The soil masses of slopes were assumed to follow a nonlinear failure criterion and a nonassociated flow rule.The stability factors of slopes were calculated using vertical slice method based on limit analysis.The pote...The soil masses of slopes were assumed to follow a nonlinear failure criterion and a nonassociated flow rule.The stability factors of slopes were calculated using vertical slice method based on limit analysis.The potential sliding mass was divided into a series of vertical slices as well as the traditional slice technique.Equating the external work rate to the internal energy dissipation,the optimum solutions to stability factors were determined by the nonlinear programming algorithm.From the numerical results,it is found that the present solutions agree well with previous results when the nonlinear criterion reduces to the linear criterion,and the nonassociated flow rule reduces to the associated flow rule.The stability factors decrease by 39.7%with nonlinear parameter varying from 1.0 to 3.0.Dilation and nonlinearity have significant effects on the slope stability factors.展开更多
Photodissociation dynamics of dichlorodifluoromethane (CF2Cl2) around 235 nm has been studied using the time-sliced velocity map imaging technology in combination with the resonance enhanced multi-photon ionization te...Photodissociation dynamics of dichlorodifluoromethane (CF2Cl2) around 235 nm has been studied using the time-sliced velocity map imaging technology in combination with the resonance enhanced multi-photon ionization technology. By measuring the raw images of chlorine atoms which are formed via one-photon dissociation of CF2Cl2, the speed and angular distributions can be directly obtained. The speed distribution of excited-state chlorine atoms consists of high translation energy (ET) and low ET components, which are related to direct dissociation on 3Q0 state and predissociation on the ground state induced by internal conversion, respectively. The speed distribution of ground-state chlorine atoms also consists of high ET and low ET components which are related to predissociation between 3Q0 and 1Q1 states and predissociation on the ground state induced by internal conversion, respectively. Radical dissociation channel is confirmed, nevertheless, secondary dissociation and three-body dissociation channels are excluded.展开更多
Petri net is an important tool to model and analyze concurrent systems,but Petri net models are frequently large and complex,and difficult to understand and modify.Slicing is a technique to remove unnecessary parts wi...Petri net is an important tool to model and analyze concurrent systems,but Petri net models are frequently large and complex,and difficult to understand and modify.Slicing is a technique to remove unnecessary parts with respect to a criterion for analyzing programs,and has been widely used in specification level for model reduction,but researches on slicing of Petri nets are still limited.According to the idea of program slicing,this paper extends slicing technologies of Petri nets to four kinds of slices,including backward static slice,backward dynamic slice,forward static slice and forward dynamic slice.Based on the structure properties,the algorithms of obtaining two kinds of static slice are constructed.Then,a new method of slicing backward dynamic slice is proposed based on local reachability graph which can locally reflect the dynamic properties of Petri nets.At last,forward dynamic slice can be obtained through the reachability marking graph under a special marking.The algorithms can be used to reduce the size of Petri net,which can provide the basic technical support for simplifying the complexity of formal verification and analysis.展开更多
Sliced velocity mapping ion imaging technique was employed to investigate the dynamics of the hydroxyl elimination channel in the photodissociaiton of nitric acid in the ultraviolet region. The OH product was detected...Sliced velocity mapping ion imaging technique was employed to investigate the dynamics of the hydroxyl elimination channel in the photodissociaiton of nitric acid in the ultraviolet region. The OH product was detected by (2+1) resonance enhanced multiphoton ionization via the D^2∑^- electronic state. The total kinetic energy spectra of the OH+NO2 channel from the photolysis of HONO2 show that both :NO2(X2A1) and NO2(A2B2) channels are present, suggesting that both 1^1A″ and 2^1A″ excited electronic states of HONO2 are involved in the excitation. The parallel angular distributions suggest that the dissociation of the nitric acid is a fast process in comparison with the rotational period of the HNO3 molecule. The anisotropy parameter β for the hydroxyl elimination channel is found to be dependent on the OH product rotational state as well as the photolysis energy.展开更多
The half-dry cutting employs cryogenic compressed air cooled down to (10 to 40) and a micro-dosage of lubricating oil, called cryogenic cold air jet cutting was studied. On the basis of a comparative experiment on dr...The half-dry cutting employs cryogenic compressed air cooled down to (10 to 40) and a micro-dosage of lubricating oil, called cryogenic cold air jet cutting was studied. On the basis of a comparative experiment on dry and cryogenic cold air jet cuttings carried out for grade 45 steel, the effects of cryogenic cold air jet on the breaking of chips were discussed. The experimental results reveal that in the valid ranges of pressure and temperature, the cryogenic cold air jet widens the chip breaking areas effectively. When the cutting depth is not greater than 1 mm, the influence of chip breaking is much more significant. But different injecting angle of cold air has different influence on the chip-break. From the experiment, the optimized jet injecting angle, temperature effecting range and pressure working range of cold air are obtained. These results can offer a foundation for industrial manufacturing.展开更多
This paper aims to the research of the impact of fluid shear stress on the adhesion between vascular endothelial cells and leukocyte induced by tumor necrosis factor-α(TNF-α) by microfliudic chip technology.Microflu...This paper aims to the research of the impact of fluid shear stress on the adhesion between vascular endothelial cells and leukocyte induced by tumor necrosis factor-α(TNF-α) by microfliudic chip technology.Microfluidic chip was fabricated by soft lithograph; Endothelial microfluidic chip was constructed by optimizing types of the extracellular matrix proteins modified in the microchannel and cell incubation time;human umbilical vein endothelial cells EA.Hy926 lined in the microchannel were exposed to fluid shear stress of 1.68 dynes/cm^2 and 8.4 dynes/cm^2 respectively.Meanwhile,adhesion between EA.Hy926 cells and leukocyte was induced by TNF-αunder a flow condition.EA.Hy926 cell cultured in the static condition was used as control group.The numbers of fluorescently-labeled leukocyte in microchannel were counted to quantize the adhesion level between EA.Hy926 cells and leukocyte; cell immunofluorescence technique was used to detect the intercellular adhesion molecule(ICAM-1) expression.The constructed endothelial microfluidic chip can afford to the fluid shear stress and respond to exogenous stimulus of TNF-α; compared with the adhesion numbers of leukocyte in control group,adhesion between EA.Hy926 cells exposed to low fluid shear stress and leukocyte was reduced under the stimulus of TNF-α at a concentration of 10 ng/ml(P<0.05); leukocyte adhesion with EA.Hy926 cells exposed to high fluid shear stress was reduced significantly than EA.Hy926 cells in control group and EA.1Hy926 cells exposed to low fluid shear stress(P<0.01); the regulation mechanism of fluid shear stress to the adhesion between EA.Hy926 cells and leukocyte induced by TNF-αwas through the way of ICAM-1.The endothelial microfluidic chip fabricated in this paper could be used to study the functions of endothelial cell in vitro and provide a new technical platform for exploring the pathophysiology of the related cardiovascular system diseases under a flow environment.展开更多
基金Project(200550)supported by the Foundation for the Author of National Excellent Doctoral Dissertation of ChinaProject(200631878557)supported by West Traffic of Science and Technology of China
文摘The soil masses of slopes were assumed to follow a nonlinear failure criterion and a nonassociated flow rule.The stability factors of slopes were calculated using vertical slice method based on limit analysis.The potential sliding mass was divided into a series of vertical slices as well as the traditional slice technique.Equating the external work rate to the internal energy dissipation,the optimum solutions to stability factors were determined by the nonlinear programming algorithm.From the numerical results,it is found that the present solutions agree well with previous results when the nonlinear criterion reduces to the linear criterion,and the nonassociated flow rule reduces to the associated flow rule.The stability factors decrease by 39.7%with nonlinear parameter varying from 1.0 to 3.0.Dilation and nonlinearity have significant effects on the slope stability factors.
基金supported by the Natural Science Foundation of the Jiangsu Higher Education Institutions of China (No.17KJB150005 and No.17KJD510001)the Natural Science Foundation of Changzhou Institute of Technology (No.YN1507 and No.YN1611)+1 种基金Undergraduate Training Program for Innovation of Changzhou Institute of Technology (No.2017276Y)the National Natural Science Foundation of China (No.21273212)
文摘Photodissociation dynamics of dichlorodifluoromethane (CF2Cl2) around 235 nm has been studied using the time-sliced velocity map imaging technology in combination with the resonance enhanced multi-photon ionization technology. By measuring the raw images of chlorine atoms which are formed via one-photon dissociation of CF2Cl2, the speed and angular distributions can be directly obtained. The speed distribution of excited-state chlorine atoms consists of high translation energy (ET) and low ET components, which are related to direct dissociation on 3Q0 state and predissociation on the ground state induced by internal conversion, respectively. The speed distribution of ground-state chlorine atoms also consists of high ET and low ET components which are related to predissociation between 3Q0 and 1Q1 states and predissociation on the ground state induced by internal conversion, respectively. Radical dissociation channel is confirmed, nevertheless, secondary dissociation and three-body dissociation channels are excluded.
基金Supported by the National Natural Science Foundation of China(No.90818023)the National Basic Research Program of China(No.2010CB328101)+2 种基金Shanghai Science&Technology Research Plan(No.09JC1414200,09510701300)"Dawn"Program of Shanghai Education Commission,Program for Changjiang Scholars and Innovative Research Team in University(PCSIRT),National Major Projects of Scienceand Technology(No.2009ZX01036-001-002:part 5)Natural Science Foundation of Educational Government of Anhui Province(No.KJ2011A086)
文摘Petri net is an important tool to model and analyze concurrent systems,but Petri net models are frequently large and complex,and difficult to understand and modify.Slicing is a technique to remove unnecessary parts with respect to a criterion for analyzing programs,and has been widely used in specification level for model reduction,but researches on slicing of Petri nets are still limited.According to the idea of program slicing,this paper extends slicing technologies of Petri nets to four kinds of slices,including backward static slice,backward dynamic slice,forward static slice and forward dynamic slice.Based on the structure properties,the algorithms of obtaining two kinds of static slice are constructed.Then,a new method of slicing backward dynamic slice is proposed based on local reachability graph which can locally reflect the dynamic properties of Petri nets.At last,forward dynamic slice can be obtained through the reachability marking graph under a special marking.The algorithms can be used to reduce the size of Petri net,which can provide the basic technical support for simplifying the complexity of formal verification and analysis.
基金Ⅴ. ACKNOWLEDGMENTS This work was supported by the National Natural Science Foundation of China, the Ministry of Sciences and Technology, and the Chinese Academy of Sciences.
文摘Sliced velocity mapping ion imaging technique was employed to investigate the dynamics of the hydroxyl elimination channel in the photodissociaiton of nitric acid in the ultraviolet region. The OH product was detected by (2+1) resonance enhanced multiphoton ionization via the D^2∑^- electronic state. The total kinetic energy spectra of the OH+NO2 channel from the photolysis of HONO2 show that both :NO2(X2A1) and NO2(A2B2) channels are present, suggesting that both 1^1A″ and 2^1A″ excited electronic states of HONO2 are involved in the excitation. The parallel angular distributions suggest that the dissociation of the nitric acid is a fast process in comparison with the rotational period of the HNO3 molecule. The anisotropy parameter β for the hydroxyl elimination channel is found to be dependent on the OH product rotational state as well as the photolysis energy.
文摘The half-dry cutting employs cryogenic compressed air cooled down to (10 to 40) and a micro-dosage of lubricating oil, called cryogenic cold air jet cutting was studied. On the basis of a comparative experiment on dry and cryogenic cold air jet cuttings carried out for grade 45 steel, the effects of cryogenic cold air jet on the breaking of chips were discussed. The experimental results reveal that in the valid ranges of pressure and temperature, the cryogenic cold air jet widens the chip breaking areas effectively. When the cutting depth is not greater than 1 mm, the influence of chip breaking is much more significant. But different injecting angle of cold air has different influence on the chip-break. From the experiment, the optimized jet injecting angle, temperature effecting range and pressure working range of cold air are obtained. These results can offer a foundation for industrial manufacturing.
文摘This paper aims to the research of the impact of fluid shear stress on the adhesion between vascular endothelial cells and leukocyte induced by tumor necrosis factor-α(TNF-α) by microfliudic chip technology.Microfluidic chip was fabricated by soft lithograph; Endothelial microfluidic chip was constructed by optimizing types of the extracellular matrix proteins modified in the microchannel and cell incubation time;human umbilical vein endothelial cells EA.Hy926 lined in the microchannel were exposed to fluid shear stress of 1.68 dynes/cm^2 and 8.4 dynes/cm^2 respectively.Meanwhile,adhesion between EA.Hy926 cells and leukocyte was induced by TNF-αunder a flow condition.EA.Hy926 cell cultured in the static condition was used as control group.The numbers of fluorescently-labeled leukocyte in microchannel were counted to quantize the adhesion level between EA.Hy926 cells and leukocyte; cell immunofluorescence technique was used to detect the intercellular adhesion molecule(ICAM-1) expression.The constructed endothelial microfluidic chip can afford to the fluid shear stress and respond to exogenous stimulus of TNF-α; compared with the adhesion numbers of leukocyte in control group,adhesion between EA.Hy926 cells exposed to low fluid shear stress and leukocyte was reduced under the stimulus of TNF-α at a concentration of 10 ng/ml(P<0.05); leukocyte adhesion with EA.Hy926 cells exposed to high fluid shear stress was reduced significantly than EA.Hy926 cells in control group and EA.1Hy926 cells exposed to low fluid shear stress(P<0.01); the regulation mechanism of fluid shear stress to the adhesion between EA.Hy926 cells and leukocyte induced by TNF-αwas through the way of ICAM-1.The endothelial microfluidic chip fabricated in this paper could be used to study the functions of endothelial cell in vitro and provide a new technical platform for exploring the pathophysiology of the related cardiovascular system diseases under a flow environment.