Due to diminishing demographic dividend characterized by a falling workingage population and rising dependency ratio, China's long-term potential growth rates will keep declining, likely to be a mere 6.6% during t...Due to diminishing demographic dividend characterized by a falling workingage population and rising dependency ratio, China's long-term potential growth rates will keep declining, likely to be a mere 6.6% during the 13 th Five-Year Plan period(2016-2020). China's economic growth sustainability hinges upon its transition from the previous dependence on demographic dividend to the future reform dividend. In the growth accounting equation, we have simulated various reform initiatives and arrived at the following findings. First, although both the labor participation rate and TFP can increase China's potential growth rate, the former will only achieve a short-term growth effect, which will diminish in the long run. By contrast, the growth effect of TFP demonstrates the tendency of continuous increase. This further indicates that China's economic growth will increasingly rely on TFP improvement instead of traditional factor input. Second, different from the diminishing growth effect of enrolment rate, training may play a pivotal role in human capital development to significantly enhance potential growth rates. Third, if all reform initiatives can achieve their expected effects, integrated reform dividends may reach one or two percentage points of China's potential growth rate.展开更多
In this article,we study the initial boundary value problem of coupled semi-linear degenerate parabolic equations with a singular potential term on manifolds with corner singularities.Firstly,we introduce the corner t...In this article,we study the initial boundary value problem of coupled semi-linear degenerate parabolic equations with a singular potential term on manifolds with corner singularities.Firstly,we introduce the corner type weighted p-Sobolev spaces and the weighted corner type Sobolev inequality,the Poincare′inequality,and the Hardy inequality.Then,by using the potential well method and the inequality mentioned above,we obtain an existence theorem of global solutions with exponential decay and show the blow-up in finite time of solutions for both cases with low initial energy and critical initial energy.Significantly,the relation between the above two phenomena is derived as a sharp condition.Moreover,we show that the global existence also holds for the case of a potential well family.展开更多
This article prognosticates the hydrocarbon generation potential of core samples from fields A, B, C and D in Niger delta, Nigeria. The objectives of this study are to characterize the quality of these core samples by...This article prognosticates the hydrocarbon generation potential of core samples from fields A, B, C and D in Niger delta, Nigeria. The objectives of this study are to characterize the quality of these core samples by organic geochemical analyses. A total of ten core samples collected from fields A, B, C and D in Niger delta were analyzed using total organic carbon(TOC) content analysis, rock-eval pyrolysis technique. The analytical results of the studied core samples reveal that they have generally high total organic carbon contents(TOC), suggesting that conditions in the Niger delta favour organic matter production and preservation. There is a variation in the kerogen types and this may be attributed to the relative stratigraphic positions of the core samples within the Niger delta. The rock-eval results indicate that the samples from fields C and D contain predominantly Type II kerogen with a capacity to generate oil and gas and hence have good generative potential. The samples from fields A and B contain mainly Type III kerogen and are gas-prone with moderate generative potential.展开更多
An accurate total energy calculation is essential in materials computation.To date,many tight-binding(TB)approaches based on parameterized hopping can produce electronic structures comparable to those obtained using f...An accurate total energy calculation is essential in materials computation.To date,many tight-binding(TB)approaches based on parameterized hopping can produce electronic structures comparable to those obtained using first-principles calculations.However,TB approaches still have limited applicability for determining material properties derived from the total energy.That is,the predictive power of the TB total energy is impaired by an inaccurate evaluation of the repulsive energy.The complexity associated with the parametrization of TB repulsive potentials is the weak link in this evaluation.In this study,we propose a new method for obtaining the pairwise TB repulsive potential for crystalline materials by employing the Chen-Möbius inversion theorem.We show that the TB-based phonon dispersions,calculated using the resulting repulsive potential,compare well with those obtained by first-principles calculations for various systems,including covalent and ionic bulk materials and twodimensional materials.The present approach only requires the first-principles total energy and TB electronic band energy as input and does not involve any parameters.This striking feature enables us to generate repulsive potentials programmatically.展开更多
The Bozhong Sag is the largest petroliferous sag in the Bohai Bay Basin,and the source rocks of Paleogene Dongying and Shahejie Formations were buried deeply.Most of the drillings were located at the structural high,a...The Bozhong Sag is the largest petroliferous sag in the Bohai Bay Basin,and the source rocks of Paleogene Dongying and Shahejie Formations were buried deeply.Most of the drillings were located at the structural high,and there were few wells that met good quality source rocks,so it is difficult to evaluate the source rocks in the study area precisely by geochemical analysis only.Based on the Rock-Eval pyrolysis,total organic carbon(TOC)testing,the organic matter(OM)abundance of Paleogene source rocks in the southwestern Bozhong Sag were evaluated,including the lower of second member of Dongying Formation(E_(3)d2L),the third member of Dongying Formation(E_(3)d_(3)),the first and second members of Shahejie Formation(E_(2)s_(1+2)),the third member of Shahejie Formation(E_(2)s_(3)).The results indicate that the E_(2)s_(1+2)and E_(2)s_(3)have better hydrocarbon generative potentials with the highest OM abundance,the E_(3)d_(3)are of the second good quality,and the E_(3)d2L have poor to fair hydrocarbon generative potential.Furthermore,the well logs were applied to predict TOC and residual hydrocarbon generation potential(S_(2))based on the sedimentary facies classification,usingΔlogR,generalizedΔlogR,logging multiple linear regression and BP neural network methods.The various methods were compared,and the BP neural network method have relatively better prediction accuracy.Based on the pre-stack simultaneous inversion(P-wave impedance,P-wave velocity and density inversion results)and the post-stack seismic attributes,the three-dimensional(3D)seismic prediction of TOC and S_(2)was carried out.The results show that the seismic near well prediction results of TOC and S_(2)based on seismic multi-attributes analysis correspond well with the results of well logging methods,and the plane prediction results are identical with the sedimentary facies map in the study area.The TOC and S_(2)values of E_(2)s_(1+2)and E_(2)s_(3)are higher than those in E_(3)d_(3)and E_(3)d_(2)L,basically consistent with the geochemical analysis results.This method makes up the deficiency of geochemical methods,establishing the connection between geophysical information and geochemical data,and it is helpful to the 3D quantitative prediction and the evaluation of high-quality source rocks in the areas where the drillings are limited.展开更多
Systematic total Routhian surface calculations for even–even N = 104 midshell isotones with 66≤Z≤82 have been carried out based on a more realistic diffuse-surface deformed Woods–Saxon nuclear potential in (β_2, ...Systematic total Routhian surface calculations for even–even N = 104 midshell isotones with 66≤Z≤82 have been carried out based on a more realistic diffuse-surface deformed Woods–Saxon nuclear potential in (β_2, γ, β_4) deformation space, focusing on the rotation-induced shapecoexisting phenomena. As an example and basic test, the oblate property at the ground state in ^(184)Hg is well reproduced and the microscopic origin is analyzed from the single-particle structure. The present calculated results are compared with available experimental information, showing a good agreement. It is systematically found that in this isotonic chain several bands with different shapes(e.g., prolate, oblate and superdeformed prolate bands, seven non-collective band) may show a strong competition and coexisting phenomenon at a certain domain of the rotational frequency.展开更多
The title compound（2S,3S,E）-4-（3,4-dihydroxybenzylidene）-3-（3,4-dihydroxyphenyl）-5-oxotetrahydrofuran-2-carboxylic acid was synthesized and the 2D structure was characterized by ^1H-NMR ^13C-NMR and LCMS. The ab...The title compound（2S,3S,E）-4-（3,4-dihydroxybenzylidene）-3-（3,4-dihydroxyphenyl）-5-oxotetrahydrofuran-2-carboxylic acid was synthesized and the 2D structure was characterized by ^1H-NMR ^13C-NMR and LCMS. The absolute configuration was determined by single-crystal X-ray diffraction of the key intermediate（2S,3S,E）-ethyl 4-（3,4-dimethoxybenzylidene）-3-（3,4-dimethoxyphenyl）-5-oxotetrahydrofuran-2-carboxylate. The crystal belongs to tetragonal system, space group P41 with a = 13.0665（2）, b = 13.0665（2）, c = 13.4735（2）A, V = 2300.4（6） A^3, Z = 4, Dc = 1.278 g/cm^3, μ（CuKα） = 0.801 mm^-1, F（000） = 936, S = 1.050, R = 0.0364 and wR（I 〉 2σ（I）） = 0.1071. X-ray diffraction results showed that the molecular structure is stabilized totally by Van der Waals force. The antibacterial activity tests showed that the title compound possesses slight synergistic effect against MRSA and Acinetobacter baumanii.展开更多
The occurrence and accumulation of total mercury (T-Hg) in sediments collected from the Yarlung Zangbo River (YLZB),the Lhasa River,the Niyang River and the Palongzangbu River were analyzed and the soil samples simult...The occurrence and accumulation of total mercury (T-Hg) in sediments collected from the Yarlung Zangbo River (YLZB),the Lhasa River,the Niyang River and the Palongzangbu River were analyzed and the soil samples simultaneously collected from the bank were employed as control.Meanwhile,pollution status and potential ecological risk of Hg were calculated and assessed using index of geoaccumulation ( I geo ) and potential ecological risk assessment method (Er) in this study.The results showed that the T-Hg concentrations in sediments at eight sections of YLZB ranged from 4.23 to 48.1 μg/kg with mean concentration of 25.1 μg/kg,which was higher than background Hg value of soils in Tibet.T-Hg concentrations in sediments at three typical segments of YLZB were all significantly higher than those in soils collected from its bank (P<0.05).The Igeo and E r indexes revealed that the T-Hg pollution levels were slight pollution in two sections and moderate ecological risk in six sections of YLZB.Hg pollution risks also existed in the sediments of partial sections of the Lhasa River and the Niyang River,and slightly moderate Hg contamination with high ecological risk was presented in Lhasa urban district.The level of Hg in sediments of YLZB showed a notable spatial distribution characteristic with a trend of increasing firstly and then declining.Human activities played an important role in increasing Hg content in sediments of the river.展开更多
A new modified formulation of the Additivity Rule (AR) was proposed to calculate the total electron scattering cross sections for CH4, CO2, NO2, and N2O, considering the overlapping between atoms in molecules and the ...A new modified formulation of the Additivity Rule (AR) was proposed to calculate the total electron scattering cross sections for CH4, CO2, NO2, and N2O, considering the overlapping between atoms in molecules and the not fully transparency of the molecules. The present calculation covers the range of impact energy from 10 to 3000 eV. The results are compared with experimental data and other theories where available. The atoms are presented by spherical complex optical potential, which is composed of static, exchange, polarization, and absorption terms.展开更多
基金supported by the National Science and Technology Major Projects (2008ZX05025)the Project of National Oil and Gas Resources Strategic Constituency Survey and Evaluation of the Ministry of Land and Resources,China (XQ-2007-05)
文摘边察觉和改进技术通常在用潜在的域数据认出地质的身体的边被使用。我们在场一种新边识别技术基于有边察觉和改进技术的功能的全部的水平衍生物的规范的垂直衍生物。首先，我们计算潜在地的数据的全部的水平衍生物(THDR ) 然后计算 n 顺序 THDR 的垂直衍生物(VDRn ) 。为 n 顺序垂直衍生物，全部的水平衍生物(PTHDR ) 的山峰价值用比 0 大的阀值价值被获得。这 PTHDR 能被用于边察觉。第二， PTHDR 价值被全部的水平衍生物划分并且由最大的价值使正常化。最后，我们使用了数字模型的不同类型验证新边识别技术的有效性和可靠性。
基金the National Social Sciences Foundation Program "A Study on the Effects of Changing Demographic Structure on China's Economic Deceleration and Countermeasures"
文摘Due to diminishing demographic dividend characterized by a falling workingage population and rising dependency ratio, China's long-term potential growth rates will keep declining, likely to be a mere 6.6% during the 13 th Five-Year Plan period(2016-2020). China's economic growth sustainability hinges upon its transition from the previous dependence on demographic dividend to the future reform dividend. In the growth accounting equation, we have simulated various reform initiatives and arrived at the following findings. First, although both the labor participation rate and TFP can increase China's potential growth rate, the former will only achieve a short-term growth effect, which will diminish in the long run. By contrast, the growth effect of TFP demonstrates the tendency of continuous increase. This further indicates that China's economic growth will increasingly rely on TFP improvement instead of traditional factor input. Second, different from the diminishing growth effect of enrolment rate, training may play a pivotal role in human capital development to significantly enhance potential growth rates. Third, if all reform initiatives can achieve their expected effects, integrated reform dividends may reach one or two percentage points of China's potential growth rate.
文摘In this article,we study the initial boundary value problem of coupled semi-linear degenerate parabolic equations with a singular potential term on manifolds with corner singularities.Firstly,we introduce the corner type weighted p-Sobolev spaces and the weighted corner type Sobolev inequality,the Poincare′inequality,and the Hardy inequality.Then,by using the potential well method and the inequality mentioned above,we obtain an existence theorem of global solutions with exponential decay and show the blow-up in finite time of solutions for both cases with low initial energy and critical initial energy.Significantly,the relation between the above two phenomena is derived as a sharp condition.Moreover,we show that the global existence also holds for the case of a potential well family.
文摘This article prognosticates the hydrocarbon generation potential of core samples from fields A, B, C and D in Niger delta, Nigeria. The objectives of this study are to characterize the quality of these core samples by organic geochemical analyses. A total of ten core samples collected from fields A, B, C and D in Niger delta were analyzed using total organic carbon(TOC) content analysis, rock-eval pyrolysis technique. The analytical results of the studied core samples reveal that they have generally high total organic carbon contents(TOC), suggesting that conditions in the Niger delta favour organic matter production and preservation. There is a variation in the kerogen types and this may be attributed to the relative stratigraphic positions of the core samples within the Niger delta. The rock-eval results indicate that the samples from fields C and D contain predominantly Type II kerogen with a capacity to generate oil and gas and hence have good generative potential. The samples from fields A and B contain mainly Type III kerogen and are gas-prone with moderate generative potential.
基金supported by the National Natural Science Foundation of China(Grant Nos.12274035,and 11874088)supported by the Fundamental Research Funds for the Central Universities。
文摘An accurate total energy calculation is essential in materials computation.To date,many tight-binding(TB)approaches based on parameterized hopping can produce electronic structures comparable to those obtained using first-principles calculations.However,TB approaches still have limited applicability for determining material properties derived from the total energy.That is,the predictive power of the TB total energy is impaired by an inaccurate evaluation of the repulsive energy.The complexity associated with the parametrization of TB repulsive potentials is the weak link in this evaluation.In this study,we propose a new method for obtaining the pairwise TB repulsive potential for crystalline materials by employing the Chen-Möbius inversion theorem.We show that the TB-based phonon dispersions,calculated using the resulting repulsive potential,compare well with those obtained by first-principles calculations for various systems,including covalent and ionic bulk materials and twodimensional materials.The present approach only requires the first-principles total energy and TB electronic band energy as input and does not involve any parameters.This striking feature enables us to generate repulsive potentials programmatically.
文摘The Bozhong Sag is the largest petroliferous sag in the Bohai Bay Basin,and the source rocks of Paleogene Dongying and Shahejie Formations were buried deeply.Most of the drillings were located at the structural high,and there were few wells that met good quality source rocks,so it is difficult to evaluate the source rocks in the study area precisely by geochemical analysis only.Based on the Rock-Eval pyrolysis,total organic carbon(TOC)testing,the organic matter(OM)abundance of Paleogene source rocks in the southwestern Bozhong Sag were evaluated,including the lower of second member of Dongying Formation(E_(3)d2L),the third member of Dongying Formation(E_(3)d_(3)),the first and second members of Shahejie Formation(E_(2)s_(1+2)),the third member of Shahejie Formation(E_(2)s_(3)).The results indicate that the E_(2)s_(1+2)and E_(2)s_(3)have better hydrocarbon generative potentials with the highest OM abundance,the E_(3)d_(3)are of the second good quality,and the E_(3)d2L have poor to fair hydrocarbon generative potential.Furthermore,the well logs were applied to predict TOC and residual hydrocarbon generation potential(S_(2))based on the sedimentary facies classification,usingΔlogR,generalizedΔlogR,logging multiple linear regression and BP neural network methods.The various methods were compared,and the BP neural network method have relatively better prediction accuracy.Based on the pre-stack simultaneous inversion(P-wave impedance,P-wave velocity and density inversion results)and the post-stack seismic attributes,the three-dimensional(3D)seismic prediction of TOC and S_(2)was carried out.The results show that the seismic near well prediction results of TOC and S_(2)based on seismic multi-attributes analysis correspond well with the results of well logging methods,and the plane prediction results are identical with the sedimentary facies map in the study area.The TOC and S_(2)values of E_(2)s_(1+2)and E_(2)s_(3)are higher than those in E_(3)d_(3)and E_(3)d_(2)L,basically consistent with the geochemical analysis results.This method makes up the deficiency of geochemical methods,establishing the connection between geophysical information and geochemical data,and it is helpful to the 3D quantitative prediction and the evaluation of high-quality source rocks in the areas where the drillings are limited.
基金supported by the Natural Science Foundation of China(Nos.11675148 and 11505157)the Project of Youth Backbone Teachers of Colleges and Universities of Henan Province(No.2017GGJS008)+2 种基金the Foundation and Advanced Technology Research Program of Henan Province(No.162300410222)the Outstanding Young Talent Research Fund of Zhengzhou University(No.1521317002)the Physics Research and Development Program of Zhengzhou University(No.32410017)
文摘Systematic total Routhian surface calculations for even–even N = 104 midshell isotones with 66≤Z≤82 have been carried out based on a more realistic diffuse-surface deformed Woods–Saxon nuclear potential in (β_2, γ, β_4) deformation space, focusing on the rotation-induced shapecoexisting phenomena. As an example and basic test, the oblate property at the ground state in ^(184)Hg is well reproduced and the microscopic origin is analyzed from the single-particle structure. The present calculated results are compared with available experimental information, showing a good agreement. It is systematically found that in this isotonic chain several bands with different shapes(e.g., prolate, oblate and superdeformed prolate bands, seven non-collective band) may show a strong competition and coexisting phenomenon at a certain domain of the rotational frequency.
基金financially sponsored by the Shanghai Rising-Star Program(B)(16QB1403800)
文摘The title compound（2S,3S,E）-4-（3,4-dihydroxybenzylidene）-3-（3,4-dihydroxyphenyl）-5-oxotetrahydrofuran-2-carboxylic acid was synthesized and the 2D structure was characterized by ^1H-NMR ^13C-NMR and LCMS. The absolute configuration was determined by single-crystal X-ray diffraction of the key intermediate（2S,3S,E）-ethyl 4-（3,4-dimethoxybenzylidene）-3-（3,4-dimethoxyphenyl）-5-oxotetrahydrofuran-2-carboxylate. The crystal belongs to tetragonal system, space group P41 with a = 13.0665（2）, b = 13.0665（2）, c = 13.4735（2）A, V = 2300.4（6） A^3, Z = 4, Dc = 1.278 g/cm^3, μ（CuKα） = 0.801 mm^-1, F（000） = 936, S = 1.050, R = 0.0364 and wR（I 〉 2σ（I）） = 0.1071. X-ray diffraction results showed that the molecular structure is stabilized totally by Van der Waals force. The antibacterial activity tests showed that the title compound possesses slight synergistic effect against MRSA and Acinetobacter baumanii.
基金Supported by Investigation on Fishery Resources and Environment in Key Waters of TibetSpecial Scientific Research Projects of Public Welfare Industry(Agriculture)(201503108)
文摘The occurrence and accumulation of total mercury (T-Hg) in sediments collected from the Yarlung Zangbo River (YLZB),the Lhasa River,the Niyang River and the Palongzangbu River were analyzed and the soil samples simultaneously collected from the bank were employed as control.Meanwhile,pollution status and potential ecological risk of Hg were calculated and assessed using index of geoaccumulation ( I geo ) and potential ecological risk assessment method (Er) in this study.The results showed that the T-Hg concentrations in sediments at eight sections of YLZB ranged from 4.23 to 48.1 μg/kg with mean concentration of 25.1 μg/kg,which was higher than background Hg value of soils in Tibet.T-Hg concentrations in sediments at three typical segments of YLZB were all significantly higher than those in soils collected from its bank (P<0.05).The Igeo and E r indexes revealed that the T-Hg pollution levels were slight pollution in two sections and moderate ecological risk in six sections of YLZB.Hg pollution risks also existed in the sediments of partial sections of the Lhasa River and the Niyang River,and slightly moderate Hg contamination with high ecological risk was presented in Lhasa urban district.The level of Hg in sediments of YLZB showed a notable spatial distribution characteristic with a trend of increasing firstly and then declining.Human activities played an important role in increasing Hg content in sediments of the river.
文摘A new modified formulation of the Additivity Rule (AR) was proposed to calculate the total electron scattering cross sections for CH4, CO2, NO2, and N2O, considering the overlapping between atoms in molecules and the not fully transparency of the molecules. The present calculation covers the range of impact energy from 10 to 3000 eV. The results are compared with experimental data and other theories where available. The atoms are presented by spherical complex optical potential, which is composed of static, exchange, polarization, and absorption terms.
