Preconsolidation stress （ σP） is the maximum effective stress that a soil has suffered throughout its life. From a geotech- nical point of view, pre-consolidation stress has great importance because it separates el...Preconsolidation stress （ σP） is the maximum effective stress that a soil has suffered throughout its life. From a geotech- nical point of view, pre-consolidation stress has great importance because it separates elastic and reversible deformations from inelastic and only partially irreversible deformations and marks the starting point of high compressibility. In this study we calculated the preconsolidation stress for 72 undisturbed soil samples from the Yellow River Delta, using the oedometer test and applying the method proposed by Casagrande. The results showed that the over-consolidation ratio （OCR-the ratio of pre-consolidation stress to current natural overburden stress） values of the soil from soil surface to 6m depth varied from 1.72 to 15.34 and the maximum pre- consolidation stress was above 200 kPa. In consequence, the soils of the Yellow River Delta are highly over-consolidated within the upper 6m, the OCR decreasing gradually with depth from 6 to 12m. For samples from deeper than 12m the soils were found to be under-consolidated, which was proved by standard penetration tests （SPTs）. The main causes of this type of consolidation are the mineral composition and the designability of the soil body.展开更多
In the past 30 years,signed directed graph(SDG) ,one of the qualitative simulation technologies,has been widely applied for chemical fault diagnosis.However,SDG based fault diagnosis,as any other qualitative method,ha...In the past 30 years,signed directed graph(SDG) ,one of the qualitative simulation technologies,has been widely applied for chemical fault diagnosis.However,SDG based fault diagnosis,as any other qualitative method,has poor diagnostic resolution.In this paper,a new method that combines SDG with qualitative trend analysis(QTA) is presented to improve the resolution.In the method,a bidirectional inference algorithm based on assumption and verification is used to find all the possible fault causes and their corresponding consistent paths in the SDG model.Then an improved QTA algorithm is used to extract and analyze the trends of nodes on the consis-tent paths found in the previous step.New consistency rules based on qualitative trends are used to find the real causes from the candidate causes.The resolution can be improved.This method combines the completeness feature of SDG with the good diagnostic resolution feature of QTA.The implementation of SDG-QTA based fault diagno-sis is done using the integrated SDG modeling,inference and post-processing software platform.Its application is illustrated on an atmospheric distillation tower unit of a simulation platform.The result shows its good applicability and efficiency.展开更多
A precise understanding of the redox chemistry of Nm-Mn+(like N4-Fe^(2+))systems is essential for fundamental studies and rational design of Nm-Mn+-based electrocatalysts for the oxygen reduction reaction(ORR).Herein,...A precise understanding of the redox chemistry of Nm-Mn+(like N4-Fe^(2+))systems is essential for fundamental studies and rational design of Nm-Mn+-based electrocatalysts for the oxygen reduction reaction(ORR).Herein,three different iron phthalocyanines(FePcs)adsorbed on carbon nanotubes((NH2)4FePc@CNTs,(t-Bu)4FePc@CNTs,and FePc@CNTs)were evaluated to demonstrate the effect of the electron donating power of the substituents on the Fe^(3+)/Fe^(2+)redox potential of FePc@CNTs and the role of these composites as ORR mediators in alkaline media.The Fe^(3+)/Fe^(2+)redox potential of the FePcs was found to shift towards the cathodic region upon substitution with electron-donating groups.This up-field shift in the eg-orbital leads to a lower overlap between the onset potential of the Fe^(3+)/Fe^(2+)redox couple and that of the ORR,and thus,the ORR activity decreased in the following order based on the substitution of FePc:-H>-t-Bu>-NH2.展开更多
Electrocatalytic production of ammonia from dinitrogen is considered as a sustainable alternative to the energy-demanding and pollutive Haber-Bosch process.A promising class of materials for selective nitrogen reducti...Electrocatalytic production of ammonia from dinitrogen is considered as a sustainable alternative to the energy-demanding and pollutive Haber-Bosch process.A promising class of materials for selective nitrogen reduction(NRR)corresponds to transition-metal oxides given that these electrodes do not show a high activity toward the competing hydrogen evolution reaction.So far,density functional theory calculations have been used to comprehend trends in a class of materials by using the concept of scaling relations and volcano plots.This thermodynamic theory pinpoints that either the formation of the*NNH adsorbate or the formation of ammonia are reconciled with the potential-determining reaction steps.Thus,the development of NRR catalyst has largely focused on the optimization of these two elementary processes.In the present contribution,overpotential and kinetic effects are factored into the volcano plot for the NRR over transition-metal oxides by making use of the recently introduced activity descriptor G_(max)(η).It is illustrated that the thermodynamic volcano picture is too simplistic as the limiting reaction step may alter close to the volcano apex:there,particularly surface reactions may govern the reaction rate.In addition,it is demonstrated how to include the formation of hydrazine as a competing side reaction into the volcano plot,which is of importance for weak binding*NNH catalysts where the formation of hydrazine may compete with the formation of ammonia.Given that the outlined methodology in this manuscript is universal and not restricted to the class of transition-metal oxides,the presented kinetic volcano picture may contribute to the development of NRR catalysts for nitrogen fixation.展开更多
The response surface methodology （Box-behnken design） was acknowledged for the production of optimized protein enriched pasta. Studied responses （protein, overall acceptability, hue angle and hardness） resulted to...The response surface methodology （Box-behnken design） was acknowledged for the production of optimized protein enriched pasta. Studied responses （protein, overall acceptability, hue angle and hardness） resulted to high protein pasta. The optima were at 12.5%,5 mung bean, 10% whey protein concentrate and 6% egg albumen in combination. Best combination of protein source and their respective level for high protein pasta on the quality evaluation basis were mung bean （15%） ＋ whey protein concentrate （10%）; mung bean （15%） ＋ egg albumen （6%）; mung bean （15%） ＋ whey protein concentrate （10%） ＋ egg albumen （6%）. Hue angle and Hardness remained within acceptable range. Model adequacy was supported with lack of fit test. Enriched protein pasta had excellent cooking and sensory quality during storage period of 4 months. ERH value ranged from 34-36 per cent had supported the results. Rheological properties and good storage behaviour （4 months） had also enhanced the quality of optimized protein enriched pasta. Enriched pasta was rated excellent by 70 per cent of the consumers in mass acceptability trials.展开更多
In the present paper, with the aid of symbolic computation, families of new nontrivial solutions of the first-order sub-ODE F12 = AF2 ＋ BF2＋p ＋ CF2＋2p （where F1= dF/dε, p 〉 0） are obtained. To our best knowled...In the present paper, with the aid of symbolic computation, families of new nontrivial solutions of the first-order sub-ODE F12 = AF2 ＋ BF2＋p ＋ CF2＋2p （where F1= dF/dε, p 〉 0） are obtained. To our best knowledge, these nontrivial solutions have not been found in [X.Z. Li and M.L. Wang, Phys. Lett. A 361 （2007） 115] and IS. Zhang, W. Wang, and J.L. Tong, Phys. Lett. A 372 （2008） 3808] and other existent papers until now. Using these nontrivial solutions, the sub-ODE method is described to construct several kinds of exact travelling wave solutions for the generalized KdV-mKdV equation with higher-order nonlinear terms and the generalized ZK equation with higher-order nonlinear terms. By means of this method, many other physically important nonlinear partial differential equations with nonlinear terms of any order can be investigated and new nontrivial solutions can be explicitly obtained with the help of symbolic computation system Maple or Mathematics.展开更多
基金supported by the National Natural Science Foundation of China (Nos. 40472137 and 40606020)
文摘Preconsolidation stress （ σP） is the maximum effective stress that a soil has suffered throughout its life. From a geotech- nical point of view, pre-consolidation stress has great importance because it separates elastic and reversible deformations from inelastic and only partially irreversible deformations and marks the starting point of high compressibility. In this study we calculated the preconsolidation stress for 72 undisturbed soil samples from the Yellow River Delta, using the oedometer test and applying the method proposed by Casagrande. The results showed that the over-consolidation ratio （OCR-the ratio of pre-consolidation stress to current natural overburden stress） values of the soil from soil surface to 6m depth varied from 1.72 to 15.34 and the maximum pre- consolidation stress was above 200 kPa. In consequence, the soils of the Yellow River Delta are highly over-consolidated within the upper 6m, the OCR decreasing gradually with depth from 6 to 12m. For samples from deeper than 12m the soils were found to be under-consolidated, which was proved by standard penetration tests （SPTs）. The main causes of this type of consolidation are the mineral composition and the designability of the soil body.
基金Supported by the Science and Technological Tackling Project of Heilongjiang Province(GB06A106)
文摘In the past 30 years,signed directed graph(SDG) ,one of the qualitative simulation technologies,has been widely applied for chemical fault diagnosis.However,SDG based fault diagnosis,as any other qualitative method,has poor diagnostic resolution.In this paper,a new method that combines SDG with qualitative trend analysis(QTA) is presented to improve the resolution.In the method,a bidirectional inference algorithm based on assumption and verification is used to find all the possible fault causes and their corresponding consistent paths in the SDG model.Then an improved QTA algorithm is used to extract and analyze the trends of nodes on the consis-tent paths found in the previous step.New consistency rules based on qualitative trends are used to find the real causes from the candidate causes.The resolution can be improved.This method combines the completeness feature of SDG with the good diagnostic resolution feature of QTA.The implementation of SDG-QTA based fault diagno-sis is done using the integrated SDG modeling,inference and post-processing software platform.Its application is illustrated on an atmospheric distillation tower unit of a simulation platform.The result shows its good applicability and efficiency.
文摘A precise understanding of the redox chemistry of Nm-Mn+(like N4-Fe^(2+))systems is essential for fundamental studies and rational design of Nm-Mn+-based electrocatalysts for the oxygen reduction reaction(ORR).Herein,three different iron phthalocyanines(FePcs)adsorbed on carbon nanotubes((NH2)4FePc@CNTs,(t-Bu)4FePc@CNTs,and FePc@CNTs)were evaluated to demonstrate the effect of the electron donating power of the substituents on the Fe^(3+)/Fe^(2+)redox potential of FePc@CNTs and the role of these composites as ORR mediators in alkaline media.The Fe^(3+)/Fe^(2+)redox potential of the FePcs was found to shift towards the cathodic region upon substitution with electron-donating groups.This up-field shift in the eg-orbital leads to a lower overlap between the onset potential of the Fe^(3+)/Fe^(2+)redox couple and that of the ORR,and thus,the ORR activity decreased in the following order based on the substitution of FePc:-H>-t-Bu>-NH2.
文摘Electrocatalytic production of ammonia from dinitrogen is considered as a sustainable alternative to the energy-demanding and pollutive Haber-Bosch process.A promising class of materials for selective nitrogen reduction(NRR)corresponds to transition-metal oxides given that these electrodes do not show a high activity toward the competing hydrogen evolution reaction.So far,density functional theory calculations have been used to comprehend trends in a class of materials by using the concept of scaling relations and volcano plots.This thermodynamic theory pinpoints that either the formation of the*NNH adsorbate or the formation of ammonia are reconciled with the potential-determining reaction steps.Thus,the development of NRR catalyst has largely focused on the optimization of these two elementary processes.In the present contribution,overpotential and kinetic effects are factored into the volcano plot for the NRR over transition-metal oxides by making use of the recently introduced activity descriptor G_(max)(η).It is illustrated that the thermodynamic volcano picture is too simplistic as the limiting reaction step may alter close to the volcano apex:there,particularly surface reactions may govern the reaction rate.In addition,it is demonstrated how to include the formation of hydrazine as a competing side reaction into the volcano plot,which is of importance for weak binding*NNH catalysts where the formation of hydrazine may compete with the formation of ammonia.Given that the outlined methodology in this manuscript is universal and not restricted to the class of transition-metal oxides,the presented kinetic volcano picture may contribute to the development of NRR catalysts for nitrogen fixation.
文摘The response surface methodology （Box-behnken design） was acknowledged for the production of optimized protein enriched pasta. Studied responses （protein, overall acceptability, hue angle and hardness） resulted to high protein pasta. The optima were at 12.5%,5 mung bean, 10% whey protein concentrate and 6% egg albumen in combination. Best combination of protein source and their respective level for high protein pasta on the quality evaluation basis were mung bean （15%） ＋ whey protein concentrate （10%）; mung bean （15%） ＋ egg albumen （6%）; mung bean （15%） ＋ whey protein concentrate （10%） ＋ egg albumen （6%）. Hue angle and Hardness remained within acceptable range. Model adequacy was supported with lack of fit test. Enriched protein pasta had excellent cooking and sensory quality during storage period of 4 months. ERH value ranged from 34-36 per cent had supported the results. Rheological properties and good storage behaviour （4 months） had also enhanced the quality of optimized protein enriched pasta. Enriched pasta was rated excellent by 70 per cent of the consumers in mass acceptability trials.
文摘In the present paper, with the aid of symbolic computation, families of new nontrivial solutions of the first-order sub-ODE F12 = AF2 ＋ BF2＋p ＋ CF2＋2p （where F1= dF/dε, p 〉 0） are obtained. To our best knowledge, these nontrivial solutions have not been found in [X.Z. Li and M.L. Wang, Phys. Lett. A 361 （2007） 115] and IS. Zhang, W. Wang, and J.L. Tong, Phys. Lett. A 372 （2008） 3808] and other existent papers until now. Using these nontrivial solutions, the sub-ODE method is described to construct several kinds of exact travelling wave solutions for the generalized KdV-mKdV equation with higher-order nonlinear terms and the generalized ZK equation with higher-order nonlinear terms. By means of this method, many other physically important nonlinear partial differential equations with nonlinear terms of any order can be investigated and new nontrivial solutions can be explicitly obtained with the help of symbolic computation system Maple or Mathematics.
