Feasibility of using pre-stressed carbon fiber plates to strengthen reinforced concrete beams was studied. Based on the characteristics of carbon fiber plates, we developed a pre-stress clamp and a device for applying...Feasibility of using pre-stressed carbon fiber plates to strengthen reinforced concrete beams was studied. Based on the characteristics of carbon fiber plates, we developed a pre-stress clamp and a device for applying the pre-stress. Contrast tests were conducted between ordinary carbon fiber plates and a pre-stressed carbon fiber plate and between secondary loaded carbon fiber plates and a concrete beam strengthened with a secondary loaded carbon fiber plate. On this basis, we analyzed the failure pattern, the width of cracks and their distribution, the cracking load, the yield load, the limit load and the relation between load and deflec- tion. The results indicate that using pre-stressed carbon fiber plates to strengthen concrete beams is feasible and effective.展开更多
-<sup>11</sup>C and <sup>17</sup>F secondary beams have been successfully tuned on the CIAE sec-ondary radioactive beam line at the HI-13 tandem accelerator.The setting parametersof the seconda...-<sup>11</sup>C and <sup>17</sup>F secondary beams have been successfully tuned on the CIAE sec-ondary radioactive beam line at the HI-13 tandem accelerator.The setting parametersof the secondary beam line and the beam quality for <sup>11</sup>C and <sup>17</sup>F are given.A <sup>11</sup>C beamis produced with intensity 1.2×10<sup>5</sup> particles/s and energy 41±1.0 MeV.展开更多
Seeded nucleation of lithium carbonate in aqueous solution during reactive crystallization was monitored by FBRM(focused beam reflectance measurement) and PVM(particle video microscope).The impacts of operating variab...Seeded nucleation of lithium carbonate in aqueous solution during reactive crystallization was monitored by FBRM(focused beam reflectance measurement) and PVM(particle video microscope).The impacts of operating variables,such as seed size and loading,stirring speed,on induction period and secondary nucleation were investigated and explained by an adsorption model.The results show that seed surface area plays an important role in secondary nucleation,for more surface area has higher adsorption capacity and consumes more supersaturation on seed growth,thus restrains nucleation better.A method through comparison between pure breakage/attrition and nucleation process was put forward to distinguish attrition-induced and surface-induced nucleations quantitatively,which can reveal the contributions of different nucleation mechanisms.The nucleation processes in different conditions were studied,the principles and valuable experimental data were obtained for seeding approach primarily.FBRM and PVM are useful on-line apparatuses to facilitate seed selection and seeding optimization.展开更多
The materials with different moduli in tension and compression are called bi-modulus materials. Graphene is such a kind of materials with the highest strength and the thinnest thickness. In this paper, the mechanical ...The materials with different moduli in tension and compression are called bi-modulus materials. Graphene is such a kind of materials with the highest strength and the thinnest thickness. In this paper, the mechanical response of the bi-modulus beam subjected to the temperature effect and placed on the Winkler foundation is studied. The differential equations about the neutral axis position and undetermined parameters of the normal strain of the bi-modulus foundation beam are established. Then, the analytical expressions of the normal stress, bending moment, and displacement of the foundation beam are derived. Simultaneously, a calculation procedure based on the finite element method （FEM） is developed to obtain the temperature stress of the bi-modulus struc- tures. It is shown that the obtained bi-modulus solutions can recover the classical modulus solution, and the results obtained by the analytical expressions, the present FEM proce- dure, and the traditional FEM software are consistent, which verifies the accuracy and reliability of the present analytical model and procedure. Finally, the difference between the bi-modulus results and the classical same modulus results is discussed, and several reasonable suggestions for calculating and optimizing the certain bi-modulus member in practical engineering are presented.展开更多
文摘Feasibility of using pre-stressed carbon fiber plates to strengthen reinforced concrete beams was studied. Based on the characteristics of carbon fiber plates, we developed a pre-stress clamp and a device for applying the pre-stress. Contrast tests were conducted between ordinary carbon fiber plates and a pre-stressed carbon fiber plate and between secondary loaded carbon fiber plates and a concrete beam strengthened with a secondary loaded carbon fiber plate. On this basis, we analyzed the failure pattern, the width of cracks and their distribution, the cracking load, the yield load, the limit load and the relation between load and deflec- tion. The results indicate that using pre-stressed carbon fiber plates to strengthen concrete beams is feasible and effective.
基金The project supported in part by National Natural Science Foundation of ChinaChina Nuclear Industry Science Foundation.
文摘-<sup>11</sup>C and <sup>17</sup>F secondary beams have been successfully tuned on the CIAE sec-ondary radioactive beam line at the HI-13 tandem accelerator.The setting parametersof the secondary beam line and the beam quality for <sup>11</sup>C and <sup>17</sup>F are given.A <sup>11</sup>C beamis produced with intensity 1.2×10<sup>5</sup> particles/s and energy 41±1.0 MeV.
基金Supported by Shanghai Leading Academic Discipline Project (No.B506)Program for New Century Excellent Talents in University (No. NCET-08-0776)
文摘Seeded nucleation of lithium carbonate in aqueous solution during reactive crystallization was monitored by FBRM(focused beam reflectance measurement) and PVM(particle video microscope).The impacts of operating variables,such as seed size and loading,stirring speed,on induction period and secondary nucleation were investigated and explained by an adsorption model.The results show that seed surface area plays an important role in secondary nucleation,for more surface area has higher adsorption capacity and consumes more supersaturation on seed growth,thus restrains nucleation better.A method through comparison between pure breakage/attrition and nucleation process was put forward to distinguish attrition-induced and surface-induced nucleations quantitatively,which can reveal the contributions of different nucleation mechanisms.The nucleation processes in different conditions were studied,the principles and valuable experimental data were obtained for seeding approach primarily.FBRM and PVM are useful on-line apparatuses to facilitate seed selection and seeding optimization.
基金supported by the National Natural Science Foundation of China(Nos.11072143 and11272200)
文摘The materials with different moduli in tension and compression are called bi-modulus materials. Graphene is such a kind of materials with the highest strength and the thinnest thickness. In this paper, the mechanical response of the bi-modulus beam subjected to the temperature effect and placed on the Winkler foundation is studied. The differential equations about the neutral axis position and undetermined parameters of the normal strain of the bi-modulus foundation beam are established. Then, the analytical expressions of the normal stress, bending moment, and displacement of the foundation beam are derived. Simultaneously, a calculation procedure based on the finite element method （FEM） is developed to obtain the temperature stress of the bi-modulus struc- tures. It is shown that the obtained bi-modulus solutions can recover the classical modulus solution, and the results obtained by the analytical expressions, the present FEM proce- dure, and the traditional FEM software are consistent, which verifies the accuracy and reliability of the present analytical model and procedure. Finally, the difference between the bi-modulus results and the classical same modulus results is discussed, and several reasonable suggestions for calculating and optimizing the certain bi-modulus member in practical engineering are presented.
