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Background The two-line method based on the photoperiod and thermo-sensitive genic male sterile (PTGMS) lines is more cost-effective, simple, and efficient than the three-line system based on cytoplasmic male-sterility. Blast and drought are the most prevalent biotic and abiotic stress factors hampering rice production. Molecular techniques demonstrate higher efficacy in the pyramiding of disease resistance genes, providing green performance under the background of water-saving and drought-resistance rice. Results This study employed molecular marker-assisted selection, conventional hybridization, and high-intensity stress screening to integrate three broad-spectrum blast resistance genes Pi9, Pi5, and Pi54 into Huhan 1S. Subsequently, a novel water-saving and drought-resistance rice (WDR) PTGMS line Huhan 74S was developed. The drought resistance of the new PTGMS line Huhan 74S was comparable to that of Huhan 1S. Pathogenicity assays involving the inoculation of 14 blast prevalent isolates in the glasshouse showed that the blast resistance frequency of Huhan 74S was 85.7%. Further evaluation under natural blast epidemic field conditions showed that Huhan 74S and its hybrids were resistant to leaf and neck blast. The critical temperature point of fertility-sterility alteration of Huhan 74S was 23 °C daily mean temperature. The complete male sterility under natural growth conditions in 2017 at Shanghai lasted for 67 days. Also, both the agronomic and grain quality traits met the requirement for two-line hybrid rice production. Conclusion These results indicate that the newly bred PTGMS line Huhan 74S can be used to breed high-yielding, good-quality, disease-resistant two-line hybrid water-saving and drought-resistance rice (WDR), hence promoting sustainable rice production in China.

Background Stigma exsertion rate (SER) is a key determinant of outcrossing in hybrid rice seed production. A quantitative trait locus (QTL) for stigma exsertion rate in rice, qSER-7, has previously been detected on chromosome 7 by using a F2 population derived from two indica cytoplasmic male sterility (CMS) maintainers, Huhan 1B and II-32B. Results The chromosomal location of qSER-7 was precisely delimited by fine-scale mapping. Near-isogenic lines (NILs) were established, one of which isolated the locus in the qSER-7II-32B line, which contains an introgressed segment of II-32B in the Huhan 1B genetic background, and exhibits a significantly higher stigma exsertion rate than that of the recurrent parent. Using 3192 individuals from the BC4F2 segregation population, the QTL qSER-7 was narrowed down to a 28.4-kb region between the markers RM3859 and Indel4373 on chromosome 7. According to the rice genome annotation database, three genes were predicted within the target region. Real-time PCR analysis showed significantly higher expression levels of LOC_Os07g15370 and LOC_Os07g15390 in II-32B than in Huhan 1B. LOC_Os07g15370(OsNRAMP5) was a previously reported gene for Mn and Cd transporter. The stigma exertion rates of OsNRAMP5-overexpressing plants were significantly higher than that of wild type plants, in contrast, a T-DNA insertion mutant osnramp5 showed a lower stigma exertion rate. Conclusions In the present study, the QTL qSER-7 was isolated to a region between the markers RM3859 and Indel4373. Two candidate genes were selected based on the expression difference between the two parents, which can facilitate the further cloning of the gene underlying the quantitative trait associated with qSER-7 as well as the marker-assisted transfer of desirable genes for stigma exsertion rate improvement in rice. Electronic supplementary material The online version of this article (10.1186/s12284-019-0304-z) contains supplementary material, which is available to authorized users.

Today, the accuracy of the fault mechanical diagnosis of transformer winding is low and the fault types cannot be judged, this study proposes a machine condition diagnosis method of transformer winding based on the combination of short-circuit reactance and mechanical vibration. During the process of diagnosis, first of all, from a power transformer's one and two side current and voltage, it can calculate the internal short-circuit reactance of the winding to judge the winding state. Then, it uses the wavelet transform to analyse the vibration signals of the transformer windings under different conditions and it uses the signal spectrum entropy as the input feature vector. Finally, using multi class support vector machine to train and test the feature vector, it realises the classification diagnosis of transformer winding in different states. By setting the actual different transformer winding faults of type S11-M-500/35, it gathers the corresponding parameter data and it tests the diagnosis method for the fault diagnosis of transformer winding verification. The diagnosis results are consistent with the actual fault, which verifies the validity and accuracy of the proposed method that is applied to the transformer winding fault diagnosis.

Low amylose content (AC) is a desirable trait for rice (Oryza sativa L.) cooking quality and is selected in soft rice breeding. The Wx hp allele was derived from a Yunnan rice landrace in China, Haopi, with low AC. To efficiently and rapidly utilize the low amylose content-associated gene Wx hp in rice molecular breeding programs, we developed a tetra-primer amplification refractory mutation system-polymerase chain reaction (ARMS-PCR) method, according to the single-nucleotide variation of the Wx hp . Four Wx hp -specific primers were used to perform PCR assays using genomic DNA extracted from several rice varieties. Based on the band pattern of the amplified products after electrophoresis, this method can accurately distinguish three Wx hp -related genotypes (i.e., Wx hp homozygotes, Wx hp heterozygotes, and wild-type), and the genotypes completely correspond to the appearance of mature endosperm. This method represents a novel approach that is both inexpensive and highly efficient and can be widely used for genotyping Wx hp alleles in rice germplasm collections and may aid breeding programs with marker-assisted selection (MAS).

Additional file 1: Table S1. Gene specific markers used in this study.

Works based on the theory of engineering electromagnetic fields and high current busbar, study on the GIS (Gas Insulate Substation, referred to as GIS) in the steady-state model of the equivalent shell, and calculate the model parameters. Normal operation, circulation value of the shell and busbar load current is essentially the same order of magnitude. They also have a huge circulation loss and influent transmission capacity of the system. The phenomenon of heat loss also occurs at the same time of circulation loss generating. When circulation above a certain value, heat loss over heat capacity of the shell. It will lead to local heat and accelerate aging of insulation. Therefore, it is great significance for the value of the steady circulation to establish an accurate equivalent model of GIS shell. By referring to the existing home and abroad on the aspects of research about the equivalent model of the GIS shell, use the high-current busbar theory to establish an accurate equivalent model of GIS shell.

Promoting the construction of 10kV pole-type transformer substation is an important embodiment of state Grid corporation of China to fully implement the scientific development concept, build a "resource-saving and environment-friendly" society, and greatly improve its integrated innovation ability. In this paper, based on the design of 10kV transformer substation reactive compensation capacitor bank dynamic switching test system, a controllable load device with adjustable line power factor is developed. Calculate load under different ways of working condition of reactive power compensation device of flow capacity, insulation level and reactive power compensation simulation calculation of line current voltage waveform diagram, test to prove the reliability and accuracy of the controllable load device, and the results of the study for improving the 10 kv 10kV transformer substation operation reliability and power quality and power distribution network to provide technical support and testing methods.

The 12kV drop-out fuse pre-arc time-current characteristic test is an important method to verify the quality of the fuse and the reliability of the fuse breaking. This paper summarizes the technical requirements of domestic and foreign test standards, combines test experience, analyzes the impact of test methods on product performance parameter test results, and gives test technical solutions and test standards. The results show that the reading value of the test current is the effective value of the full waveform of the test current, the expected current value is controlled within the range of -5% to + 5% of the target current value, and the test error meets the pre-arc time-current characteristic detection requirements; during the test process The current should be reasonably compensated according to the current attenuation to ensure that the current attenuation rate is less than 10%. The research results are a summary of the pre-arc time-current characteristic test schemes and standards for 12kV drop-out fuses, and have important practical guiding significance for improving the quality level of distribution fuses.

In order to effectively control the quality of the 10kV drop fuse, the main reason for the operation of the fuse in the system is given, and the quality improvement method is proposed. The State Grid Corporation conducts the sampling test of the 10kV drop fuse. Through the material analysis and temperature rise test of the fuse, the material temperature of the contact surface of the main circuit conductor of the 10kV drop fuse is tested, and the test standard temperature rise limit is given. Combined with the temperature rise test results, the operating conditions and quality problems of the fuse equipment were analyzed. The test analyzes the root cause of the different operating currents of the fuses and the overheating at different locations. The temperature rise curve and the rising rate of the fuses at different positions are given. The results show that the fuse materials generally have different degrees of defects, the material testing failure rate is 88.9%, and the temperature rise test failure rate is 44.4%. The heat rise point of the fuse temperature rise test is mainly concentrated on the sliding position of the upper conductive piece and the upper contact, the screw connection position of the upper contact nut and the fusion tube, and the fastening position of the fuse and the lower conductor bolt. Therefore, strictly controlling the material quality of the 10kV drop fuse is of great significance for improving the stable operation of the 10kV drop fuse. The research results in this paper provide technical support for the material procurement of State Grid Corporation.

According to ZFW20A-252 GIS equipment, this paper proposes a low-cost GIS (Gas Insulated Switchgear) digital transformation program that carries out a design and implementation of the Intelligent Electronic Device (IED) operated by digital GIS. By making a lot of experiments about IED GOOSE messages, opening and closing state, IED upload displacement messages, as well as response time, it is confirmed that the program not only meets the requirements that fast message transmission delay must be less than 3ms, but also improves the stability of the transmission delay under different conditions. The program meets the demand of Smart Grid, and improves the promotion of production technology with digital GIS.

According to the requirement of opening and closing characteristics of vacuum circuit breaker. A new actuator of cylindrical permanent magnet brushless DC motor is designed. The overall design of the actuator of the cylindrical permanent magnet brushless DC motor is carried out and the kinematic and dynamic characteristics of the actuator are analyzed. The structure and main parameters of the linear motor are designed. Simulation analysis of magnetic circuit and dynamic process of motor and the displacement and velocity curves of the motor are obtained. The average opening speed and closing speed are 1.9m/s and 1.3m/s respectively, the results show that permanent magnet linear motor actuator can meet the demands of breaker's closing requirements.

In order to improve the opening and closing operation performance and intelligent level of vacuum circuit breaker, a commutation control mode based on the winding current of motor actuator is proposed. According to the equivalent mathematical model of permanent magnet BLDCM, the corresponding relationship between back EMF and rotor speed is obtained by spline interpolation method. The rotor position is calculated by combining the winding current value and trapezoid quadrature method, and the winding current is detected in real time. The commutation time is calculated by DSP, and the phase change operation is controlled. The on-line test results of the motor actuator of the vacuum circuit breaker show that the method can realize the commutation operation of the drive motor. The angle error between the commutation position of the motor and the commutation position of the hall disk is less than 1°. The influence of the commutation error on the operation time of the circuit breaker is less than 1ms, which meets the requirements of the operation characteristics of the circuit breaker.

The resource and environmental challenges faced by rice production call for resource-saving and environment-friendly rice varieties. Water-saving and drought-resistance rice (WDR) is a new type of cultivated rice combining both high yield potential and acceptable grain quality as a current lowland paddy rice, as well as water-saving and drought resistance as a traditional upland rice. The lowland and upland rice are two ecotypes adapted to contrasting soil water status, originating mainly because of their differentiated drought resistance. Upland rice, domesticated in a water–limited environment and experiencing a bidirectional selection process, has better drought resistance and especially better drought avoidance. Though the potential tradeoff between drought resistance and productivity is very common in rice, the bidirectional selection could overcome this tradeoff and accumulate recombination genotypes. It is very important to choose elite parents on the basis of studies on the great genetic diversity of rice yield and drought resistance among the rice germplasm resources and adapt the bidirectional selection strategies to especially integrate drought avoidance, drought tolerance, high water use efficiency, and productivity in WDR breeding. The breeding history and genomic studies indicated that lowland paddy rice and upland rice hybridization breeding with suitable selection in different environments is an effective approach to improving complex traits such as yield potential and drought resistance. Meanwhile, molecular technology shows higher efficiency on value-added breeding such as transferring and pyramiding pest- and disease-resistant genes, which helps WDR obtain other green characters. Twenty-two WDR varieties were registered and distributed to farmers in recent years and could be planted in both irrigated and rainfed ecosystems, thus showing promising application prospects. The major crop management technology of WDR in lowland paddy fields with water-saving cultivation and in rainfed fields by dry seeding with aerobic cultivation were also discussed in this article.

More than 70% of global rice production depends on irrigation water, which has brought on a progressive reduction in the groundwater table. Further groundwater withdrawal are unsustainable for future rice production. Sustainable rice production calls for the use of resource-saving and environmentally friendly rice varieties. This study investigated the morphological and physiological mechanisms of biomass and tissue phosphorus accumulation in a water-saving and drought-resistance rice variety (Hanyou73) and a normal paddy rice variety (Hyou518) under different water management regimes. The two rice cultivars were grown in pot experiments carried out with factorial combinations of three water regimes, conventional irrigation (high irrigation rate, HR), 60% of conventional irrigation (medium irrigation rate, MR), and 20% of conventional irrigation (low irrigation rate, LR) for four-years. While the grain yield of Hanyou73 was similar as Hyou518 under HR, it was significantly higher than Hyou518 under MR and LR. Under deficit irrigation, the tissue-specific biomass of Hanyou73 was higher than that of Hyou518, and the total P accumulation of Hanyou73 was 70% greater than that of Hyou518. Meanwhile, the root growth, root oxidation activity, and absorption area of Hanyou73 under the MR and LR treatments were significantly higher than those of Hyou518. Analysis of root exudate metabolites revealed an abundance of organic acids produced by the Hanyou73 roots under, which may account for its higher P uptake. Overall, the findings of this study indicate that Hanyou73 promoted P uptake to maintain higher yields under deficit irrigation. The higher P uptake by Hanyou73 may be related to its altered root physiology, which may be the mechanism by which Hanyou73 adapts to water saving irrigation conditions and maintains its yield traits.

To improve the reliability and intelligent level of the AC transmission system, the radial basis function-based proportional-integral-derivative (RBF-PID) control method for the motor actuator used in the 550 kV gas-insulated switchgear (GIS) disconnector is proposed. According to the dynamic mathematical model of the motor actuator, the main structure of the RBF neural network based on the gradient descent method for learning algorithm is constructed. An identification function is formed by taking values of the output error square, and then by gathering information on the real-time tuning parameters of PID. Based on that, the simulation of the control system is constructed. The comparative analyses of the tracking control characteristics and the servo following error of the disconnector's contact speed between double-loop PID and RBF-PID are done through the computational and experiment methods, respectively. The results show that 550 kV GIS disconnector with the motor actuator by the RFB-PID control method has better controllability, and the servo following error is controlled within 0.1 m/s.

On the basis of studying the application of Voronoi diagram, considering the influence of geographical factors such as roads and rivers on the power supply area, the method of substation power supply partitioning combined with weighted Voronoi diagram and road grid is proposed. Firstly, according to the urban road network, the power supply area is divided into several grids, and then the substation is taken as the center. Considering the main capacity of the substation, a weighted Voronoi diagram is generated, which makes the result of the power supply area division more scientific and reasonable. Finally, the actual example proves that the method has certain validity and rationality.

In this paper, dielectric recovery characteristic during operation of high voltage SF6 circuit breaker is studied by test method. The test circuit of dynamic breakdown characteristics is built. Circuit breaker closing and opening dynamic breakdown voltage curves under positive and negative polarity are obtained. Impact of inflatable pressure and closing speed to dielectric recovery characteristic are analyzed. Breaking dielectric recovery rate and closing pre-strike time under different experimental conditions are given. The results showed that: the positive polarity breakdown voltage is greater than negative polarity of SF6 gas. The impact of closing speed on the closing pre-strike characteristic is significantly. The maximum closing pre-strike time is 1.18ms under closing speed 6.6m/s. The maximum closing pre-strike time is 2.21ms under closing speed 4.7m/s. It can be seen, to improve the closing speed is an effective method to control pre-strike time. When P=0.7Mpa and P=0.5MPa respectively within 0.5ms and 1ms after contact separation, breakdown may occur again. Therefore, breaking process should be avoided in this time range extinction.