Aim The general arbitrary cracked problem in an elastic plane was discussed. Methods For the purpose of acquiring the solution of the problem, a new formulation on the problem was proposed. Compared with the classic...Aim The general arbitrary cracked problem in an elastic plane was discussed. Methods For the purpose of acquiring the solution of the problem, a new formulation on the problem was proposed. Compared with the classical plane elastic crack model, only the known conditions were revised in the new formulation, which are greatly convenient to solve the problem, and no other new condition was given. Results and Conclusion The general exact analytic solution is given here based on the formulation though the problem is very complicated. Furthermore, the stress intensity factors K Ⅰ, K Ⅱ of the problem are also given.展开更多
[Objective] This study was to explore the effects of dilute acid hydrolysis on fermentative biohydrogen production capacity of maize stalk. [Method] Using maize stalks subjected to mechanical disintegration,steam expl...[Objective] This study was to explore the effects of dilute acid hydrolysis on fermentative biohydrogen production capacity of maize stalk. [Method] Using maize stalks subjected to mechanical disintegration,steam explosion and dilute acid hydrolysis as experimental materials,we measured and analyzed the effects of different treatments and particle size of maize stalk were analyzed. [Result] The optimal fermentative biohydrogen production was found under following parameters：pretreatment of 0.8% dilute H2SO4 following steam explosion,particle size of maize stalk of 0.425-0.850 mm,liquid-solid ratio [0.8% H2SO4 （M）：stalk （W）] of 10：1. [Conclusion] Post steam explosion,dilute 0.8% dilute H2SO4 intensified hydrolysis on maize stalk could produce fermentative biohydrogen production capacity.展开更多
Superexcited states of NO molecule and their neutral dissociation processes have been studied both experimentally and theoretically. Neutral excited N^＊ and O^＊ atoms are detected by fluorescence spectroscopy for th...Superexcited states of NO molecule and their neutral dissociation processes have been studied both experimentally and theoretically. Neutral excited N^＊ and O^＊ atoms are detected by fluorescence spectroscopy for the NO molecule upon interaction with 800 nm intense laser radiation of duration 60 fs and intensity 0.2 PW/cm^2. Intense laser pulse causes neutral dissociation of superexcited NO molecule by way of multiphoton excitation, which is equivalent to single photon excitation in the extreme-ultraviolet region by synchrotron radiation. Potential energy curves （PECs） are also built using the calculated superexcited state of NO^＋. In light of the PECs, direct dissociation and pre-dissociation mechanisms are proposed respectively for the neutral dissociation leading to excited fragments N^＊ and O^＊.展开更多
This paper investigates the self-similar singular solution of the p-Laplacian evolution equation with the nonlinear gradient absorption terms u t=div(u p-2u)-uq for 1<p<2 and q>in Rn× (0, ∞). It has ...This paper investigates the self-similar singular solution of the p-Laplacian evolution equation with the nonlinear gradient absorption terms u t=div(u p-2u)-uq for 1<p<2 and q>in Rn× (0, ∞). It has been proved that when 1<q<p-n/(n+1) there exists a unique self-similar very singular solution.展开更多
[Objective] This study aimed to investigate the primary and secondary metabolisms during the germination of Scutellaria baicalensis Georgi seeds under different light intensities. [Method] The activities of CHL, solub...[Objective] This study aimed to investigate the primary and secondary metabolisms during the germination of Scutellaria baicalensis Georgi seeds under different light intensities. [Method] The activities of CHL, soluble sugar, PAL, C4H and CHS were determined with ultraviolet spectrophotometry. The secondary metabolites were detected by High Performance Liquid Chromatography （HPLC）. [Result] The results indicate that the germination of Scutellaria baicalensis Georgi seeds is not sensitive to light and the seedlings were very sensitive to light. The CHL, soluble sugar, PAL, C4H and CHS continuously increased with light intensity. The content of secondary metabolites also increased. [Conclusion] Light increased the formation of leaf photosynthetic pigment, thereby affecting the primary metabolites. The activities of PAL, C4H and CHS significantly increased with the development of light intensity. Finally the secondary metabolites of medicinal plants increased sharply. Therefore, the quality of Scutellaria baicalensis Georgi materials can be improved by increasing the light intensity moderately.展开更多
In this paper, we consider a strongly-coupled parabolic system with initial boundary values. Under the appropriate conditions, using Gagliard-Nirenberg inequality, Poincare inequality, Gronwall inequality and imbeddin...In this paper, we consider a strongly-coupled parabolic system with initial boundary values. Under the appropriate conditions, using Gagliard-Nirenberg inequality, Poincare inequality, Gronwall inequality and imbedding theorem, we obtain the global existence of solutions.展开更多
A multifunctional Cu2O/Ag micro-nanocomposite, which has the characteristics of high cat- alytic activities under the visible light and high surface-enhanced Raman scattering （SERS） activity, was fabricated via a fa...A multifunctional Cu2O/Ag micro-nanocomposite, which has the characteristics of high cat- alytic activities under the visible light and high surface-enhanced Raman scattering （SERS） activity, was fabricated via a facile method and employed for the in situ SERS monitoring of the photocatalytic degradation reaction of crystal violet. Through the variation of the AgNO3 concentration, Ag content on the Cu2O template can be controllably tuned, which has great influence on the SERS effect. The results indicate that Ag nanopartieles form on the Cu2O nanoframes to obtain the Cu2O/Ag nanoeomposite, which can act as an excellent bifunetional platform for in situ monitoring of photocatalytic degradation of organic pollutions by SERS.展开更多
SnO2intermediate layers were coated on the titanium(Ti)substrate by thermal decomposition.Scanning electronmicroscope(SEM)and X-ray diffraction(XRD)results show that uniform SnO2intermediate layers with rutile crystal...SnO2intermediate layers were coated on the titanium(Ti)substrate by thermal decomposition.Scanning electronmicroscope(SEM)and X-ray diffraction(XRD)results show that uniform SnO2intermediate layers with rutile crystal structure weresuccessfully achieved.According to the results of linear sweep voltammetry(LSV),oxygen evolution potential(OEP)of theTi/SnO2/MnO2electrodes decreases with increasing SnO2content,indicating that the electro-catalytic oxidation activity of theelectrode increases.Accelerated service life tests results demonstrate that SnO2intermediate layer can improve the service life of theTi/SnO2/MnO2electrode.As the content of SnO2intermediate layer increases,the cell voltage and the energy consumption decreaseapparently.展开更多
As China's energy intensity fluctuated in recent years, it is necessary to examine whether this fluctuation happened at a regional level. This paper establishes a decomposition model by using the structural decomp...As China's energy intensity fluctuated in recent years, it is necessary to examine whether this fluctuation happened at a regional level. This paper establishes a decomposition model by using the structural decomposition analysis (SDA) method at a regional level. Then this model is employed to empirically analyze the changes of Beijing's energy intensity. The conclusions are as follows: during 2002-2010, except petroleum, the energy intensity decreased and the changes were mostly attributed to the technology changes, while the final use variation actually increased the energy intensity; comparing different periods of 2002-2010, the decline rates of energy intensity for coal and hydropower were decreasing, resulting from the production technology being more energy-intensive than before; the energy intensity changes of petroleum firstly increased substantially and then decreased moderately.展开更多
With the increase of mining depth of mineral resources,the rock mass stress state is being more and more complex.The rock mass show different features,namely,with the increase of hydrostatic pressure,rock mass failure...With the increase of mining depth of mineral resources,the rock mass stress state is being more and more complex.The rock mass show different features,namely,with the increase of hydrostatic pressure,rock mass failure mode turns from brittle tension failure to structure ductile failure and its limit strength also increases.The restriction of minimal principal stress on the initiation and development of microcrack and the change of micro-unit stress state by the intermediate principal stress play a decisive role in the increase of rock mass limit strength.Based on the rock mass failure behavior law under complex stress state and the σ2-dependence on the rock mass strength,we proposed a Modified Mohr-Coulomb(M-MC) strength criterion which is smooth and convex.Finally,the M-MC criterion is validated by multiaxial test data of eight kinds of rock mass.We also compared the fitting results with Mohr-Coulomb criterion(MC).It shows that the new criterion fits the test data better than the Mohr-Coulomb criterion.So the M-MC strength criterion well reveals the rock mass bearing behavior and can be widely used in the rock mass strength analysis.The results can provide theoretical foundations for stability analysis and reinforcement design of complex underground engineering.展开更多
Acoustic wave propagation in piezoelectric crystals of classes 43m and 23 is studied. The crystals Tl3VS4 and Tl3TaSe4 （43m） of the Chalcogenide family and the crystal Bi12TiO20 （23） possess strong piezoelectric e...Acoustic wave propagation in piezoelectric crystals of classes 43m and 23 is studied. The crystals Tl3VS4 and Tl3TaSe4 （43m） of the Chalcogenide family and the crystal Bi12TiO20 （23） possess strong piezoelectric effect. Because the surface Bleustein-Gulyaev waves cannot exist in piezoelectric cubic crystals, it was concluded that new solutions for shear-horizontal surface acoustic waves （SH-SAWs） are found in the monocrystals using different electrical boundary conditions such as electrically ＂short＂ and ＂open＂ free-surfaces for the unique [ 101 ] direction of wave propagation. For the crystal Tl3TaSe4 with coefficient of electromechanical coupling （CEMC） Ke^2=e^2/（C×g）-1/3, the phase velocity Vph for the new SH-SAWs can be calculated with the following formula： Vph=（Vα＋Vt）/2, where Vt is the speed of bulk SH-wave, Vt=Vt4（1＋Ke^2）^1/2, Vα=αKVt4, αK=2[Ke（1＋Ke^2）^1/2-Ke^2]^1/2, and Vt4=（C44/p）^1/2. It was found that the CEMC K2 evaluation for Tl3TaSe4 gave the value of K^2=2（Vf-Vm）/Vf-0.047 （-4.7%）, where Vf-848 m/s and Vm-828 m/s are the new-SAW velocities for the free and metallized surfaces, respectively. This high value of KZ（Tl3TaSe4） is significantly greater than K2（Tl3VS4）-3% and about five times that of K2（Bi12YiO20）.展开更多
The dissimilar joining of biodegradable magnesium alloy to pure commercial titanium by rotational friction welding with rotational speeds of 1100,1200 and 1300 r/min for the production of bio-screw was investigated.Th...The dissimilar joining of biodegradable magnesium alloy to pure commercial titanium by rotational friction welding with rotational speeds of 1100,1200 and 1300 r/min for the production of bio-screw was investigated.The metallographic analysis revealed that a good joining was obtained at the Ti/Mg alloy joint.On the magnesium alloy side,various regions such as the weld center zone(WCZ),dynamic recrystallization zone(DRX),thermo-mechanically affected zone(TMAZ)and partially deformed zone(PDZ)were observed.The highest tensile and shear strengths were 173 and 103.2 MPa,respectively at a rotational speed of 1300 r/min.The Ti/Mg alloy dissimilar friction welded joint failed at the vicinity of the intermetallic zone containing Ti3Al phase.The hardness values from the base metal magnesium alloy to the joining point increased mainly due to grain refinement(8.57μm in diameter)and the presence of titanium particles,while the hardness values were constant on the titanium side.It was also found that the corrosion rate of the Ti/Mg alloy joint was higher compared with that of the Ti and Mg alloy from the immersion studies.Additionally,the sample with a rotational speed of 1300 r/min showed better biocompatibility and a cell viability of 98.12%due to better corrosion resistance.展开更多
It is traditionally assumed that the relationship between wave steepness and wave age is inde- pendent of the wind wave growth state. In fact, the traditional relationship can not describe the whole course of wind w...It is traditionally assumed that the relationship between wave steepness and wave age is inde- pendent of the wind wave growth state. In fact, the traditional relationship can not describe the whole course of wind wave growth. This paper assumes that the relationship between wave steepness and wave age changes with the variety of dimensionless fetch. Based on the relationship proposed by Hou and Wen (1990), a new relation- ship in the course of wind wave growth is revealed. Comparisons between the present study and other previous relationships show that this new relationship explains better the observations than the other existing relationships. In the case of small fetch, wave age value increases more quickly than other models while it is in opposition to that in the case of large fetch. The result in present paper can clearly reflect the whole course of wind wave growth, it is an improvement for traditional results.Key words: wave steepness, wave age, relationship between wave steepness and wave age展开更多
The conductivities of LiBr, LiCl, and LiNO 3 in methanol, ethanol, 1-propanol, and 2-propanol (with electrolyte concentrations <0.08 mol·L-1 ) were determined at 298.15 K, 313.15 K, and 323.15 K at atmosphere ...The conductivities of LiBr, LiCl, and LiNO 3 in methanol, ethanol, 1-propanol, and 2-propanol (with electrolyte concentrations <0.08 mol·L-1 ) were determined at 298.15 K, 313.15 K, and 323.15 K at atmosphere pressure separately by using a conductivity meter. The conductivity data were correlated with Foss-Chen-Justice (FCJ) equation and the limiting molar conductivities were obtained. The mean ionic activity coefficients of the salts in the organic solvents were calculated according to the Debye-Hückel limiting law and Onsager-Falkenhangen equations. The calculated results were compared with those activity coefficients in literature.展开更多
文摘Aim The general arbitrary cracked problem in an elastic plane was discussed. Methods For the purpose of acquiring the solution of the problem, a new formulation on the problem was proposed. Compared with the classical plane elastic crack model, only the known conditions were revised in the new formulation, which are greatly convenient to solve the problem, and no other new condition was given. Results and Conclusion The general exact analytic solution is given here based on the formulation though the problem is very complicated. Furthermore, the stress intensity factors K Ⅰ, K Ⅱ of the problem are also given.
基金Supported by National Basic Research Program of China(2006CB708407 2009CB220005)+2 种基金National Natural Science Foun-dation of China (90610001 20871106)Program of 211 Projectfor Zhengzhou University from Ministry of Education~~
文摘[Objective] This study was to explore the effects of dilute acid hydrolysis on fermentative biohydrogen production capacity of maize stalk. [Method] Using maize stalks subjected to mechanical disintegration,steam explosion and dilute acid hydrolysis as experimental materials,we measured and analyzed the effects of different treatments and particle size of maize stalk were analyzed. [Result] The optimal fermentative biohydrogen production was found under following parameters：pretreatment of 0.8% dilute H2SO4 following steam explosion,particle size of maize stalk of 0.425-0.850 mm,liquid-solid ratio [0.8% H2SO4 （M）：stalk （W）] of 10：1. [Conclusion] Post steam explosion,dilute 0.8% dilute H2SO4 intensified hydrolysis on maize stalk could produce fermentative biohydrogen production capacity.
文摘Superexcited states of NO molecule and their neutral dissociation processes have been studied both experimentally and theoretically. Neutral excited N^＊ and O^＊ atoms are detected by fluorescence spectroscopy for the NO molecule upon interaction with 800 nm intense laser radiation of duration 60 fs and intensity 0.2 PW/cm^2. Intense laser pulse causes neutral dissociation of superexcited NO molecule by way of multiphoton excitation, which is equivalent to single photon excitation in the extreme-ultraviolet region by synchrotron radiation. Potential energy curves （PECs） are also built using the calculated superexcited state of NO^＋. In light of the PECs, direct dissociation and pre-dissociation mechanisms are proposed respectively for the neutral dissociation leading to excited fragments N^＊ and O^＊.
基金TheKeyProjectofChineseMinistryofEducation (No .10 40 90 ) .
文摘This paper investigates the self-similar singular solution of the p-Laplacian evolution equation with the nonlinear gradient absorption terms u t=div(u p-2u)-uq for 1<p<2 and q>in Rn× (0, ∞). It has been proved that when 1<q<p-n/(n+1) there exists a unique self-similar very singular solution.
基金Supported by Agricultural Improved Variety Project of Shandong Province(No.2005LZ08,2008LZ013)~~
文摘[Objective] This study aimed to investigate the primary and secondary metabolisms during the germination of Scutellaria baicalensis Georgi seeds under different light intensities. [Method] The activities of CHL, soluble sugar, PAL, C4H and CHS were determined with ultraviolet spectrophotometry. The secondary metabolites were detected by High Performance Liquid Chromatography （HPLC）. [Result] The results indicate that the germination of Scutellaria baicalensis Georgi seeds is not sensitive to light and the seedlings were very sensitive to light. The CHL, soluble sugar, PAL, C4H and CHS continuously increased with light intensity. The content of secondary metabolites also increased. [Conclusion] Light increased the formation of leaf photosynthetic pigment, thereby affecting the primary metabolites. The activities of PAL, C4H and CHS significantly increased with the development of light intensity. Finally the secondary metabolites of medicinal plants increased sharply. Therefore, the quality of Scutellaria baicalensis Georgi materials can be improved by increasing the light intensity moderately.
文摘In this paper, we consider a strongly-coupled parabolic system with initial boundary values. Under the appropriate conditions, using Gagliard-Nirenberg inequality, Poincare inequality, Gronwall inequality and imbedding theorem, we obtain the global existence of solutions.
基金This work was supported by tile Key Projects of Natural Science Research of Universities in Anhui Province （No.KJ2015A183, No.KJ2015A201） and Talents Foundation of Hefei University （No.15RC05）, Anhui Province Natural Science Foundation （No.1608085MD78）, the Key Projects of Anhui Province University Outstanding Youth Talent Support Program （gxyqZD2016274）, the National Natural Science Foundation of China （No.21305142, No.51403048）.
文摘A multifunctional Cu2O/Ag micro-nanocomposite, which has the characteristics of high cat- alytic activities under the visible light and high surface-enhanced Raman scattering （SERS） activity, was fabricated via a facile method and employed for the in situ SERS monitoring of the photocatalytic degradation reaction of crystal violet. Through the variation of the AgNO3 concentration, Ag content on the Cu2O template can be controllably tuned, which has great influence on the SERS effect. The results indicate that Ag nanopartieles form on the Cu2O nanoframes to obtain the Cu2O/Ag nanoeomposite, which can act as an excellent bifunetional platform for in situ monitoring of photocatalytic degradation of organic pollutions by SERS.
基金Project(51574287) supported by the National Natural Science Foundation of ChinaProject supported by the Collaborative Innovation Center of Manganese-Zinc-Vanadium Industrial Technology
文摘SnO2intermediate layers were coated on the titanium(Ti)substrate by thermal decomposition.Scanning electronmicroscope(SEM)and X-ray diffraction(XRD)results show that uniform SnO2intermediate layers with rutile crystal structure weresuccessfully achieved.According to the results of linear sweep voltammetry(LSV),oxygen evolution potential(OEP)of theTi/SnO2/MnO2electrodes decreases with increasing SnO2content,indicating that the electro-catalytic oxidation activity of theelectrode increases.Accelerated service life tests results demonstrate that SnO2intermediate layer can improve the service life of theTi/SnO2/MnO2electrode.As the content of SnO2intermediate layer increases,the cell voltage and the energy consumption decreaseapparently.
基金Supported by Strategic Priority Research Program of the Chinese Academy of Sciences (No. XDA05150600)National Natural Science Foundation of China (No. 71273027 and No. 70903066)Beijing Planning Office of Philosophy and Social Science (No. 11JGC105)
文摘As China's energy intensity fluctuated in recent years, it is necessary to examine whether this fluctuation happened at a regional level. This paper establishes a decomposition model by using the structural decomposition analysis (SDA) method at a regional level. Then this model is employed to empirically analyze the changes of Beijing's energy intensity. The conclusions are as follows: during 2002-2010, except petroleum, the energy intensity decreased and the changes were mostly attributed to the technology changes, while the final use variation actually increased the energy intensity; comparing different periods of 2002-2010, the decline rates of energy intensity for coal and hydropower were decreasing, resulting from the production technology being more energy-intensive than before; the energy intensity changes of petroleum firstly increased substantially and then decreased moderately.
基金supported by the National Natural Science Foundation of China (Nos.50774082 and 50804046)
文摘With the increase of mining depth of mineral resources,the rock mass stress state is being more and more complex.The rock mass show different features,namely,with the increase of hydrostatic pressure,rock mass failure mode turns from brittle tension failure to structure ductile failure and its limit strength also increases.The restriction of minimal principal stress on the initiation and development of microcrack and the change of micro-unit stress state by the intermediate principal stress play a decisive role in the increase of rock mass limit strength.Based on the rock mass failure behavior law under complex stress state and the σ2-dependence on the rock mass strength,we proposed a Modified Mohr-Coulomb(M-MC) strength criterion which is smooth and convex.Finally,the M-MC criterion is validated by multiaxial test data of eight kinds of rock mass.We also compared the fitting results with Mohr-Coulomb criterion(MC).It shows that the new criterion fits the test data better than the Mohr-Coulomb criterion.So the M-MC strength criterion well reveals the rock mass bearing behavior and can be widely used in the rock mass strength analysis.The results can provide theoretical foundations for stability analysis and reinforcement design of complex underground engineering.
文摘Acoustic wave propagation in piezoelectric crystals of classes 43m and 23 is studied. The crystals Tl3VS4 and Tl3TaSe4 （43m） of the Chalcogenide family and the crystal Bi12TiO20 （23） possess strong piezoelectric effect. Because the surface Bleustein-Gulyaev waves cannot exist in piezoelectric cubic crystals, it was concluded that new solutions for shear-horizontal surface acoustic waves （SH-SAWs） are found in the monocrystals using different electrical boundary conditions such as electrically ＂short＂ and ＂open＂ free-surfaces for the unique [ 101 ] direction of wave propagation. For the crystal Tl3TaSe4 with coefficient of electromechanical coupling （CEMC） Ke^2=e^2/（C×g）-1/3, the phase velocity Vph for the new SH-SAWs can be calculated with the following formula： Vph=（Vα＋Vt）/2, where Vt is the speed of bulk SH-wave, Vt=Vt4（1＋Ke^2）^1/2, Vα=αKVt4, αK=2[Ke（1＋Ke^2）^1/2-Ke^2]^1/2, and Vt4=（C44/p）^1/2. It was found that the CEMC K2 evaluation for Tl3TaSe4 gave the value of K^2=2（Vf-Vm）/Vf-0.047 （-4.7%）, where Vf-848 m/s and Vm-828 m/s are the new-SAW velocities for the free and metallized surfaces, respectively. This high value of KZ（Tl3TaSe4） is significantly greater than K2（Tl3VS4）-3% and about five times that of K2（Bi12YiO20）.
文摘The dissimilar joining of biodegradable magnesium alloy to pure commercial titanium by rotational friction welding with rotational speeds of 1100,1200 and 1300 r/min for the production of bio-screw was investigated.The metallographic analysis revealed that a good joining was obtained at the Ti/Mg alloy joint.On the magnesium alloy side,various regions such as the weld center zone(WCZ),dynamic recrystallization zone(DRX),thermo-mechanically affected zone(TMAZ)and partially deformed zone(PDZ)were observed.The highest tensile and shear strengths were 173 and 103.2 MPa,respectively at a rotational speed of 1300 r/min.The Ti/Mg alloy dissimilar friction welded joint failed at the vicinity of the intermetallic zone containing Ti3Al phase.The hardness values from the base metal magnesium alloy to the joining point increased mainly due to grain refinement(8.57μm in diameter)and the presence of titanium particles,while the hardness values were constant on the titanium side.It was also found that the corrosion rate of the Ti/Mg alloy joint was higher compared with that of the Ti and Mg alloy from the immersion studies.Additionally,the sample with a rotational speed of 1300 r/min showed better biocompatibility and a cell viability of 98.12%due to better corrosion resistance.
基金Supported by the NSFC (No. 40176010) and the national "863" Projectof China (No. 2001AA633070).
文摘It is traditionally assumed that the relationship between wave steepness and wave age is inde- pendent of the wind wave growth state. In fact, the traditional relationship can not describe the whole course of wind wave growth. This paper assumes that the relationship between wave steepness and wave age changes with the variety of dimensionless fetch. Based on the relationship proposed by Hou and Wen (1990), a new relation- ship in the course of wind wave growth is revealed. Comparisons between the present study and other previous relationships show that this new relationship explains better the observations than the other existing relationships. In the case of small fetch, wave age value increases more quickly than other models while it is in opposition to that in the case of large fetch. The result in present paper can clearly reflect the whole course of wind wave growth, it is an improvement for traditional results.Key words: wave steepness, wave age, relationship between wave steepness and wave age
文摘The conductivities of LiBr, LiCl, and LiNO 3 in methanol, ethanol, 1-propanol, and 2-propanol (with electrolyte concentrations <0.08 mol·L-1 ) were determined at 298.15 K, 313.15 K, and 323.15 K at atmosphere pressure separately by using a conductivity meter. The conductivity data were correlated with Foss-Chen-Justice (FCJ) equation and the limiting molar conductivities were obtained. The mean ionic activity coefficients of the salts in the organic solvents were calculated according to the Debye-Hückel limiting law and Onsager-Falkenhangen equations. The calculated results were compared with those activity coefficients in literature.
