Influence of Thermal Expansion on Eccentricity and Critical Speed in Dry Submersible Induction Motors

Qiang Lv,Xiaohua Bao,Yigang He 대한전기학회 2014 Journal of Electrical Engineering & Technology Vol.9 No.1

Rotor eccentricity is one of the major factors that directly influence the security of horizontal electrical machines, and the critical speed of the shaft has a close relationship with vibration. This paper deals with the influence of thermal expansion on the rotor eccentricity and critical speed in large dry submersible motors. The dynamic eccentricity (where the rotor is still turning around the stator bore centre but not its own centre) and critical speed of a three-phase squirrelcage submersible induction motor are calculated via hybrid analytical/finite element method. Then the influence of thermal expansion is investigated by simulation. It is predicted from the study that the thermal expansion of the rotor and stator gives rise to a significant air-gap length decrement and an inconspicuous slower critical speed. The results show that the thermal expansion should be considered as an impact factor when designing the air gap length.

Influence of Thermal Expansion on Eccentricity and Critical Speed in Dry Submersible Induction Motors

Lv, Qiang,Bao, Xiaohua,He, Yigang The Korean Institute of Electrical Engineers 2014 Journal of Electrical Engineering & Technology Vol.9 No.1

Rotor eccentricity is one of the major factors that directly influence the security of horizontal electrical machines, and the critical speed of the shaft has a close relationship with vibration. This paper deals with the influence of thermal expansion on the rotor eccentricity and critical speed in large dry submersible motors. The dynamic eccentricity (where the rotor is still turning around the stator bore centre but not its own centre) and critical speed of a three-phase squirrel-cage submersible induction motor are calculated via hybrid analytical/finite element method. Then the influence of thermal expansion is investigated by simulation. It is predicted from the study that the thermal expansion of the rotor and stator gives rise to a significant air-gap length decrement and an inconspicuous slower critical speed. The results show that the thermal expansion should be considered as an impact factor when designing the air gap length.

Inductances Evaluation of a Squirrel-Cage Induction Motor with Curved Dynamic Eccentricity

Qiang Lv,Xiaohua Bao,Yigang He,Yong Fang,Xiaowei Cheng 대한전기학회 2014 Journal of Electrical Engineering & Technology Vol.9 No.5

Eccentricity faults more or less exist in all rotating electrical machines. This paper establishes a more precise model of dynamic eccentricity (DE) in electrical machines named as curved dynamic eccentricity. It is a kind of axial unequal eccentricity which has not been investigated in detail so far but occurs in large electrical machines. The inductances of a large three-phase squirrel-cage induction machine (SCIM) under different levels of curved DE conditions are evaluated using winding function approach (WFA). These inductances include the stator self and mutual inductances, rotor self and mutual inductances, and mutual inductances between stator phases and rotor loops. A comparison is made between the calculation results under curved DE and the corresponding pure DE conditions. It indicates that the eccentricity condition will be more terrible than the monitored eccentricity based on the conventional pure DE model.

Inductances Evaluation of a Squirrel-Cage Induction Motor with Curved Dynamic Eccentricity

Lv, Qiang,Bao, Xiaohua,He, Yigang,Fang, Yong,Cheng, Xiaowei The Korean Institute of Electrical Engineers 2014 Journal of Electrical Engineering & Technology Vol.9 No.5

Eccentricity faults more or less exist in all rotating electrical machines. This paper establishes a more precise model of dynamic eccentricity (DE) in electrical machines named as curved dynamic eccentricity. It is a kind of axial unequal eccentricity which has not been investigated in detail so far but occurs in large electrical machines. The inductances of a large three-phase squirrel-cage induction machine (SCIM) under different levels of curved DE conditions are evaluated using winding function approach (WFA). These inductances include the stator self and mutual inductances, rotor self and mutual inductances, and mutual inductances between stator phases and rotor loops. A comparison is made between the calculation results under curved DE and the corresponding pure DE conditions. It indicates that the eccentricity condition will be more terrible than the monitored eccentricity based on the conventional pure DE model.

Effect of Trichostatin A on Anti HepG2 Liver Carcinoma Cells: Inhibition of HDAC Activity and Activation of Wnt/β-Catenin Signaling

Shi, Qing-Qiang,Zuo, Guo-Wei,Feng, Zi-Qiang,Zhao, Lv-Cui,Luo, Lian,You, Zhi-Mei,Li, Dang-Yang,Xia, Jing,Li, Jing,Chen, Di-Long Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.18

Purpose: To investigate the effect of deacetylase inhibitory trichostatin A (TSA) on anti HepG2 liver carcinoma cells and explore the underlying mechanisms. Materials and Methods: HepG2 cells exposed to different concentrations of TSA for 24, 48, or 72h were examined for cell growth inhibition using CCK8, changes in cell cycle distribution with flow cytometry, cell apoptosis with annexin V-FTIC/PI double staining, and cell morphology changes under an inverted microscope. Expression of ${\beta}$-catenin, HDAC1, HDAC3, H3K9, CyclinD1 and Bax proteins was tested by Western blotting. Gene expression for ${\beta}$-catenin, HDAC1and HDAC3 was tested by q-PCR. ${\beta}$-catenin and H3K9 proteins were also tested by immunofluorescence. Activity of Renilla luciferase (pTCF/LEF-luc) was assessed using the Luciferase Reporter Assay system reagent. The activity of total HDACs was detected with a HDACs colorimetric kit. Results: Exposure to TSA caused significant dose-and time-dependent inhibition of HepG2 cell proliferation (p<0.05) and resulted in increased cell percentages in G0/G1 and G2/M phases and decrease in the S phase. The apoptotic index in the control group was $6.22{\pm}0.25%$, which increased to $7.17{\pm}0.20%$ and $18.1{\pm}0.42%$ in the treatment group. Exposure to 250 and 500nmol/L TSA also caused cell morphology changes with numerous floating cells. Expression of ${\beta}$-catenin, H3K9and Bax proteins was significantly increased, expression levels of CyclinD1, HDAC1, HDAC3 were decreased. Expression of ${\beta}$-catenin at the genetic level was significantly increased, with no significant difference in HDAC1and HDAC3 genes. In the cytoplasm, expression of ${\beta}$-catenin fluorescence protein was not obvious changed and in the nucleus, small amounts of green fluorescence were observed. H3K9 fluorescence protein were increased. Expression levels of the transcription factor TCF werealso increased in HepG2 cells following induction by TSA, whikle the activity of total HDACs was decreased. Conclusions: TSA inhibits HDAC activity, promotes histone acetylation, and activates Wnt/${\beta}$-catenin signaling to inhibit proliferation of HepG2 cell, arrest cell cycling and induce apoptosis.

Three partial mitochondrial genomes from Ips (Coleoptera: Curculionidae, Scolytinae) contribute to the phylogeny of Scolytinae

Lv Fei,Yang Wen-Yan,Chen Zhi-Teng,Xu Qiang,Zhou Yi-Jing,Du Yu-Zhou 한국응용곤충학회 2017 Journal of Asia-Pacific Entomology Vol.20 No.3

Partial mitogenomes of three species from the genus Ips (Coleoptera; Curculionidae), Ips grandicollis, Ips sexdentatus and Ips typographus were sequenced and analyzed. The three mitogenomes are 11,553-bp with 28 genes, 13,135-bp with 30 genes, and 13,502-bp with 30 genes, respectively. Their gene arrangements are consistent with that of Drosophila yakuba. The three Ips species shared the conserved overlapping sequence motif “ATGATAG” between ATP8 and ATP6, using TTG as start codon for ND1 genes and TAG as stop codon for ATP8 genes. All tRNA genes could fold into typical cloverleaf structures except for tRNASer1. Three tRNASer1 genes lack the DHU arm and instead formed the D-loop. The phylogenetic analyses indicate that Scolytinae is paraphyly and belongs to Curculionidae. The Eurasian I. sexdentatus is sister group to the North American I. grandicollis and the Eurasian I. typographus. The phylogeny of Ips based on COI genes indicates that Ips is paraphyly, Ips perroti and Orthotomicus suturalis are sister groups and Ips spinifer is grouped with (Orthotomicus chaokhao + Orthotomicus erosus).

Pattern Recognition of Partial Discharge in Power Transformer Based on InfoGAN and CNN

Lv Fangcheng,Liu Guilin,Wang Qiang,Lu Xiuquan,Lei Shengfeng,Wang Shenghui,Ma Kang 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.2

As an important equipment in the power system, it has a significant meaning in scientifically diagnosing the insulation state of oil-immersed power transformers. At present, the pattern recognition of partial discharge (PD) in a transformer has the problem of the insufficient generalization ability of the classifier due to scarcity and imbalance of samples, resulting in low recognition accuracy. To solve this problem, this paper proposes a pattern recognition of the PD method based on information maximizing generative adversarial nets (InfoGAN) and convolutional neural networks. In this method, phase-resolved partial discharge (PRPD) maps, constructed from pulse current waveforms, are chosen as the training samples. First, the InfoGAN is trained to generate new samples which expanded the original sample database, then various classifiers are trained by using the expanded sample database to realize the pattern recognition. Results of the test show that the proposed method can generate new highly similar samples more stable than other data enhancement methods, and effectively enrich the data diversity. In addition, the classifier trained by the expanded sample database has better generalization ability and is applicable to different classifiers, while residual network 18 has the highest recognition rate of 99.0%. This method can effectively balance and expand PRPD samples, and improve the recognition accuracy of the classifier to a certain extent. It has a good application prospect in PD diagnosis engineering.

Operation start time and long-term outcome of hepatocellular carcinoma after curative hepatic resection

Qiang Lu,Qing-Shan Li,Wei Zhang,Kang Liu,Tao Li,Jia-Wei Yu,Yi Lv,Xu-Feng Zhang 대한외과학회 2020 Annals of Surgical Treatment and Research(ASRT) Vol.99 No.1

Purpose: The objective of the current study was to examine the potential effects of surgery start times (morning vs. afternoon) on the long-term prognosis of patients after hepatic resection (HR) for hepatocellular carcinoma (HCC). Methods: All eligible patients were divided into 2 groups according to the start time of surgery: group M (morning surgery, 8 AM–1 PM) and group A (afternoon surgery, 1 PM–6 PM). Clinicopathologic and surgical parameters, as well as oncologic outcomes were compared between the 2 groups. Results: In total, 231 patients were included in the study. There was no difference in age, body mass index, comorbidities, tumor size, tumor location, tumor stages, surgical procedures, or surgical margin between morning and afternoon surgery (all P > 0.05). In contrast, patients in group M experienced longer operation duration than those in group A (median, 240 minutes vs. 195 minutes, P = 0.004). However, no differences of overall survival were observed between morning and afternoon surgery groups in the whole cohort or stratified by surgical margin (all P > 0.05). Conclusion: Surgery start times during the work day have no measurable influence on patient outcome following curative HR for HCC, indicating good self-regulation and professional judgment of surgeons for progressive fatigue during surgery

Real-time prediction of wave-induced hull girder loads for a large container ship based on the recurrent neural network model and error correction strategy

Wang Qiang,Yu Pengyao,Lv Mingdong,Wu Xiangcheng,Li Chenfeng,Chang Xin,Wu Lihong 대한조선학회 2024 International Journal of Naval Architecture and Oc Vol.16 No.-

Real-time acquisition of wave-induced hull girder loads of a sailing ship will help the captain make reasonable decisions, which is of great significance for improving the safety of the ship’s navigation. This paper investigates the real-time prediction method of hull girder loads based on the Recurrent Neural Network (RNN) model and error correction strategy. Firstly, taking the vertical bending moment, horizontal bending moment, and torsional moment at the mid-ship position of a large container ship as examples, corresponding neural network prediction models are established through parameter influence analysis. Secondly, various sea state conditions are used to verify the feasibility of established network prediction models to predict the hull girder loads in real-time. The VBM prediction model performs better than the TM prediction model and HBM prediction model, and the errors of the TM prediction model and HBM prediction model are slightly larger in some cases. Lastly, an improved prediction model based on an error correction strategy is proposed to improve the prediction accuracy of the neural network prediction model, and the adequate performance of the error correction strategy is discussed.

Phytochemistry and pharmacology of natural prenylated flavonoids

Hua-Wei Lv,Qiao-Liang Wang,Meng Luo,Meng-Di Zhu,Hui-Min Liang,Wen-Jing Li,Hai Cai,Zhong-Bo Zhou,Hong Wang,Sheng-Qiang Tong,Xing-Nuo Li 대한약학회 2023 Archives of Pharmacal Research Vol.46 No.4

Prenylated flavonoids are a special kind of flavonoid derivative possessing one or more prenyl groups in the parent nucleus of the flavonoid. The presence of the prenyl side chain enriched the structural diversity of flavonoids and increased their bioactivity and bioavailability. Prenylated flavonoids show a wide range of biological activities, such as anti-cancer, anti-inflammatory, neuroprotective, anti-diabetic, anti-obesity, cardioprotective effects, and anti-osteoclastogenic activities. In recent years, many compounds with significant activity have been discovered with the continuous excavation of the medicinal value of prenylated flavonoids, and have attracted the extensive attention of pharmacologists. This review summarizes recent progress on research into natural active prenylated flavonoids to promote new discoveries of their medicinal value.