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The fault location technology for single-phase grounding fault of line has been mature, but there is little research on cable head in switchgear using this technology. Because the grounding line selection device cannot effectively identify and locate the single-phase grounding fault of the cable head in the switchgear, a cable head fault model is established. The synthetic zero-sequence current signal of three-phase CT and the zero-sequence current signal of zero-sequence CT are decomposed by variational mode decomposition (VMD). The grey correlation degree is then calculated to analyze the similarity of the two signals. Thus, the precise fault location technology of cable head in switchgear based on the measurement of phase CT and zero-sequence CT is proposed, and the correctness and feasibility of the proposed technology are verified by ATP simulation software.

Tooth wear is one of the most common faults in gear transmission systems. However, due to its limited influences on gear dynamics, the condition monitoring of gear wear experiences more challenges. To investigate the relationship between tooth wear and gear dynamics, this study develops an eight-degree of freedom dynamic model which takes into account the gear mesh impact induced by tooth wear. In this model, the gear mesh impact force induced by tooth wear was calculated as an extra input excitation for the gear dynamic model. Besides, a comparative study was carried out to explore the real reason that causes the poor dynamic behaviour due to the wear from two points of view: 1) the reduction in gear mesh stiffness; 2) the increase in gear mesh impact force. The simulation results show that the wear causes a slight reduction in gear mesh stiffness, thus leading to the decrease in the amplitude of gear mesh frequency. This is not consistent with the phenomena observed in the lab experiment which shows the increase in the gear vibrations. The second simulation of impact force demonstrates that the wear causes an increase in the impact force which further leads to the increase in the amplitude of gear mesh frequency. This study investigates the cause for the deterioration in gear dynamics induced by gear wear, which can benefit the early condition monitoring and fault diagnosis of the gear tooth wear.

In this experiment, ‘Huangguogan’ introduced from Shimian to Jiangyou was used as the materialand Shimian ‘Huangguogan’ as the reference. The adaptability of ‘Huangguogan’ was studied from three aspects: site climate conditions, basic indicators of tree bodyand fruit quality. The results showed that the overall situation of Shimian ‘Huangguogan’ was better than Jiangyou ‘Huangguogan’, especially the internal quality of the fruit, which indicated that Jiangyou was not suitable to introduce ‘Huangguogan’.

This experiment compared the phenophase, morphological features and fruit quality of the two citrus varieties. The results showed that the whole growth period of Lemon Siranui was about 12 days longer than Siranui. The flowering period, two physiological fruit drop periods and fruit color change period of Lemon Siranui were about 5-7 days later than Siranui. While this study illustrated differences in morphological features that Lemon Siranui tree was stronger than Siranui. And the fruit of Lemon Siranui was heavier than Siranui. It was clear to see that the percentages of soluble solids as well as vitamin C in Lemon Siranui were larger than those in Siranui, which led to better taste qualities. Overall, Lemon Siranui was a new high-quality strain citrus variety with excellent traits which was worth promoting from the analysis of appearance quality and nutritional quality.

In order to further enrich the structure of citrus varieties in the Jintang area of Sichuan, and to solve the problems of old and single varieties and relatively concentrated listing periods. In this experiment, four excellent and new citrus varieties, ‘Kanpei’, ‘Niahinoka’, ‘Or’ and ‘Qingfeng’ is introduced, and the local cultivar ‘Shiranui’ is used as a control. The traits and fruit quality indicators are investigated, measured and analyzed. The results show: The ‘Kanpei’ and ‘Or’ trees are strong, the ‘Niahinoka’, ‘Qingfeng’ and ‘Shiranui’ are medium, ‘Or’ has the highest ratio of sugar to acid, ‘Niahinoka’ has the highest vitamin C and soluble solids. Compared with the control, the ratio of sugar to acid and the per mu yield in the ‘Niahinoka’ is 27.78% and 13.62% higher than ‘Shiranui’, ‘Qingfeng’ performance is poor. According to a comprehensive analysis, ‘Kanpei’, ‘Niahinoka’ and ‘Or’ are suitable for introduction, and ‘Qingfeng’ is not suitable for introduction.

Based on the selenium stress, the effects of living Pterocypsela laciniata and its straws on phosphorus (P) uptake of grape seedlings were carried out. There were some important results and showed that in parts of grape seedlings. The total P content was lower in roots than that in stems, leaves and shoot. Among five treatments, there was quite different about the total P content. Compared to grape seedlings monoculture, living P. laciniata and its straws could significantly increase the total P content in parts of grape seedlings. Among them, applying the leaf straw of P. laciniata in soil made the total P content the highest. For the total P content in root, stem, leaf and shoot of grape seedlings, it was always ordered from high to low: PLG > PG > PRG > PSG > MG. The available P content in soil was a little changed in relation to the total P content in plants. Applying P. laciniata straws also could increase the available P content. On the contrary, grape seedlings intercropping with P. laciniata seedlings decreased the available content, compared to the monoculture. In a word, living P. laciniata and its straws was good for the growth of grape seedlings and improved the P uptake in plants.

In this study, it is found that as-prepared gold nanorods can be linked to each other in an end-to-end way by using cysteine as a molecular bridge. Both transmission electron microscopy and UV-visible optical spectroscopy demonstrated the uniaxial assembly of the gold nanorods. The controlled addition of cysteine into the gold nanorod solution resulted in their preferential binding to the two ends of the gold nanorods. As a result, end-to-end assembly was achieved through cooperative hydrogen bonding of bound cysteine molecules. The as-synthesized end-to-end linked assembly of gold nanorods is well ordered and on a large scale. For comparison, three other neutral amino acids, glycine, alanine and valine, were also investigated but the orderliness of their assembly is not as good as that in the case of cysteine.

Motor current signal analysis has been an effective way for many years of monitoring electrical machines themselves. However, little work has been carried out in using this technique for monitoring their downstream equipment because of difficulties in extracting small fault components in the measured current signals. This paper investigates the characteristics of electrical current signals for monitoring the faults from a downstream gearbox using a modulation signal bispectrum (MSB), including phase effects in extracting small modulating components in a noisy measurement. An analytical study is firstly performed to understand amplitude, frequency and phase characteristics of current signals due to faults. It then explores the performance of MSB analysis in detecting weak modulating components in current signals. Experimental study based on a 10kw two stage gearbox, driven by a three phase induction motor, shows that MSB peaks at different rotational frequencies can be based to quantify the severity of gear tooth breakage and the degrees of shaft misalignment. In addition, the type and location of a fault can be recognized based on the frequency at which the change of MSB peak is the highest among different frequencies.

Vibration signals from a gearbox are usually very noisy which makes it difficult to find reliable symptoms of a fault in a multistage gearbox. This paper explores the use of time synchronous average (TSA) to suppress the noise and Continue Wavelet Transformation (CWT) to enhance the non-stationary nature of fault signal for more accurate fault diagnosis. The results obtained in diagnosis an incipient gear breakage show that fault diagnosis results can be improved by using an appropriate wavelet. Moreover, a new scheme based on the level of wavelet coefficient amplitudes of baseline data alone, without faulty data samples, is suggested to select an optimal wavelet.