A Pipe Heat Insulation Device Featuring Vacuum Valve Box Structure

Fang-jiang Lv,Cheng-cheng Shao 한국디자인학회 2014 디자인학연구 Vol.27 No.4

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.

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.

Hypermethylation of TET1 Promoter Is a New Diagnosic Marker for Breast Cancer Metastasis

Sang, Yi,Cheng, Chun,Tang, Xiao-Feng,Zhang, Mei-Fang,Lv, Xiao-Bin Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.3

Breast cancer metastasis is a major cause of cancer-related death in women. However, markers for diagnosis of breast cancer metastasis are rare. Here, we reported that TET1, a tumor suppressor gene, was downregulated and hypermethylated in highly metastatic breast cancer cell lines. Moreover, silencing of TET1 in breast cancer cells increased the migration and spreading of breast cancer cells. In breast cancer clinical samples, TET1 expression was reduced in LN metastases compared with primary tissues. Besides, the methylation level of the TET1 promoter was increased significantly in LN metastases. Taken together, these findings indicate that promoter hypermethylation may contribute to the downregulation of TET1 and could be used as a promising marker for diagnosis in patients with breast cancer metastasis.

Genetic Organization of ascB-dapE Internalin Cluster Serves as a Potential Marker for Listeria monocytogenes Sublineages IIA, IIB, and IIC

( Jian Shun Chen ),( Chun Fang ),( Ning Yu Zhu ),( Yong Hui Lv ),( Chang Yong Cheng ),( Yi Jiang Bei ),( Tianlun Zheng ),( Wei Huan Fang ) 한국미생물 · 생명공학회 2012 Journal of microbiology and biotechnology Vol.22 No.5

Listeria monocytogenes is an important foodborne pathogen that comprises four genetic lineages: I, II, III, and IV. Of these, lineage II is frequently recovered from foods and environments and responsible for the increasing incidence of human listeriosis. In this study, the phylogenetic structure of lineage II was determined through sequencing analysis of the ascB-dapE internalin cluster. Fifteen sequence types proposed by multilocus sequence typing based on nine housekeeping genes were grouped into three distinct sublineages, IIA, IIB, and IIC. Organization of the ascBdapE internalin cluster could serve as a molecular marker for these sublineages, with inlGHE, inlGC2DE, and inlC2DE for IIA, IIB, and IIC, respectively. These sublineages displayed specific genetic and phenotypic characteristics. IIA and IIC showed a higher frequency of recombination (ρ/θ). However, recombination events had greater effect (r/m) on IIB, leading to its high nucleotide diversity. Moreover, IIA and IIB harbored a wider range of internalin and stress-response genes, and possessed higher nisin tolerance, whereas IIC contained the largest portion of low-virulent strains owing to premature stop codons in inlA. The results of this study indicate that IIA, IIB, and IIC might occupy different ecological niches, and IIB might have a better adaptation to a broad range of environmental niches.

The effects of a short sequence enhancer (50-GTGAAATAAATGCAAATAAAGT) and its derived sequences on green fluorescent protein expression

Zhihong Ma,Zhanjun Lv,Xiu-Fang Wang,Xiangyang Jing,Jianjun Cheng 한국유전학회 2014 Genes & Genomics Vol.36 No.4

Cis-regulatory elements are regions of DNAthat regulate the expression of genes located on that samemolecule of DNA. Though these elements are important forgene expression regulation, the functions of cis elementsremain largely unknown. To explore the mechanisms ofgene activation by short sequence enhancers, we examinedthe enhancer activity of short sequence DNA and itsderived sequences using a GFP expression system. Wefound that AA sequence (50-GTGAAATAAATGCAAATAAAGT) induced strong GFP gene expression, while7pieA (50-GTGAAAAAAATGCAAAAAAAGT) did not. We mutated the five T bases of the AA sequence to A, C orG. Our findings indicated that sequences retaining the 7thand/or 17th Ts possessed strong enhancer activity. RT-PCRand RNA synthesis inhibition analysis using actinomycin Drevealed that the enhanced GFP gene expression inducedby the AA sequence occurred at the transcriptional level. To determine whether the AA sequence formed a secondarystructure via atypical complementation, PAGE methodwas used, and the results showed that the AA sequenceformed a secondary structure. Our results support previousevidence that AATAAA is an important composition of ciselements (enhancer/promoter), and suggest that the formationof an unstable stem-loop structure via atypicalcomplementation may be a new mechanism of enhanceractivity.

Corona generated Radio Interference of the 750 kV AC Bundle Conductors in Sandy and Dusty Weather Condition in the High Altitude Area

Yun-Peng Liu,Lei Zhu,Fang-Cheng Lv,Bao-Quan Wan,Chun-Ming Pei 대한전기학회 2014 Journal of Electrical Engineering & Technology Vol.9 No.5

Sandy and dusty weather condition often occurs in the high altitude areas of China, which may greatly influence the corona generated radio interference (RI) characteristics of the bundle conductors of 750 kV AC power transmission lines. Corona generated RI of the conductors of the 750 kV AC power transmission lines used in practice is measured by EMI receiver with a coupling circuit and a coupling capacitor connected between the high voltage side and the earth side in fine and sandy and dusty condition. The measuring frequency is 0.5 MHz, and the quasi-peak detection is used. RI excitation function is calculated based on the corona RI current measured by the EMI receiver. Corona generated RI characteristics were analyzed from sand concentration and sand particle size. The test result shows that the corona generated RI excitation function is influenced by the sandy and dusty condition. Corona discharge of the conductors is more serious in sandy and dusty condition with an ultraviolet (UV) detector. Corona generated RI excitation function increases with the increase of sand concentration and also increases with the increase of particle size.

Negative Corona Onset Characteristic of the UHV Conductors Based on the Corona Cage

Liu, Yun-Peng,Zhu, Lei,Lv, Fang-Cheng,Xie, Xiongjie The Korean Institute of Electrical Engineers 2014 Journal of Electrical Engineering & Technology Vol.9 No.6

Negative corona onset characteristics of the stranded conductors based on the ultra-high voltage (UHV) corona cage were studied in the paper. Based on the corona self-sustaining criterion in extreme uneven electric fields and the secondary emission process of the photoelectrons, the corona onset calculation model in the UHV corona cage is established and the corona current tests of the single LGJ900-75, 6 bundle LGJ900-75, 8 bundle LGJ400-35 conductors in dry and rain conditions were done in the UHV corona cage, and the rain rates are 2.4 mm/h, 20 mm/h and 30 mm/h. Corona onset electric field strength is gained by E-I tangent method, and the onset electric field strength in dry condition proves that the calculation model can be used to calculate the corona onset characteristics of the bundle conductors in the UHV corona cage. A further analysis proves that: the negative corona onset voltage of the conductor increases with the bundle number and the diameter of the sub conductor, but decreases with the bundle space in the corona cage. The onset electric field strength is influenced little by bundle space and bundle number, but decreases with the increase of the diameter of the sub-conductor. The surface irregularity coefficient decreases with the rain rate.

Negative Corona Onset Characteristic of the UHV Conductors Based on the Corona Cage

Yun-Peng Liu,Lei Zhu,Fang-Cheng Lv,Xiongjie Xie 대한전기학회 2014 Journal of Electrical Engineering & Technology Vol.9 No.6

Negative corona onset characteristics of the stranded conductors based on the ultra-high voltage (UHV) corona cage were studied in the paper. Based on the corona self-sustaining criterion in extreme uneven electric fields and the secondary emission process of the photoelectrons, the corona onset calculation model in the UHV corona cage is established and the corona current tests of the single LGJ900-75, 6 bundle LGJ900-75, 8 bundle LGJ400-35 conductors in dry and rain conditions were done in the UHV corona cage, and the rain rates are 2.4 mm/h, 20 mm/h and 30 mm/h. Corona onset electric field strength is gained by E-I tangent method, and the onset electric field strength in dry condition proves that the calculation model can be used to calculate the corona onset characteristics of the bundle conductors in the UHV corona cage. A further analysis proves that: the negative corona onset voltage of the conductor increases with the bundle number and the diameter of the sub conductor, but decreases with the bundle space in the corona cage. The onset electric field strength is influenced little by bundle space and bundle number, but decreases with the increase of the diameter of the sub-conductor. The surface irregularity coefficient decreases with the rain rate.

Corona generated Radio Interference of the 750 kV AC Bundle Conductors in Sandy and Dusty Weather Condition in the High Altitude Area

Liu, Yun-Peng,Zhu, Lei,Lv, Fang-Cheng,Wan, Bao-Quan,Pei, Chun-Ming The Korean Institute of Electrical Engineers 2014 Journal of Electrical Engineering & Technology Vol.9 No.5

Sandy and dusty weather condition often occurs in the high altitude areas of China, which may greatly influence the corona generated radio interference (RI) characteristics of the bundle conductors of 750 kV AC power transmission lines. Corona generated RI of the conductors of the 750 kV AC power transmission lines used in practice is measured by EMI receiver with a coupling circuit and a coupling capacitor connected between the high voltage side and the earth side in fine and sandy and dusty condition. The measuring frequency is 0.5 MHz, and the quasi-peak detection is used. RI excitation function is calculated based on the corona RI current measured by the EMI receiver. Corona generated RI characteristics were analyzed from sand concentration and sand particle size. The test result shows that the corona generated RI excitation function is influenced by the sandy and dusty condition. Corona discharge of the conductors is more serious in sandy and dusty condition with an ultraviolet (UV) detector. Corona generated RI excitation function increases with the increase of sand concentration and also increases with the increase of particle size.