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Lightning overvoltage often leads to transmission lines trip, which is the weak link of power system. In this paper, 110-kV transmission line model is studied on the basis of the EMTP software. Several simulation models are established for back flashover lightning, induced lightning, shield failure. The transient process of lightning stroke is studied. According to the contrast of simulation results of three kinds of lightning, a set of discriminant basis to distinguish lightning on transmission line is put forward.

In this paper, the anti-bending function of the concrete beam is simulated by using ANSYS software. The simulated quantity include crack loads, yield load, ultimate load, deflection, crack and crush, stress distribution, strain distribution, movement of neutral axis and so on. The simulated model is a actual structure test. As a result, the value of the yield load, the ultimate load, the deflection are consisted with the actual loads .The method may be used on simulation of structure tests, or used in teaching of some colleges.

Multi-Block OFDM (MB-OFDM) structure has been proposed recently for fiber-wireless networks. MB-OFDM transmission scheme can simultaneously solve some problems of conventional OFDM, such as high peak-to-average power ratio (PAPR), and severe sensitivity to carrier frequency offset (CFO). However, in the transmission scheme, one guard interval shared by multiple blocks, is not suitable for fast fading channel in vehicular environment. In this paper, we propose a novel MB-OFDM structure and use the frame to transmit data in vehicle-to-vehicle (V2V) communication scenario. From computer simulation, it is confirmed that proposed structure can provide better ICI cancellation performance than conventional OFDM.

A novel OFDM radar processing algorithm using pilot signal is proposed in this paper. Based on the prior knowledge of the pilot signal in OFDM symbol in communication system, the receiver can estimate the transmitter's range, velocity by the processing of the received modulation domain signal. In addition, we test the approach by the OFDM frame signal of the famous IEEE Std 802.11p, the results show it can work robustly and is very suitable for the vehicular application.

Based on the proppant index, a production forecast method for thick oil-bearing formation fracturing was deduced. And combined with NPV methodology, treatment scale of multistage pump-off propped fracturing can be optimized. The effects of treatment parameters, such as injection stages, pumping interval, pumping rate, the ratio of pre and post stage pumping rate, on the fracture geometry, conductivity and production were simulated and analyzed. It reveals that two injection stages, 5 minutes of pumping interval and consistent pumping rate contribute to the highest annual cumulative production. Moreover, the injection stages make the most significant influence on production. Optimization results, applied to Kunbei Oilfield, achieved satisfactory application effects. The single well average production was enhanced by7.92 t/d, the stimulation ratio was 13.56, and the stimulation validity was about 270 days.

Sampled-data interpolation algorithm is the core technology in CNC system. The principle of an arc interpolation is described, and the flowchart of an arc sampled-data interpolation algorithm is presented. The coordinate of arc-center is a key question that the formulas are inferred and to be ascertained in development of software. Finally, some of major and minor arc, the clockwise and counterclockwise arc of quadrants, development of these sampled-data interpolation algorithm software is displayed in CNC virtual simulation system based on the visual C++.

In this article, graphite oxide was prepared via Hummers method, then reduced by L-ascorbic acid to obtain colloidal suspension of graphene. The resultant graphene was characterized by FT-IR, UV-vis, Raman, XRD, AFM, TEM in detail, and it was found that the the sp2 domain of graphene oxide is restored efficiently, the suspension is very stable and most of the graphene is single-layer. Compared to hydrazine hydrate, L-ascorbic acid has higher deoxygenation efficiency and inclines to gain few-layer graphene and its stable suspensions.

To solve the problem that hydropower stations equipped with propeller turbine are not able to work under small flow conditions in dry seasons, after analyzing the influencing factors, a rebuilding scheme for decreasing capacity to increase efficiency is proposed. The distribution of velocity circulation at the inlet and the outlet is researched in this paper. Some key technologies in computer-aided hydraulic design, including unfolded aerofoil converted to cylindrical surface and intelligent extension for curves, are solved. The proposed version is feasible and the composed CAD software is reliable and accurate.

Polycrystalline Ca3-xMgxCo4O9(x=0-0.3)ceramics were prepared by the sol–gel method combined with the ordinary pressing sintering and the thermoelectric properties were measured from room temperature to 673 K. The substitution of Mg2+for Ca2+had a greater impact on the thermoelectric properties of Ca3Co4O9. The electrical conductivity and the thermal conductivity reduced significantly with increasing Mg content, and the Seebeck coefficient increased simultaneously. The influence of Mg doping on the thermal conductivity is mainly embodied in the lattice thermal conductivity of Ca3Co4O9. The lattice thermal conductivity showed a significant change with the increase of the dopant content, while the carrier thermal conductivity had no obvious change with the doping increasing. These results indicated that the thermoelectric properties of the material could be optimized remarkably with the substitution of Mg. The figure of meritZreached 1.08×10-4K-1at 573 K for the sample of Ca2.8Mg0.2Co4O9.

Polycrystalline Ca3-xMgxCo4O9（x=0-0.3）ceramics were prepared by the sol–gel method combined with the ordinary pressing sintering and the thermal conductivities were measured from room temperature to 673 K. The influence of Mg2+ substitution for Ca2+ on the thermal conductivities of Ca3Co4O9 ceramics was investigated systematically. The influence of Mg doping on the thermal conductivities is mainly embodied in the lattice thermal conductivities, which shows a significant decrease with the increase of the dopant content for the samples with x ≤ 0.2, while the carrier thermal conductivity had no obvious change with Mg doping increasing. These results indicated that the thermal conductivities of the material could be reduced remarkably with the substitution of Mg from 1.427 W/m·K to 0.731 W/m·K at 573 K with x = 0.2.