Higher order stress fields for a mode Ⅰ crack perpendicular to the direction of property variation in a functionally gradient material(FGM), which has an exponential variation of elastic modulus along the gradient di...Higher order stress fields for a mode Ⅰ crack perpendicular to the direction of property variation in a functionally gradient material(FGM), which has an exponential variation of elastic modulus along the gradient direction, were obtained through an asymptotic analysis. The Poisson’s ratio of the FGMs was assumed to be constant throughout the analysis. The first five terms in the asymptotic expansions of crack tip stress fields were derived to bring out the influence of nonhomogeneity on the structure of the stress field explicitly. The analysis reveals that only the higher order terms in the expansion are influenced by the material nonhomogeneity. Moreover, it can be seen from expressions of higher order stress fields that at least three terms must be considered in the case of FGMs in order to explicitly account for the nonhomogeneity effects on the structure of crack tip stress fields.展开更多
The cutting properties of the functionally gradient ceramic cutting tools relate closely to the gradient distribution. A cutting model of the functionally gradient ceramic tool is firstly designed in the present paper...The cutting properties of the functionally gradient ceramic cutting tools relate closely to the gradient distribution. A cutting model of the functionally gradient ceramic tool is firstly designed in the present paper. The optimum of gradient distribution is obtained by way of the FEM analyses.展开更多
Rice varieties Handao 2,Zhongbai 4,Han-jingzi,and Akihikari were treated with gradi-ent magnetic fileld to study the effect of gradi-ent field on rice.The magnetic field was madeup of 12 plots magnetic plates arranged...Rice varieties Handao 2,Zhongbai 4,Han-jingzi,and Akihikari were treated with gradi-ent magnetic fileld to study the effect of gradi-ent field on rice.The magnetic field was madeup of 12 plots magnetic plates arranged in eachother south and north pole.The magneticstrength was 0-40 mT.Each four varieties wasput under the magnetic plate 15 cm away,andwent through the magnetic field with the speedof 20 cm/s.The same varieties without thetreatment were used as CK.Both of the seedswere soaked in water for 48 h in room temper-ature,and then sprouted on the porcelain platewith absorbed water paper.When the展开更多
基金Projects(90305023 59731020) supported by the National Natural Science Foundation of China
文摘Higher order stress fields for a mode Ⅰ crack perpendicular to the direction of property variation in a functionally gradient material(FGM), which has an exponential variation of elastic modulus along the gradient direction, were obtained through an asymptotic analysis. The Poisson’s ratio of the FGMs was assumed to be constant throughout the analysis. The first five terms in the asymptotic expansions of crack tip stress fields were derived to bring out the influence of nonhomogeneity on the structure of the stress field explicitly. The analysis reveals that only the higher order terms in the expansion are influenced by the material nonhomogeneity. Moreover, it can be seen from expressions of higher order stress fields that at least three terms must be considered in the case of FGMs in order to explicitly account for the nonhomogeneity effects on the structure of crack tip stress fields.
基金supported by the National Natural Science Foundation of China(59875091)
文摘The cutting properties of the functionally gradient ceramic cutting tools relate closely to the gradient distribution. A cutting model of the functionally gradient ceramic tool is firstly designed in the present paper. The optimum of gradient distribution is obtained by way of the FEM analyses.
文摘Rice varieties Handao 2,Zhongbai 4,Han-jingzi,and Akihikari were treated with gradi-ent magnetic fileld to study the effect of gradi-ent field on rice.The magnetic field was madeup of 12 plots magnetic plates arranged in eachother south and north pole.The magneticstrength was 0-40 mT.Each four varieties wasput under the magnetic plate 15 cm away,andwent through the magnetic field with the speedof 20 cm/s.The same varieties without thetreatment were used as CK.Both of the seedswere soaked in water for 48 h in room temper-ature,and then sprouted on the porcelain platewith absorbed water paper.When the
