The effects of hydrogen atoms on behaviour of low cycle fatigue of 2.25Cr-1Mo steel have been investigated in present work. The results indicate that the cyclic softening rate and low cycle fatigue life are respective...The effects of hydrogen atoms on behaviour of low cycle fatigue of 2.25Cr-1Mo steel have been investigated in present work. The results indicate that the cyclic softening rate and low cycle fatigue life are respectively increased and reduced remarkably by hydrogen atoms. In addition, hydrogen atoms make the original stress amplitude of low cycle fatigue increase, which is because of the drag effect of hydrogen atoms on the moving dislocations. Analyses using electron microscopy show that hydrogen atoms accelerate crack initiation of low cycle fatigue from inclusion and transfer the source of low cycle fatigue crack from the surface of specimen to the inclusion, which results in the marked decrease of low cycle fatigue life. The increase of cyclic softening rate for hydrogen charged specimen is due to hydrogen atoms accelerating the initiating and growing of microvoids from the secondary phase particles in the steel. The reducing of the drag effect of hydrogen atoms on moving dislocations is also helpful to the increase of the cyclic softening rate.展开更多
To study the effects of 17β-estradiol(E2) on the growth of cultured rat vascular smooth muscle cells (VSMC).Methods The cell cycle and the expressions of Cyclin D1 and CDK4 proteins were examined by flow cytometry in...To study the effects of 17β-estradiol(E2) on the growth of cultured rat vascular smooth muscle cells (VSMC).Methods The cell cycle and the expressions of Cyclin D1 and CDK4 proteins were examined by flow cytometry in VSMC cultured in different concentrations (0～100 nmol/L) of 17β-estradiol with or without serum.Results Under serum-stimulating conditions,17β-estradiol(1,10,100 nmol/L) promoted VSMC proliferation by accelerating their cell cycle progression from G1 to S phases,and the cell rates at S were (31.89±9.14)%(35.90±4.59)% and (30.77±1.20)% respectively,significantly higher than the corresponding values of control cells (21.63±1.80)%.This was accompanied by the significantly increased expression of Cyclin D1 and CDK4 proteins.In the cultures without serum,however,high concentrations (10,100 nmol/L) of E2 induced a cell cycle arrest at G1 phase,which was characterizsed by decreased cell rates at S phase [(9.93±1.43)% and (8.76±1.80)% respectively,P<0.05] as compared with the corresponding control values and a down-regulation of expressions of Cyclin D1 and CDK4 proteins.Conclusion E2 can either promote or inhibit VSMC proliferation depending upon the presence or absence of serum mitogens.The underlying mechanism may be associated with the hormone’s action on the expression of Cyclin D1 and CDK4 which act as the G1 phase regulators.4 refs.展开更多
Ecosystem changes can simultaneously generate various climate-related effects,such as evapotranspiration(vapor flux)effects,carbon-cycle effects,and surface temperature effects.These effects are coupled with one anoth...Ecosystem changes can simultaneously generate various climate-related effects,such as evapotranspiration(vapor flux)effects,carbon-cycle effects,and surface temperature effects.These effects are coupled with one another because they are generated through the same biophysical and biogeochemical processes.Consequently,given an easily measurable effect,other effects can be predicted from the measured effect.Here,based on global eddy covariance(EC)observations,we show that the ratio of the daytime to daily vapor flux(RATIO)reflects the complexity of various ecosystem types and is highly coupled with climate effects of ecosystem changes.For the same daily RATIO,the magnitudes of the same EC variable remain unchanged across all of the ecosystems and,thus,EC observations for an ecosystem or place can be mapped to other ecosystems or places in accordance with their daily RATIO values.By applying the daily RATIO,the effects of ecosystem changes on the surface temperature in different climatic zones(including the Tibetan Plateau)can be predicted,which is highly consistent with all previous studies.We found that cooling or warming effects are controlled by the RATIO,not by enhanced or reduced evapotranspiration as many studies have suggested.This study provides a new and simple approach for evaluating the climate effects of ecosystem changes at all spatial-temporal scales worldwide.展开更多
The effect of thermal cycling under loading on martensitic transformation and two-way shape memory effect was investigated for Ti-49.8 at, pet Ni alloy. It is shown that M(s), and M(f) temperature increase with increa...The effect of thermal cycling under loading on martensitic transformation and two-way shape memory effect was investigated for Ti-49.8 at, pet Ni alloy. It is shown that M(s), and M(f) temperature increase with increasing the number of cycles, while A(s) and A(f) temperature decrease during thermal cycling. The total strain at and permanent strain epsilon (p) increase with increasing applied stress and number of cycles. The two-way shape memory effect can be improved by proper thermal cycling training under loading, while excessively high applied stress results in the deterioration of TWSME. The reason for the changes in martensitic transformation characteristics and two-way shape memory effect during thermal cycling under loading is discussed based on the analysis of microstructure by TEM observations.展开更多
Objective:To study thei nhibitory effect of purified trichosanthin component on the proliferation of malignant melanoma.Methods:The effect of purified trichosanthin componenton the DNA synthesis,cell cycle and cell ap...Objective:To study thei nhibitory effect of purified trichosanthin component on the proliferation of malignant melanoma.Methods:The effect of purified trichosanthin componenton the DNA synthesis,cell cycle and cell apoptos is of murinemelanomacellsweredetected by flow cytometry when culture dinvitro.Results:The significantG0/G1phasearrest was revealed by the inc rease of cellsinG0/G1 phase and decrease of cell sinS phase.The obviousapoptosis of melanoma cells was in duced bypuri fied trichos anthin component.G0/G1phase arrest was high lycorrelated withapop to sis(r=0.8705).Conclusion:The purified trichos anthin component can markedly inhibit melanoma cells by the suppression of DNA syn the sisin S phaseand cell mitosisas well as induction of cell apoptosis.展开更多
Automatic gain control （AGC） has been used in many applications. The key features of AGC, including a steady state output and static/dynamic timing response, depend mainly on key parameters such as the reference and...Automatic gain control （AGC） has been used in many applications. The key features of AGC, including a steady state output and static/dynamic timing response, depend mainly on key parameters such as the reference and the filter coefficients. A simple model developed to describe AGC systems based on several simple assumptions shows that AGC always converges to the reference and that the timing constant depends on the filter coefficients. Measures are given to prevent oscillations and limit cycle effects. The simple AGC system is adapted to a multiple AGC system for a TV tuner in a much more efficient model. Simulations using the C language are 16 times faster than those with MATLAB, and 10 times faster than those with a mixed register transfer level （RTL）-simulation program with integrated circuit emphasis （SPICE） model.展开更多
文摘The effects of hydrogen atoms on behaviour of low cycle fatigue of 2.25Cr-1Mo steel have been investigated in present work. The results indicate that the cyclic softening rate and low cycle fatigue life are respectively increased and reduced remarkably by hydrogen atoms. In addition, hydrogen atoms make the original stress amplitude of low cycle fatigue increase, which is because of the drag effect of hydrogen atoms on the moving dislocations. Analyses using electron microscopy show that hydrogen atoms accelerate crack initiation of low cycle fatigue from inclusion and transfer the source of low cycle fatigue crack from the surface of specimen to the inclusion, which results in the marked decrease of low cycle fatigue life. The increase of cyclic softening rate for hydrogen charged specimen is due to hydrogen atoms accelerating the initiating and growing of microvoids from the secondary phase particles in the steel. The reducing of the drag effect of hydrogen atoms on moving dislocations is also helpful to the increase of the cyclic softening rate.
文摘To study the effects of 17β-estradiol(E2) on the growth of cultured rat vascular smooth muscle cells (VSMC).Methods The cell cycle and the expressions of Cyclin D1 and CDK4 proteins were examined by flow cytometry in VSMC cultured in different concentrations (0～100 nmol/L) of 17β-estradiol with or without serum.Results Under serum-stimulating conditions,17β-estradiol(1,10,100 nmol/L) promoted VSMC proliferation by accelerating their cell cycle progression from G1 to S phases,and the cell rates at S were (31.89±9.14)%(35.90±4.59)% and (30.77±1.20)% respectively,significantly higher than the corresponding values of control cells (21.63±1.80)%.This was accompanied by the significantly increased expression of Cyclin D1 and CDK4 proteins.In the cultures without serum,however,high concentrations (10,100 nmol/L) of E2 induced a cell cycle arrest at G1 phase,which was characterizsed by decreased cell rates at S phase [(9.93±1.43)% and (8.76±1.80)% respectively,P<0.05] as compared with the corresponding control values and a down-regulation of expressions of Cyclin D1 and CDK4 proteins.Conclusion E2 can either promote or inhibit VSMC proliferation depending upon the presence or absence of serum mitogens.The underlying mechanism may be associated with the hormone’s action on the expression of Cyclin D1 and CDK4 which act as the G1 phase regulators.4 refs.
基金supported by the National Natural Science Foundation of China(nos.42130506 and 42071031)the Special Technology Innovation Fund of Carbon Peak and Carbon Neutrality in Jiangsu Province(no.BK20231515).
文摘Ecosystem changes can simultaneously generate various climate-related effects,such as evapotranspiration(vapor flux)effects,carbon-cycle effects,and surface temperature effects.These effects are coupled with one another because they are generated through the same biophysical and biogeochemical processes.Consequently,given an easily measurable effect,other effects can be predicted from the measured effect.Here,based on global eddy covariance(EC)observations,we show that the ratio of the daytime to daily vapor flux(RATIO)reflects the complexity of various ecosystem types and is highly coupled with climate effects of ecosystem changes.For the same daily RATIO,the magnitudes of the same EC variable remain unchanged across all of the ecosystems and,thus,EC observations for an ecosystem or place can be mapped to other ecosystems or places in accordance with their daily RATIO values.By applying the daily RATIO,the effects of ecosystem changes on the surface temperature in different climatic zones(including the Tibetan Plateau)can be predicted,which is highly consistent with all previous studies.We found that cooling or warming effects are controlled by the RATIO,not by enhanced or reduced evapotranspiration as many studies have suggested.This study provides a new and simple approach for evaluating the climate effects of ecosystem changes at all spatial-temporal scales worldwide.
文摘The effect of thermal cycling under loading on martensitic transformation and two-way shape memory effect was investigated for Ti-49.8 at, pet Ni alloy. It is shown that M(s), and M(f) temperature increase with increasing the number of cycles, while A(s) and A(f) temperature decrease during thermal cycling. The total strain at and permanent strain epsilon (p) increase with increasing applied stress and number of cycles. The two-way shape memory effect can be improved by proper thermal cycling training under loading, while excessively high applied stress results in the deterioration of TWSME. The reason for the changes in martensitic transformation characteristics and two-way shape memory effect during thermal cycling under loading is discussed based on the analysis of microstructure by TEM observations.
文摘Objective:To study thei nhibitory effect of purified trichosanthin component on the proliferation of malignant melanoma.Methods:The effect of purified trichosanthin componenton the DNA synthesis,cell cycle and cell apoptos is of murinemelanomacellsweredetected by flow cytometry when culture dinvitro.Results:The significantG0/G1phasearrest was revealed by the inc rease of cellsinG0/G1 phase and decrease of cell sinS phase.The obviousapoptosis of melanoma cells was in duced bypuri fied trichos anthin component.G0/G1phase arrest was high lycorrelated withapop to sis(r=0.8705).Conclusion:The purified trichos anthin component can markedly inhibit melanoma cells by the suppression of DNA syn the sisin S phaseand cell mitosisas well as induction of cell apoptosis.
基金Supported by the National Natural Science Foundation of China (No. 60572087)
文摘Automatic gain control （AGC） has been used in many applications. The key features of AGC, including a steady state output and static/dynamic timing response, depend mainly on key parameters such as the reference and the filter coefficients. A simple model developed to describe AGC systems based on several simple assumptions shows that AGC always converges to the reference and that the timing constant depends on the filter coefficients. Measures are given to prevent oscillations and limit cycle effects. The simple AGC system is adapted to a multiple AGC system for a TV tuner in a much more efficient model. Simulations using the C language are 16 times faster than those with MATLAB, and 10 times faster than those with a mixed register transfer level （RTL）-simulation program with integrated circuit emphasis （SPICE） model.
