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After long-term operation of a generator, the stator winding will gradually experience aging or electrical corrosion, and scientific experimental analysis methods are needed to diagnose the health status of equipment. By analyzing the leakage current data of stator winding DC withstand voltage tests of multiple large tubular generators, this paper proposed an insulation performance evaluation method and measures to prevent winding breakdown; according to the electrical corrosion and high operating temperature of stator winding of wall mounted structure, we studied a series of innovative designs and processes for stator renovation, and conducted finite element simulation calculation of stator temperature field. The temperature rise test data shows that the operating temperature of the generator after stator modification is effectively reduced, and there is significant reduction in temperature deviation at each measuring point. The research results are close to the simulation calculation values, proving that the new process adopted for stator transformation is effective and feasible. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Dalian University of Technology / Dalian Ligong Daxue Xuebao is the property of Journal of Dalian University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper investigates the impact of surface pollution on abnormal heating with 110kV composite insulators as the research subject. Firstly, infrared inspections were conducted on three full-sized composite insulators at various pollution classes, and the infrared spectrum characteristics of contaminated composite insulators were analyzed. Subsequently, water absorption experiments were performed on silicone rubber flat samples to analyze the effects of pollution on insulator moisture absorption properties and dielectric performance. Finally, tests were conducted on short samples with protective sheaths of six levels of pollution classes in an artificial climate chamber to analyze the influence of leakage current on temperature rise and to assess the impact of pollution on the surface electric field distribution of insulators using the finite element method. The research results indicated that pollution caused and exacerbated abnormal heating in composite insulators. In a high-humidity environment, when the pollution level of full-sized samples exceeded class B, the heating temperature of insulator exceeded 0.5 ℃. Pollution had a more significant impact on the aging of the composite insulator materials; polluted composite insulators exhibited a 'U'-shaped distribution pattern of the surface electric field, with the heating region primarily concentrated in the high-field strength area of the end sheath. The wet pollution state had a significant impact on the electric field of composite insulators, with the maximum electric field strength increasing from the original 4.8 kV/cm to 6.2 kV/cm. The primary cause of abnormal temperature rise in polluted composite insulators was the polarization loss generated by the sheath and the absorption of moisture by pollution, with surface resistive leakage current having a relatively minor influence. This study can serve as a theoretical reference for online infrared diagnostics and the mitigation of abnormal heating issues in polluted composite insulators. [ABSTRACT FROM AUTHOR]

Copyright of Railway Standard Design is the property of Railway Standard Design Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Corrosion & Protection in Petrochemical Industry is the property of Corrosion & Protection in Petrochemical Industry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to evaluate the corrosion of adjacent pipelines caused by stray currents in newly built metro lines，the stray currents leaked from metro lines operating in Xi'an，China for 3 years were tested.The weight loss method was used to test the effect of simulated stray currents on the corrosion rate of adjacent pipelines under the condition of an external DC interference potential of 0～1.2 V.Results showed that the stray current leaked by the metro line showed a triangular wave，with a maximum when the locomotive passed through and a minimum when it drove far.The ground potential of the out-of-service metro was fluctuated around 0.04 V.When the soil moisture content around the track was less than 20%(mass fraction，the same below)，soil moisture had a greater effect on the corrosion of the underground steel pipe than stray currents.Contrarily，when the moisture in the soil was greater than 20%，the stray current had a greater influence on the corrosion of underground steel pipes.When the soil moisture content was 25%～30%，the corrosion rate of steel pipes in the soil reached its maximum，and the corrosion of the underground soil steel pipe was accelerated by the combination of stray current and soil water.When the ground potential caused by stray currents was lower than 0.3 V and the soil moisture content was less than 20%，the corrosion rate of steel in the soil increased by less than 8%compared to that without stray current.

Copyright of Journal of Chongqing University of Technology (Natural Science) is the property of Chongqing University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Corrosion & Protection in Petrochemical Industry is the property of Corrosion & Protection in Petrochemical Industry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Bearing is the property of Bearing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Electric Machines & Control / Dianji Yu Kongzhi Xuebao is the property of Electric Machines & Control and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper investigated the variations in module temperature T and I-V,and analyzed the output law of photovoltaic modules in a day. Firstly, the temperature of the module during the day was found to be a result of coupling factors, not just related to the light intensity. The module output power was primarily determined by current, but not by voltage. Secondly, the series-parallel resistance of the modules basically decreased and then increased during the day. This was attributed to the increase in leakage current caused by high temperature and intense solar irradiance at noon. Compared with the series resistance, the parallel resistance was more affected by the environment during the day. Finally, the series and parallel resistances were relatively stable at high temperature conditions. The reason was that the nonlinear coupling factors that affect modules performance were more complex at low temperature condition. The above results were proved by comparing the theoretical and experimental series resistance. [ABSTRACT FROM AUTHOR]

To study the durability of ultra-high performance concrete (UHPC) under stray current environment, the effects of environmental type, chloride ion concentration and cementing material type on the corrosion morphology, ultrasonic velocity loss rate, damage depth, porosity and strength loss of UHPC under stray current environment were studied by electromigration accelerated corrosion test. The results show that UHPC specimens first generate cracks and spalling on the surface under stray current environment. With the increase of time of impressed current, the damage develops from the surface to the inside, and the internal fibers are seriously corroded and separated from the matrix. Under stray current environment, the damage depth of UHPC increases with the increase of time of impressed current approximately in a quadratic function. In the absence of chloride ion environment or less than 1% ( mass fraction) of chloride ion concentration, the effect on the damage depth of UHPC is not significant, but with the increase of chloride ion concentration, the effect gradually becomes significant. The damage depth of UHPC at 3% chloride ion concentration is twice as large as that at 1%. Under the same conditions, the denser the UHPC is, the stronger the ability to resist stray current damage is. Adding phosphorus slag powder or fly ash to UHPC helps to enhance its corrosion resistance. [ABSTRACT FROM AUTHOR]

Copyright of Electroplating & Finishing is the property of Electroplating & Finishing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

BiFe1-xZnxO3 (BFZO) (x = 0, 2%, 4%, 6%) thin films were successfully prepared on Pt/Ti/SiO2/Si substrates by sol-gel method. The effect of Zn doping on the structure, surface morphology, leakage current density, ferroelectric and ferromagnetic properties of BiFeO3 (BFO) thin films were investigated systematically. XRD patterns show that all samples match well with the perovskite structure without impurity phase. SEM images show that BFZO thin films with x = 4% exhibit uniform fine grains and higher density, which is instrumental for the improvement of leakage current density. The leakage current density curve shows that BiFe0.96Zn0.04O3 thin films have the lowest leakage current density (J = 1. 56 x 10-6 A/cm²) under the electric field strength of 300 kV/ cm, which is three orders of magnitude lower than that of pure BFO thin films. Furthermore, BiFe0.96Zn0.04O3 thin film exhibits the largest remnant polarization (2Pr = 20. 91 μC/cm²) at room temperature, which is more than four times as large as that of pure BFO (2Pr = 4. 96 μC/cm²). Additionally, compared with BFO thin film, Zn doping also enhances the ferromagnetic properties of BFO thin films, and as Zn doping concentration increases, the saturation magnetization of BFZO thin films is significantly enhanced, which provides potential applications in information storage. [ABSTRACT FROM AUTHOR]

In order to study the co-aging effect of various parameters of haze and corona discharge on composite insulator sheds, this paper uses a silicone rubber material as the test sample to carry out corona aging tests for different time periods in single haze, salt fog and haze environments. The flashover voltage, resistivity, hydrophobicity and leakage current of the aging test sample are evaluated and analyzed. The results show that the flashover voltage decreases with the increase of the aging time. The surface resistivity, volume resistivity and hydrophobic loss characteristics of the sample after aging have little to do with the aging environment. At the early stage of corona aging, the particle impact in the haze environment is the main reason for the destruction of the silicone rubber surface. At the later stage, the inorganic salt in the environment accelerates the corona aging, and the effect of ammonium sulfate is stronger than that of sodium nitrate. The research results can provide a theoretical basis for evaluating the service life of composite insulators in haze-prone areas and a reference for anti-haze and anti-pollution flashover of composite insulators. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Guangdong University of Technology is the property of Journal of Guangdong University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Railway Science & Engineering is the property of Journal of Railway Science & Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Electric Machines & Control / Dianji Yu Kongzhi Xuebao is the property of Electric Machines & Control and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Electric Power Automation Equipment / Dianli Zidonghua Shebei is the property of Electric Power Automation Equipment Press and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Railway Standard Design is the property of Railway Standard Design Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of New Building Materials / Xinxing Jianzhu Cailiao is the property of New Building Materials Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of Liquid Crystal & Displays is the property of Chinese Journal of Liquid Crystal & Displays and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Electric Machines & Control / Dianji Yu Kongzhi Xuebao is the property of Electric Machines & Control and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Electric Machines & Control / Dianji Yu Kongzhi Xuebao is the property of Electric Machines & Control and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of Liquid Crystal & Displays is the property of Chinese Journal of Liquid Crystal & Displays and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to improve the insulation performance of MgO materials for electric heating tubes, modified Al2O3-SiO2 composite powders with different mass ratios of Al2O3/SiO2 were prepared by KH-550 organic modifier, and then the modified composite powder and MgO powder were mixed evenly according to the mass ratio of 1: 10 to obtain Al2O3-SiO2-MgO composite powder. The properties of the Al2O3-SiO2 composite powder and the electrical insulation properties of the Al2O3-SiO2-MgO composite powder were studied. The results show that: the surface of organically modified SiO2 and Al2O3 powders is grafted with coupling agent, and the agglomeration between particles is improved; when m(SiO2) m(SiO2) =14, the tap density of the Al2O3-SiO2 composite powder is 0.90 g ⋅ cm-3, the activation index is 40. 9%, and the dispersion and fluidity are the best; the leakage current of the Al2O3-SiO2-MgO powder is 0. 33 mA,and the electrical insulation performance is the best. [ABSTRACT FROM AUTHOR]

Copyright of Railway Standard Design is the property of Railway Standard Design Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Materials Engineering / Cailiao Gongcheng is the property of Journal of Materials Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

AlGaN-based materials are ideal for the preparation of ultraviolet (UV) optoelectronic devices as tunable, direct and wide band gap semiconductor materials. In the absence of access to large-size, low-cost homogeneous substrates, heterogeneous epitaxy of high-quality AlN films is the key to facilitate the development of UV optoelectronic devices. In this work, the metal organic chemical vapor deposition (MOCVD) growth pattern of AlN on sapphire substrates was adjusted to generate high density nanoscale holes, and the holes were used to reduce the dislocations of AlN. Based on this, the AlGaN quantum well structure was epitaxially developed. Deep-UV LED films in the 275 nm band were obtained by epitaxy, and a deep-UV LED device with an on voltage of 4.8V and a reverse leakage current of 2.23 μA (at - 3.0 V voltage) was fabricated. [ABSTRACT FROM AUTHOR]

Copyright of Railway Standard Design is the property of Railway Standard Design Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Bulletin of the Chinese Ceramic Society is the property of Bulletin of the Chinese Ceramic Society Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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Copyright of Chinese Journal of Liquid Crystal & Displays is the property of Chinese Journal of Liquid Crystal & Displays and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Electric Machines & Control / Dianji Yu Kongzhi Xuebao is the property of Electric Machines & Control and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Phase change materials (PCMs) can widely be used to absorb and release large amounts of latent heat at temperatures when the physical state changes. Heat storage systems depend mainly on the high latent heat density and small temperature intervals in PCMs during phase transition. However, there is a great leakage of current solid-liquid PCMs in the liquid phase, resulting from a large volume change above the melting point. Alternatively, the porous metal-organic frameworks (MOFs) have been investigated as solid support for a variety of storage purposes. A MOFs matrix material can also be expected to deal with the leakage of a shape-stabilized composite PCM in the most practical way. It is highly demanding for the extremely large surface area, large pore volume, and chemical tunability in the MOFs as the ideal matrix for PCMs. In particular, MOFs can also be designed for several aspects, such as pore shape and size, framework topology, and surface properties in the inner channels. A combination of fatty acids and porous MOF supports can be utilized to maintain the solid shape in the liquid PCM composite, where the phase change temperature of paraffin is within the range of normal human environments. Paraffin also presents high latent heat, suitable melting temperature range, non-corrosivity/non-toxicity, excellent chemical stability, and easy availability. The outstanding energy storage density and suitable phase change temperature also allow for the paraffin highly practical in the building materials. In this study, a facile solution impregnating approach was proposed to access a novel type of shape-stabilized PCM with metal-organic frameworks as the matrix. As such, a paraffin/MOF composite PCM was developed for heating storage, where paraffin was used as a phase change core, while Fe-MIL-101-NH2 was the supporting matrix. Solvent evaporation was finally conducted to successfully prepared 40 wt%~70 wt% paraffin/Fe-MIL-101-NH2 shape-stable phase change material (ss-PCM). Scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy were also conducted to characterize the morphology and structure of ss-PCM composites. Thermal gravimetric analysis (TGA) was used to determine the thermal stability, while differential scanning calorimetry (DSC) to the supercooling, the energy storage, and thermal cycle stability of ss-PCM. SEM images showed that the maximum loading of paraffin wax was 70%, mostly distributed in the interior and external core of Fe-MIL-101-NH2. XRD and FTIR showed that the paraffin wax and Fe-MIL-101-NH2 were physically combined in the ss-PCM. DSC analysis indicated that the highest energy storage capacity (51.3 J/g) was achieved in the 70 wt% paraffin/ Fe-MIL-101-NH2. In addition, there was no significant decrease in the thermal enthalpy of 70 wt% paraffin/Fe-MIL-101-NH2 (47.6 J/g) after 50 cycles, indicating an excellent heat cycle stability. Consequently, a novel paraffin/Fe-MIL-101-NH2 composite PCM can be expected to serve as the heat storage application. This finding can also provide a novel approach to access the shape-stabilized composite PCMs, which can potentially be extended to a variety of solid-liquid phase change materials. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Liquid Crystal & Displays is the property of Chinese Journal of Liquid Crystal & Displays and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of Liquid Crystal & Displays is the property of Chinese Journal of Liquid Crystal & Displays and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Clean Coal Technology is the property of Clean Coal Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In view of problem that stray currents generate serious threat to safety production of coal mine, the paper proposed detection system of stray currents in coal mine based on magnetoresistance effects. It introduced detection principle of the system, designed detection circuit and sensor peripheral circuit, and completed experiment. The experimental result shows that the system can measure stray current accurately and stably, current detection accuracy basically meets detection requirements and the non-contact method is safe and reliable. The proposed system has great practical significance for mine stray current control.

Aimming at the problems of cathodic protection potential measurement of buried steel gas pipeline under the influence of metro stray current and the evaluation criteria of stray current flowing into and out of buried steel gas pipeline, the measurement technique of close interval potential was introduced into buried steel gas pipeline, switching off potention test was conducted, the relationship between switching off potential and delay time was established, we found that the switching off potential was real cathodic protection potential of pipeline when measurement unit delayed 100 ms. On the basis of the measurement technology of the close interval potential, the buried steel gas pipeline affected by metro stray current was tested, the switching off potential of buried steel gas pipeline under and without the influence of metro stray current were measured( denoted by VoffD and VoffN, respectively). The experimental results show that: when VoffD is positive than Voff N, here is the stray current flow out; when VoffD is negative than VoffN, here is the stray current flow point. [ABSTRACT FROM AUTHOR]

Copyright of Electric Machines & Control / Dianji Yu Kongzhi Xuebao is the property of Electric Machines & Control and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)