The influence of hygrothermal effects on the buckling and postbuckling of composite laminated cylindrical shells subjected to axial compression is investigated using a micro-to-macro-mechanical analytical model. The m...The influence of hygrothermal effects on the buckling and postbuckling of composite laminated cylindrical shells subjected to axial compression is investigated using a micro-to-macro-mechanical analytical model. The material properties of the composite are affected hy the variation of temperature and moisture, and are hosed on a micromechanical model of a laminate. The governing equations are based on the classical laminated shell theory, and including hygrothermal effects. The nonlinear prebuckling deformations and initial geometric imperfections of the shell were both taken into account. A boundary layer theory of shell buckling was extended to the case of laminated cylindrical shells under hygrothermal environments, and a singular peturbation technique was employed to determine buckling loads and postbuckling equilibrium paths. The numerical illustrations concern the postbuckling behavior of perfect and imperfect, cross-ply laminated cylindrical shells under different sets of environmental conditions. The influences played by temperature rise, the degree of moisture concentration, fiber volume fraction, shell geometric parameter, total number of plies, stacking sequences and initial geometric imperfections are studied.展开更多
Vegetative cells of Porphyra yezoensis are isolated with sea snail enzyme and cultured on the solidified agar medium. The results of experiments show that the isolated cells can survive,divide and regenerate well on t...Vegetative cells of Porphyra yezoensis are isolated with sea snail enzyme and cultured on the solidified agar medium. The results of experiments show that the isolated cells can survive,divide and regenerate well on the medium solidified with agar. The first division on the solid medium starts after 7 days' culture, 4 days later than the liquid culture. The survival rate of isolated cells is 71.3% on the solid medium, lower than the 86.2% of that in seawater.Thalli, thalloids,conchocelis, spermatangia and multicellular masses are developed on the solid/medium in the first month, slowly but normally. Spermatangia sacs disappear within 4 weeks. Without adding nutrient liquid onto the surface of solid medium or injecting seawater under the agar layer in order to keep moisture, the thalli and cell groups release monospores to form new thalli instead of enlarging their areas after 5 weeks' culturing. Some monospores regenerate new thalli. Other monospores lose their pigments and minimize their volume and divide quickly to form light pink calli. After 16 weeks, numerous calli can be seen on the solid medium and after 24 weeks' culturing, almost only calli and conchocelis can be seen. If the calli are immersed in seawater, the monospores are released and may develop into young thallus.展开更多
A new steroid named as Zhonghualiaoine I (1) was isolated from Polygonum nodosum Pers (Chinese name 揨honghualiao? Berberidaceae). Its structure was deduced on the basis of its spectral data.
Objective： To observe the clinical efficacy of Penyanqing Capsule （盆炎清胶囊, PYQC） in treating pelvic inflammation of Qi-stagnation with blood stasis syndrome. Methods： The randomized, single blinded, parallel p...Objective： To observe the clinical efficacy of Penyanqing Capsule （盆炎清胶囊, PYQC） in treating pelvic inflammation of Qi-stagnation with blood stasis syndrome. Methods： The randomized, single blinded, parallel positive drug controlled method was adopted, with 82 patients assigned into two groups by envelop method. The 42 patients in the treated group received PYQC 3 times a day, 4 capsules each time taken orally; the 40 patients in the control group were given orally Fuyankang tablets （妇炎康片, FYKT） 3 times a day, 6 tablets each time. The therapeutic course for both groups was 2 months, and 2 courses of treatment were given successively to observe the comprehensive effect, changes of symptoms and signs before and after treatment. The effects of PYQC on hemorrheological character in part of the patients and on the pathogenetic chlamydia and mycoplasma were also observed. Results： The total effective rate in the treated group was 83.3%, which was insignificantly different from that in the control group （77.5%, P〉0.05）. However, PYQC could significantly lower the hemorrheologic indexes in patients and showed definite influence on the pathogenetic chlamydia and mycoplasma. Conclusion： PYQC has good therapeutic effect in treating chronic pelvic inflammation of Qi-stagnation with blood stasis syndrome, and showed definite effect on chlamydia and mycoplasma.展开更多
A new method for preparing effective inhibition film on copper has been developed. Phenylthiourea (PT) was first absorbed to copper surface to form a monolayer. 1-Dodecanethiol (DT) was then assembled on the surface...A new method for preparing effective inhibition film on copper has been developed. Phenylthiourea (PT) was first absorbed to copper surface to form a monolayer. 1-Dodecanethiol (DT) was then assembled on the surface for modification. Finally, AC voltage was loaded on copper covered the mixed film to improve it further. After these processes, an effective inhibition film was gained because of its high charge transfer resistance and low corrosion current density shown in electrochemical impedance spectra and polarization. The inhibition efficiency was more than 97%.展开更多
The Northern Qilian high-pressure metamorphic belt has experienced multipledeformation-metamorphism, which consists of at least four stages. In 550.8-526 Ma, eclogites wereformed. High temperature and pressure caused ...The Northern Qilian high-pressure metamorphic belt has experienced multipledeformation-metamorphism, which consists of at least four stages. In 550.8-526 Ma, eclogites wereformed. High temperature and pressure caused the escape of a large quantity of gas-liquid fluidsfrom rocks while silicate melt was generated. In the late stage, small amounts of CO_2 and H_2Oinfiltrating along fractures were introduced. In the formation of glaucophane schist (447-362 Ma),devolatilization reactions were dominated during the subduction-uplift stage of the paleoplate. Inthe uplift-exhumation stage (400-380 Ma) the increase of internal space of fractures in the rocksfavoured fluid infiltration and concentration. These fluids participated in hydration reactions inthe retro-metamorphism. The fluids participating in the mineral reactions have the compositions ofCaCl_2-NaCl-H_2O. In subsequent thrusting (<380 Ma), the metamorphic terrain was uplifted to theshallower crust and ductile-shearing deformation took place, which caused mainly dehydrationreactions of minerals. In a near-surface environment the metamorphic terrain experienced brittledeformation, forming many accompanying fractures. Immiscible CO_2 and low-salinity aqueous fluidsoccurred in these secondary microfractures and were trapped and sealed. The thermodynamic conditionsof different deformation-metamorphic stages of the metamorphic terrain were calculated and thecorresponding P-T-t path was deduced, showing that the metamorphic terrain has experienced aclockwise path indicated by T- and P-rising, and T- and P-falling processes. This reveals that thesubduction zone has undergone multiple tectono-dynamic processes, i.e. initial deep burial,subsequent quick uplift and near-surface tectonism.展开更多
In the seismic safety evaluation (SSE) for key projects, the probability-consistent spectrum (PCS), usually obtained from probabilistic seismic hazard analysis (PSHA), is not consistent with the design response spectr...In the seismic safety evaluation (SSE) for key projects, the probability-consistent spectrum (PCS), usually obtained from probabilistic seismic hazard analysis (PSHA), is not consistent with the design response spectrum given by Code for Seismic Design of Buildings (GB50011-2001). Sometimes, there may be a remarkable difference be-tween them. If the PCS is lower than the corresponding code design response spectrum (CDS), the seismic fortifi-cation criterion for the key projects would be lower than that for the general industry and civil buildings. In the paper, the relation between PCS and CDS is discussed by using the ideal simple potential seismic source. The re-sults show that in the most areas influenced mainly by the potential sources of the epicentral earthquakes and the regional earthquakes, PCS is generally lower than CDS in the long periods. We point out that the long-period re-sponse spectra of the code should be further studied and combined with the probability method of seismic zoning as much as possible. Because of the uncertainties in SSE, it should be prudent to use the long-period response spectra given by SSE for key projects when they are lower than CDS.展开更多
Nonlinear modeling of a flexible beam with large deformation was investigated. Absolute nodal cooridnate formulation is employed to describe the motion, and Lagrange equations of motion of a flexible beam are derived ...Nonlinear modeling of a flexible beam with large deformation was investigated. Absolute nodal cooridnate formulation is employed to describe the motion, and Lagrange equations of motion of a flexible beam are derived based on the geometric nonlinear theory. Different from the previous nonlinear formulation with Euler-Bernoulli assumption, the shear strain and transverse normal strain are taken into account. Computational example of a flexible pendulum with a tip mass is given to show the effects of the shear strain and transverse normal strain. The constant total energy verifies the correctness of the present formulation.展开更多
This paper presents an optimal production model for manufacturer in a supply chain with a fixed demand at a fixed interval with respect to the learning effect on production capacity. An algorithm is employed to find t...This paper presents an optimal production model for manufacturer in a supply chain with a fixed demand at a fixed interval with respect to the learning effect on production capacity. An algorithm is employed to find the optimal delay time for production and production time sequentially. It is found that the optimal delay time for production and the production time are not static, but dynamic and variant with time. It is important for a manufacturer to schedule the production so as to prevent facilities and workers from idling.展开更多
The paper deals with active drive system for colonoscope. The system is mainly composed of soft mobile mechanism for earthworm locomotion and turning mechanism based on shape memory effect. The soft mobile mechanism c...The paper deals with active drive system for colonoscope. The system is mainly composed of soft mobile mechanism for earthworm locomotion and turning mechanism based on shape memory effect. The soft mobile mechanism contacts colon wall with air in inflatable balloons, so the robot has better soft and non invasive properties. The turning mechanism can be actively bent by shape memory alloy components. It ensures the colonoscope to adapt to the tortuous shape of colon. Some experiment results are given in the paper.展开更多
On the basis of plasticity and fracture mechanics for quasi-brittle materials, this article presented a constitutive model for gradual softening behavior of joints of geomaterials. Corresponding numerical tests are ca...On the basis of plasticity and fracture mechanics for quasi-brittle materials, this article presented a constitutive model for gradual softening behavior of joints of geomaterials. Corresponding numerical tests are carried out at the local level. Characteristics of the model proposed are 1) plastic softening and dilatancy behavior are directly related to the fracture process of joint, and much less material and model parameters are required compared with those proposed by references; 2) the process of decohesion coupled with frictional sliding at both micro-scale and macro-scale is described.展开更多
A closed-form full-field solution for the problem of a partially debonded conducting rigid elliptical inclusion embedded in a piezoelectric matrix is obtained by employing the eight-dimensional Stroh formula in conjun...A closed-form full-field solution for the problem of a partially debonded conducting rigid elliptical inclusion embedded in a piezoelectric matrix is obtained by employing the eight-dimensional Stroh formula in conjunction with the techniques of conformal mapping, analytical continuation and singularity analysis. Some new identities and stuns for anisotropic piezoelectric media are also derived, through which real-form expressions for the stresses and electric displacements along the interface as well as the rotation of the rigid inclusion con be obtained. As is expected, the stresses and electric displacements at the tips of the debonded part of the interface exhibit the same singular behavior os in the case of a straight Griffith interface crack between dissimilar piezoelectric media. Some numerical examples are presented to validate the correctness of the obtained solution and also to illustrate the generality of the exact solution and the effects of various eletromechanical loading conditions, geometry parameters and material constants on the distribution of stresses and electric displacements along the interface.展开更多
The contained underground explosion (CUE) usually generates huge number of aftershocks. This kind of after-shocks induced by three CUEs was investigated in the paper. The conclusions show that the duration of aftersho...The contained underground explosion (CUE) usually generates huge number of aftershocks. This kind of after-shocks induced by three CUEs was investigated in the paper. The conclusions show that the duration of aftershock waveforms are rather short, 70 percent of them range from 2 to 7; the occurrences of the aftershocks conform to negative power function, which has the power of -1.6. The aftershock sequence attenuates a little bit faster, with power of -1.0, within two weeks of post-explosions. During the early stage of post-explosions the aftershocks show up in a cluster, however, they usually show up individually during the late stage of post-explosions. The number of aftershocks generated by the compatible explosions differs by several times because of different me-dium and geological structure; within one month after an explosion with Richater magnitude of 5.5, the number of aftershocks attenuates to the background. Hereafter there are still tiny numbers of aftershocks.展开更多
This paper discusses the relation between two-step seismic design and the standard of probability of exceedance, and the relation of three-levels seismic ground motion parameters given by probability method and compre...This paper discusses the relation between two-step seismic design and the standard of probability of exceedance, and the relation of three-levels seismic ground motion parameters given by probability method and comprehensive probability method. The relative size relations of the ground motions with 2%, 10%, 63% probability of exceedance in 50 years, namely large earthquake, moderate earthquake, and small earthquake, are discussed through a practical example of seismic hazard analysis. The methods to determine seismic fortification criterion are discussed.展开更多
文摘The influence of hygrothermal effects on the buckling and postbuckling of composite laminated cylindrical shells subjected to axial compression is investigated using a micro-to-macro-mechanical analytical model. The material properties of the composite are affected hy the variation of temperature and moisture, and are hosed on a micromechanical model of a laminate. The governing equations are based on the classical laminated shell theory, and including hygrothermal effects. The nonlinear prebuckling deformations and initial geometric imperfections of the shell were both taken into account. A boundary layer theory of shell buckling was extended to the case of laminated cylindrical shells under hygrothermal environments, and a singular peturbation technique was employed to determine buckling loads and postbuckling equilibrium paths. The numerical illustrations concern the postbuckling behavior of perfect and imperfect, cross-ply laminated cylindrical shells under different sets of environmental conditions. The influences played by temperature rise, the degree of moisture concentration, fiber volume fraction, shell geometric parameter, total number of plies, stacking sequences and initial geometric imperfections are studied.
基金This work was supported by a fund for doctorate candidate scientific research from the Ministry of Education (98042303)doctor start fund of Suzhou University (Q4114928)
文摘Vegetative cells of Porphyra yezoensis are isolated with sea snail enzyme and cultured on the solidified agar medium. The results of experiments show that the isolated cells can survive,divide and regenerate well on the medium solidified with agar. The first division on the solid medium starts after 7 days' culture, 4 days later than the liquid culture. The survival rate of isolated cells is 71.3% on the solid medium, lower than the 86.2% of that in seawater.Thalli, thalloids,conchocelis, spermatangia and multicellular masses are developed on the solid/medium in the first month, slowly but normally. Spermatangia sacs disappear within 4 weeks. Without adding nutrient liquid onto the surface of solid medium or injecting seawater under the agar layer in order to keep moisture, the thalli and cell groups release monospores to form new thalli instead of enlarging their areas after 5 weeks' culturing. Some monospores regenerate new thalli. Other monospores lose their pigments and minimize their volume and divide quickly to form light pink calli. After 16 weeks, numerous calli can be seen on the solid medium and after 24 weeks' culturing, almost only calli and conchocelis can be seen. If the calli are immersed in seawater, the monospores are released and may develop into young thallus.
基金supported by the Northwest Normal University-Bring Forth new Idea Project of Science and Technology P. R. China
文摘A new steroid named as Zhonghualiaoine I (1) was isolated from Polygonum nodosum Pers (Chinese name 揨honghualiao? Berberidaceae). Its structure was deduced on the basis of its spectral data.
基金Supported by the Foundation of Guangdong Provincial Ad-ministration of TCM(No .97206)
文摘Objective： To observe the clinical efficacy of Penyanqing Capsule （盆炎清胶囊, PYQC） in treating pelvic inflammation of Qi-stagnation with blood stasis syndrome. Methods： The randomized, single blinded, parallel positive drug controlled method was adopted, with 82 patients assigned into two groups by envelop method. The 42 patients in the treated group received PYQC 3 times a day, 4 capsules each time taken orally; the 40 patients in the control group were given orally Fuyankang tablets （妇炎康片, FYKT） 3 times a day, 6 tablets each time. The therapeutic course for both groups was 2 months, and 2 courses of treatment were given successively to observe the comprehensive effect, changes of symptoms and signs before and after treatment. The effects of PYQC on hemorrheological character in part of the patients and on the pathogenetic chlamydia and mycoplasma were also observed. Results： The total effective rate in the treated group was 83.3%, which was insignificantly different from that in the control group （77.5%, P〉0.05）. However, PYQC could significantly lower the hemorrheologic indexes in patients and showed definite influence on the pathogenetic chlamydia and mycoplasma. Conclusion： PYQC has good therapeutic effect in treating chronic pelvic inflammation of Qi-stagnation with blood stasis syndrome, and showed definite effect on chlamydia and mycoplasma.
基金Subsidized with the Special Funds for the Major State Basic Research Projects G19990650 and the Chinese National Science Fund (No. 20173033).
文摘A new method for preparing effective inhibition film on copper has been developed. Phenylthiourea (PT) was first absorbed to copper surface to form a monolayer. 1-Dodecanethiol (DT) was then assembled on the surface for modification. Finally, AC voltage was loaded on copper covered the mixed film to improve it further. After these processes, an effective inhibition film was gained because of its high charge transfer resistance and low corrosion current density shown in electrochemical impedance spectra and polarization. The inhibition efficiency was more than 97%.
文摘The Northern Qilian high-pressure metamorphic belt has experienced multipledeformation-metamorphism, which consists of at least four stages. In 550.8-526 Ma, eclogites wereformed. High temperature and pressure caused the escape of a large quantity of gas-liquid fluidsfrom rocks while silicate melt was generated. In the late stage, small amounts of CO_2 and H_2Oinfiltrating along fractures were introduced. In the formation of glaucophane schist (447-362 Ma),devolatilization reactions were dominated during the subduction-uplift stage of the paleoplate. Inthe uplift-exhumation stage (400-380 Ma) the increase of internal space of fractures in the rocksfavoured fluid infiltration and concentration. These fluids participated in hydration reactions inthe retro-metamorphism. The fluids participating in the mineral reactions have the compositions ofCaCl_2-NaCl-H_2O. In subsequent thrusting (<380 Ma), the metamorphic terrain was uplifted to theshallower crust and ductile-shearing deformation took place, which caused mainly dehydrationreactions of minerals. In a near-surface environment the metamorphic terrain experienced brittledeformation, forming many accompanying fractures. Immiscible CO_2 and low-salinity aqueous fluidsoccurred in these secondary microfractures and were trapped and sealed. The thermodynamic conditionsof different deformation-metamorphic stages of the metamorphic terrain were calculated and thecorresponding P-T-t path was deduced, showing that the metamorphic terrain has experienced aclockwise path indicated by T- and P-rising, and T- and P-falling processes. This reveals that thesubduction zone has undergone multiple tectono-dynamic processes, i.e. initial deep burial,subsequent quick uplift and near-surface tectonism.
文摘In the seismic safety evaluation (SSE) for key projects, the probability-consistent spectrum (PCS), usually obtained from probabilistic seismic hazard analysis (PSHA), is not consistent with the design response spectrum given by Code for Seismic Design of Buildings (GB50011-2001). Sometimes, there may be a remarkable difference be-tween them. If the PCS is lower than the corresponding code design response spectrum (CDS), the seismic fortifi-cation criterion for the key projects would be lower than that for the general industry and civil buildings. In the paper, the relation between PCS and CDS is discussed by using the ideal simple potential seismic source. The re-sults show that in the most areas influenced mainly by the potential sources of the epicentral earthquakes and the regional earthquakes, PCS is generally lower than CDS in the long periods. We point out that the long-period re-sponse spectra of the code should be further studied and combined with the probability method of seismic zoning as much as possible. Because of the uncertainties in SSE, it should be prudent to use the long-period response spectra given by SSE for key projects when they are lower than CDS.
基金National Natural Science Foundation ofChina (No.10472066,10372057)
文摘Nonlinear modeling of a flexible beam with large deformation was investigated. Absolute nodal cooridnate formulation is employed to describe the motion, and Lagrange equations of motion of a flexible beam are derived based on the geometric nonlinear theory. Different from the previous nonlinear formulation with Euler-Bernoulli assumption, the shear strain and transverse normal strain are taken into account. Computational example of a flexible pendulum with a tip mass is given to show the effects of the shear strain and transverse normal strain. The constant total energy verifies the correctness of the present formulation.
基金Funded by National Social Sciences Fund for Young Scholar ( No.020JY027)
文摘This paper presents an optimal production model for manufacturer in a supply chain with a fixed demand at a fixed interval with respect to the learning effect on production capacity. An algorithm is employed to find the optimal delay time for production and production time sequentially. It is found that the optimal delay time for production and the production time are not static, but dynamic and variant with time. It is important for a manufacturer to schedule the production so as to prevent facilities and workers from idling.
文摘The paper deals with active drive system for colonoscope. The system is mainly composed of soft mobile mechanism for earthworm locomotion and turning mechanism based on shape memory effect. The soft mobile mechanism contacts colon wall with air in inflatable balloons, so the robot has better soft and non invasive properties. The turning mechanism can be actively bent by shape memory alloy components. It ensures the colonoscope to adapt to the tortuous shape of colon. Some experiment results are given in the paper.
基金Foundation item:the Natural Science Foundation of Liaoning Povince(070091)
文摘On the basis of plasticity and fracture mechanics for quasi-brittle materials, this article presented a constitutive model for gradual softening behavior of joints of geomaterials. Corresponding numerical tests are carried out at the local level. Characteristics of the model proposed are 1) plastic softening and dilatancy behavior are directly related to the fracture process of joint, and much less material and model parameters are required compared with those proposed by references; 2) the process of decohesion coupled with frictional sliding at both micro-scale and macro-scale is described.
文摘A closed-form full-field solution for the problem of a partially debonded conducting rigid elliptical inclusion embedded in a piezoelectric matrix is obtained by employing the eight-dimensional Stroh formula in conjunction with the techniques of conformal mapping, analytical continuation and singularity analysis. Some new identities and stuns for anisotropic piezoelectric media are also derived, through which real-form expressions for the stresses and electric displacements along the interface as well as the rotation of the rigid inclusion con be obtained. As is expected, the stresses and electric displacements at the tips of the debonded part of the interface exhibit the same singular behavior os in the case of a straight Griffith interface crack between dissimilar piezoelectric media. Some numerical examples are presented to validate the correctness of the obtained solution and also to illustrate the generality of the exact solution and the effects of various eletromechanical loading conditions, geometry parameters and material constants on the distribution of stresses and electric displacements along the interface.
文摘The contained underground explosion (CUE) usually generates huge number of aftershocks. This kind of after-shocks induced by three CUEs was investigated in the paper. The conclusions show that the duration of aftershock waveforms are rather short, 70 percent of them range from 2 to 7; the occurrences of the aftershocks conform to negative power function, which has the power of -1.6. The aftershock sequence attenuates a little bit faster, with power of -1.0, within two weeks of post-explosions. During the early stage of post-explosions the aftershocks show up in a cluster, however, they usually show up individually during the late stage of post-explosions. The number of aftershocks generated by the compatible explosions differs by several times because of different me-dium and geological structure; within one month after an explosion with Richater magnitude of 5.5, the number of aftershocks attenuates to the background. Hereafter there are still tiny numbers of aftershocks.
文摘This paper discusses the relation between two-step seismic design and the standard of probability of exceedance, and the relation of three-levels seismic ground motion parameters given by probability method and comprehensive probability method. The relative size relations of the ground motions with 2%, 10%, 63% probability of exceedance in 50 years, namely large earthquake, moderate earthquake, and small earthquake, are discussed through a practical example of seismic hazard analysis. The methods to determine seismic fortification criterion are discussed.
