This paper deals with the influence of water content on the mechanical properties of gypsum breccia with different initial water contents. The experimental research was taken on the GDS (geotechnical digital systems) ...This paper deals with the influence of water content on the mechanical properties of gypsum breccia with different initial water contents. The experimental research was taken on the GDS (geotechnical digital systems) tri-axial experiment system by strain rate control. The mechanical properties,including stress-strain curves,peak deviator stress,relative residual strength,elastic modulus,Poisson's ratio,angle of internal friction and cohesion of gypsum breccia,were studied by experiment. The results showed that the water content has obvious infiuence on the mechanical properties of gypsum breccia. With increasing of water content,the angle of internal friction and cohesion of gypsum breccia decrease linearly. Meanwhile,the stress-strain curves go through from the declining,hump curve to the strain hardening curve. At the same confining pressure,the peak deviator stress and elastic modulus decrease exponentially,while Poisson's ratio increases linearly with the increasing of the water content. At the same water content,with increasing of the confining pressure,the peak deviator stress,elastic modulus and the peak deviator stress increase trend but Poisson's ratio decreases at a lower water content. While at a high water contents,the Poisson's ratio doesn't change much. It shows that water content plays an important role in the process of changing from the brittleness to plastic for the mechanical properties of gypsum breccia.展开更多
The effects of A L tonic capsule on DNA content in rat experimental hepatocarcinogenesis induced by diethylnitrosamine (DENA) were observed. The experimental rats were divided into 4 groups. With exception of group D...The effects of A L tonic capsule on DNA content in rat experimental hepatocarcinogenesis induced by diethylnitrosamine (DENA) were observed. The experimental rats were divided into 4 groups. With exception of group D in which the rats were only administered with DENA, the rats in the groups A, B, C were previously, simultaneously and subsequently fed with A L tonic capsule respectively while they were administered with DENA. The DNA content of all rat livers was measured using automatic image analysis technique 20 weeks after administration of DENA. The results showed that the highest and lowest DNA contents were respectively seen in the groups D and A. There was significant difference in DNA contents between the groups A or B or C and D, and also between the groups A and B or C (both P <0.01). 4 components (4C) and ≥5C cells were predominant in the group D, while 2C cells were the minority. The number of 2C cells in the groups A, B, C was significantly higher than that in the group D, and the number of ≥5C cells in the groups A, B, C was markedly lower than that in the group D ( P <0.01). Also, there was very significant difference in the number of 2C and ≥5C cells between group A and B or C ( P <0.01). It was concluded that A L tonic capsule could effectively inhibit the increase of DNA content of hepatocytes and improve the distribution of DNA content in rat hepatocarcinogenesis, especially in group A.展开更多
This paper first concludes the relevant definitions of experimental teaching of college English,which can deepen the understanding of the scientific positioning,connotation and importance of experimental teaching of c...This paper first concludes the relevant definitions of experimental teaching of college English,which can deepen the understanding of the scientific positioning,connotation and importance of experimental teaching of college English,and then explores the relevant strategies for the construction of experimental teaching system of college English in various China’s colleges.This paper provides a reference for the development of experimental teaching of college English.展开更多
Food losses in the developing country are thought to be 50% of the fruits and vegetables grown and 25% of harvested food grain. Food preservation can reduce wastage of a harvest surplus, allow storage for food shortag...Food losses in the developing country are thought to be 50% of the fruits and vegetables grown and 25% of harvested food grain. Food preservation can reduce wastage of a harvest surplus, allow storage for food shortages, and in some cases facilitate export to high-value markets. Drying is one of the oldest methods of food preservation. Drying makes produce lighter, smaller, and less likely to spoil and helps to minimize the moisture content in coffee beans as high moisture content during storage is certain to ruin the taste and appearance of coffee. This work presents the results of an experimental study of forced convection drying of coffee cherries in a modified Icaro solar dryer. The study aims to validate the numerical models developed for further research. The experimental tests envisaged also aim to determine the mass loss curves of the product by fixing or calculating its initial mass (1 kg), its initial water content (70%), the ambient temperature, the drying airflow (0.02 m<sup>3.</sup>s<sup>-1</sup> to 0.09 m<sup>3.</sup>s<sup>-1</sup>) and the exchange coefficients. The influence of these aerothermal parameters on the drying time of a most commercialized coffee variety (Robusta) was studied. Finally, the results revealed an increase in the efficiency of the heat transfer air and a reduction in the water content of the coffee cherry from 70% to 9.87%, after 30.2 hours.展开更多
Actually recent investigation in developing semiconducting-superconducting composites based in CdS and Bi-based superconductors has attracted interest in processing thin superconducting films. In this work are reporte...Actually recent investigation in developing semiconducting-superconducting composites based in CdS and Bi-based superconductors has attracted interest in processing thin superconducting films. In this work are reported Bi-Pb-Sr-Ca-Cu-O (BPSCCO) thin films grown on MgO substrates by spray pyrolysis technique from a solution containing Bi(NO3)3, Pb(NO3)2, Sr(NO3)2, Ca(NO3)2 and Cu(NO3)2, with a subsequent solid state reaction for growing the Bi-based superconducting phases. Annealed films were characterized by X-ray diffraction, atomic absorption spectroscopy and resistance measurements. Interdependence between Pb content, annealing time and temperature, in the formation of superconducting phases was studied applying a fractional factorial design 3III4-2. Interrelation between Pb content, ta and Ta exists. The presence of Pb is necessary to stabilize the high-Tc phase but its content depends on the annealing conditions.展开更多
文摘This paper deals with the influence of water content on the mechanical properties of gypsum breccia with different initial water contents. The experimental research was taken on the GDS (geotechnical digital systems) tri-axial experiment system by strain rate control. The mechanical properties,including stress-strain curves,peak deviator stress,relative residual strength,elastic modulus,Poisson's ratio,angle of internal friction and cohesion of gypsum breccia,were studied by experiment. The results showed that the water content has obvious infiuence on the mechanical properties of gypsum breccia. With increasing of water content,the angle of internal friction and cohesion of gypsum breccia decrease linearly. Meanwhile,the stress-strain curves go through from the declining,hump curve to the strain hardening curve. At the same confining pressure,the peak deviator stress and elastic modulus decrease exponentially,while Poisson's ratio increases linearly with the increasing of the water content. At the same water content,with increasing of the confining pressure,the peak deviator stress,elastic modulus and the peak deviator stress increase trend but Poisson's ratio decreases at a lower water content. While at a high water contents,the Poisson's ratio doesn't change much. It shows that water content plays an important role in the process of changing from the brittleness to plastic for the mechanical properties of gypsum breccia.
文摘The effects of A L tonic capsule on DNA content in rat experimental hepatocarcinogenesis induced by diethylnitrosamine (DENA) were observed. The experimental rats were divided into 4 groups. With exception of group D in which the rats were only administered with DENA, the rats in the groups A, B, C were previously, simultaneously and subsequently fed with A L tonic capsule respectively while they were administered with DENA. The DNA content of all rat livers was measured using automatic image analysis technique 20 weeks after administration of DENA. The results showed that the highest and lowest DNA contents were respectively seen in the groups D and A. There was significant difference in DNA contents between the groups A or B or C and D, and also between the groups A and B or C (both P <0.01). 4 components (4C) and ≥5C cells were predominant in the group D, while 2C cells were the minority. The number of 2C cells in the groups A, B, C was significantly higher than that in the group D, and the number of ≥5C cells in the groups A, B, C was markedly lower than that in the group D ( P <0.01). Also, there was very significant difference in the number of 2C and ≥5C cells between group A and B or C ( P <0.01). It was concluded that A L tonic capsule could effectively inhibit the increase of DNA content of hepatocytes and improve the distribution of DNA content in rat hepatocarcinogenesis, especially in group A.
文摘This paper first concludes the relevant definitions of experimental teaching of college English,which can deepen the understanding of the scientific positioning,connotation and importance of experimental teaching of college English,and then explores the relevant strategies for the construction of experimental teaching system of college English in various China’s colleges.This paper provides a reference for the development of experimental teaching of college English.
文摘Food losses in the developing country are thought to be 50% of the fruits and vegetables grown and 25% of harvested food grain. Food preservation can reduce wastage of a harvest surplus, allow storage for food shortages, and in some cases facilitate export to high-value markets. Drying is one of the oldest methods of food preservation. Drying makes produce lighter, smaller, and less likely to spoil and helps to minimize the moisture content in coffee beans as high moisture content during storage is certain to ruin the taste and appearance of coffee. This work presents the results of an experimental study of forced convection drying of coffee cherries in a modified Icaro solar dryer. The study aims to validate the numerical models developed for further research. The experimental tests envisaged also aim to determine the mass loss curves of the product by fixing or calculating its initial mass (1 kg), its initial water content (70%), the ambient temperature, the drying airflow (0.02 m<sup>3.</sup>s<sup>-1</sup> to 0.09 m<sup>3.</sup>s<sup>-1</sup>) and the exchange coefficients. The influence of these aerothermal parameters on the drying time of a most commercialized coffee variety (Robusta) was studied. Finally, the results revealed an increase in the efficiency of the heat transfer air and a reduction in the water content of the coffee cherry from 70% to 9.87%, after 30.2 hours.
文摘Actually recent investigation in developing semiconducting-superconducting composites based in CdS and Bi-based superconductors has attracted interest in processing thin superconducting films. In this work are reported Bi-Pb-Sr-Ca-Cu-O (BPSCCO) thin films grown on MgO substrates by spray pyrolysis technique from a solution containing Bi(NO3)3, Pb(NO3)2, Sr(NO3)2, Ca(NO3)2 and Cu(NO3)2, with a subsequent solid state reaction for growing the Bi-based superconducting phases. Annealed films were characterized by X-ray diffraction, atomic absorption spectroscopy and resistance measurements. Interdependence between Pb content, annealing time and temperature, in the formation of superconducting phases was studied applying a fractional factorial design 3III4-2. Interrelation between Pb content, ta and Ta exists. The presence of Pb is necessary to stabilize the high-Tc phase but its content depends on the annealing conditions.
