To investigate the long-term stability of deep rocks,a three-dimensional(3D)time-dependent model that accounts for excavation-induced damage and complex stress state is developed.This model comprises three main compon...To investigate the long-term stability of deep rocks,a three-dimensional(3D)time-dependent model that accounts for excavation-induced damage and complex stress state is developed.This model comprises three main components:a 3D viscoplastic isotropic constitutive relation that considers excavation damage and complex stress state,a quantitative relationship between critical irreversible deformation and complex stress state,and evolution characteristics of strength parameters.The proposed model is implemented in a self-developed numerical code,i.e.CASRock.The reliability of the model is validated through experiments.It is indicated that the time-dependent fracturing potential index(xTFPI)at a given time during the attenuation creep stage shows a negative correlation with the extent of excavationinduced damage.The time-dependent fracturing process of rock demonstrates a distinct interval effect of the intermediate principal stress,thereby highlighting the 3D stress-dependent characteristic of the model.Finally,the influence of excavation-induced damage and intermediate principal stress on the time-dependent fracturing characteristics of the surrounding rocks around the tunnel is discussed.展开更多
A series of numerical simulations of conventional and true triaxial tests for soft rock materials using the three-dimensional finite difference code FLAC3D were presented. A hexahedral element and a strain hardening/s...A series of numerical simulations of conventional and true triaxial tests for soft rock materials using the three-dimensional finite difference code FLAC3D were presented. A hexahedral element and a strain hardening/softening constitutive model based on the unified strength theory(UST) were used to simulate both the consolidated-undrained(CU) triaxial and the consolidated-drained(CD) true triaxial tests. Based on the results of the true triaxial tests simulation, the effect of the intermediate principal stress on the strength of soft rock was investigated. Finally, an example of an axial compression test for a hard rock pillar with a soft rock interlayer was analyzed using the two-dimensional finite difference code FLAC. The CD true triaxial test simulations for diatomaceous soft rock suggest the peak and residual strengths increase by 30% when the effect of the intermediate principal stress is taken into account. The axial compression for a rock pillar indicated the peak and residual strengths increase six-fold when the soft rock interlayer approached the vertical and the effect of the intermediate principal stress is taken into account.展开更多
The main subject of the report consists in showing positive course of Russian agriculture over the last years-entering the global market. That＇s why it is essential to make following steps to support manufactures aim...The main subject of the report consists in showing positive course of Russian agriculture over the last years-entering the global market. That＇s why it is essential to make following steps to support manufactures aiming them more actively at export： to develop export operations; to develop actively agro-industrial complex perspectives for entering the WTO; to ensure the food safety of agro-industrial complex while exporting the products; in the context of globalization Russian regions are entering more actively the global market as the relatively independent subjects of international economical relationships. The food safety of Russia-such condition of the state economy, when food independence of the country is provided, provision; physical and economic utility of food products is guaranteed by the state and corresponds to requirements of the legislation of the Russian Federation in safety and quality. Participation in the WTO gives to the country set of advantages in the decision food independence. In the world, the country and in region management of efficiency agriculture with a view of advancement to food safety, should be coordinated necessarily with food independence. State support of the Russian agro-industrial complex on the federal and regional levels when entering into the world market-is a factor of the formation of a new geopolitical status of Russia in the world arena, it is the new selection mechanism of the development of globalization processes in favor of the active participation of the agro-industrial complex of Russia in the world economy.展开更多
[Cu_(0.84)Au_(0.16)(PPh_3)_2(SC(Ph)NHPh)Cl]·0.5CS_2=,Mr=895.79,monoclinic,space group P2_1/a,a=17.231(3),b=14.611(2),c=18.000(3) ,β=105.56(2)°,V=4365(1) ~3, Z=4,D_c=1.37g/cm^3.,λ(MoK_α)=0.71073 ,μ=12.15c...[Cu_(0.84)Au_(0.16)(PPh_3)_2(SC(Ph)NHPh)Cl]·0.5CS_2=,Mr=895.79,monoclinic,space group P2_1/a,a=17.231(3),b=14.611(2),c=18.000(3) ,β=105.56(2)°,V=4365(1) ~3, Z=4,D_c=1.37g/cm^3.,λ(MoK_α)=0.71073 ,μ=12.15cm^(-1),F(000)=1855,R=0.052, R_W=0.045 for 3930 observed reflections with Ⅰ>1.5σ(Ⅰ).The central metal atom has a dis. torted tetrahedral geometry with bond lengths Cu-S=2.384(2) (Au-S=2.389(4)), Cu-Cl=2.481(3)(Au-Cl=2.474(1))and Cu-P=2.269(2)-2.289(2)(Au-P=2.270(4)-2.279(4)) .展开更多
The apparatus for static and dynamic universal triaxial and torsional shear soil testing is employed to perform stress-controlled cyclic single-direction torsional shear tests and two-direction coupled shear tests und...The apparatus for static and dynamic universal triaxial and torsional shear soil testing is employed to perform stress-controlled cyclic single-direction torsional shear tests and two-direction coupled shear tests under unconsolidated-undrained conditions. Through a series of tests on saturated clay, the effects of initial shear stress and stress reversal on the clay’s strain-stress behavior are examined, and the behavior of pore water pressure is studied. The experimental results indicate that the patterns of stress-strain relations are distinctly influenced by the initial shear stress in the cyclic single-direction shear tests. When the initial shear stress is large and no stress reversal occurs, the predominant deformation behavior is characterized by an accumulative effect. When the initial shear stress is zero and symmetrical cyclic stress occurs, the predominant deformation behavior is characterized by a cyclic effect. The pore water pressure fluctuates around the confining pressure with the increase of cycle number. It seems that the fluctuating amplitude increases with the increase of the cyclic stress. But a buildup of pore water pressure does not occur. The de- formations of clay samples under the complex initial and the cyclic coupled stress conditions include the normal deviatoric deforma- tion and horizontal shear deformation, the average deformation and cyclic deformation. A general strain failure criterion taking into account these deformations is recommended and is proved more stable and suitable compared to the strain failure criteria currently used.展开更多
Based on the asymmetric characteristic of skeleton curve obtained from dynamic tests on soils,a function with double asymptotes is proposed for describing the dynamic constitutive relations of soils.The hysteresis loo...Based on the asymmetric characteristic of skeleton curve obtained from dynamic tests on soils,a function with double asymptotes is proposed for describing the dynamic constitutive relations of soils.The hysteresis loops observed during unloading and reloading show the same form as the skeleton curve and are constructed by taking the ultimate stress as the corresponding asymptote.The coeffcient of initial unloading modulus is used to ensure that the constructed hysteresis loop fts well with the experimental data.Then,a new dynamic constitutive model considering the asymmetry of skeleton curve is elaborated.The verifcation tests on saturated Nanjing fne sand are performed using a hollow cylinder apparatus to verify the applicability of the UD model.It is found that the predicted curves by the UD model agree well with the test data.展开更多
In this paper, we use the cellular automation model to imitate earthquake process and draw some conclusionsof general applicability. First, it is confirmed that earthquake process has some ordering characters, and it ...In this paper, we use the cellular automation model to imitate earthquake process and draw some conclusionsof general applicability. First, it is confirmed that earthquake process has some ordering characters, and it isshown that both the existence and their mutual arrangement of faults could obviously influence the overallcharacters of earthquake process. Then the characters of each stage of model evolution are explained withself-organized critical state theory. Finally, earthquake sequences produced by the models are analysed interms pf algorithmic complexity and the result shows that AC-values of algorithmic complexity could be usedto study earthquake process and evolution.展开更多
Copper complexes that can experience reversible heat-induced dehydration and rehydration in the solid state were rarely reported although thermochromic copper complexes have been widely reported, and their heat-induce...Copper complexes that can experience reversible heat-induced dehydration and rehydration in the solid state were rarely reported although thermochromic copper complexes have been widely reported, and their heat-induced magnetic properties have not been studied. We firstly observed the reversible thermochromic phenomena of the known copper（II） complex [Cu（bpy）（OOCCH3）2]n·xn H2O（x = 2.5 or 3; bpy = 4,4＇-bipyridine） in the solid state, which is associated with the dehydration and rehydration processes, and found that heat-induced coloration clearly enhanced the magnetic susceptibility.展开更多
Echo state network （ESN） has become one of the most popular recurrent neural networks （RNN） for its good prediction performance of non-linear time series and simple training process. But several problems still pre...Echo state network （ESN） has become one of the most popular recurrent neural networks （RNN） for its good prediction performance of non-linear time series and simple training process. But several problems still prevent ESN from becoming a widely used tool. The most prominent problem is its high complexity with lots of random parameters. Aiming at this problem, a minimum complexity ESN model （MCESN） was proposed. In this paper, we proposed a new wavelet minimum complexity ESN model （WMCESN） to improve the prediction accuracy and increase the practical applicability. Our new model inherits the characters of minimum complexity ESN model using the fixed parameters and simple circle topology. We injected wavelet neurons to replace the original neurons in internal reservoir and designed a wavelet parameter matrix to reduce the computing time. By using different datasets, our new model performed better than the minimum complexity ESN model with normal neurons, but only utilized tiny time cost. We also used our own packets of transmission control protocol （TCP） and user datagram protocol （UDP） dataset to prove that our model can deal with the data packet bit prediction problem well.展开更多
This paper presents a stochastic fatigue damage model for concrete subjected to complex stress states.A constitutive framework considering the tensile and shear damage mechanisms and elastic and plastic energy dissipa...This paper presents a stochastic fatigue damage model for concrete subjected to complex stress states.A constitutive framework considering the tensile and shear damage mechanisms and elastic and plastic energy dissipations is employed.The damage law is established through a multiscale analysis of the damage evolution mechanism.Validation results against test data show that the model can effectively predict the static strength,stress-strain curve,fatigue life,and scattering range of concrete under various multidimensional loading scenarios.展开更多
Asphalt mixture is the most widely used pavement material all over the world. In China, more than 90% of service expressways are asphalt pavement. However, current asphalt pavement design method still has irrationalit...Asphalt mixture is the most widely used pavement material all over the world. In China, more than 90% of service expressways are asphalt pavement. However, current asphalt pavement design method still has irrationality. Even though maximum tensile stress theory is used as failure criterion, pavement structure under the effects of wheel load is in three-dimensional complex stress state. Obviously, one-dimensional strength theory cannot reflect the failure characteristics and the resistance of pavement structure. So it is necessary to study the failure criterion of asphalt mixture under three-dimensional com- plex stress state. Due to limitations of test equipment, there are almost no studies in related area. Under this background, this paper develops a new triaxial test method, ac- cording to the investigation of strength characteristics of asphalt mixture under complex stress state through plane isobaric/axial tensile test, plane isobaric/axial compression test, plane tensile and compression/axial tensile test, to reveal the general rules of asphalt mixture＇s strength failure. The failure mode is divided into three types： tensile failure, shear failure and rheological failure. The tensile meridian and compression meridian in the stress space and strength envelope in the π plane where hydrostatic pressure is greater than zero are obtained, and the failure criterion of asphalt mixture under complex stress state is established, providing theoretical method and scientific basis for structure design as well as strength check of asphalt pavement under three-dimensional stress state.展开更多
9-Fluorenylidenemalononitrile (FDCN) or 1,1 diphenyl 2,2 dicyanoethylene (DPCN) reacted with 10 methyl 9,10 dihydroacridine (AcrH 2) under irradiation ( λ >320 nm) to give couping products. In order t...9-Fluorenylidenemalononitrile (FDCN) or 1,1 diphenyl 2,2 dicyanoethylene (DPCN) reacted with 10 methyl 9,10 dihydroacridine (AcrH 2) under irradiation ( λ >320 nm) to give couping products. In order to gain further insight into the mechanism of the photo induced reaction, the photophysics of the reactions of FDCN or DPCN with AcrH 2 have been investigated by using UV vis spectroscopy, fluorescence spectroscopy, excitation spectroscopy and time resolved fluorescence spectroscopy, respectively. The results show that FDCN or DPCN interacts with AcrH 2 in the ground states to form a charge transfer complex, which further reacts to give the coupling product upon irradiation.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.52125903)the China Postdoctoral Science Foundation(Grant No.2023M730367)the Fundamental Research Funds for Central Public Welfare Research Institutes of China(Grant No.CKSF2023323/YT).
文摘To investigate the long-term stability of deep rocks,a three-dimensional(3D)time-dependent model that accounts for excavation-induced damage and complex stress state is developed.This model comprises three main components:a 3D viscoplastic isotropic constitutive relation that considers excavation damage and complex stress state,a quantitative relationship between critical irreversible deformation and complex stress state,and evolution characteristics of strength parameters.The proposed model is implemented in a self-developed numerical code,i.e.CASRock.The reliability of the model is validated through experiments.It is indicated that the time-dependent fracturing potential index(xTFPI)at a given time during the attenuation creep stage shows a negative correlation with the extent of excavationinduced damage.The time-dependent fracturing process of rock demonstrates a distinct interval effect of the intermediate principal stress,thereby highlighting the 3D stress-dependent characteristic of the model.Finally,the influence of excavation-induced damage and intermediate principal stress on the time-dependent fracturing characteristics of the surrounding rocks around the tunnel is discussed.
基金Projects(41172276,51279155)supported by the National Natural Science Foundation of ChinaProjects(106-00X101,106-5X1205)supported by the Central Financial Funds for the Development of Characteristic Key Disciplines in Local University,China
文摘A series of numerical simulations of conventional and true triaxial tests for soft rock materials using the three-dimensional finite difference code FLAC3D were presented. A hexahedral element and a strain hardening/softening constitutive model based on the unified strength theory(UST) were used to simulate both the consolidated-undrained(CU) triaxial and the consolidated-drained(CD) true triaxial tests. Based on the results of the true triaxial tests simulation, the effect of the intermediate principal stress on the strength of soft rock was investigated. Finally, an example of an axial compression test for a hard rock pillar with a soft rock interlayer was analyzed using the two-dimensional finite difference code FLAC. The CD true triaxial test simulations for diatomaceous soft rock suggest the peak and residual strengths increase by 30% when the effect of the intermediate principal stress is taken into account. The axial compression for a rock pillar indicated the peak and residual strengths increase six-fold when the soft rock interlayer approached the vertical and the effect of the intermediate principal stress is taken into account.
文摘The main subject of the report consists in showing positive course of Russian agriculture over the last years-entering the global market. That＇s why it is essential to make following steps to support manufactures aiming them more actively at export： to develop export operations; to develop actively agro-industrial complex perspectives for entering the WTO; to ensure the food safety of agro-industrial complex while exporting the products; in the context of globalization Russian regions are entering more actively the global market as the relatively independent subjects of international economical relationships. The food safety of Russia-such condition of the state economy, when food independence of the country is provided, provision; physical and economic utility of food products is guaranteed by the state and corresponds to requirements of the legislation of the Russian Federation in safety and quality. Participation in the WTO gives to the country set of advantages in the decision food independence. In the world, the country and in region management of efficiency agriculture with a view of advancement to food safety, should be coordinated necessarily with food independence. State support of the Russian agro-industrial complex on the federal and regional levels when entering into the world market-is a factor of the formation of a new geopolitical status of Russia in the world arena, it is the new selection mechanism of the development of globalization processes in favor of the active participation of the agro-industrial complex of Russia in the world economy.
基金Project supported by the National Natural Science Foundation of China
文摘[Cu_(0.84)Au_(0.16)(PPh_3)_2(SC(Ph)NHPh)Cl]·0.5CS_2=,Mr=895.79,monoclinic,space group P2_1/a,a=17.231(3),b=14.611(2),c=18.000(3) ,β=105.56(2)°,V=4365(1) ~3, Z=4,D_c=1.37g/cm^3.,λ(MoK_α)=0.71073 ,μ=12.15cm^(-1),F(000)=1855,R=0.052, R_W=0.045 for 3930 observed reflections with Ⅰ>1.5σ(Ⅰ).The central metal atom has a dis. torted tetrahedral geometry with bond lengths Cu-S=2.384(2) (Au-S=2.389(4)), Cu-Cl=2.481(3)(Au-Cl=2.474(1))and Cu-P=2.269(2)-2.289(2)(Au-P=2.270(4)-2.279(4)) .
基金This work is supported by the National Natural Science Foundation of China （Grant Nos. 50579006, 50639010 and 50179006）.
文摘The apparatus for static and dynamic universal triaxial and torsional shear soil testing is employed to perform stress-controlled cyclic single-direction torsional shear tests and two-direction coupled shear tests under unconsolidated-undrained conditions. Through a series of tests on saturated clay, the effects of initial shear stress and stress reversal on the clay’s strain-stress behavior are examined, and the behavior of pore water pressure is studied. The experimental results indicate that the patterns of stress-strain relations are distinctly influenced by the initial shear stress in the cyclic single-direction shear tests. When the initial shear stress is large and no stress reversal occurs, the predominant deformation behavior is characterized by an accumulative effect. When the initial shear stress is zero and symmetrical cyclic stress occurs, the predominant deformation behavior is characterized by a cyclic effect. The pore water pressure fluctuates around the confining pressure with the increase of cycle number. It seems that the fluctuating amplitude increases with the increase of the cyclic stress. But a buildup of pore water pressure does not occur. The de- formations of clay samples under the complex initial and the cyclic coupled stress conditions include the normal deviatoric deforma- tion and horizontal shear deformation, the average deformation and cyclic deformation. A general strain failure criterion taking into account these deformations is recommended and is proved more stable and suitable compared to the strain failure criteria currently used.
基金the fnancial support by the Major Research Plan Integration Project of the National Natural Science Foundation of China under Grant No.91215301by the National Basic Research Program of China under Grant No.2011CB013601
文摘Based on the asymmetric characteristic of skeleton curve obtained from dynamic tests on soils,a function with double asymptotes is proposed for describing the dynamic constitutive relations of soils.The hysteresis loops observed during unloading and reloading show the same form as the skeleton curve and are constructed by taking the ultimate stress as the corresponding asymptote.The coeffcient of initial unloading modulus is used to ensure that the constructed hysteresis loop fts well with the experimental data.Then,a new dynamic constitutive model considering the asymmetry of skeleton curve is elaborated.The verifcation tests on saturated Nanjing fne sand are performed using a hollow cylinder apparatus to verify the applicability of the UD model.It is found that the predicted curves by the UD model agree well with the test data.
文摘In this paper, we use the cellular automation model to imitate earthquake process and draw some conclusionsof general applicability. First, it is confirmed that earthquake process has some ordering characters, and it isshown that both the existence and their mutual arrangement of faults could obviously influence the overallcharacters of earthquake process. Then the characters of each stage of model evolution are explained withself-organized critical state theory. Finally, earthquake sequences produced by the models are analysed interms pf algorithmic complexity and the result shows that AC-values of algorithmic complexity could be usedto study earthquake process and evolution.
基金supported by the NNSFC(21373225,21221001,21471149)the NSF of Fujian Province(2014J07003,2014J01065)Youth Innovation Promotion Association,CAS
文摘Copper complexes that can experience reversible heat-induced dehydration and rehydration in the solid state were rarely reported although thermochromic copper complexes have been widely reported, and their heat-induced magnetic properties have not been studied. We firstly observed the reversible thermochromic phenomena of the known copper（II） complex [Cu（bpy）（OOCCH3）2]n·xn H2O（x = 2.5 or 3; bpy = 4,4＇-bipyridine） in the solid state, which is associated with the dehydration and rehydration processes, and found that heat-induced coloration clearly enhanced the magnetic susceptibility.
基金supported by the National Natural Science Foundation of China (61201153)the National Basic Research Program of China (2012CB315805)the National Key Science and Technology Projects (2010ZX03004-002-02)
文摘Echo state network （ESN） has become one of the most popular recurrent neural networks （RNN） for its good prediction performance of non-linear time series and simple training process. But several problems still prevent ESN from becoming a widely used tool. The most prominent problem is its high complexity with lots of random parameters. Aiming at this problem, a minimum complexity ESN model （MCESN） was proposed. In this paper, we proposed a new wavelet minimum complexity ESN model （WMCESN） to improve the prediction accuracy and increase the practical applicability. Our new model inherits the characters of minimum complexity ESN model using the fixed parameters and simple circle topology. We injected wavelet neurons to replace the original neurons in internal reservoir and designed a wavelet parameter matrix to reduce the computing time. By using different datasets, our new model performed better than the minimum complexity ESN model with normal neurons, but only utilized tiny time cost. We also used our own packets of transmission control protocol （TCP） and user datagram protocol （UDP） dataset to prove that our model can deal with the data packet bit prediction problem well.
基金supported by the National Natural Science Foundation of China (Grant No. 51538010)the Shanghai Municipal Education Commission (Grant No. 02102360152)。
文摘This paper presents a stochastic fatigue damage model for concrete subjected to complex stress states.A constitutive framework considering the tensile and shear damage mechanisms and elastic and plastic energy dissipations is employed.The damage law is established through a multiscale analysis of the damage evolution mechanism.Validation results against test data show that the model can effectively predict the static strength,stress-strain curve,fatigue life,and scattering range of concrete under various multidimensional loading scenarios.
基金supported by the Key Program of National Natural Science Foundation of China (51038002)National Natural Science Foundation of China (50808026, 11072041, 51208066)+1 种基金supported by Open Fund of the Key Laboratory of Highway Engineering of Ministry of Education, Changsha University of Science & Technology (kfj130103)the Planned Science and Technology Project of Hunan Province (2014TT2032)
文摘Asphalt mixture is the most widely used pavement material all over the world. In China, more than 90% of service expressways are asphalt pavement. However, current asphalt pavement design method still has irrationality. Even though maximum tensile stress theory is used as failure criterion, pavement structure under the effects of wheel load is in three-dimensional complex stress state. Obviously, one-dimensional strength theory cannot reflect the failure characteristics and the resistance of pavement structure. So it is necessary to study the failure criterion of asphalt mixture under three-dimensional com- plex stress state. Due to limitations of test equipment, there are almost no studies in related area. Under this background, this paper develops a new triaxial test method, ac- cording to the investigation of strength characteristics of asphalt mixture under complex stress state through plane isobaric/axial tensile test, plane isobaric/axial compression test, plane tensile and compression/axial tensile test, to reveal the general rules of asphalt mixture＇s strength failure. The failure mode is divided into three types： tensile failure, shear failure and rheological failure. The tensile meridian and compression meridian in the stress space and strength envelope in the π plane where hydrostatic pressure is greater than zero are obtained, and the failure criterion of asphalt mixture under complex stress state is established, providing theoretical method and scientific basis for structure design as well as strength check of asphalt pavement under three-dimensional stress state.
文摘9-Fluorenylidenemalononitrile (FDCN) or 1,1 diphenyl 2,2 dicyanoethylene (DPCN) reacted with 10 methyl 9,10 dihydroacridine (AcrH 2) under irradiation ( λ >320 nm) to give couping products. In order to gain further insight into the mechanism of the photo induced reaction, the photophysics of the reactions of FDCN or DPCN with AcrH 2 have been investigated by using UV vis spectroscopy, fluorescence spectroscopy, excitation spectroscopy and time resolved fluorescence spectroscopy, respectively. The results show that FDCN or DPCN interacts with AcrH 2 in the ground states to form a charge transfer complex, which further reacts to give the coupling product upon irradiation.
