The integrated structure parts are widely used in aircraft. The distortion caused by residual stresses in thick pre-stretched aluminum plates during machining integrated parts is a common and serious problem. To predi...The integrated structure parts are widely used in aircraft. The distortion caused by residual stresses in thick pre-stretched aluminum plates during machining integrated parts is a common and serious problem. To predict and control the machining distortion, the residual stress distribution in the thick plate must be measured firstly. The modified removal method for measuring residual stress in thick pre-stretched aluminum plates is proposed and the stress-strain relation matrix is deduced by elasticity theory. The residual stress distribution in specimen of 7050T7451 plate is measured by using the method, and measurement results are analyzed and compared with data obtained by other methods. The method is effective to measure the residual stress.展开更多
The large shift of surplus labor from agriculture to industry and services is seen in many countries around the world as well as in Vietnam in the process of industrialization and modernization of the country that has...The large shift of surplus labor from agriculture to industry and services is seen in many countries around the world as well as in Vietnam in the process of industrialization and modernization of the country that has set questions about the sustainability of rural surplus labor： is there still a source of surplus labor in rural areas？ If so, how large is the source of surplus labor and how long it can be lasting？ These questions were hotly debated in the literature abroad. But in Vietnam there is very little or hardly exchanged opinions about the concepts and methods of measurement of surplus labor in general and surplus labor in agriculture in particular. This article refers to the measurement approach of surplus labor in agriculture in Vietnam.展开更多
文摘The integrated structure parts are widely used in aircraft. The distortion caused by residual stresses in thick pre-stretched aluminum plates during machining integrated parts is a common and serious problem. To predict and control the machining distortion, the residual stress distribution in the thick plate must be measured firstly. The modified removal method for measuring residual stress in thick pre-stretched aluminum plates is proposed and the stress-strain relation matrix is deduced by elasticity theory. The residual stress distribution in specimen of 7050T7451 plate is measured by using the method, and measurement results are analyzed and compared with data obtained by other methods. The method is effective to measure the residual stress.
文摘The large shift of surplus labor from agriculture to industry and services is seen in many countries around the world as well as in Vietnam in the process of industrialization and modernization of the country that has set questions about the sustainability of rural surplus labor： is there still a source of surplus labor in rural areas？ If so, how large is the source of surplus labor and how long it can be lasting？ These questions were hotly debated in the literature abroad. But in Vietnam there is very little or hardly exchanged opinions about the concepts and methods of measurement of surplus labor in general and surplus labor in agriculture in particular. This article refers to the measurement approach of surplus labor in agriculture in Vietnam.
