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Gravitational mass wasting on steep slopes plays an important role in permanent gully development. This is typically driven by hydrological processes in the head cut and the hydromechanical response within the soil mass. In this study, erosion intensities were observed in the head cuts of two permanent gullies in the mollisol region of Northeast China during the rainy and snow melting seasons. To understand the physical process, soil water storage and drainage capacity, and suction stress during the 111 d of the rainy season and 97 d of the snow melting season, critical parameters such as soil moisture, temperature, and precipitation were investigated. This analysis also examined the increase in pore water pressure, dissipation properties, and hydromechanical properties of the mollisols. Under the same confining stress, the mollisols in the interrupted head cut of Gully No. II increased more rapidly and dissipated pore water pressure more than at the uninterrupted head cut of Gully No I. The combination of the soil water characteristic curve and the hydraulic conductivity function indicates that the mollisols of Gully No. II had a higher air entry pressure and saturated hydraulic conductivity during the wetting and drying cycles than Gully No. I. The head cut area of Gully No. II exhibited rapid water infiltration and drainage responses during rain events, with a high soil water storage capacity during torrential rain, rainstorms, and snow melting seasons. The absolute suction stresses within the mollisols of Gully No. II was lower than that in Gully No. I, which could lead to high erosion per unit of steep slope area. Soil loss from gravitational mass wasting on steep slopes is closely related to soil suction stress and we observed a correlation between erosion per unit gully bed area and the soil water storage. These findings have deepened our understanding of the physical process of permanent gully development from the perspective of the hydrological and hydromechanical behavior of gully head cuts. [ABSTRACT FROM AUTHOR]

Background and objective: Developing harmonious doctor-patient relationships is a powerful way to promote the construction of a new pattern of medical reform in developing countries. We aim to analyze the effects of China's hierarchical medical system on doctor-patient relationships, thus contributing to China's medical and health system reform. Methods: With panel data on prefectural-level cities in China from 2012 to 2019, we used a time-varying difference-in-differences model to evaluate the effect of hierarchical medical treatment policy. Results: Hierarchical medical treatment policies can significantly improve doctor-patient relationships, and this conclusion is supported by various robustness tests. And improving doctor-patient relationships can be indirectly realized by the optimization of resource allocation and saving of medical costs. In addition, the marginal effect of the pilot policy on doctor-patient relationships decreased with age within the city population. In focal cities and cities with high levels of fiscal spending on health care, the effect of the pilot policy on doctor-patient relationships was stronger. Conclusion: While reinforcing the literature on the doctor-patient relationship, this study also provides a reference for further exploration of the pilot policy of hierarchical medical treatment and the development of new medical and health system reform in developing countries. [ABSTRACT FROM AUTHOR]

In 2019, triggered lightning was used to directly strike phase C of a 1.5 km, 10 kV double‐circuit distribution line in Guangzhou, China, with 2 flashes (13 return strokes) recorded. This paper presents the characteristics of induced voltage at the closest pole on the parallel line. The induced voltage is bipolar, which can be divided into 3 stages: negative increase stage, fast and positive transition stage and slowly returning to zero stage. The positive peak value of phase A voltage ranges from 111.4 to 228.9 kV and that of phase C voltage is from 90.1 to 200.9 kV, corresponding to lightning current from −8.9 to −29.9 kA. The positive peak value of the induced voltage is approximately 3 to 10 times the negative peak value. The negative peak, positive peak and positive 10%–10% duration time of induced voltage show a good linear relationship with the peak value of the return stroke current. There was no flashover occurred during the whole process. The result in this paper can provide data support for numerical simulation and line protection analysis. [ABSTRACT FROM AUTHOR]

This paper reports the waveform characteristics and parameters of the overvoltage at the terminal of a 1.5 km 10 kV distribution line by direct triggered lightning. The three-phase overvoltage exhibited three kinds of waveforms, all including the initial rising process of the negative peak, the transition from negative peak to the positive peak or the residual voltage, and the subsequent oscillation process. It is observed that the negative peak value of the three-phase overvoltage is between −8.2 kV and −96.1 kV and the rise time of negative peak is between 3.2 μs and 31.7 μs, while the corresponding peak value of the return stroke current is between 3.3 kA and 32.9 kA. When the return stroke current is relatively small, the negative peak value of the direct struck phase overvoltage is twice or more than that of the indirect struck phase. When it is larger, the negative peak value of the indirect struck phase overvoltage is much closer to that of direct struck phase. There is good linear relation between the negative peak value of the indirect struck phase overvoltage and the peak value of the lightning return stroke current, with correlation coefficient being 0.98 and 0.90. [ABSTRACT FROM AUTHOR]

This paper reports the observation results of three‐phase overvoltage at the lightning strike point of a 1.5 km, 10 kV power distribution line that was struck directly by rocket triggered lightning to its phase wire C. The arrester of the direct struck phase at the lightning strike point operated in all return strokes corresponding to return stroke current from −3.3 kA to −32.9 kA. The waveform of direct struck phase includes an initial spike before negative peak, operation area of metal oxide varistor, and the final attenuation with oscillation. The overvoltage waveforms of the indirect struck phase at the lightning strike point show a small initial negative peak, rapid transition to a large positive peak, and the final negative attenuation with oscillation. The negative peak value of the indirect struck phase at lightning strike point ranged from −4.1 kV to −25.2 kV and that of the direct struck phase was between −78.1 kV and −167.8 kV. The positive peak value of indirect struck phase was between 0.2 kV and 49.8 kV. The negative peak value, zero‐crossing time and the peak‐to‐peak value of voltage all have a good linear relation with the peak value of lightning return stroke current. [ABSTRACT FROM AUTHOR]

This paper presents the induced voltage measured at the terminal of a 10 kV distribution line when triggered lightning taking place at a distance of 40 m. It is shown that the induced voltage waveforms exhibit three components including a slow increase preceding the initial negative peak, following a rapid polarity reversal and the attenuated oscillations. The waveform parameters are defined in this paper. The observed negative peak value ranges from −47.1 kV to −7.5 kV. The positive peak value ranges from 5.3 kV to 20.9 kV, and the peak to peak value ranges from 12.8 kV to 63.2 kV. The test results show that the negative peak value of the induced voltage at the terminal of distribution generated by nearby negative triggered lightning generally exceeds the positive peak value, and in some cases the negative peak value even reaches twice the positive peak value. The negative 10%-90% rise time ranges from 2.3 μs to 88.5 μs, and the average oscillation period is about 18 μs. Both negative and positive peaks of induced voltages show good linear relationship with the peaks of lightning return stroke current. [ABSTRACT FROM AUTHOR]

A fault location algorithm without synchronization for double-circuit transmission lines does not require sampling synchronization, reduces the cost, and has a higher engineering value, but the algorithm still needs to be improved in the false-root identification. This paper conducts further studies on this issue. First, the false-root problem of the fault location algorithm without synchronization is analyzed, and then a new false-root identification method is proposed, which is based on the difference of the existence of the false root in the calculation of the voltage amplitude along the line with different electrical moduli. It can solve the problem of the traditional method, which cannot distinguish between voltage amplitudes when they are close. Second, considering the shortcoming of the existing phase-mode transformation matrix, a new phase-mode transformation matrix applied to double-circuit lines is deduced, which is based on the six-sequence component method; it can be combined with the new false-root identification method, thereby realizing false-root identification under various types of faults. Finally, fault location is realized by using the moduli in the mold domain. The principle does not need to synchronize data in two terminals and is not affected by the fault types, fault resistances, and other factors. As is shown in a large number of Alternative Transients Program version of Electro-Magnetic Transients Program (ATP-EMTP) simulation results, the fault location has a higher accuracy © 2017 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [ABSTRACT FROM AUTHOR]

Fiber reinforcement on the practical parts with complex geometries (e.g., Y fork) is a challenge for the industrial development of composites fiber wrapping (FW). FW path planning for the Y fork is studied here, which is a prerequisite for the implementation of the FW process using a robotic work-cell. The feasibility of this work-cell is explored, and more precisely, two path generation algorithms for guiding the robot movement are proposed. One is used to calculate uniformly arranged paths at a constant angle to the axes of the tubular Y fork, where no overlaps and gaps are created under the assumption that the maximum geodesic curvature constraint in FW is ignored. Different from the first one, the second algorithm is presented where the curvature is restricted. Both of these algorithms are implemented by using the MATLABTM suite to carry out re-development of ABAQUS software. Finally, simulations are demonstrated to illustrate the validity of the methodology presented here. [ABSTRACT FROM AUTHOR]