The accounting income follows the historical cost principle and the matching principle, which is conducive to the objective reflection of the business management responsibility of the enterprise management authorities. But, due to the historical cost principle inherent defects, especially according to the present value of revenue and expenses by historical cost line, makes the calculation of accounting earnings lack of inner logical unity, and the matching principle is difficult to carry out, so that the book value of assets can not reflect its real value, cost cannot be fully compensated. And the economic benefit is measured in the current value, which reflects the actual value of the asset, which is beneficial to the full compensation of the cost. Network planning technology is a scientific method of planning and management, which is developed with the development of modern science and technology and industrial production. In the 1950s, in order to meet the needs of scientific research and the management of new production organizations, some new methods of planning management were introduced abroad. In 1956, dupont studied the key line method of network planning technology (CPM) and tried it on a chemical engineering project, and achieved good economic results. In 1958 the United States naval weapons when "Polaris" missile plans, applied the plan evaluation method (abbreviated as PERT) project plan arrangement, evaluation, audit and control, was a huge success. In the early 1960 s, the network planning technique, has been in the United States all new construction fully adopt this kind of new method for program management, could be introduced into Japan and Western Europe and other countries. With the rapid development of modern science and technology and the continuous improvement of management level, network planning technology is also developing and improving. At present, it has been widely applied in the fields of industry, defense, construction, transportation and scientific research of the world, and has become a scientific method of modern production management in developed countries. But 3D XPoint is not a strong growth area. A historical experiment. In 1934, the Chrysler corporation of the United States first adopted a streamlined body design. In 1937, German design genius fernand porsche began designing cars resembling the beetle. Not only did the beetle crawl on the ground, but it also flew in the air, and its physical resistance was small. Dr Porsche maximized the merits of the beetle's appearance, making "vw" cars the representative work of streamlined cars at the time. The "golden age" of the beatles was the "golden age" of the car from the 1930s to the late 1940s. After the black Friday rush, consumer spending is being squeezed. V6 motor