal decomposition of phenolic resin and accounts for the high char yield.
文摘In this paper, we discuss the stability of the elastic vibration of a cantilever beam with structural damping in homogeneous mass. Suppose u(t, x) represents the deviation of elastic beam from body axis. The elastic vibration of a cantilever beam can be described by the following partial differential equation stated by Song Jian:
文摘Ⅰ. INTRODUCTION There exist many vibration-rotation transition lines between 5μm to 6.5μm in electric-discharge CO lasers with a low temperature or fast gas flow or chemical CO lasers. These lines will find wide application in laser spectroscopy, laser chemistry, isotope separation, pollution monitoring, and optical pumping of other lasers. Since
文摘Ⅰ.INTRODUCTION In modern physics (such as hypernuclei, baryonic structure and fractional parentage coefficient) symmetry group normal units are more and more useful. And it is thought that to deal with reduction of groups product in terms of normal units is
基金The Project supported by National Natural Science Foundation of China.
文摘This paper gives a characteristic property of the Euler characteristic for IBN rings. The following results: are proved. （1） If R is a commutative ring, M, N are two stable free R-modules, then χ（MN）=χ（M）χ（N）, where χ denotes the Euler characteristic. （2） If f: K<sub>0</sub>（R）→Z is a ring isomorphism, where K<sub>0</sub>（R） denotes the Grothendieck group of R, K<sub>0</sub>（R） is a ring when R is commutative, then f（[M]）=χ（M） and χ（MN）=χ（M）χ（N） when M, N are finitely generated projective R-modules, where.the isomorphism class [M] is a generator of K<sub>0</sub>（R）. In addition, some applications of the results above are also obtained.
文摘S. L. Sobolev proposed a successful imbedding method for solving linear Fredholm integral equations. This method leads to the Cauchy problem of the first-order differential equation for the resolvent kernel with an initial condi-
