The nonlinear-optical coefficients of RCOB(R=Gd,Y)crystals are measured.The spatial distribution of deff effective nonlinear-optical coefficient is determined subsequently.Our experiments show that the maximum deff oc...The nonlinear-optical coefficients of RCOB(R=Gd,Y)crystals are measured.The spatial distribution of deff effective nonlinear-optical coefficient is determined subsequently.Our experiments show that the maximum deff occurs at the second quadrant.The second-harmonic-generation efficiency reaches 48%for a 6 mm-long,(113.2°,47.4°)-cut GdCOB,and 41.5%for a 5mm-long,(113°,36.5°)-cut YCOB,respectively.The intracavity frequency doubling of GdCOB is reported for the first time.展开更多
Bulk mechanical alloying （BMA） has been successfully applied to solid-state synthesis of p-type and n-type thermoelectric materials Mg2Si1-xSnx （x = 0, 0.2, 0.4, 0.6, 0.8, 1） from element-powders at the room tempe...Bulk mechanical alloying （BMA） has been successfully applied to solid-state synthesis of p-type and n-type thermoelectric materials Mg2Si1-xSnx （x = 0, 0.2, 0.4, 0.6, 0.8, 1） from element-powders at the room temperature in a relatively short time. The electrical conductivity, the Seebeck coefficient and the thermal conductivity of the Mg2Si1-xSnx are quite sensitive to the x-content. With the x-content rising, the electrical conductivity increases. When x = 0.6, it reaches the lowest and Mg2Si shows an n-type of semi-conducting However, when x = 0.2 and T 〉525 K, the Seebeck coefficient of the samples will change the opposite way. While x≥0.4, the samples present a p-type of semi-conducting. The figure of merit, Z of Mg2Si1-xSnx will be obtained in the range from 300 K to 700 K. When x = 0.6, Z proves to be higher than that of other samples at 300 K≤ T≤650 K.展开更多
The deformation behavior of the dual phase steel （DP1000 steel） was studied by the quasi-static tensile ex-periment and the dynamic tensile experiment. The experiments were carried out at strain rates ranging from 1...The deformation behavior of the dual phase steel （DP1000 steel） was studied by the quasi-static tensile ex-periment and the dynamic tensile experiment. The experiments were carried out at strain rates ranging from 10^-4 to 2 000 s^-1 at room temperature. Then the stress-strain curves of DP1000 steel in the strain rate range of 10^-4-2000 s^-1 were measured. By introducing the strain rate sensitivity factor m, Zerilli Armstrong model was optimized. The con- stitutive equation parameters which formulate the mechanical behavior of DP1000 steel were fitted based on the John-son-Cook （JC） constitutive model and the optimized Zerilli-Armstrong （ZA） constitutive model, respectively. By comparing indicators of ＂accuracy-of-fit＂, Rz terms, for the two models, the optimized Zerilli-Armstrong constitu-tive model can reflect plastic deformation behavior both at the low and high strain rates more accurately. The reasons why the optimized Zerilli-Armstrong constitutive model is more advantageous than the Johnson Cook model were discussed by using the yield strength and ultimate tensile strength （UTS） versus strain rates, and strain hardening rate versus effective plastic strain analytical methods.展开更多
基金Supported by the Key Program of the National Natural Science Foundation of China under Grant No.69890235the Key Program of Science and Technology Research of the Minis try of Education of China under Grant No.99182.
文摘The nonlinear-optical coefficients of RCOB(R=Gd,Y)crystals are measured.The spatial distribution of deff effective nonlinear-optical coefficient is determined subsequently.Our experiments show that the maximum deff occurs at the second quadrant.The second-harmonic-generation efficiency reaches 48%for a 6 mm-long,(113.2°,47.4°)-cut GdCOB,and 41.5%for a 5mm-long,(113°,36.5°)-cut YCOB,respectively.The intracavity frequency doubling of GdCOB is reported for the first time.
基金National Natural Science Foundation of China (50504002)
文摘Bulk mechanical alloying （BMA） has been successfully applied to solid-state synthesis of p-type and n-type thermoelectric materials Mg2Si1-xSnx （x = 0, 0.2, 0.4, 0.6, 0.8, 1） from element-powders at the room temperature in a relatively short time. The electrical conductivity, the Seebeck coefficient and the thermal conductivity of the Mg2Si1-xSnx are quite sensitive to the x-content. With the x-content rising, the electrical conductivity increases. When x = 0.6, it reaches the lowest and Mg2Si shows an n-type of semi-conducting However, when x = 0.2 and T 〉525 K, the Seebeck coefficient of the samples will change the opposite way. While x≥0.4, the samples present a p-type of semi-conducting. The figure of merit, Z of Mg2Si1-xSnx will be obtained in the range from 300 K to 700 K. When x = 0.6, Z proves to be higher than that of other samples at 300 K≤ T≤650 K.
基金Item Sponsored by National High Technology Research and Development Program(863Program)of China(2009AA03Z518)Basic Theory Research Fund of Engineering Research Institute of USTB of China(YJ2010-006)
文摘The deformation behavior of the dual phase steel （DP1000 steel） was studied by the quasi-static tensile ex-periment and the dynamic tensile experiment. The experiments were carried out at strain rates ranging from 10^-4 to 2 000 s^-1 at room temperature. Then the stress-strain curves of DP1000 steel in the strain rate range of 10^-4-2000 s^-1 were measured. By introducing the strain rate sensitivity factor m, Zerilli Armstrong model was optimized. The con- stitutive equation parameters which formulate the mechanical behavior of DP1000 steel were fitted based on the John-son-Cook （JC） constitutive model and the optimized Zerilli-Armstrong （ZA） constitutive model, respectively. By comparing indicators of ＂accuracy-of-fit＂, Rz terms, for the two models, the optimized Zerilli-Armstrong constitu-tive model can reflect plastic deformation behavior both at the low and high strain rates more accurately. The reasons why the optimized Zerilli-Armstrong constitutive model is more advantageous than the Johnson Cook model were discussed by using the yield strength and ultimate tensile strength （UTS） versus strain rates, and strain hardening rate versus effective plastic strain analytical methods.
