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Abstract Mycotoxins, a toxic secondary metabolite, unpredictably, and unavoidably occur in foods and feeds, leading to adverse health impacts and enormous economic losses in the agriculture industry. Moreover, mycotoxin contamination has been a great threat for the public health and agriculture economy development worldwide. Therefore, the control of the mycotoxin contamination is of great importance and has caused rising concern worldwide. Recently, emerging nanomaterials have been promisingly applied in the control of mycotoxin contamination and have obtained many achievements. In this review, first of all, the type, occurrence, and toxicity of mycotoxins are simply discussed. Then, attentions are focused on the applications of emerging nanomaterials to controlling the mycotoxin contamination, including mycotoxin assay, the inhibition of mycotoxin production, the adsorption of mycotoxins, and mycotoxin elimination. In the end, the future opportunities and challenges on the toxicity, occurrence, and control of mycotoxins are tentatively put forward.

Abstract Background Neuroendocrine neoplasm is a rare solid tumor. Metastatic pattern of the gastrointestinal neuroendocrine neoplasm (GI‐NEN) has not been fully explored. Methods Data were obtained from the Surveillance, Epidemiology, and End Results (SEER) database (SEER‐9 registry) from 1973 to 2015. Incidence was estimated by Joinpoint regression analyses. Data with additional treatment fields of GI‐NEN were extracted from the SEER‐18 registry from 1 January 2010 to 31 December 2015. A total of 14 685 GI‐NEN patients were included in this study. Statistical analyses were performed with SPSS 25.0, the Intercooled Stata SE 15.0, and GraphPad Prism 7. Results Incidence of GI‐NENs increased from 0.51 per 100 000 patients in 1973 to 6.20 per 100 000 patients in 2015. Of them, 2003 patients were stage IV GI‐NEN at the time of diagnosis, including 1459 (72.84%) patients with liver metastasis, 144 (7.19%) lung metastasis, 115 (5.74%) bone metastasis, and 27 (1.35%) brain metastasis. Esophageal NEN had the highest risk of metastasis (52.68%). The median survival for patients with liver, lung, bone, and brain metastasis was 38, 6, 9, and 2 months, respectively. The presence of lung or liver metastasis indicated higher risk of concurrent existence of bone and brain metastasis than those without. Conclusion Bone and brain metastasis should be screened in the GI‐NEN patients if they had lung or liver metastasis. Findings of the current study could help clinicians to identify distant metastasis of GI‐NENs as early as possible, and by which, to improve survival rate of GI‐NENs.

Wind power forecasting (WPF) is crucial in helping schedule and trade wind power generation at various spatial and temporal scales. With increasing number of wind farms over a region, research focus of WPF methods has been recently moved onto exploring spatial correlation among wind farms to benefit forecasting. In this study, a spatio-temporal Markov chain model is proposed for very-short-term WPF by extending the traditional discrete-time Markov chain and incorporating off-site reference information to improve forecasting accuracy of regional wind farms. Not only are the transitions between the power output states of the target wind farm itself considered in the forecasting model, but also the transitions from the output states of reference wind farms to that of the target wind farm are introduced. The forecasting results derived from multiple spatio-temporal Markov chains regarding different reference wind farms over the same region are optimally weighted using sparse optimisation to generate forecasts of the target wind farm. The proposed method is validated by comparing with both local and spatio-temporal WPF methods, using a real-world dataset.

The increasing of large-scale wind power integration capacity brings great challenges to the safe operation and management of power grid. Modern grid codes put forward the requirements of fault ride through (FRT) capability: (i) to remain continuous operation at a given time; (ii) to contribute to support the voltage stability during FRT by providing reactive current. Aiming at the FRT problem of doubly fed induction generator (DFIG), critical elements of the rotor side converter (RSC) and the grid side converter (GSC) to FRT are analysed, and the improving RSC control scheme, adding extra hardware equipment, and improving reactive current control scheme are studied. Matlab/Simulink simulation studies are conducted to verify the effectiveness of the proposed strategies. The results show that when the grid fault is light, the improving RSC control strategy can effectively control the rotor winding overcurrent, when the grid fault is serious, it needs additional hardware equipment; the coordinated control strategy of the RSC and the GSC providing reactive current support is identified as the most advantageous approach because it not only provides enhanced reactive support for the grid, but also avoids over-speed risk of DFIG based wind turbine shaft.

Wind turbines should have fault ride through capability, and also it can provide damping for the power grid by improving the control strategy. However, the currently corresponding control strategy is designed independent for the fault voltage through control and damping control. If the fault ride through control and damping control of a converter is uncoordinated under the grid fault, the output of the two control branches can be superimposed, which will affect the output power dynamic performance of doubly fed induction generator (DFIG) after clearing the fault. At the same time the overcurrent and other issues may occur in serious cases, and even lead to DFIG trip off. Based on the dynamic process analysis of DFIG after clearing the fault, an additional damping controller in the rotor side converter control of DFIG is designed, which damps the system low-frequency oscillation by modulating the rotor active current component. A coordination damping control strategy of DFIG based on a fault ride through control and damping control is proposed for damping the power oscillation after clearing the fault, the correctness of the proposed control method has been verified through time-domain simulation.

Renewable energy develops very fast in China, and China has become the largest and fastest growing country of wind and PV power in the world. However, the distribution of the wind/solar energy and load center is disharmonious, with the major wind fields and the solar fields being distributed in the area which is short of load, and making large-scaled, long-distance wind and PV power transmission is imperative. The problem of the stability of the large-scale wind and PV power grid integrated system into the high impedance weak grid is becoming more and more important. In order to shorten the electrical distance for wind power integration, the use of series compensation technology is an economically viable approach. In this study, the characteristics of the wind power transmission system with series compensation are introduced. On the basis of the analysis, the characteristics of the wind power transmission under the series compensation are analysed. Finally, after the wind power base integration, the different impedance characteristics/the order of the impact are studied.

Vacuum circuit breaker (VCB) has a longer life and shorter opening time than SF(6) circuit breaker, but current single-break VCB cannot be applied in high-voltage power system directly. Here, a fast 363 kV multi-break VCB design is presented and its voltage distribution characteristic and stray capacitors are analysed. A three-dimensional finite-element model of modularised hexa-break VCB composed of 12 vacuum interrupter modules installed on three series connected platforms is developed to calculate the voltage distribution and distributed capacitances. The result shows that the voltage distribution is uneven, and the first break shares the 67.974% of the whole applied voltage. On account of distributed capacitances parameters, an equivalent capacitance model with PSCAD is built to discuss the voltage distribution characteristic at different grading capacitance values, and the optimal grading capacitance value is determined to 10 nF.