ON HIGHER ORDER IRREGULAR SETS

Jinjun Li,Min Wu 대한수학회 2017 대한수학회지 Vol.54 No.1

To indicate the statistical complexity of dynamical systems, we introduce the notions of higher order irregular set and higher order maximal Birkhoff average oscillation in this paper. We prove that, in the setting of topologically mixing Markov chain, the set consisting of those points having maximal $k$-order Birkhoff average oscillation for all positive integers $k$ is as large as the whole space from the topological point of view. As applications, we discuss the corresponding results on a repeller.

A Novel Control Method of PAPF for Resonance Damping and Harmonics Compensation in Power System

WU Longhui,ZHUO Fang,LI Hui,LIU Jinjun,WANG Zhaoan 전력전자학회 2007 ICPE(ISPE)논문집 Vol.- No.-

In power system, capacitors are widely used to compensate reactive power, which generally cause resonance problems in harmonic distorted network. In this paper, parallel active power filter (PAPF) is used to damp the resonances. Firstly, the damping characteristics of PAPF with traditional load current detection methods (detecting current including or not including the capacitor current) are analyzed respectively. The analysis results show that PAPF with traditional load current detection methods is effective for parallel resonance damping, but can not damp series resonance when capacitor current is not included in the detecting current. And when capacitor current is included in the detecting current, PAPF is prone to be unstable and can not damp parallel and series resonance. Then a novel control method of PAPF is proposed. PAPF with the proposed control method has excellent performance in damping of both parallel resonance and series resonance, whether the capacitor current is included in the detecting current of PAPF or not. Also the PAPF with proposed method has strong ability in harmonic compensation. Finally, the experiment results are presented to verify the analysis.

ON HIGHER ORDER IRREGULAR SETS

Li, Jinjun,Wu, Min Korean Mathematical Society 2017 대한수학회지 Vol.54 No.1

To indicate the statistical complexity of dynamical systems, we introduce the notions of higher order irregular set and higher order maximal Birkhoff average oscillation in this paper. We prove that, in the setting of topologically mixing Markov chain, the set consisting of those points having maximal k-order Birkhoff average oscillation for all positive integers k is as large as the whole space from the topological point of view. As applications, we discuss the corresponding results on a repeller.

Knoevenagel Reaction of Pyropheophorbide and Synthesis of Its Heterocyclo-substituted Derivatives

Wang, Jinjun,Wu, Xuran,Han, Guangfan,Shen, Rongji 科學出版社 2005 CHINESE JOURNAL OF ORGANIC CHEMISTRY Vol.25 No.3

<P>Methyl pyropheophorbide-c? was used as starting material and the Knoevenagel reaction of the aldehyde group on pyropheophorbide with active methylene group in /?-diketone, a-cyanoketone or malono-nitrile was carried out to complete the synthesis of derivatives of methyl pyropheophorbide-a substituted with five-membered heterocycle at 3-positipon. The structures of all these new compounds were characterized by elemental analysis, UV, IR and LH NMR spectra.</P>

Load Power Estimation Based Secondary Control for Microgrids

Teng Wu,Jinjun Liu,Zeng Liu,Shike Wang,Baojin Liu 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

The well-known active power-frequency and reactive power-voltage amplitude droop control is widely used in the coordinative control of parallel inverters in microgrids. However, this conventional droop method may cause frequency and voltage deviation, which affects the accuracy of power supply. This paper proposes a novel secondary control strategy to compensate this deviation. This strategy mimics the Master-Slave control but requires no communication lines among the parallel inverters. The master inverter adopts conventional droop method (using power to control frequency and voltage amplitude) and is controlled as a voltage source while the slave inverters adopt reversed droop method (using frequency and voltage amplitude to control power) and are controlled as current sources. The droop characteristic bias of slave inverters is designed online based on the estimation of load power demand. Through this method, frequency and voltage deviation can be eliminated and power sharing can be realized among all the slave inverters. Simulation and experimental results are provided to prove the effectiveness of the proposed control strategy.

Oxidation Reaction along Qy Axis and Rearrangement Reaction in E-Ring of Chlorophyll-a and Its Derivatives

Wang, Jinjun,Han, Guangfan,Wu, Xuran,Shen, Rongji CHINESE MEDICAL ASSOCIATION 2005 CHINESE JOURNAL OF ORGANIC CHEMISTRY Vol.25 No.1

<P>The chlorophyll-a (1) was converted into the chlorins 2b<SUP>4</SUP>b by air-oxidation in acid or basic condition. The methyl pheophorbide-a (5) was obtained from chlorophyll-a by transesterification and de-metallation. The addition to double bond at 3-position of 5 with hydrochloric acid yielded alcohol chlorin 6 which was oxidized purpure-18 derivative (7) by air-oxidation in basic condition. The methyl pheophor-bide-a (5) was oxidized with osmium oxide and sodium periodate to give chlorin 8 which was converted into aldehyde purpure-18 (9) and purpure-7 trimethyl ester (10) by air-oxidation in butanol in the presence of so-dium. The purpure-18 ester (3), prepared also from the pheophorbide-a (4) in the same reaction condition like the chlorophyll-a (1), reacted with 2-methylbutylamine to give AH2-methylbutyl)-purpure-18 imide (lla) and 12-formyl-purpure-18 imide (lib). The structures of all chlorophyll derivatives were characterized by UV, IR, JH NMR spectra and elemental analysis. The possible mechanisms in accordance with the corre-sponding chemical reaction and reaction condition were tentatively proposed.</P>

Bromination Reaction of Methyl Pyropheophorbide--a

Wang, Jinjun,Han, Guangfan,Wu, Xuran,Wang, Lumin,Shen, Rongji CHINESE MEDICAL ASSOCIATION 2004 CHINESE JOURNAL OF ORGANIC CHEMISTRY Vol.24 No.5

<P>Methyl pyropheophorbide-a (MPP-a) was used as starting material for the synthesis of new bromine-substituted chlorin compounds. The bromines were introduced into 3-position and meso-position of the chlorin chromophore by addition reaction and substitution reaction with the bromide reagents to give mono-bromine- and tri-bromine-substituted chlorines. The formal addition product, hydrolyzate and esterified product were obtained by addition reaction with 30% hydrogen bromide in acetic acid. MPP-a was oxidized with OsO<SUB>4</SUB> in THF containing catalytic pyridine at 0 ℃, and followed by glycol cleavage with sodium periodate in aqueous THF to give the methyl pyropheophorbide- d (MPP-d) which was reacted with carbon tetrabromide and triphenylphosphine to generate gem-dibromine substituted product at 3~b-position. The structures of all new compounds were characterized by elemental analysis, UV, IR and ]H NMR spectra.</P>

A Single Phase Power Electronic Transformer considering Harmonic Compensation in Scott Traction System

Shaodi Ouyang,Jinjun Liu,Xinyu Wang,Shuguang Song,Xueyu Hou,Teng Wu 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

Power electronic transformer(PET) has been the focus of interest in recent years. Compared with conventional low frequency transformers, PETs can offer many additional functions such as phase shifting, frequency shifting and reactive power/harmonic compensation. This paper proposes a single phase PET for the Scott railway power system. The PET achieves active power control which balances the Scott’s secondary currents. The PET also achieves reactive/harmonic compensation. The configuration and control strategy of the proposed PET is discussed. Simulation results from PLECS verifies the effectiveness of the proposed PET and its control strategy.

The Prognostic Significance of Notch1 and Fatty Acid Binding Protein 7 (FABP7) Expression in Resected Tracheobronchial Adenoid Cystic Carcinoma: A Multicenter Retrospective Study

Mian Xie,Xiaojun Wu,Jinjun Zhang,Chaosheng He,Shenhai Wei,Junyao Huang,Xinge Fu,Yingying Gu 대한암학회 2018 Cancer Research and Treatment Vol.50 No.4

Purpose Adenoid cystic carcinoma (ACC) of the trachea and bronchus is a rare tumor. Although MYBNFIB oncogene fusion and Notch1 mutation have been identified in ACC, little is known about the expression and clinical significance of Notch1 and its target gene fatty acid binding protein 7 (FABP7) in tracheobronchial ACC. Materials and Methods Primary tracheobronchial ACC that were resected between 1998 and 2014 were identified through the pathology and oncology database from five thoracic oncology centers in China. A tissue array was constructed from the patients’ samples and the expressions of Notch1 and FABP7 were evaluated by immunohistochemistry. The association between the expression of both markers and survival was determined. Results Overexpression of Notch1 and FABP7, detected in 37.8% and 38.3% of 368 patients with tracheobronchial ACC, respectively, was an independent prognostic indicator for recurrencefree survival (RFS) by multivariable Cox proportional hazard model (p=0.032 and p=0.048, respectively). Overexpression of Notch1, but not of FABP7, predicted overall survival (OS) (p=0.018). When categorized into four groups according to coexpression of Notch1 and FABP7, patients with overexpression of both Notch1 and FABP7 belonged to the group with the shortest RFS and OS (p=0.01 and p=0.048, respectively). Conclusion Expression of Notch1 and FABP7, and coexpression of Notch1 and FABP7, is strongly associated with poor survival in resected tracheobronchial ACC. These data are consistent with the hypothesis that poor differentiation of tracheobronchial ACC correlates with the activation of Notch signaling.

MODELING AND CONTROL OF A HIGH SPEED ON/OFF VALVE ACTUATOR

Jigen Fang,Xifeng Wang,Jinjun Wu,Shuai Yang,Liang Li,Xiang Gao,Yue Tian 한국자동차공학회 2019 International journal of automotive technology Vol.20 No.6

Accurate electromagnetic force control in a high speed on/off valve actuator (HSVA) can improve the performance of a vehicle braking system, and an accurate theoretical model is the key to smoothly controlling the high speed on/off valve. Therefore, a nonlinear model of an HSVA is proposed in this paper. Three subsystems are modeled as a spring/ mass/damper system, a nonlinear resistor/inductor system and a multiwall heat transfer system, respectively. Then, a slidingmodel controller combined with a sliding-model observer is designed to adjust the electromagnetic force for an accurate HSVA state control, taking the effect of the coil heating into account. The feasibility of the three submodels and the slidingmodel controller are verified by comparing the simulation results with the experimental results obtained on a test bench. Our study shows that the three subsystems are coupled to one another through resistance, displacement, and temperature. When the excitation voltage exceeds 9 V, the coil temperature can reach more than 150 degrees Celsius within 300 s, and the electromagnetic force decreases by approximately 30 %. However, by applying the above control strategy, the electromagnetic force can also be stable, fluctuating within 5 % even if the temperature of the coil rises to the thermal equilibrium temperature.