Ten specimens were tested in this paper in order to study the bond behavior and the process of force transfer when bars adhered to mortar. The development of the bond stress between bars and mortar was calculated. Tes...Ten specimens were tested in this paper in order to study the bond behavior and the process of force transfer when bars adhered to mortar. The development of the bond stress between bars and mortar was calculated. Test results show that the maximum bond-stress is not influenced by the bar bond length and increases as the increased splitting strength of mortar for block. The local bond stress-slip curve was obtained. Then,based on the regressive analysis of test data,two bond shearing stress-slip constitutive models between bars and mortar were proposed. The models can be used in the numerical simulation or finite element analysis and provide references for the improvement of the corresponding design codes.展开更多
The constitutive relation of bond-slip on steel and concrete interface is proposed for short steel reinforced concrete （SRC） column. Based on the experimental research on bond-slip performance, a mechanical model of...The constitutive relation of bond-slip on steel and concrete interface is proposed for short steel reinforced concrete （SRC） column. Based on the experimental research on bond-slip performance, a mechanical model of short SRC column in pulling or pushing test is established. By means of the elasto-plasticity theory the explicit formulation of bond-slip constitutive relation τ-s in different anchor-hold place of push and pull member is investigated under the conditions of balance and boundary. The study shows that the constitutive relation is relevant to the embedment length and the thickness of concrete cover. The results are continuous descriptions of bond-slip constitutive relation and can be used to analyze the non-linear performance of SRC members. Results indicate that the principle of the method is correct and it performs well for short SRC column.展开更多
-Based on the experimental data, a stress variation model of the bond stress-slip relationship between steel bar and concrete is established. The characteristic of the model is that the boundary conditions are satisfi...-Based on the experimental data, a stress variation model of the bond stress-slip relationship between steel bar and concrete is established. The characteristic of the model is that the boundary conditions are satisfied very well; the effects of the material properties, the concrete cover, the crack spacing and the distance from the cracked cross section are considered. Good agreement between measured and calculated bond stress-slip relationship is found. This model is useful for the study of the stiffness, deformation and crack width of reinforced concrete members, and for the nonlinear analysis of reinforced concrete structures by the finite element method.展开更多
In a microfluidic system, flow slip velocity on a solid wall can be the same order of magnitude as the average velocity in a microchannel. The flow-electricity interaction in a complex microfluidic system subjected to...In a microfluidic system, flow slip velocity on a solid wall can be the same order of magnitude as the average velocity in a microchannel. The flow-electricity interaction in a complex microfluidic system subjected to joint action of wall slip and electro-viscous effect is an important topic. This paper presents an analytic solution of pressuredriven liquid flow velocity and flow-induced electric field in a two-dimensional microchannel made of different materials with wall slip and electro-viscous effects. The Poisson- Boltzmann equation and the Navier-Stokes equation are solved for the analytic solutions. The analytic solutions agree well with the numerical solutions. It was found that the wall slip amplifies the fow-induced electric field and enhances the electro-viscous effect on flow. Thus the electro-viscous effect can be significant in a relatively wide microchannel with relatively large kh, the ratio of channel width to thickness of electric double layer, in comparison with the channel without wall slip.展开更多
Solid-state diffusion bonding has been done to produce transition joint between TC4 and QAl10-3-1.5 at the temperature 850℃ for 60 min. The produced diffusion bonded couples were evaluated by scanning electron micros...Solid-state diffusion bonding has been done to produce transition joint between TC4 and QAl10-3-1.5 at the temperature 850℃ for 60 min. The produced diffusion bonded couples were evaluated by scanning electron microscopy （SEM）, energy dispersive spectroscopy （EDS） and X-ray diffraction （XRD）. SEM revealed the presences of the different reaction regions in the diffusion zone and “kirkendall voids” were observed in the interface. This study indicated the existences of Cu3 Ti, Cu and Ti phases in the diffusion zone of the joint confirmed by XRD. The microhardness tests revealed that the microhardness of TC4 jointing affected zone （ JAZ） is higher than the TC4 base materials, and transition zone close to TC4 possesses the highest microhardness value.展开更多
To establish bonding stress—slip constitutive model between bars and grout concrete,13 test specimens were employed to study the bonding behavior and the force transfer of bars adhered to grout concrete. The bonding ...To establish bonding stress—slip constitutive model between bars and grout concrete,13 test specimens were employed to study the bonding behavior and the force transfer of bars adhered to grout concrete. The bonding stress development of bars adhered to grout concrete was analyzed. The local bonding stress—slip curve was obtained. Based on the test results,a new bonding stress— slip constitutive model between bars and grout concrete was proposed. The results show that the maximum bonding stress is not influenced by the bar bond length,but it is strengthened when the splitting strength of grout concrete is increased. The model matches the experimental results well,and the regressing coefficient equals 1.7.展开更多
A new mono-nuclear CuII complex [Cu（DPP）（DP）Br]（ClO4）H2O （DPP = 2-（3,5- dimethyl-1H-pyrazol-1-yl）-1,10-phenanthroline, DP = 3,5-dimethyl-1H-pyrazole） has been syn- thesized with 2-（3,5-dimethyl-1H-pyrazol-1...A new mono-nuclear CuII complex [Cu（DPP）（DP）Br]（ClO4）H2O （DPP = 2-（3,5- dimethyl-1H-pyrazol-1-yl）-1,10-phenanthroline, DP = 3,5-dimethyl-1H-pyrazole） has been syn- thesized with 2-（3,5-dimethyl-1H-pyrazol-1-yl）-1,10-phenanthroline and 3,5-dimethyl-1H-pyrazole as ligands, and its crystal structure was determined by X-ray crystallography. The crystal is of monoclinic system, space group P21/c with a = 13.765（2）, b = 17.044（3）, c = 10.9044（16）, β= 97.112（2）°, V = 2538.5（6）3, Z = 4, C22H24BrClCuN6O5, Mr = 631.37, Dc = 1.652 g/cm3, F（000） = 1276 and μ= 2.585 mm-1. In the crystal, DPP functions as a tridentate ligand and CuII ions assume a distorted square pyramidal geometry with Br atom lying on the apex, and at the same time, there is π-π stacking between adjacent complexes, which deals with two 1,10-phenanthroline plane rings. In addition to the π-π stacking, there are C-H···Br non-classic hydrogen bonds between adjacent complexes. The theoretical calculations reveal that the π-π stacking and C-H···Br non-classic hydrogen bond result in a weak anti-ferromagnetic interaction with 2J = -5.34 cm-1 and a weak ferromagnetic 2J = 5.92 cm-1, respectively. The magnetic coupling sign from the π-π stacking could be explained with McConnell I spin-polarization mechanism.展开更多
The experimental investigation of the direct diffusion bonding of Ti-6Al-4V to ZQSn10-10 was carried out in vacuum. The microstructure of bonded joint was studied by scanning electron microscopy （SEM）, energy disper...The experimental investigation of the direct diffusion bonding of Ti-6Al-4V to ZQSn10-10 was carried out in vacuum. The microstructure of bonded joint was studied by scanning electron microscopy （SEM）, energy dispersive spectroscopy （ EDS ） and the mechanical properties were detected by the tensile experiments. The microstructure and tensile strength of the joint mainly depend on the bonding temperature and bonding time. A satisfying diffusion bonded interface with a tensile strength of 73.9 MPa can be obtained under the condition of bonding temperature 850℃ for 30 rain. Three kinds of reaction products were observed in the bonded interface, namely β-Ti, CoaTi and CuSn3Ti5. And the brittle Cu3Ti and CuSn3 Ti5 are mainly responsible for lowering the strength of the bonded joint. The diffusion distances of Sn , Cu and Ti and square root of bonding time are approximately linear relationship. And diffusion velocity of Sn, Cu and Ti in the diffusion reaction layer are 0. 013 9,0. 069 7 and 0. 056 4 mm^2/s.展开更多
The pressing bonding of steel plate with QTi3.5-3.5graphite slurry was studied. The relationship among preheating temperature of steel plate, preheating temperature of dies, solid fraction of QTi3.5-3.5graphite slurry...The pressing bonding of steel plate with QTi3.5-3.5graphite slurry was studied. The relationship among preheating temperature of steel plate, preheating temperature of dies, solid fraction of QTi3.5-3.5graphite slurry, and interfacial shear strength of bonding plate could be established with artificial neural networks perfectly. This model could be optimized with a genetic algorithm. The results show that the optimum bonding parameters are: 618℃ for preheating temperature of steel plate, 526℃ for preheating temperature of dies and 46.2% for solid fraction of QTi3.5-3.5graphite slurry, and the largest interfacial shear strength of bonding plate is 128.3 MPa.展开更多
基金Sponsored by the National Science and Technology Pillar Program during the 11th Five-Year Plan Period of China(Grant No. 2009BAK58B03-03 and 2006BAJ03A01-05)the Key Laboratory of Structural Engineering of Shenyang Jianzhu University,China(Grant No. JG200705)the Science & Re-search Program of Shenyang,China(Grant No. 1091064-A-00)
文摘Ten specimens were tested in this paper in order to study the bond behavior and the process of force transfer when bars adhered to mortar. The development of the bond stress between bars and mortar was calculated. Test results show that the maximum bond-stress is not influenced by the bar bond length and increases as the increased splitting strength of mortar for block. The local bond stress-slip curve was obtained. Then,based on the regressive analysis of test data,two bond shearing stress-slip constitutive models between bars and mortar were proposed. The models can be used in the numerical simulation or finite element analysis and provide references for the improvement of the corresponding design codes.
基金Sponsored by the Science and Technology Program Project of Henan Province(002462004)
文摘The constitutive relation of bond-slip on steel and concrete interface is proposed for short steel reinforced concrete （SRC） column. Based on the experimental research on bond-slip performance, a mechanical model of short SRC column in pulling or pushing test is established. By means of the elasto-plasticity theory the explicit formulation of bond-slip constitutive relation τ-s in different anchor-hold place of push and pull member is investigated under the conditions of balance and boundary. The study shows that the constitutive relation is relevant to the embedment length and the thickness of concrete cover. The results are continuous descriptions of bond-slip constitutive relation and can be used to analyze the non-linear performance of SRC members. Results indicate that the principle of the method is correct and it performs well for short SRC column.
文摘-Based on the experimental data, a stress variation model of the bond stress-slip relationship between steel bar and concrete is established. The characteristic of the model is that the boundary conditions are satisfied very well; the effects of the material properties, the concrete cover, the crack spacing and the distance from the cracked cross section are considered. Good agreement between measured and calculated bond stress-slip relationship is found. This model is useful for the study of the stiffness, deformation and crack width of reinforced concrete members, and for the nonlinear analysis of reinforced concrete structures by the finite element method.
基金supported by the National Natural Science Foundation of China(10872076)
文摘In a microfluidic system, flow slip velocity on a solid wall can be the same order of magnitude as the average velocity in a microchannel. The flow-electricity interaction in a complex microfluidic system subjected to joint action of wall slip and electro-viscous effect is an important topic. This paper presents an analytic solution of pressuredriven liquid flow velocity and flow-induced electric field in a two-dimensional microchannel made of different materials with wall slip and electro-viscous effects. The Poisson- Boltzmann equation and the Navier-Stokes equation are solved for the analytic solutions. The analytic solutions agree well with the numerical solutions. It was found that the wall slip amplifies the fow-induced electric field and enhances the electro-viscous effect on flow. Thus the electro-viscous effect can be significant in a relatively wide microchannel with relatively large kh, the ratio of channel width to thickness of electric double layer, in comparison with the channel without wall slip.
文摘Solid-state diffusion bonding has been done to produce transition joint between TC4 and QAl10-3-1.5 at the temperature 850℃ for 60 min. The produced diffusion bonded couples were evaluated by scanning electron microscopy （SEM）, energy dispersive spectroscopy （EDS） and X-ray diffraction （XRD）. SEM revealed the presences of the different reaction regions in the diffusion zone and “kirkendall voids” were observed in the interface. This study indicated the existences of Cu3 Ti, Cu and Ti phases in the diffusion zone of the joint confirmed by XRD. The microhardness tests revealed that the microhardness of TC4 jointing affected zone （ JAZ） is higher than the TC4 base materials, and transition zone close to TC4 possesses the highest microhardness value.
基金Project(2006BAJ03A01-05) supported by National Science and Technology Pillar Program during the 11th Five-Year Plan Period of ChinaProject (JG200705) supported by Key Laboratory of Structural Engineering of Shenyang Jianzhu University, China
文摘To establish bonding stress—slip constitutive model between bars and grout concrete,13 test specimens were employed to study the bonding behavior and the force transfer of bars adhered to grout concrete. The bonding stress development of bars adhered to grout concrete was analyzed. The local bonding stress—slip curve was obtained. Based on the test results,a new bonding stress— slip constitutive model between bars and grout concrete was proposed. The results show that the maximum bonding stress is not influenced by the bar bond length,but it is strengthened when the splitting strength of grout concrete is increased. The model matches the experimental results well,and the regressing coefficient equals 1.7.
基金supported by the National Natural Science Foundation of China (No. 20971080)the Natural Science Foundation of Shandong Province (No. ZR2009BM026 and ZR2009BL002)
文摘A new mono-nuclear CuII complex [Cu（DPP）（DP）Br]（ClO4）H2O （DPP = 2-（3,5- dimethyl-1H-pyrazol-1-yl）-1,10-phenanthroline, DP = 3,5-dimethyl-1H-pyrazole） has been syn- thesized with 2-（3,5-dimethyl-1H-pyrazol-1-yl）-1,10-phenanthroline and 3,5-dimethyl-1H-pyrazole as ligands, and its crystal structure was determined by X-ray crystallography. The crystal is of monoclinic system, space group P21/c with a = 13.765（2）, b = 17.044（3）, c = 10.9044（16）, β= 97.112（2）°, V = 2538.5（6）3, Z = 4, C22H24BrClCuN6O5, Mr = 631.37, Dc = 1.652 g/cm3, F（000） = 1276 and μ= 2.585 mm-1. In the crystal, DPP functions as a tridentate ligand and CuII ions assume a distorted square pyramidal geometry with Br atom lying on the apex, and at the same time, there is π-π stacking between adjacent complexes, which deals with two 1,10-phenanthroline plane rings. In addition to the π-π stacking, there are C-H···Br non-classic hydrogen bonds between adjacent complexes. The theoretical calculations reveal that the π-π stacking and C-H···Br non-classic hydrogen bond result in a weak anti-ferromagnetic interaction with 2J = -5.34 cm-1 and a weak ferromagnetic 2J = 5.92 cm-1, respectively. The magnetic coupling sign from the π-π stacking could be explained with McConnell I spin-polarization mechanism.
基金This research was supported by National Natural Science Foundation of China(No 50375065)State Key Laboratory of Advanced Welding Production Technology(04005)
文摘The experimental investigation of the direct diffusion bonding of Ti-6Al-4V to ZQSn10-10 was carried out in vacuum. The microstructure of bonded joint was studied by scanning electron microscopy （SEM）, energy dispersive spectroscopy （ EDS ） and the mechanical properties were detected by the tensile experiments. The microstructure and tensile strength of the joint mainly depend on the bonding temperature and bonding time. A satisfying diffusion bonded interface with a tensile strength of 73.9 MPa can be obtained under the condition of bonding temperature 850℃ for 30 rain. Three kinds of reaction products were observed in the bonded interface, namely β-Ti, CoaTi and CuSn3Ti5. And the brittle Cu3Ti and CuSn3 Ti5 are mainly responsible for lowering the strength of the bonded joint. The diffusion distances of Sn , Cu and Ti and square root of bonding time are approximately linear relationship. And diffusion velocity of Sn, Cu and Ti in the diffusion reaction layer are 0. 013 9,0. 069 7 and 0. 056 4 mm^2/s.
基金This project was supported by the National Natural Science Foundation of China(No.50274047 and 50304001)the Bejing Jiaotong University Foundation.
文摘The pressing bonding of steel plate with QTi3.5-3.5graphite slurry was studied. The relationship among preheating temperature of steel plate, preheating temperature of dies, solid fraction of QTi3.5-3.5graphite slurry, and interfacial shear strength of bonding plate could be established with artificial neural networks perfectly. This model could be optimized with a genetic algorithm. The results show that the optimum bonding parameters are: 618℃ for preheating temperature of steel plate, 526℃ for preheating temperature of dies and 46.2% for solid fraction of QTi3.5-3.5graphite slurry, and the largest interfacial shear strength of bonding plate is 128.3 MPa.
