A series of scaled-model shaking table tests and its simulation analyses using dynamic finite element method were performed to clarify the dynamic behaviors and the seismic stability of embedded corrugated steel culve...A series of scaled-model shaking table tests and its simulation analyses using dynamic finite element method were performed to clarify the dynamic behaviors and the seismic stability of embedded corrugated steel culverts due to strong earth-quakes like the 1995 Hyogoken-nanbu earthquake. The dynamic strains of the embedded culvert models and the seismic soil pressure acting on the models due to sinusoidal and random strong motions were investigated. This study verified that the cor-rugated culvert model was subjected to dynamic horizontal forces (lateral seismic soil pressure) from the surrounding ground, which caused the large bending strains on the structure; and that the structures do not exceed the allowable plastic deformation and do not collapse completely during strong earthquake like Hyogoken-nanbu earthquake. The results obtained are useful for design and construction of embedded long span corrugated steel culverts in seismic regions.展开更多
We have investigated the quasinormal modes （QNMs） of phantom scalar perturbation in a Reissner Nordstr6m （RN） background. We find that the dependence of Q, NMs on the mass of the field for the phantom perturbation...We have investigated the quasinormal modes （QNMs） of phantom scalar perturbation in a Reissner Nordstr6m （RN） background. We find that the dependence of Q, NMs on the mass of the field for the phantom perturbation is totally different from that of usual massive perturbation. However, we obtain the same critical value of the overtone number for an angular quantum number from which the mass will begin to have a reverse effect on the real part of QNM frequencies and the perturbation-independent relation between the Q, NMs and the second order thermodynamic phase transition.展开更多
Wind tunnel testing is experimental support of research and development during the design phase of aircraft and missile projects. The paper presents the developed method of manufacturing management by providing the re...Wind tunnel testing is experimental support of research and development during the design phase of aircraft and missile projects. The paper presents the developed method of manufacturing management by providing the required quality and accuracy of the wind tunnel models. The price of the wind tunnel model is several hundred thousand dollars and for this reason a manufacturing defect is not allowed. Additionally, any delays in the production process cause delay of testing in the wind tunnel. The costs of the delay are very high, because the wind tunnel laboratory is extremely expensive. All the foregoing is why the issue of the model＇s production is very important. Manufacturing of wind tunnel model within the contracted deadline and the required quality define tasks and objectives of production process management： identification of critical machining operations and activities; minimizing the time of coordinate inspections between cutting operations; identifying the main parameters of quality （shape, position in space, and angular relations）; and material management for all other machining operations that follow. Specially developed methods of coordinate metrology are crucial for the management of the manufacturing process. Worldwide used specialized coordinate inspection programs have no option to measure the flaps deflection angles and wing dihedral angle. This paper introduces the originally developed coordinate inspection methods for determining the angular relations between lift and control surfaces. The methods presented in this paper have been confirmed in several international projects. The quality and accuracy of the models for wind tunnel testing are conditio sine qua non.展开更多
Along with the rapid development of social networks, social network worms have constituted one of the major internet security problems. The root of worm is the inevitable software vulnerability during the design and i...Along with the rapid development of social networks, social network worms have constituted one of the major internet security problems. The root of worm is the inevitable software vulnerability during the design and implementation process of software. So it is hard to completely avoid worms in the existing software engineering systems. Due to lots of bandwidth consumption, the patch cannot be transmitted simultaneously by the network administrator to all hosts. This paper studies how to prevent the propagation of social network worms through the immunization of key nodes. Unlike existing containment models for worm propagation, a novel immunization strategy is proposed based on network vertex influence. The strategy selects the critical vertices in the whole network. Then the immunization is applied on the selected vertices to achieve the maximal effect of worm containment with minimal cost. Different algorithms are implemented to select vertices. Simulation experiments are presented to analyze and evaluate the performance of different algorithms.展开更多
文摘A series of scaled-model shaking table tests and its simulation analyses using dynamic finite element method were performed to clarify the dynamic behaviors and the seismic stability of embedded corrugated steel culverts due to strong earth-quakes like the 1995 Hyogoken-nanbu earthquake. The dynamic strains of the embedded culvert models and the seismic soil pressure acting on the models due to sinusoidal and random strong motions were investigated. This study verified that the cor-rugated culvert model was subjected to dynamic horizontal forces (lateral seismic soil pressure) from the surrounding ground, which caused the large bending strains on the structure; and that the structures do not exceed the allowable plastic deformation and do not collapse completely during strong earthquake like Hyogoken-nanbu earthquake. The results obtained are useful for design and construction of embedded long span corrugated steel culverts in seismic regions.
基金Supported by the National Natural Science Foundation of China under Grant No.10905020the China Postdoctoral Science Foundation under Grant Nos.201003245 and 20090460592
文摘We have investigated the quasinormal modes （QNMs） of phantom scalar perturbation in a Reissner Nordstr6m （RN） background. We find that the dependence of Q, NMs on the mass of the field for the phantom perturbation is totally different from that of usual massive perturbation. However, we obtain the same critical value of the overtone number for an angular quantum number from which the mass will begin to have a reverse effect on the real part of QNM frequencies and the perturbation-independent relation between the Q, NMs and the second order thermodynamic phase transition.
文摘Wind tunnel testing is experimental support of research and development during the design phase of aircraft and missile projects. The paper presents the developed method of manufacturing management by providing the required quality and accuracy of the wind tunnel models. The price of the wind tunnel model is several hundred thousand dollars and for this reason a manufacturing defect is not allowed. Additionally, any delays in the production process cause delay of testing in the wind tunnel. The costs of the delay are very high, because the wind tunnel laboratory is extremely expensive. All the foregoing is why the issue of the model＇s production is very important. Manufacturing of wind tunnel model within the contracted deadline and the required quality define tasks and objectives of production process management： identification of critical machining operations and activities; minimizing the time of coordinate inspections between cutting operations; identifying the main parameters of quality （shape, position in space, and angular relations）; and material management for all other machining operations that follow. Specially developed methods of coordinate metrology are crucial for the management of the manufacturing process. Worldwide used specialized coordinate inspection programs have no option to measure the flaps deflection angles and wing dihedral angle. This paper introduces the originally developed coordinate inspection methods for determining the angular relations between lift and control surfaces. The methods presented in this paper have been confirmed in several international projects. The quality and accuracy of the models for wind tunnel testing are conditio sine qua non.
基金supported by Fundamental Research Funds of the Central Universities under Grant no. N120317001 and N100704001Program for New Century Excellent Talents in University (NCET13-0113)+1 种基金Natural Science Foundation of Liaoning Province of China under Grant no. 201202059Program for Liaoning Excellent Talents in University under LR2013011
文摘Along with the rapid development of social networks, social network worms have constituted one of the major internet security problems. The root of worm is the inevitable software vulnerability during the design and implementation process of software. So it is hard to completely avoid worms in the existing software engineering systems. Due to lots of bandwidth consumption, the patch cannot be transmitted simultaneously by the network administrator to all hosts. This paper studies how to prevent the propagation of social network worms through the immunization of key nodes. Unlike existing containment models for worm propagation, a novel immunization strategy is proposed based on network vertex influence. The strategy selects the critical vertices in the whole network. Then the immunization is applied on the selected vertices to achieve the maximal effect of worm containment with minimal cost. Different algorithms are implemented to select vertices. Simulation experiments are presented to analyze and evaluate the performance of different algorithms.
