Integrated battery chargers are highly effective for saving costs and improving the power density of on-board chargers in electric vehicles (EVs), However, achieving torque elimination of the commonly used three-phase...Integrated battery chargers are highly effective for saving costs and improving the power density of on-board chargers in electric vehicles (EVs), However, achieving torque elimination of the commonly used three-phase (3p) motors during the fast-charging process is challenging. In this paper, the general torque cancelation law applied in 3p permanent magnet synchronous motors (PMSMs) and induction motors (IMs) is derived to design high power density integrated fast battery chargers. Two novel integrated systems with fast-charging and vehicle-to-grid (V2G) capabilities are proposed based on this law. The main advantages of the proposed systems are: (1) Two filter inductors are constituted by the stator windings while charging, and only one external inductor and several contactors are supplemented to the motor-drive circuit. Therefore, the proposed integrated systems possess high power density;(2) The 3p open-winding (OW) motor is employed, with no need to modify the propulsion system or redesign the interior structure of the motor;(3) Employing an individual controller for each phase of the inner current loop control, the proposed systems realize unity power factors and low current harmonics in the fast-charging and V2G mode. Simulation and experimental results verify the feasibility of the proposed topologies and control strategies.展开更多
Objective To identify novel tumor suppressor genes at chromosome 3p24-26 in human nasopharyngeal carcinoma (NPC).Methods Twenty epithelial-derived expressed sequence tags (EST) were selected from chromosome 3p24-26. R...Objective To identify novel tumor suppressor genes at chromosome 3p24-26 in human nasopharyngeal carcinoma (NPC).Methods Twenty epithelial-derived expressed sequence tags (EST) were selected from chromosome 3p24-26. RT-PCR and Northern blot were used to detect the expression of the ESTs in NPC cell line, HNE-1, and primary cultures of normal nasopharyngeal epithelial cells. One EST, which was substantially downregulated in the HNE-1 cell line, was detected in 19 NPC biopsy samples, cDNA library screening was used to get its full sequence and the sequence of this novel gene was analyzed.Results A novel gene located at chromosome 3p25.3 was obtained and named NAG-7. It was downregulated in 26.3％ (5/19) of NPC biopsy samples. Its 1677 bp full length cDNA had a potential open reading frame predicting a 94 amino acid protein with a molecular weight of 11023.87 Dalton. Analysis of the NAG-7 gene showed that it was a transmembrane protein containing a protein kinase C phosphorylation site and a myristyl site. It has no significant homology to any reported genes in the database of GenBank. Conclusion NAG-7 is a novel gene downregulated in NPC, suggesting that it may be involved in the development of NPC.展开更多
The unobserved J^P= 0^-radial excitation Ds（2^1S0） is anticipated to have mass 2650 Me V（denoted as Ds（2650））. Study of hadronic production is an important way to identify highly excited states. We study hadroni...The unobserved J^P= 0^-radial excitation Ds（2^1S0） is anticipated to have mass 2650 Me V（denoted as Ds（2650））. Study of hadronic production is an important way to identify highly excited states. We study hadronic production of Ds（2650） from higher excited resonances in a3P0 model. Relevant hadronic partial decay widths are found to be very small, which implies it is difficult to observe Ds（2650） in hadronic decays of higher excited resonances. Hadronic decay widths of radially excited Ds（3P） have also been estimated. The total decay widths of four Ds（3P） are large, but the branching ratios in the Ds（2650）η channel are very small, which implies that it seems impossible to observe Ds（2650） in hadronic decays of Ds（3P）. The dominant decay channels of the four Ds（3P） have been pointed out, and D1（2420）, D1（2430）, D＊2（2460）, D（2550）, D（2600）,（1-1D2）D（2750） and D3^（2760） are possible to observe in hadronic production from Ds（3P）.展开更多
This paper is about a reflective practice happened in the author' s College English teaching.Since 2005,a 5-minute oral-presentation was required for all the students in turn,in order to raise opportunities for th...This paper is about a reflective practice happened in the author' s College English teaching.Since 2005,a 5-minute oral-presentation was required for all the students in turn,in order to raise opportunities for them to practice oral English.But the students' responses were always disappointing since they only took the task as a burden.After the teacher lift the limits on presentation time,form,sequence,partner,etc.,better learning outcomes were achieved.When reflecting on this change,Biggs'3P Models of "constructive alignment" is taken into account.Any teaching and learning activity (TLA) cannot put the students' and the teacher' s presage aside since the students' ability,interests,motivation as well as the teacher' s objective,assessment approach and so on are co-determinants of a successful TLA.Further suggestions are given based on this reflection at the end of the paper.展开更多
基金supported by the Guangdong Provincial Natural Science Research Team Project(2017B030312001).
文摘Integrated battery chargers are highly effective for saving costs and improving the power density of on-board chargers in electric vehicles (EVs), However, achieving torque elimination of the commonly used three-phase (3p) motors during the fast-charging process is challenging. In this paper, the general torque cancelation law applied in 3p permanent magnet synchronous motors (PMSMs) and induction motors (IMs) is derived to design high power density integrated fast battery chargers. Two novel integrated systems with fast-charging and vehicle-to-grid (V2G) capabilities are proposed based on this law. The main advantages of the proposed systems are: (1) Two filter inductors are constituted by the stator windings while charging, and only one external inductor and several contactors are supplemented to the motor-drive circuit. Therefore, the proposed integrated systems possess high power density;(2) The 3p open-winding (OW) motor is employed, with no need to modify the propulsion system or redesign the interior structure of the motor;(3) Employing an individual controller for each phase of the inner current loop control, the proposed systems realize unity power factors and low current harmonics in the fast-charging and V2G mode. Simulation and experimental results verify the feasibility of the proposed topologies and control strategies.
文摘Objective To identify novel tumor suppressor genes at chromosome 3p24-26 in human nasopharyngeal carcinoma (NPC).Methods Twenty epithelial-derived expressed sequence tags (EST) were selected from chromosome 3p24-26. RT-PCR and Northern blot were used to detect the expression of the ESTs in NPC cell line, HNE-1, and primary cultures of normal nasopharyngeal epithelial cells. One EST, which was substantially downregulated in the HNE-1 cell line, was detected in 19 NPC biopsy samples, cDNA library screening was used to get its full sequence and the sequence of this novel gene was analyzed.Results A novel gene located at chromosome 3p25.3 was obtained and named NAG-7. It was downregulated in 26.3％ (5/19) of NPC biopsy samples. Its 1677 bp full length cDNA had a potential open reading frame predicting a 94 amino acid protein with a molecular weight of 11023.87 Dalton. Analysis of the NAG-7 gene showed that it was a transmembrane protein containing a protein kinase C phosphorylation site and a myristyl site. It has no significant homology to any reported genes in the database of GenBank. Conclusion NAG-7 is a novel gene downregulated in NPC, suggesting that it may be involved in the development of NPC.
基金Supported by National Natural Science Foundation of China(11475111)
文摘The unobserved J^P= 0^-radial excitation Ds（2^1S0） is anticipated to have mass 2650 Me V（denoted as Ds（2650））. Study of hadronic production is an important way to identify highly excited states. We study hadronic production of Ds（2650） from higher excited resonances in a3P0 model. Relevant hadronic partial decay widths are found to be very small, which implies it is difficult to observe Ds（2650） in hadronic decays of higher excited resonances. Hadronic decay widths of radially excited Ds（3P） have also been estimated. The total decay widths of four Ds（3P） are large, but the branching ratios in the Ds（2650）η channel are very small, which implies that it seems impossible to observe Ds（2650） in hadronic decays of Ds（3P）. The dominant decay channels of the four Ds（3P） have been pointed out, and D1（2420）, D1（2430）, D＊2（2460）, D（2550）, D（2600）,（1-1D2）D（2750） and D3^（2760） are possible to observe in hadronic production from Ds（3P）.
文摘This paper is about a reflective practice happened in the author' s College English teaching.Since 2005,a 5-minute oral-presentation was required for all the students in turn,in order to raise opportunities for them to practice oral English.But the students' responses were always disappointing since they only took the task as a burden.After the teacher lift the limits on presentation time,form,sequence,partner,etc.,better learning outcomes were achieved.When reflecting on this change,Biggs'3P Models of "constructive alignment" is taken into account.Any teaching and learning activity (TLA) cannot put the students' and the teacher' s presage aside since the students' ability,interests,motivation as well as the teacher' s objective,assessment approach and so on are co-determinants of a successful TLA.Further suggestions are given based on this reflection at the end of the paper.
