In this paper the plane elasticity problem for a functionally graded strip containing a crack is considered. It is assumed that the reciprocal of the shear modulus is a linear function of the thickness-coordinate, whi...In this paper the plane elasticity problem for a functionally graded strip containing a crack is considered. It is assumed that the reciprocal of the shear modulus is a linear function of the thickness-coordinate, while the Possion＇s ratio keeps constant. By utilizing the Fourier transformation technique and the transfer matrix method, the mixed boundary problem is reduced to a system of singular integral equations that are solved numerically. The influences of the geometric parameters and the graded parameter on the stress intensity factors and the strain energy release rate are investigated. The numerical results show that the graded parameters, the thickness of the strip and the crack size have significant effects on the stress intensity factors and the strain energy release rate.展开更多
Temperature change plays a crucial role in global change sciences. In the past several decades, comprehensive find- ings have been achieved on temperature change in China for the past 100 years. Several time series ha...Temperature change plays a crucial role in global change sciences. In the past several decades, comprehensive find- ings have been achieved on temperature change in China for the past 100 years. Several time series have been created to illustrate the averaged surface air temperature for the country. The correlations of these series range from 0.73 to 0.97. It is also achieved in better data quality, wider spatial data coverage, improved homogeneity of time series, and enhanced reliability of findings. The results show an annual mean temperature increase by 0.78±0.27℃ per 100 years in China for the period 1906-2005. After prolonging the period till 2007, it is found that 2007 is rated as the warmest year in the past 100 years. Although all the series, except one, reflect temperature changes in the eastern part of China before the 1930s, they represent the general temperature change in most parts of the country after the 1930s.展开更多
Objective: To investigate the factors affecting progno- sis of patients with primary hepatocellular carcinoma (PHC) after resection. Methods: From 1976 to 1992, 213 patients with PHC treated with hepatectomy were foll...Objective: To investigate the factors affecting progno- sis of patients with primary hepatocellular carcinoma (PHC) after resection. Methods: From 1976 to 1992, 213 patients with PHC treated with hepatectomy were followed up for more than 5 years. Thirty-one of the patients who had sur- vived for more than 5 years were compared with 56 patients who had survived for less than 5 years. Results: Early detection of tumor, radical resection, number of tumors, capsule formation, operation safe distance, presence of portal tumor embolus, pre- sence of cirrhosis and tumor size were important fac- tors affecting the prognosis of patients with PHC. The proportion of small liver cancer in the patients who had survived for more than 5 years was greatly larger than that in the control group. Conclusions: Early detection of tumor and radical re- section are of value in raising the 5-year survival rate. Much remains to be investigated about the rela- tionship between safe margin distance and prognosis of patients with PHC.展开更多
The design of the active region structures,including the modifications of structures of the quantum barrier(QB)and electron blocking layer(EBL),in the deep ultraviolet(DUV)Al Ga N laser diode(LD)is investigated numeri...The design of the active region structures,including the modifications of structures of the quantum barrier(QB)and electron blocking layer(EBL),in the deep ultraviolet(DUV)Al Ga N laser diode(LD)is investigated numerically with the Crosslight software.The analyses focus on electron and hole injection efficiency,electron leakage,hole diffusion,and radiative recombination rate.Compared with the reference QB structure,the step-like QB structure provides high radiative recombination and maximum output power.Subsequently,a comparative study is conducted on the performance characteristics with four different EBLs.For the EBL with different Al mole fraction layers,the higher Al-content Al Ga N EBL layer is located closely to the active region,leading the electron current leakage to lower,the carrier injection efficiency to increase,and the radiative recombination rate to improve.展开更多
基金Project supported by the National Natural Science Foundation of China (No. 10432030 and No. 10125209).
文摘In this paper the plane elasticity problem for a functionally graded strip containing a crack is considered. It is assumed that the reciprocal of the shear modulus is a linear function of the thickness-coordinate, while the Possion＇s ratio keeps constant. By utilizing the Fourier transformation technique and the transfer matrix method, the mixed boundary problem is reduced to a system of singular integral equations that are solved numerically. The influences of the geometric parameters and the graded parameter on the stress intensity factors and the strain energy release rate are investigated. The numerical results show that the graded parameters, the thickness of the strip and the crack size have significant effects on the stress intensity factors and the strain energy release rate.
基金supported by the National Science & Technology Pillar Program during the Eleventh Five-Year Plan Period of China(2007BAC03A01)the Climatic Change Project of China Meteorological Administration(CCCSF2008-10)
文摘Temperature change plays a crucial role in global change sciences. In the past several decades, comprehensive find- ings have been achieved on temperature change in China for the past 100 years. Several time series have been created to illustrate the averaged surface air temperature for the country. The correlations of these series range from 0.73 to 0.97. It is also achieved in better data quality, wider spatial data coverage, improved homogeneity of time series, and enhanced reliability of findings. The results show an annual mean temperature increase by 0.78±0.27℃ per 100 years in China for the period 1906-2005. After prolonging the period till 2007, it is found that 2007 is rated as the warmest year in the past 100 years. Although all the series, except one, reflect temperature changes in the eastern part of China before the 1930s, they represent the general temperature change in most parts of the country after the 1930s.
文摘Objective: To investigate the factors affecting progno- sis of patients with primary hepatocellular carcinoma (PHC) after resection. Methods: From 1976 to 1992, 213 patients with PHC treated with hepatectomy were followed up for more than 5 years. Thirty-one of the patients who had sur- vived for more than 5 years were compared with 56 patients who had survived for less than 5 years. Results: Early detection of tumor, radical resection, number of tumors, capsule formation, operation safe distance, presence of portal tumor embolus, pre- sence of cirrhosis and tumor size were important fac- tors affecting the prognosis of patients with PHC. The proportion of small liver cancer in the patients who had survived for more than 5 years was greatly larger than that in the control group. Conclusions: Early detection of tumor and radical re- section are of value in raising the 5-year survival rate. Much remains to be investigated about the rela- tionship between safe margin distance and prognosis of patients with PHC.
基金Project supported by the Special Project for Inter-government Collaboration of State Key Research and Development Program,China(Grant No.2016YFE0118400)the Key Project of Science and Technology of Henan Province,China(Grant No.172102410062)the National Natural Science Foundation of China and Henan Provincial Joint Fund Key Project(Grant No.U1604263)
文摘The design of the active region structures,including the modifications of structures of the quantum barrier(QB)and electron blocking layer(EBL),in the deep ultraviolet(DUV)Al Ga N laser diode(LD)is investigated numerically with the Crosslight software.The analyses focus on electron and hole injection efficiency,electron leakage,hole diffusion,and radiative recombination rate.Compared with the reference QB structure,the step-like QB structure provides high radiative recombination and maximum output power.Subsequently,a comparative study is conducted on the performance characteristics with four different EBLs.For the EBL with different Al mole fraction layers,the higher Al-content Al Ga N EBL layer is located closely to the active region,leading the electron current leakage to lower,the carrier injection efficiency to increase,and the radiative recombination rate to improve.
