OFDM (Orthogonal Frequency Division Multiplexing) is a special kind of multi-carrier digital modulation technique. Each OFDM subcarrier exists orthogonality and great use of spectrum resources. To a certain extent, the problem of shortage of spectrum resources will be eased in the future. OFDM has a good ability to resist inter symbol interference and fight against frequency selective fading, and be able to adapt to the future wireless high-speed data transmission without distortion. Each channel modulation and demodulation with FFT and IFFT is easy to implement and meet the need of the business in the wireless communication system. The paper introduces the basic principle of OFDM technology, describes the advantages of OFDM and the defects needed to be overcome. Moreover, we analyzes the characteristics of 4G technology and discusses the application of OFDM in 4G mobile network.
In this paper, the definition of additive consistent intuitionistic fuzzy complementary judgement matrix (ACIFCJM) was given; The addition and subtraction algorithms of intuitionistic fuzzy value representing the relative importance degree in the matrix were given, then the definition of the scale transition matrix of intuitionistic fuzzy complementary judgement matrix (IFCJM) was given; The additive consistency recursive iterative adjustment algorithm about the IFCJM was given, then priority vectors formula of IFCJM was introduced; At last, the steps of intuitionistic fuzzy analytic hierarchy process (IFAHP) were introduced, then the method was applied in actual examples, and its effectiveness was verified.
With the globalization of economic development, the competition between the enterprises becomes more intense. If you want to have a survival advantage in the fierce competition, you must find ways to achieve high efficiency and low cost strategy. But simply to raise revenue or simply to cut costs can't satisfy the requirement of enterprise survival and development. Therefore, to increase income and reduce cost, the combination of both, become the first background of enterprise development. The concept of supply chain cost management meets the requirement of this strategy. Diversity of the concept of supply chain, and constant adjustment along with the market determines the supply chain cost management is comprehensive and complicated system engineering.
Cathode samples of titanium-based nanodiamond field emission were prepared by electrophoresis dispersed solutions in different formulas. Observe the surface and structure of the coating by using metaloscope, microscopy, scanning electron microscopy (SEM) and X-ray diffraction (XRD); Test the field emission characteristic after annealing; Analyze the relation between the samples’ light photos and the uniformity of coating; Discuss the mechanism of the improved field emission characteristic after annealing. Under the same conditions the surface uniformity of diamond coating prepared by isobutyl alcohol is best,it is the minimum threshold electric field emission, 5.5 V/μm, the current density can reach to 85μA/cm2 at the field of 15V/μm. Field emission characteristic and luminescence could be best after annealing.
A cathode process of nanodiamond field emission display based on diode structure by electrophoretic deposition has been explored. In this process, a certain proportion of nanodiamond electrophoresis liquid has been developed, the nanodiamond field emission cathode has been deposited on the polished metal titanium substrate by electrophoresis. The surface appearance and microstructures of the coating has been observed by scanning electron microscopy and Raman spectroscopy and the field emission properties of the prepared cathode coating has been tested. The experimental results show, the diamond-coated surface which has been deposited on titanium substrate is thin and uniform. Compared with the cathode prepared by the spin coating process, it has more field emission current density and better field emission current uniformity and stability. With a simple, low cost and large-area production and other advantages, it can be widely used in flat panel displays.
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