The purpose of this paper is to investigate the convergence of the mixed finite element method for the initial-boundary value problem for the Sobolev equation Ut-div{aut + b1 u} = f based on the Raviart-Thomas space ...The purpose of this paper is to investigate the convergence of the mixed finite element method for the initial-boundary value problem for the Sobolev equation Ut-div{aut + b1 u} = f based on the Raviart-Thomas space Vh × Wh H(div; × L2(). Optimal order estimates are obtained for the approximation of u, ut, the associated velocity p and divp respectively in L(0,T;L2()), L(0,T;L2()), L(0,T;L2()2), and L2(0, T; L2()). Quasi-optimal order estimates are obtained for the approximations of u, ut in L(0, T; L()) and p in L(0,T; L()2).展开更多
Abstract In this paper, the higher order neutral differential equation with continuous distributed delay is concerned and the oscillatory criteria are given.
Hexagonal gallium nitride films were successfully fabricated throughammoniating Ga_2O_3 films deposited on silicon (111) substrates by electrophoresis. The structure,composition, and surface morphology of the formed f...Hexagonal gallium nitride films were successfully fabricated throughammoniating Ga_2O_3 films deposited on silicon (111) substrates by electrophoresis. The structure,composition, and surface morphology of the formed films were characterized by X-ray diffraction(XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and transmissionelectron microscopy (TEM). The measurement results reveal that the polycrystalline GaN films withhexagonal wurtzite structure were successfully grown on the silicon (111) substrates. Preliminaryresults suggest that varying the ammoniating temperature has obvious effect on the quality of theGaN films formed with this method.展开更多
A novel kinetic mechanism of esterification reaction of 1-hexanoic acid with 1-butanol, catalyzed by lipase, was studied in water-in-oil microemulsions. The microemulsions were formed by alkyl polyglucoside C10G1.54/1...A novel kinetic mechanism of esterification reaction of 1-hexanoic acid with 1-butanol, catalyzed by lipase, was studied in water-in-oil microemulsions. The microemulsions were formed by alkyl polyglucoside C10G1.54/1-butanol / cyclohexane/phosphate buffer solution. The result shows that when the ratio of mol concentration of 1-butanol to 1-hexanoic acid is about 3.0, the initial rate V0 get the maximum values. This phenomenon was explained by the modified fishlike phase diagrams.展开更多
Using geometry optimization and DFT method at the B3LYP/6-31G* level for C20H10, an equilibrium geometry is identified to have the form of polyhedral hydrocarbon with five carbon-carbon single bonds linking two pentap...Using geometry optimization and DFT method at the B3LYP/6-31G* level for C20H10, an equilibrium geometry is identified to have the form of polyhedral hydrocarbon with five carbon-carbon single bonds linking two pentaprismane cages. Thus, C20H10 is a tri-cage molecule with three pentaprismane cages. Vibrational frequencies and infrared spectrum are computed at the same level. The heat of formation for this molecule has also been estimated in this paper.展开更多
Abstract: The authors found five sodium (Na+) and chloride (Cl-.) hyperaccumulating halophytes in the Temperate Desert of Xinjiang, China and studied two of them (Suaeda salsa (L.) Pall. and Kalidium folium (Pall.) Mo...Abstract: The authors found five sodium (Na+) and chloride (Cl-.) hyperaccumulating halophytes in the Temperate Desert of Xinjiang, China and studied two of them (Suaeda salsa (L.) Pall. and Kalidium folium (Pall.) Moq.). K. folium and S. salsa had a NaCl content of 32.1% and 29.8%, respectively, on a dry weight basis. X-ray microanalysis of the Na+ in the vacuole, apoplasts and cytoplasm of the two plants indicated a ratio of 7.3:5.6:1.0 in K. folium and 7.3:6.6:1.0 in S. salsa. These data show that K. folium and S. salsa both have a high Na+ and Cl- accumulating capacity, which is related to high activity of tonoplast H+-ATPase and H+-PPase.展开更多
As an emerging class of crystalline porous materials, covalent organic frameworks（COFs） have been widely used as catalysts or catalyst supports. Flexible regulation of the pores and easy introduction of functional a...As an emerging class of crystalline porous materials, covalent organic frameworks（COFs） have been widely used as catalysts or catalyst supports. Flexible regulation of the pores and easy introduction of functional active sites onto the skeleton of COFs make them promising platforms for many catalysis applications. However, only a single function is generally observed in these COFs. Herein, we synthesized a negatively charged ionic COF（I-COF） and successfully incorporated functionalized counter ions, that is, metallic Mn2＋ and a coordination complex of manganese（Ⅱ） bipyridine complexes（[Mn（bpy）2]2＋）, via a simple ion exchange process. The resulting I-COFs can act as effective heterogeneous catalysts for epoxidation reactions. We envisage that with this type of ionic architecture, a variety of other functional cations could be exchanged into the frameworks, thus making the COF a versatile platform for different applications.展开更多
The three-phase behavior in the quaternary system of an alkyl (C8/10- or C12/14-) polyglucoside / 1-butanol / n-octane / water has been studied at 40 ℃ with the modified fishlike phase diagram, which is presented by ...The three-phase behavior in the quaternary system of an alkyl (C8/10- or C12/14-) polyglucoside / 1-butanol / n-octane / water has been studied at 40 ℃ with the modified fishlike phase diagram, which is presented by us for the first time. The mass fraction of 1-butanol in the hydrophile-lipophile balanced interfacial layer, AS, the coordinates of the start point B and the end point E of the phase diagram, and the solubilities of alkyl polyglucoside and 1-butanol in n-octane phase were calculated. The solubilization of the microemulsion was also discussed.展开更多
Habitat pattern change of red-crowned cranes (Grus japonensis) in t he Liaohe Delta between 1988 and 1998 was analyzed with the help of Spatial Dive rsity Index based on remote sensing data and field investigation. Th...Habitat pattern change of red-crowned cranes (Grus japonensis) in t he Liaohe Delta between 1988 and 1998 was analyzed with the help of Spatial Dive rsity Index based on remote sensing data and field investigation. The result sho wed that the influence from human activities on the wetland habitat of red-crow ned cranes was prominent with the development of oil and agricultural exploitati on, and the habitat pattern of red-crowned cranes had been obviously changed by the human disturbance during the ten years. The areas with high Spatial Diversi ty values (SD≥0.65) and that with mid-high values (0.5≤SD< 0.65), which const ituted the main part of suitable habitat of red-crowned cranes,had reduced to 9142ha and 5576ha respectively, with the shrinking of natural land cover, such a s reed and Suaeda community. The habitat pattern became more fragmented, which w as caused by roads and wells during oil exploration. It was indicated that the s uitability and quality of habitat for red-crowned cranes in the Liaohe Delta we re degraded in the last decade. The results also showed that diversity index cou ld reflect the habitat suitability of red-crowned cranes quantitatively and des cribe the spatial pattern of the habitat explicitly. This study will provide a s cientific basis for habitat protection of red-crowned cranes and other rare spe cies in wetlands.展开更多
GaN microcrystalline grains were grown by hot-wall chemical vapor deposition on Si(111)substrate.These grains with diameters of 2-4 μm were detected by scanning electron microscopy.X-ray diffraction,Fourier transform...GaN microcrystalline grains were grown by hot-wall chemical vapor deposition on Si(111)substrate.These grains with diameters of 2-4 μm were detected by scanning electron microscopy.X-ray diffraction,Fourier transformation infrared transmission spectroscopy and photoluminescence were used to analyze the structure, composition and the optical properties of the samples.The results show that the microcrystalline grains are hexagonal wurtzite GaN,and the property of the grains was greatly affected by the growth time.展开更多
The surface morphological changes produced by Nd:YAG pulsed laser ablation of metal Al and semiconductor Si were carefully examined and analyzed by using scanning electron microscope. The formation mechanism of the dr...The surface morphological changes produced by Nd:YAG pulsed laser ablation of metal Al and semiconductor Si were carefully examined and analyzed by using scanning electron microscope. The formation mechanism of the droplets was discussed, and the reasons for formation of the microcracks on the laser irradiated area of the target surface were analyzed by calculating the thermal stress, the vapor pressure and the shock pressure induced by the laser supported detonation.展开更多
This paper generalizes the quantum clock synchronization protocol of Josza, et al., [Richard Jozsa, et al.,Phys. Rev. Lett. 85 (2000) 2010] to synchronize space and thne simultaneously.
Heat shock cognate proteins 70 (hsp70s) act as molecular chaperones. Some hsp70s are also expressed in unstressed plants, known as hsc70. To gain further knowledge about the hsc70, the Thellungiella halophila hsc70 (T...Heat shock cognate proteins 70 (hsp70s) act as molecular chaperones. Some hsp70s are also expressed in unstressed plants, known as hsc70. To gain further knowledge about the hsc70, the Thellungiella halophila hsc70 (Thhsc70) gene that encoded the cytosolic hsc70 in salt cress (T.halophila (C.A.Mey.) O.E.Schulz) was identified. In unstressed plants the expression of Thhsc70was shown to be tissue-specific. The Thhsc70 gene was induced by heat and cold stresses, but almost not by salt and drought stresses. Overexpression of Thhsc7Ocould increase thermctolerance and chilling tolerance in transgenic Arabidopsis plants.展开更多
By the application of the extended homogeneous balance method, we derive anauto-Backlund transformation (BT) for (2+1)-dimensional variable coefficient generalized KPequations. Based on the BT, in which there are two ...By the application of the extended homogeneous balance method, we derive anauto-Backlund transformation (BT) for (2+1)-dimensional variable coefficient generalized KPequations. Based on the BT, in which there are two homogeneity equations to be solved, we obtainsome exact solutions containing single solitary waves.展开更多
With the application of learner-centered instruction mode to College English teaching in recent years, an increasing number of College English teachers place more weight on identifying the local needs of their student...With the application of learner-centered instruction mode to College English teaching in recent years, an increasing number of College English teachers place more weight on identifying the local needs of their students and working toward meeting those needs. As a result, more and more students are highly motivated to participate in discussion or展开更多
文摘The purpose of this paper is to investigate the convergence of the mixed finite element method for the initial-boundary value problem for the Sobolev equation Ut-div{aut + b1 u} = f based on the Raviart-Thomas space Vh × Wh H(div; × L2(). Optimal order estimates are obtained for the approximation of u, ut, the associated velocity p and divp respectively in L(0,T;L2()), L(0,T;L2()), L(0,T;L2()2), and L2(0, T; L2()). Quasi-optimal order estimates are obtained for the approximations of u, ut in L(0, T; L()) and p in L(0,T; L()2).
文摘Abstract In this paper, the higher order neutral differential equation with continuous distributed delay is concerned and the oscillatory criteria are given.
基金This work is financially supported by the Key Research Program of National Natural Science Foundation of China (No. 90201025)the National Natural Science Foundation of China (No. 60071006)
文摘Hexagonal gallium nitride films were successfully fabricated throughammoniating Ga_2O_3 films deposited on silicon (111) substrates by electrophoresis. The structure,composition, and surface morphology of the formed films were characterized by X-ray diffraction(XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and transmissionelectron microscopy (TEM). The measurement results reveal that the polycrystalline GaN films withhexagonal wurtzite structure were successfully grown on the silicon (111) substrates. Preliminaryresults suggest that varying the ammoniating temperature has obvious effect on the quality of theGaN films formed with this method.
文摘A novel kinetic mechanism of esterification reaction of 1-hexanoic acid with 1-butanol, catalyzed by lipase, was studied in water-in-oil microemulsions. The microemulsions were formed by alkyl polyglucoside C10G1.54/1-butanol / cyclohexane/phosphate buffer solution. The result shows that when the ratio of mol concentration of 1-butanol to 1-hexanoic acid is about 3.0, the initial rate V0 get the maximum values. This phenomenon was explained by the modified fishlike phase diagrams.
基金This work was supported by the Natural Science Foundation of Shandong Province (Y2002G11)
文摘Using geometry optimization and DFT method at the B3LYP/6-31G* level for C20H10, an equilibrium geometry is identified to have the form of polyhedral hydrocarbon with five carbon-carbon single bonds linking two pentaprismane cages. Thus, C20H10 is a tri-cage molecule with three pentaprismane cages. Vibrational frequencies and infrared spectrum are computed at the same level. The heat of formation for this molecule has also been estimated in this paper.
基金国家重点基础研究发展计划(973计划)，the Foundation of Excellent Young/Scientists of Shandong Province
文摘Abstract: The authors found five sodium (Na+) and chloride (Cl-.) hyperaccumulating halophytes in the Temperate Desert of Xinjiang, China and studied two of them (Suaeda salsa (L.) Pall. and Kalidium folium (Pall.) Moq.). K. folium and S. salsa had a NaCl content of 32.1% and 29.8%, respectively, on a dry weight basis. X-ray microanalysis of the Na+ in the vacuole, apoplasts and cytoplasm of the two plants indicated a ratio of 7.3:5.6:1.0 in K. folium and 7.3:6.6:1.0 in S. salsa. These data show that K. folium and S. salsa both have a high Na+ and Cl- accumulating capacity, which is related to high activity of tonoplast H+-ATPase and H+-PPase.
基金supported by the National Natural Science Foundation of China(21473196,21676264)the 100-Talents Program of CASthe State Key Laboratory of Fine Chemicals,Dalian University of Technology(KF1415)~~
文摘As an emerging class of crystalline porous materials, covalent organic frameworks（COFs） have been widely used as catalysts or catalyst supports. Flexible regulation of the pores and easy introduction of functional active sites onto the skeleton of COFs make them promising platforms for many catalysis applications. However, only a single function is generally observed in these COFs. Herein, we synthesized a negatively charged ionic COF（I-COF） and successfully incorporated functionalized counter ions, that is, metallic Mn2＋ and a coordination complex of manganese（Ⅱ） bipyridine complexes（[Mn（bpy）2]2＋）, via a simple ion exchange process. The resulting I-COFs can act as effective heterogeneous catalysts for epoxidation reactions. We envisage that with this type of ionic architecture, a variety of other functional cations could be exchanged into the frameworks, thus making the COF a versatile platform for different applications.
文摘The three-phase behavior in the quaternary system of an alkyl (C8/10- or C12/14-) polyglucoside / 1-butanol / n-octane / water has been studied at 40 ℃ with the modified fishlike phase diagram, which is presented by us for the first time. The mass fraction of 1-butanol in the hydrophile-lipophile balanced interfacial layer, AS, the coordinates of the start point B and the end point E of the phase diagram, and the solubilities of alkyl polyglucoside and 1-butanol in n-octane phase were calculated. The solubilization of the microemulsion was also discussed.
基金Supported by the National Natural Science Foundation of China (No.10171057)the Rewarded Foundation of Outstanding Middle and Young Scientist of Shandong Province
文摘This paper presents some results on the existence of double solutions for singular impulsive boundary value problems on the half line.
文摘Habitat pattern change of red-crowned cranes (Grus japonensis) in t he Liaohe Delta between 1988 and 1998 was analyzed with the help of Spatial Dive rsity Index based on remote sensing data and field investigation. The result sho wed that the influence from human activities on the wetland habitat of red-crow ned cranes was prominent with the development of oil and agricultural exploitati on, and the habitat pattern of red-crowned cranes had been obviously changed by the human disturbance during the ten years. The areas with high Spatial Diversi ty values (SD≥0.65) and that with mid-high values (0.5≤SD< 0.65), which const ituted the main part of suitable habitat of red-crowned cranes,had reduced to 9142ha and 5576ha respectively, with the shrinking of natural land cover, such a s reed and Suaeda community. The habitat pattern became more fragmented, which w as caused by roads and wells during oil exploration. It was indicated that the s uitability and quality of habitat for red-crowned cranes in the Liaohe Delta we re degraded in the last decade. The results also showed that diversity index cou ld reflect the habitat suitability of red-crowned cranes quantitatively and des cribe the spatial pattern of the habitat explicitly. This study will provide a s cientific basis for habitat protection of red-crowned cranes and other rare spe cies in wetlands.
文摘GaN microcrystalline grains were grown by hot-wall chemical vapor deposition on Si(111)substrate.These grains with diameters of 2-4 μm were detected by scanning electron microscopy.X-ray diffraction,Fourier transformation infrared transmission spectroscopy and photoluminescence were used to analyze the structure, composition and the optical properties of the samples.The results show that the microcrystalline grains are hexagonal wurtzite GaN,and the property of the grains was greatly affected by the growth time.
文摘The surface morphological changes produced by Nd:YAG pulsed laser ablation of metal Al and semiconductor Si were carefully examined and analyzed by using scanning electron microscope. The formation mechanism of the droplets was discussed, and the reasons for formation of the microcracks on the laser irradiated area of the target surface were analyzed by calculating the thermal stress, the vapor pressure and the shock pressure induced by the laser supported detonation.
文摘This paper generalizes the quantum clock synchronization protocol of Josza, et al., [Richard Jozsa, et al.,Phys. Rev. Lett. 85 (2000) 2010] to synchronize space and thne simultaneously.
文摘Heat shock cognate proteins 70 (hsp70s) act as molecular chaperones. Some hsp70s are also expressed in unstressed plants, known as hsc70. To gain further knowledge about the hsc70, the Thellungiella halophila hsc70 (Thhsc70) gene that encoded the cytosolic hsc70 in salt cress (T.halophila (C.A.Mey.) O.E.Schulz) was identified. In unstressed plants the expression of Thhsc70was shown to be tissue-specific. The Thhsc70 gene was induced by heat and cold stresses, but almost not by salt and drought stresses. Overexpression of Thhsc7Ocould increase thermctolerance and chilling tolerance in transgenic Arabidopsis plants.
文摘By the application of the extended homogeneous balance method, we derive anauto-Backlund transformation (BT) for (2+1)-dimensional variable coefficient generalized KPequations. Based on the BT, in which there are two homogeneity equations to be solved, we obtainsome exact solutions containing single solitary waves.
文摘With the application of learner-centered instruction mode to College English teaching in recent years, an increasing number of College English teachers place more weight on identifying the local needs of their students and working toward meeting those needs. As a result, more and more students are highly motivated to participate in discussion or
